Tag Archives: osteoarthritis

A systematic review of injectable corticosteroid for osteoarthritis of the first metatarsophalangeal joint

by Ian Reilly BSc, MSc, MCPod, FCPodS, FFPM RCPS(Glasg); Gillian Bromley BSc(Hons), MCPod; George Flanagan BSc(Hons), MCPod, FCPodS

The Foot and Ankle Online Journal 13 (3): 12

Intra-articular steroid injection is a common treatment modality for relief of pain and inflammation associated with degenerative joint disease. Use of injectable steroid preparations is widely accepted as safe and effective for the treatment of osteoarthritis of the 1st metatarsophalangeal joint. Despite the frequency of use, literature specific to pathology of the 1st metatarsophalangeal joint is sparse. The aim of this systematic review was to determine if good quality research exists to enable clinicians to adopt an evidenced based approach to corticosteroid injection of the 1st metatarsophalangeal joint. Despite the frequency of use, this review found no high quality studies that support the use of intra-articular corticosteroid injection of the 1st metatarsophalangeal joint in osteoarthritis.

Keywords: steroid injection, first metatarsophalangeal joint, osteoarthritis, hallux rigidus, systematic review

ISSN 1941-6806
doi: 10.3827/faoj.2020.1303.0012

1 – Department of Podiatric Surgery, Northamptonshire Healthcare Foundation NHS Trust, Danetre Hospital, Daventry, Northamptonshire, NN11 4DY. UK
* – Corresponding author: ianreilly@nhs.net

The use of injectable corticosteroid as part of a treatment strategy for painful joints is a common treatment modality. In degenerative disease the intended aim is to reduce the pain and inflammation associated with osteoarthritis (OA) as well as improve joint function [1]. The use of intra-articular (IA) corticosteroid injections (CSIs) for the treatment of OA is supported by guidelines provided by the United Kingdom (UK) National Institute for Health and Care Excellence (NICE) in patients who experience joint pain that is not adequately controlled by oral and/or topical options or where such treatment is contraindicated [2]. The basis for this guidance is largely derived from conclusions drawn from research into the efficacy of IA CSI’s at the knee and shoulder [3,4]: data from these studies has been extrapolated and applied to other synovial joints such as the first metatarsophalangeal joint (1st MPJ).

Osteoarthritis is the leading cause of disability in adults worldwide and results in significant morbidity [5]. Joints in the foot are often affected by this condition with the 1st MPJ being most commonly affected pedal joint [6]. Symptomatic 1st MPJ OA affects approximately 10% of the adult population and the prevalence increases with age – as do comorbidities amongst sufferers – with the result that reduced pharmacological treatment options available for pain relief in these patients [7]. Symptoms arising from OA are notoriously difficult to manage with oral analgesics alone: this ultimately results in a significant burden on primary care services [8]. This provides the niche for IA CSI, i.e. where other conservative treatment has failed, is contraindicated or where there is a desire or requirement to postpone the need for surgical intervention. Unmanaged foot pain is an independent risk factor for depression and falls in adults [9,10,11].

The authors are experienced injectors and are active in teaching CSI techniques to under- and postgraduate students. Anecdotally, we find that 80-90% of patients experience improvement following IA CSI for 1st MPJ OA but the extent and duration of that improvement varies. The variability in outcomes following CSI for 1st MPJ OA raises numerous questions: to what extent is pain reduced? Is joint function improved? Which patients are most likely to benefit from this treatment? What is the frequency with which corticosteroid should be administered and whether the use of ultrasound guided injections improves treatment outcomes [12,13,14]. Furthermore, there has been debate surrounding whether a steroid based solution, when combined with local analgesia, may even be chondrotoxic [15]. A Cochrane Review from 2010 [16] concerned with identifying optimal treatment modalities for 1st MPJ OA found low level evidence for physical therapy only. A systematic literature review was therefore undertaken (as part of a larger body of work being undertaken by the lead author) in order to identify randomized trials that had used IA CSI for OA of the 1st MPJ.


The research question is: is the use of corticosteroid injections for osteoarthritis of the first metatarsophalangeal joint in adults a safe and effective method of reducing pain and improving joint function?

In order to ensure a systematic review, minimize the risk of bias and provide transparency for replication of the process, a predetermined research methodology protocol was used, based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist [17]. This was registered with PROSPERO. (Trial registration number: CRD42019135950. Available from: http://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42019135950).

Selection criteria


Predetermined inclusion and exclusion criteria were used. Only systematic reviews, randomized controlled trials (RCTs), quasi randomized trials and controlled clinical trials were considered for inclusion as they form the hierarchy of evidence and are most likely to provide a robust evidence base suitable for informing clinical practice [18]. Those papers found were then screened for the following criteria:

  • Trials in which an IA CSI into the 1st MPJ used for the treatment of OA in adults,
  • Diagnosis and grading of OA in participants could be achieved via clinical examination and/ or via radiological means [19],
  • Any gender or ethnicity was considered.

In order to be able to determine the efficacy of treatment, trials were required to have provided quantitative or qualitative measures both pre- and post-intervention in order to be able to ascertain the mean differences relating to pain and/or joint function outcomes.


Trials in which intradermal, subcutaneous, intramuscular or extracapsular corticosteroid injections were performed were excluded, as were not trials that tested the efficacy of IA CSIs for conditions other than for OA, or tested CSIs at joints other than the 1st MPJ. Due to the high risk of bias, cohort and case studies, articles based on expert opinion, retrospective studies and narrative-based literature reviews were excluded [18].

Search strategy and data sources

To answer the research question a keyword search of six electronic databases (AMED, CINAHL, EMBASE, MEDLINE, PUBMED, and COCHRANE) up to February 2020 was undertaken by graduate research podiatrist (GB) to identify clinical trials that had tested the efficacy of IA CSI for the treatment of 1st MPJ OA.

AMED (1985 to 05.02.2020)

CINAHL (1982 to 05.02.2020)

EMBASE (1974 to 05.02.2020)

MEDLINE (1950 to 05.02.2020)

PUBMED (1966 to 05.02.2020)

COCHRANE (1966 to 05.02.2020)

No date or language restrictions were applied. Reference lists were reviewed, and key author searches were made to reduce the risk of any pertinent literature being missed. A list of keywords and results yielded are provided in Table 1.

# Database Search term Results
1 AMED (osteoarthritis).ti,ab 2945
2 AMED (hallux).ti,ab 1252
3 AMED (metatarsophalangeal).ti,ab 771
4 AMED (injection).ti,ab 2035
5 AMED (steroid).ti,ab 454
6 AMED (hallux limitus).ti,ab 62
7 AMED (hallux rigidus).ti,ab 178
8 AMED (1 AND 2) 35
9 AMED (1 AND 3) 37
10 AMED (6 OR 7 OR 8 OR 9) 272
11 AMED (4 AND 10) 5
23 CINAHL (osteoarthritis).ti,ab 21838
24 CINAHL (hallux).ti,ab 2033
25 CINAHL (metatarsophalangeal).ti,ab 1197
26 CINAHL (injection).ti,ab 43132
27 CINAHL (steroid).ti,ab 15241
28 CINAHL (hallux limitus).ti,ab 100
29 CINAHL (hallux rigidus).ti,ab 319
30 CINAHL (23 AND 24) 63
31 CINAHL (23 AND 25) 82
32 CINAHL (28 OR 29 OR 30 OR 31) 472
33 CINAHL (26 AND 32) 13
34 EMBASE (osteoarthritis).ti,ab 79498
35 EMBASE (hallux).ti,ab 5812
36 EMBASE (metatarsophalangeal).ti,ab 3924
37 EMBASE (injection).ti,ab 581417
38 EMBASE (steroid).ti,ab 163137
39 EMBASE (hallux limitus).ti,ab 153
40 EMBASE (hallux rigidus).ti,ab 664
41 EMBASE (34 AND 35) 183
42 EMBASE (34 AND 36) 258
43 EMBASE (39 OR 40 OR 41 OR 42) 1068
44 EMBASE (37 AND 43) 21
45 EMBASE (38 AND 43) 12
46 CINAHL (27 AND 32) 5
48 AMED (5 AND 10) 4
49 Medline (osteoarthritis).ti,ab 54837
50 Medline (hallux).ti,ab 4904
51 Medline (metatarsophalangeal).ti,ab 3209
52 Medline (injection).ti,ab 449653
53 Medline (steroid).ti,ab 125109
54 Medline (hallux limitus).ti,ab 139
55 Medline (hallux rigidus).ti,ab 586
56 Medline (49 AND 50) 137
57 Medline (49 AND 51) 189
58 Medline (54 OR 55 OR 56 OR 57) 858
59 Medline (52 AND 58) 13
60 Medline (53 AND 58) 5
61 PubMed (osteoarthritis).ti,ab 80277
62 PubMed (hallux).ti,ab 6554
63 PubMed (metatarsophalangeal).ti,ab 4096
64 PubMed (injection).ti,ab 708493
65 PubMed (steroid).ti,ab 936715
66 PubMed (hallux limitus).ti,ab 167
67 PubMed (hallux rigidus).ti,ab 656
68 PubMed (61 AND 62) 251
69 PubMed (61 AND 63) 298
70 PubMed (66 OR 67 OR 68 OR 69) 1054
71 PubMed (64 AND 70) 26
72 PubMed (65 AND 70) 10

Table 1 Search terminology and results yielded by database.

Risk of bias

In order to assess their validity, RCTs were reviewed using the Critical Appraisal Skills Programme (CASP) checklist [20], which uses six quality assessments of studies and considers the risk of (selection, performance, detection, attrition and reporting) bias. Systematic reviews were appraised using a Centre for Evidence-Based Medicine (CEBM) appraisal tool for systematic reviews [21] which uses six quality assessments to determine validity of reviews based on methodological design. Each quality assessment for data was awarded a ‘low’, ‘high’ or ‘unclear’ risk of bias. Two reviewers independently (GB, GF) appraised the studies and results were collated. If there was disparity between results, a discussion was to be raised. If consensus could not be achieved the senior author (INR – a consultant podiatric surgeon with a special interest in injection therapy) was appointed to make the final decision. Evidence from the identified literature was considered and an appropriate weighting awarded based on the quality of evidence they provided.

Initial inter-rater results following an appraisal of studies was 84% consistent between two reviewers. Following a discussion regarding the variation in quality assessment, 100% consensus between reviewers was achieved. Evidence from the identified literature was considered and an appropriate weighting awarded based on the quality of evidence they provided. Themes regarding joint pain, function and the safety of CSIs are discussed. Due to only one RCT being identified for inclusion, no meta-analysis was possible.

Data extraction

Data was extracted from research that fulfilled the inclusion criteria by using a predetermined list of parameters to determine the efficacy of the intervention and validity of methods used for testing.

Figure 1 PRISMA flow chart for trials selected for review [17].

These parameters considered: the design of study, sample size, demographics, diagnostic criteria used, disease severity, intervention tested (type, dosage, method of administration), outcomes, follow up and results. Reported adverse effects (type, duration and severity) were recorded to determine the safety of the intervention. Data from these themes was entered into a spreadsheet to be used for discussion.


A search of electronic databases identified 111 studies for possible inclusion. Sixty-four duplicates were excluded and 47 titles and abstracts were assessed. Titles and abstracts were assessed independently (GB and GF) and evaluated against the aims of this study and its predetermined selection criteria. Full-text articles believed to be appropriate were accessed and further assessed for relevance against the predetermined inclusion criteria. If there was a difference in opinion as to whether an article should be included for review, a discussion was raised between the two main authors and if it was not possible to reach a consensus then the senior author was given the final vote on selection. 36 articles were rejected and 11 full-text articles were retrieved for assessment against the selection criteria (Figure 1). One RCT and one systematic review were identified for inclusion in this review.

Randomized controlled trials

One single blinded randomized trial that compared the efficacy of a single dose of intra-articular triamcinolone acetonide (TA) with sodium hyaluronate (SH) delivered without image guidance for mild symptomatic hallux rigidus in thirty-seven adults was identified for inclusion [22] – see Table 2. The title of the paper was misleading (sodium hyaluronate in the treatment of hallux rigidus. A single blind randomized study) in that its use of CSI was not mentioned.

Pons et al. 2007 [22]
Quality Assessment: Result: Bias Risk: Quality score:
Did the trial ask a clearly focused question? Yes Screening question 2/2
Was the assignment of patients randomized? Unclear Selection bias 1/2
Were all the patients who entered the trial properly accounted for at its conclusion? Yes Attrition bias, reporting bias 2/2
Were patients, health care workers and study personnel ‘blind’ to treatment? No Performance bias, detection bias 0/2
Were the groups similar at the start of the trial? Unclear Selection bias 1/2
Aside from the experimental intervention, were the groups treated equally? Yes Performance bias 2/2

Table 2 Quality assessment of randomised controlled trials (CASP checklist).

Zammit et al. 2010 [16]
Quality Assessment: Result: Quality Score:
What question did the systematic review address? Which interventions are optimal for treating osteoarthritis of the big toe? 2/2
Is it unlikely that important, relevant studies were missed? Yes 2/2
Were the criteria used to select articles for inclusion appropriate? Yes 2/2
Were the included studies sufficiently valid for the type of question asked? No, identified a lack of available evidence and high risk of bias. 0/2
Were the results similar from study to study? One study identified for inclusion only. 0/2

Table 3 Quality assessment of systematic reviews (CEBM framework).

Changes in joint pain and function

A reduction in mean visual analogue scale (VAS) pain scores at rest or on palpation was observed in both treatment groups. Mean VAS scores (n/100 mm) reduced at baseline from 58.7 mm to 34.1 mm in the TA group. A significant decrease in dorsiflexion or plantarflexion VAS pain scores was also observed in both groups: mean VAS scores decreased from 64.2 mm to 41.6 mm in the TA group. TH demonstrated reduced improvement in VAS pain scores on walking 20 metres compared to SH. Recipients of TA were reported to have a mean improvement in hallux function of 4.1 on the American Orthopaedic Foot and Ankle Society Score (AOFAS) for hallux evaluation. Overall, TA was found to be inferior in terms of the number positive responders to treatment, pain reduction and improvement in hallux function when compared to those treated with SH. Benefits were reported as relatively short lasting in both arms of the trial: 52.9% in the TA group and 46.6 % in the SH group progressed to surgery within 12 months.

The mean quality score for the RCT reviewed was 66% demonstrating limited methodological quality and potential bias. In this trial there was no attempt to blind investigators involved in data collection and evaluation of outcome measures. The trial had a small sample size with a significant female gender bias and all participants had mild joint disease potentially limiting the application of conclusions drawn from this to other patient populations. However, the most significant limitation with this trial was that interventions were administered to participants with 1st MPJ OA and hallux valgus with no sub-group analysis provided according to condition. This caused the paper to be rejected from the 2015 Cochrane review [16]. Given that the underlying pathophysiology of these distinct conditions differs, it is reasonable to expect that treatment outcomes relating to joint pain and function following an IA SCI may vary between recipients with different conditions. Furthermore, the proportion of recipients reported to have progressed to surgery may have been skewed given that the usual treatment for hallux valgus is surgical correction of the deformity. From this trial it was not possible to determine the efficacy of corticosteroids as an intervention to treat osteoarthritis at the 1st MPJ.

Adverse effects

Similarly, the lack of blinding in data collection and evaluation of adverse effects associated with the interventions administered poses a significant bias risk. Due to the lack of sub group analysis it was not possible to determine whether the frequency or type of adverse effects differed by condition. Data relating to adverse effects was collected by non-blinded investigators post intervention, were mild and arose in just 5% of recipients; no serious adverse effects were reported.

Systematic reviews

A recent review [14] that set out to provide a comprehensive list of evidence-based recommendations regarding conservative treatment modalities for 1st MPJ OA included a review of injection therapy. Authors of the review found ‘fair evidence’ to support the use of IA CSIs to treat 1st MPJ OA. However, the methodology was neither systematic nor comprehensive: only a single database was searched for clinical trials and the risk of pertinent literature having been missed was high. The author’s recommendations were made based on an appraisal system [23] that allocates a level of evidence for an intervention based solely on the design of studies identified; it does not consider the methodological quality of trials or risk of bias. Rama [24] pointed out that this system is a derivative of the levels of evidence system [25] and cautioned regarding the limitations of this style of review. He highlighted the need to not generalise evidence in order to avoid misleading conclusions being drawn.

The injection therapy trials identified in this review lacked heterogeneity in terms of solutions tested and design of trials. In spite of this, the authors grouped six trials relating to injection therapy together for data analysis and a collective level of evidence was allocated to injection therapy as a whole. Since this review did not consider the risk of bias and validity or clinical significance of outcomes from trials it identified, and failed to use a systematic methodology the study was excluded from this review as it was deemed to provide a summary of interventions for healthcare professionals only [24].

This review identified one systematic review that considered the efficacy of any treatment modality, including but not limited to injection therapy, for 1st MPJ OA [16]. The 2010 systematic review (see table 3) was a comprehensive piece of research with high quality methodology and low risk of bias. It identified one low quality study with a high risk of bias to support the use of physical therapy to reduce the pain of osteoarthritis at the big toe joint. It found no evidence to support the efficacy of corticosteroid injections for hallux rigidus (see note above re Pons et al, 2007).


Originally suggested by Cotterill in 1887 [26], hallux rigidus/limitus (1st MPJ OA) are terms used to describe arthritic changes at the 1st MPJ. Many theories regarding the etiology of 1st MPJ OA have been postulated. Traditionally, osteoarthritis was viewed simply as a degenerative condition characterized by the degeneration of joint cartilage over time that resulted in progressive pain, stiffness and loss of joint function. However, a greater understanding of the pathophysiology of osteoarthritis indicates that symptoms arising from the disease are caused by the body’s attempt to repair damaged cartilage and that it is this process of repair and remodelling that results in abnormal bone growth and inflammation that involves the entire joint [16].

In a review of 114 patients it was found that irrespective of age, females are twice as likely to develop 1st MPJ OA [27]. A positive family history is strongly associated with bilateral joint disease, whereas unilateral joint involvement is often precipitated by trauma and does not routinely progress to involve both feet. Little consensus exists between studies regarding other possible causes although Coughlin and Shurnas [27] discuss pes planus, Achilles tendon contracture, hallux valgus, hallux valgus interphalangeus, a flat metatarsal head, metatarsus adductus, a long first metatarsal, metatarsus primus elevatus, and first ray hypermobility in the development of this condition. Furthermore, a number of recent retrospective studies that have considered the natural course of 1st MPJ OA suggest that progression of the disease is far more variable than previously thought and that for many it may follow a more benign course with symptoms that can be adequately managed with conservative treatment methods such as physical, mechanical or pharmacological therapy [28]. It is therefore increasingly important for clinicians to understand when to administer IA CSIs and which patients would derive the greatest benefit from treatment.

Corticosteroid is a synthetic version of the endogenous hormone glucocorticoid found in vertebrates that is produced in the adrenal gland cortex. Amongst its other functions in the cardiovascular, metabolic and nervous systems; glucocorticoids provide a feedback mechanism within the immune system to reduce inflammation. Synthetic corticosteroids administered orally or via injection can be exploited to mimic this action and can be used to suppress unwanted, immune mediated inflammatory responses caused by many disease processes including osteoarthritis. Corticosteroids act to reduce inflammation and suppress the immune response at various levels:

  • Leukocytes and monocytes transform into macrophages, a larger and more bactericidal cell that releases lysosomal enzymes that ushers in further inflammatory processes. By suppressing the adhesion of leukocytes, the formation of macrophages is reduced which inhibits the release of lysosomal enzyme and leads to a reduction in further inflammation [29].
  • Lymphocytes aid in activation of T cells and macrophages that have been produced causing rapid division and cytokine secretion. Cytokines are associated with both the initial activation and ongoing sensitization of the nociceptive receptors on sensory neurons perceived as chronic pain mediators. By reducing the effect of lymphocytes by depleting the amount of T cells and secretion of cytokines pain is reduced [30].
  • Cytokines are also responsible for releasing eicosanoid, a signalling molecule that stimulates other inflammatory mediators including histamine and prostaglandins. Both histamine and prostaglandins cause vasodilation of the surrounding blood vessels. This vasodilation leads to increased swelling and also contributes to the sensitisation of nerves resulting in pain perception. By reducing vasodilation and stimulation of pain receptors swelling and pain are reduced [31].

This systematic review was conducted in order to assess the effectiveness and safety of intra-articular corticosteroid injection as a treatment modality for 1st MPJ OA. A thorough and systematic literature search was completed in order to identify pertinent literature on the subject area and forty-seven studies were identified for possible inclusion. After exclusions were applied from the selection criteria to ensure that the correct condition, joint and treatment were being considered 11 pieces of literature remained of which two have been considered in detail. The remaining literature was mainly comprised of studies that provide low level evidence such as narrative reviews, retrospective case studies or non-controlled clinical trials.

One single blind randomized trial that compared the efficacy of a single corticosteroid injection with hyaluronate was identified [22]. A critical appraisal of this trial found it to have a high risk of bias. Furthermore, the solutions administered to participants were for two distinct conditions, hallux valgus and hallux rigidus and no details for sub group analysis were provided. It was therefore not possible to determine what influence this may have had on the outcome measures relating to pain reduction and improved joint function for hallux rigidus. From this trial it was not possible to determine with any level of certainty or specificity the efficacy of corticosteroids as an intervention to treat osteoarthritis at the hallux.

CSIs are generally considered safe drugs with steroid flare being the most commonly reported adverse event, though rare complications that may arise following administration of intra-articular steroid including anaphylaxis, disturbance of menstrual pattern and avascular necrosis [32]. Data relating to adverse effects was collected by Pons, et al., post intervention were mild, and arose in just 5% of recipients. It was not possible to determine the quality of reporting of adverse effects in this trial or whether adverse effects arose in hallux valgus and/or hallux rigidus joints. However, the reported rate of adverse effects is homogenous with the 6% rate of mild adverse effects reported by following 1,708 steroid injections into both soft tissue and joints of the foot and ankle [33]. The most common side effect reported was a steroid ‘flare’, an acute inflammatory reaction to the steroid solution which made up 75% of the reported side effects. Vasovagal episodes, facial flushing, local skin reactions, short term paraesthesia and a temporary increase in blood glucose levels were also reported but were rare. No infections were reported by the study, a result consistent with the view that joint infection is a very rare complication resulting in septic arthritis. No adverse effects following the administration of 22 CSIs for hallux rigidus were noted by Grice, et al., [34] although they do report that the positive results (seen in 20 of the 22 patients) only lasted longer than three months in three of that cohort. At two years, two patients (9%) remained asymptomatic, but 12 patients (55%) had undergone surgery. Peterson and Hodler [35] and Kilmartin [36] also note that most adverse effects experienced following an intra-articular joint injection of steroid are mild and transient and can be managed by the patient with self-care advice. These papers support the anecdotal view that in general, CSIs are safe and that adverse effects tend to be moderate and time-limited.

Numerous narrative reviews exist regarding treatments for hallux rigidus and include CSIs but provide no evidence-based recommendations for treatment. An exception to this was a comprehensive review [14], the aim of which was to provide evidence-based recommendations regarding conservative treatment modalities for hallux rigidus and included a review of injection therapy. Authors of the review based their recommendations on an established appraisal system [23] that allocates a level of evidence for an intervention based on the design of studies identified. Rama [24] pointed out that this system is a derivative of the widely established levels of evidence system [25] and cautioned regarding the limitations of this style of review. He highlighted the need to not generalize evidence in order to avoid misleading conclusions being drawn. King, et al., grouped six trials relating to injection therapy together for data analysis regardless of the fact that interventions and trial designs differed. A ‘collective’ level of evidence was allocated to injection therapy in general rather than by individual solutions. This led to skewed results given that the quality of trial design that had tested hyaluronate was superior to other interventions such as corticosteroid. Given that this review did not use a methodology that considered the risk of bias, validity or clinical significance of results of trials this study was excluded from this review as it was deemed to provide a narrative review.

One systematic literature review that included an appraisal of the efficacy of corticosteroid injections for osteoarthritis at the big toe joint [16] was included in this review. The Cochrane review was well designed, well executed and found to have a low risk of bias. Zammit, et al., [16] did not identify any robust evidence to support the efficacy of corticosteroid injections for the treatment of hallux rigidus and made no recommendations regarding its safety due to the high risk of bias. This view is consistent with the findings of this review that found it was only possible to make generalizations relating to the safety of intra-articular corticosteroid injections.

This review did not find evidence of sufficient quality to confirm whether intra-articular corticosteroid injections are an effective intervention for the management of symptomatic osteoarthritis at the 1st MPJ. The current literature that exists was found to be of poor methodological design. In the only randomized controlled clinical trial that tested corticosteroid, it was found to be mildly inferior to hyaluronate in terms of pain reduction for patients with mild osteoarthritis [22]. However, in a robust randomized placebo controlled [38] trial of intra-articular injections for osteoarthritis no benefit was derived from sodium hyaluronate vs saline placebo.


There are a number of narrative reviews concerned with the conservative and surgical treatment modalities that can be used to inform the management of symptomatic hallux rigidus. A number of cases and retrospective [26,27] studies have evaluated the use of injectable corticosteroids in the foot or ankle but controlled clinical trials in this area are few.

Many interventions exist that are intended to reduce the symptoms associated with OA of the 1st MPJ. In spite of the lack of evidence to support their use, IA CSI remains popular amongst health care professionals and patients alike because they are quick and inexpensive to administer with the perception of rapid relief, minimal recovery time and few side effects [32]. In cases of mild osteoarthritis, some retrospective studies indicate that CSIs may provide months and occasionally, years of relief for hallux rigidus [28]; a retrospective study by Smith, et al., in 2000 [37] found 75% of patients that had previously declined surgical treatment for symptomatic hallux rigidus were happy with this decision, had not experienced an increase in pain undergone despite degeneration of the joint, and were able to manage symptoms with stiff soled shoes and accommodative footwear. It is unclear whether progression to surgery has any association with the administration of intra-articular corticosteroid but given the risk of chondrotoxicity [15] this warrants further investigation.

This review found no high quality evidence to support the use of IA CSI as an effective treatment modality for symptomatic 1st MPJ OA. Uncertainty regarding variables that may influence treatment outcomes such as concomitant footwear use [39] remains. Existing research that tested intra-articular corticosteroid was found to be of poor methodological design with a high risk of bias. High quality, randomized, controlled clinical trials that test the efficacy of IA CSI are required. The severity of 1st MPJ OA amongst recipients in trials should be classified prior to intervention by clinical and radiological examination [19] and a sub group analysis of outcome measures provided according to disease severity. Further research to determine whether treatment outcomes are improved by the use of image guidance, extrapolation of side effects [40] and whether the use of IA CSI in 1st MPJ reduces surgical burden would be beneficial.


  1. Lam A, Chan JJ, Surace M F. Hallux rigidus: how do I approach it? World Journal of Orthopaedics. 2017;8(5):364-371. doi: 10.5312/wjo.v8.i5.364.
  2. National Institute of Health and Care Excellence (NICE). Osteoarthritis: care and management. Clinical Guideline [CG177] NICE (online). 2014. Available from: https://www.nice.org.uk/guidance/cg177 [Accessed 05.03.2020].
  3. Juni P, Hari R, Rutjes AWS, Fischer R, Silletta MG, Reichenbach S, Costa BR. Intra-articular corticosteroid for knee osteoarthritis. Cochrane Database of Systematic Reviews. 2015. Available from: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD005328.pub3/full [Accessed 05.03.2020].
  4. Soh E, Li W, Ong K, Chen W, Bastista D. Image guided versus blind corticosteroid injections in adults with shoulder pain: a systematic review. BMC Musculoskeletal Disorders. 2011;12(137). doi: 10.1186/1471-2474-12-137.
  5. Neogi T. The epidemiology and impact of pain in osteoarthritis. Osteoarthritis Cartilage. 2013;21(19):1145-1153. doi: 10.1016/j.joca.2013.03.018.
  6. Gould, N, Schneider, W, Ashikaga, T. Epidemiological survey of foot problems in the continental United States: 1978-1979. Foot & Ankle. 1980;1(1):8-10. doi: 10.1177/107110078000100104.
  7. Anderson MR, Ho BS, Baumhauer JF. Current concepts review: hallux rigidus. Foot and Ankle Orthopaedics. 2018;3(2):1-11. doi: 10.1177/2473011418764461.
  8. Kingsbury S R, Conaghan PG. Current osteoarthritis treatment, prescribing influences and barriers to implementation in primary care. Primary Health Care Research & Development. 2012;13(4);373-381. doi: 10.1017/S1463423612000072.
  9. Awale A, Dufour AB, Katz P, Menz HB, Hannan MT. Link between foot pain severity and depressive symptoms. Arthritis care & research. 2016;68(6): 871-876. doi: 10.1002/acr.22779.
  10. Bergin SM, Munteanu SE, Zammit GV, Nikolopoulos N, Menz HB. Impact of first metatarsophalangeal joint osteoarthritis on health-related quality of life. Arthritis Care & Research. 2012;64(11):1691-1698. doi: 10.1002/acr.21729.
  11. Van Saase JL, Romunde LK, Cats A, Vandenbroucke JP, Valkenburg HA. Epidemiology of osteoarthritis: Zoetermeer Survey. Comparison of radiological osteoarthritis in a Dutch population with that in 10 other populations. Annals of the Rheumatic Diseases. 1989;48(4):271-280. doi: 10.1136/ard.48.4.271.
  12. Pekarek B, Osher L, Buck S, Bowen M. Intra-articular corticosteroid injections: A critical review with up-to-date findings. The Foot. 2011;21(2):68-70. doi: 10.1016/j.foot.2010.12.001.
  13. Kunnasegaran R, Thevendran G. Hallux rigidus. Non operative treatment and orthotics. Foot and Ankle Clinics. 2015;20(3);1558-1934. doi: 10.1016/j.fcl.2015.04.003.
  14. King CK, James Loh SY, Zheng Q, Mehta KV. Comprehensive review of non-operative management of hallux rigidus. Cureus. 2017 Jan;9(1). doi: 10.7759/cureus.987.
  15. Farkas B, Kvell K, Czömpöly T, Illés T, Bárdos T. Increased chondrocyte death after steroid and local anesthetic combination. Clinical Orthopaedics and Related Research®. 2010 Nov 1;468(11):3112-20. doi: 10.1007/s11999-010-1443-0.
  16. Zammit GV, Menz HB, Munteanu SE, Landorf KB, Gilheany MF. Interventions for treating osteoarthritis of the big toe joint. Cochrane Database of Systematic Reviews. 2010. Available from: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD007809.pub2/media/CDSR/CD007809/CD007809_standard.pdf [Accessed 05.03.2020].
  17. Moher D, Liberati A, Tetzlaff J, Altman DG, Prisma Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS med. 2009 Jul 21;6(7):e1000097. doi: 10.1371/journal.pmed.1000097.
  18. Greenhalgh T, Peacock R. Effectiveness and efficiency of search methods in systematic reviews of complex evidence: audit of primary sources. BMJ. 2005 Nov 3;331(7524):1064-5. doi: 10.1136/bmj.38636.593461.68.
  19. Beeson P, Phillips C, Corr S, Ribbans W. Classification systems for hallux rigidus: a review of the literature. Foot & Ankle International. 2008 Apr;29(4):407-14. doi: 10.3113/FAI.2008.0407.
  20. Critical Appraisal Skills Programme. CASP Randomised Controlled Clinical Trial Checklist. [online]. 2018. Available from: https://casp-uk.net/wp-content/uploads/2018/01/CASP-Randomised-Controlled-Trial-Checklist-2018.pdf [Accessed: 05.03.2020].
  21. University of Oxford Systematic Review Critical Appraisal Sheet [online]. Oxford: Centre for Evidence Based Medicine. 2005. Available from: https://www.cebm.net/wp-content/uploads/2018/11/RCT.pdf [Accessed 05.03.2020].
  22. Pons M, Alvarez F, Solana J, Viladot R, Varela L. Sodium hyaluronate in the treatment of hallux rigidus. A single-blind, randomized study. Foot & Ankle International. 2007 Jan;28(1):38-42. doi: 10.3113/FAI.2007.0007.
  23. Wright JG, Einhorn TA, Heckman JD. Grades of recommendation. JBJS. 2005 Sep 1;87(9):1909-10. doi: 10.2106/JBJS.8709.edit.
  24. Rama KRB. Grades of Recommendation. JBJS. 2006;88(2):451. doi: 10.2106/00004623-200602000-00037.
  25. University of Oxford Levels of Evidence 1 [online]. Oxford: Centre for Evidence Based Medicine. 2009. Available from: https://www.cebm.net/2009/06/oxford-centre-evidence-based-medicine-levels-evidence-march-2009/ [Accessed 05.03.2020].
  26. Cotterill JM. Stiffness of the great toe in adolescents. BMJ. 1887 May 28;1(1378):1158. doi: 10.1136/bmj.1.1378.1158.
  27. Coughlin MJ, Shurnas PS. Hallux rigidus: grading and long-term results of operative treatment. JBJS. 2003;85(11):2072-88. PMID: 14630834.
  28. Grady JF, Axe TM, Zager EJ, Sheldon LA. A retrospective analysis of 772 patients with hallux limitus. Journal of the American Podiatric Medical Association. 2002 Feb;92(2):102-8. doi: 10.7547/87507315-92-2-102.
  29. Rhen T, Cidlowski JA. Antiinflammatory action of glucocorticoids – new mechanisms for old drugs. New England Journal of Medicine. 2005 Oct 20;353(16):1711-23. doi: 10.1056/NEJMra050541.
  30. Li YS, Luo W, Zhu SA, Lei GH. T cells in osteoarthritis: alterations and beyond. Frontiers in immunology. 2017 Mar 30;8:356. doi: 10.3389/fimmu.2017.00356.
  31. Cole BJ, Schumacher Jr RH. Injectable corticosteroids in modern practice. JAAOS-Journal of the American Academy of Orthopaedic Surgeons. 2005 Jan 1;13(1):37-46. doi: 10.5435/00124635-200501000-00006
  32. Corticosteroid injections. Reilly I, in Foot and Ankle Injection Techniques: A Practical Guide. Metcalfe SA, Reilly I. Churchill Livingstone, England. ISBN: 9780702031076.
  33. Anderson SE, Lubberts B, Strong AD, Guss D, Johnson AH, DiGiovanni CW. Adverse events and their risk factors following intra-articular corticosteroid injections of the ankle or subtalar joint. Foot & Ankle International. 2019 Jun;40(6):622-8. doi: 10.1177/1071100719835759.
  34. Grice J, Marsland D, Smith G, Calder J. Efficacy of foot and ankle corticosteroid injections. Foot & ankle international. 2017 Jan;38(1):8-13. doi: 10.1177/1071100716670160.
  35. Peterson C, Hodler J. Adverse events from diagnostic and therapeutic joint injections: a literature review. Skeletal Radiology. 2011 Jan 1;40(1):5-12. doi: 10.1007/s00256-009-0839-y.
  36. Kilmartin TE. Corticosteroid injection therapy in Podiatry. Podiatry Now. 2017;20(2), CPD pullout.
  37. Smith RW, Katchis SD, Ayson LC. Outcomes in hallux rigidus patients treated nonoperatively: a long-term follow-up study. Foot & Ankle International. 2000 Nov;21(11):906-13. doi: 10.1177/107110070002101103.
  38. Munteanu, S, Menz, H, Zammit, G, Landorf, K, Handley, C, ElZarka, A, DeLuca, J. Efficacy of intra-articular hyaluronan (Synvisc®) for the treatment of osteoarthritis affecting the first metatarsophalangeal joint of the foot (hallux limitus): study protocol for a randomized placebo controlled trial. J Foot Ankle Res. 2009;2(2). doi: 10.1186/1757-1146-2-2.
  39. Frecklington M, Dalbeth N, McNair P, Gow P, Williams A, Carroll M, Rome K. Footwear interventions for foot pain, function, impairment and disability for people with foot and ankle arthritis: a literature review. In Seminars in arthritis and rheumatism 2018 Jun 1 (Vol. 47, No. 6, pp. 814-824). WB Saunders. doi: 10.1016/j.semarthrit.2017.10.017.
  40. Kompel A, Roemer F, Murakami A, Diaz L, Crema M, Guermaz, A. Intra-articular corticosteroid injections in the hip and knee: Perhaps not as safe as we thought? Radiology. 2019;293(3). doi: 10.1148/radiol.2019190341.

Subchondroplasty in the lower extremity: A literature review

by Steven Cooperman, DPM1*; Thomas Yates, DPM1; David Shofler, DPM, MSHS1

The Foot and Ankle Online Journal 13 (3): 8

Osteoarthritis is one of the most common and debilitating conditions encountered by foot and ankle surgeons. This osteoarthritis is often accompanied by a coinciding bone marrow lesion (BML) which has been shown to result in poorer patient outcomes. The subchondroplasty procedure was developed with the aim of targeting these painful BMLs in order to slow the progression of osteoarthritic changes. There has been a trend in both orthopedic and podiatric literature towards the use of this procedure in the lower extremity. This review is meant to bring forward the information most pertinent to the procedure to help inform the foot and ankle surgeon of its uses and potential, as well as to encourage future research into the procedure.

Keywords: subchondroplasty, bone marrow lesion, osteoarthritis, calcium phosphate, bone substitute material

ISSN 1941-6806
doi: 10.3827/faoj.2020.1303.0008

1 – Department of Podiatric Medicine, Surgery, and Biomechanics, Western University College of Podiatric Medicine, 309 E 2nd Street, Pomona, CA 91766
* – Corresponding author: Scooperman@westernU.edu

Osteoarthritis (OA) remains one of most common and debilitating conditions encountered by foot and ankle surgeons. Whether the result of trauma or degenerative overuse, orthopedic and podiatric surgeons alike can agree that the sequelae of OA can be challenging to manage. The natural history of OA involves persistent joint pain, lack of normal function, and can include a vicious cycle which may progress to osteonecrosis of the affected bones. While the current body of evidence of in vitro cartilage repair and regenerative medicine is rapidly growing, there are perhaps other more readily available methods of treating OA which may ultimately demonstrate equal benefit to patients. Subchondroplasty® (SCP) (Zimmer Knee Creations, West Chester, PA) is a surgical system, developed in 2007, in which flowable bone substitute material (BSM) is injected into subchondral bone in order to fill a defect. The procedure acts to support the subchondral bone layer by providing a scaffold over which new, healthier osteochondral elements may be produced [1]. Although this technique has primarily been described in literature to treat bone marrow lesions (BMLs) in the knee joint, this technique has recently been applied to the foot and ankle with comparably successful outcomes.

This paper is not meant to serve as a technique guide, but a review of available relevant literature. As such, the use of the term subchondroplasty throughout the paper will be in reference to the procedure itself, not the proprietary system. The goal of this review is to benefit the foot and ankle surgeon by: first, providing a general understanding of the procedure and its expanding applications; second, by presenting the largely positive patient outcomes in both the orthopedic and podiatric literature in an attempt to encourage further study into a relatively new – yet promising – tool in the foot and ankle surgeon’s array of treatments.


An extensive search of available literature related to: 1) subchondral bone and the osteochondral unit; 2) lower extremity osteoarthritis; 3) bone substitute materials; 4) the subchondroplasty procedure, including its related radiographic findings and clinical outcomes in the lower extremity.


Within joints, the subchondral bone layer is a supporting structure for the overlying articular cartilage. Subchondral bone is an underappreciated, yet vital component to the function of each osteochondral unit and overall joint health [2]. Bone metabolism is dynamic, in concert with Wolff’s law, and a normal subchondral bone plate displays the same capacity to increase in thickness according to physiologic loading [3].

In osteoarthritis, this typically dynamic nature of the subchondral bone plate is disrupted. Increased and imbalanced dispersion of joint forces, combined with a concentration of stresses and synovial fluid infiltration into the subchondral bone, can lead to reduced healing capacity and abnormalities within the underlying cancellous bone. These abnormalities can be identified both histologically and on magnetic resonance imaging (MRI) as bone marrow lesions (BMLs) [4-7].

The mechanism of coinciding pain associated with these BMLs is currently under debate, but has been attributed to the healing response secondary to trauma and trabecular injury and/or impaired venous drainage [8-10]. Histologically, BMLs have been shown to be focal areas of demineralization, increased fibrosis, and vascular abnormalities. These abnormalities can mimic chronic stress fractures, which may then progress to areas of focal necrosis [6,11-15]. Clinically, it is of great importance that BMLs be identified and treated, as they have been linked to increased arthritic pain and may hasten the progression of joint deterioration [5,16-18].

These potential consequences have been attributed to both improper load transmission across the affected joints and an underlying imbalance in bone metabolism––favoring bone resorption when a BML is present [19]. A direct correlation between increasing size of BMLs and increased pain in the knee was identified in a study by Felson, et al., in 2007. Patients experiencing pain were found to have a 3.31-fold greater likelihood of significant findings on MRI compared to non-painful patients with the same radiologic degree of arthrosis [20]. Additionally, Saltzman and Kijowski found that BML prevalence, depth, and cross-sectional area under arthroscopy were each directly correlated with worsening grades of corresponding articular cartilage defects [2,21].

Osteoarthritis occurring in the hip and knee joints primarily occurs as a degenerative process. However, due to histological, anatomic, and biomechanical differences in the cartilage of the ankle joint, arthritis in the ankle most commonly occurs after significant trauma [22-24]. Due to the post-traumatic presentation of ankle joint arthritis, there exists a propensity for a wider range of ages at which osteoarthritis may present in the affected ankle, which has important implications with how these patients are definitively treated. Younger and more active patients with ankle joint arthritis are less tolerant of arthrodesis or arthroplasty procedures than are their elderly and less active counterparts. As such, it stands to reason that there should be a great deal of interest in the potential for joint sparing procedures in these patients.

The Procedure

In this procedure, BMLs are triangulated using fluoroscopy, and subsequently injected and filled with flowable, biologically-compatible ceramic materials. The injected bone substitute material (BSM) then undergoes an endothermic reaction, resulting in crystallization of the BSM which affords properties similar to that of cancellous bone. This is believed to assist in supporting the trabecular structure of the bone, and to slow or even halt the pathologic processes at work. Typically, this procedure has been performed with calcium phosphate (CaP), calcium sulfate (CaS) or hydroxyapatite (HA), with CaP being the more commonly used of the three [25]. However, in terms of osteobiology, these products only offer one component of the osteobiology triad: osteoconduction. As such, these products only function as a scaffolding upon which healing may take place.

In 2016, Hood et al proposed that the two remaining osteobiologic properties, osteogenesis and osteoinduction, could be imparted via the addition of bone marrow aspirate concentrate (BMAC) to the osteoconductive materials used during the procedure [25]. It had previously been shown that osseous regeneration occurs at a faster rate with the use of a combination of BMA and osteoconductive ceramic materials, as opposed to either alone [26]. The premise behind this is that replacing the 0.9% normal saline solution (NSS)––which is typically used for rehydration of the bone substitute material––with autogenous BMAC, bone healing potential can be improved.

The addition of BMACs, the osteoconductive CaP would have the theoretical benefit of mesenchymal stem cells (MSCs), osteoprogenitor cells (OPCs), hematopoietic stem cells (HSCs), platelets, vascular endothelial growth factor (VEGF) and transforming growth factor beta (TGF-β) to assist in the reparative process [26-29]. In patients with concomitant cartilaginous defects, particulated juvenile allograft cartilage (PJAC) can be used to address the overlying cartilaginous defect after hardening of the CaP scaffold [8].

Hood et al. presented a case report for a 26 year old female with two years of recalcitrant left ankle pain after a motor vehicle accident. This patient eventually underwent the modified SCP® technique with rehydration using BMAC for a talar dome BML [25]. It was reported that the patient’s pain decreased from a preoperative VAS score of 9 to occasional 1-2/10 discomfort at 6 weeks postoperatively.

CaP with BMAC has since become a popular choice among bone and joint surgeons, though other orthobiologic combinations have also been reported with promising results: CaS with platelet-rich plasma (PRP), HA with BMAC, and HA-tri-CaP with MSC [30-32]. Subsequent studies have aimed to clarify the following: the ideal osteoinductive/osteogenic adjunct, the proper amount and consistency of adjunct, the effect on curing time and handling, and the adjunct’s effect on the scaffolding material.

In 2015, Colon et al. evaluated in vitro injectability of common commercially available bone substitute materials (BSMs). Histologically, bone marrow lesions (BMLs) demonstrate micro-trabecular damage characteristic of stress fractures [15]. For injection of materials into these microtrabeculae to be considered possible, the materials must have the ability to be injected into a highly pressurized space. Eight of the most common commercially available BSMs were tested (AccuFill® (Zimmer, Inc.), Beta-BSM™ (Zimmer, Inc.), Cerament™ (Biomet, Inc.), HydroSet™ (Styker®), Norian™ SRS (DePuy Synthes®), Pro-Dense® (Wright Medical Inc.), StrucSure™ CP (Smith & Nephew plc), Simplex™ (Stryker®)) using the polyurethane block material, while three were additionally tested in femoral condyle cadaveric bone blocks from healthy donors (AccuFill®, Beta-BSM™ and StrucSure™). The results found that although these materials are all considered injectable BSMs, only three were able to flow into the closed structure of the polyurethane block (AccuFill®, Simplex™ and StrucSure™). Additionally, AccuFill® was shown to outperform the other BSMs in several areas: the ability to flow within micro-architecture without damage from the applied force, the lowest injection force, the highest volume injected, the greatest area covered by material injected, and the ability to set without an exothermic reaction. The knowledge that these commercial calcium phosphate (CaP) products have differing properties, and understanding how this may affect different aspects of the procedure, can help inform the decision making of the surgeon.


In 2016, Agten, et al., and Nevalainen, et al., both published papers describing diagnostic imaging related to the subchondroplasty procedure in the knee. The goal was to educate radiologists and familiarize them with expected post-procedure findings. Agten, et al., reviewed the pre- and postoperative imaging for nine patients, with the first postoperative imaging at three months post-operatively. Nevalainen, et al., discussed two knee subchondroplasty case studies. Preoperative imaging revealed that insufficiency fracture was associated with a greater amount of bone marrow edema than osteoarthritis [33].

Following the procedure, postoperative radiographs should display an increased radiodensity at the site of calcium phosphate injection, which should correlate with the locations of bone marrow edema (BME) on preoperative imaging [33,34]. CaP extravasation into soft tissues may occur along the track of the injection, which predictably mimics the appearance of heterotopic ossification. Extra-articular extravasation of calcium phosphate may resolve over time, while intra-articular leakage is a complication that should be addressed intraoperatively.

When evaluating patients, it is important to identify the cause of bone marrow edema, as this is a relatively non-specific finding, particularly on MRI. Trauma, including bone contusions, is the most common cause of positive BME findings on MRI [35]. The remaining causes of BME on MRI are transient BME syndromes (including transient osteoporosis, regional migratory osteoporosis, and complex regional pain syndrome), repetitive microtrauma and stress fractures, and non-traumatic causes such as avascular necrosis, spontaneous osteonecrosis, reactive polyarthritis, and neoplasms [2].

Classic findings of BMLs include a focal area of BME appearing as high signal intensity on T2-weighted, fat-saturated images and low signal intensity on T1-weighted, fat sensitive images. The increased signal intensity of BMLs on T2-weighted, fat-saturated MRI sequences has been suggested to be a result of increased subchondral vascularity [1]. Additionally, a low-signal-intensity line in the subchondral region of T2-weighted, fat-saturated images may be present, corresponding to impaction of the trabecular bone [35]. If present, it has been shown that a length and thickness of this line greater than 14mm and 4mm, respectively, are risk factors for lesion progression and subchondral collapse [36]. This signal should change to a decreased signal intensity on both T1-weighted fat-sensitive and T2-weighted fat-saturated images following injection of the CaP [33,34]. On fat-saturated, fluid-sensitive images there may also be a fine rim of increased signal intensity surrounding the CaP, representing surrounding edema [33,34]. It should be noted that a direct correlation between increasing BME signal intensity and more advanced cartilage degradation on MRI has also been identified [37].

Preoperative CT scan may be useful in conjunction with MRI, especially in the case of concurrent cartilage injury, as this can be difficult to assess on MRI [38,39]. Concurrent evaluation of the cartilage portion of the osteochondral unit should be considered of utmost importance, as 60% of patients with surgically confirmed chondral degeneration in the knee have been shown to have associated BMLs [21]. Additionally, both cartilage thinning and bony edema can lead to over- or underestimation of cartilage and bone damage on MRI [40]. Postoperatively on CT scan, any drill holes will be seen as a hypodense track with the surrounding hyperdense CaP [33].

Notably, the changes described correlating to post-procedure imaging have been shown to regress over time. Still, the specific time-frame is currently unclear and likely variable. In canine models, the majority of BSM has been found to be absorbed by two years postoperatively [41].

Use for OA/BML in the knee

Subchondroplasty was originally described for use in the treatment of moderate to severe osteoarthritic knee pain present for more than 2-6 months, with concomitant presence of a BML localized to the area of pain [42]. The presence of a BML in these patients is particularly concerning, as patients with knee OA compounded with a BML have a highly predictable progression to total knee arthroplasty (TKA). In fact, this occurs approximately nine times more frequently over a three year period when compared to OA in patients without a coinciding BML [4,43-45]. Previous treatment of cartilaginous defects in the knee by arthroscopic debridement alone has not been shown to yield success for patients suffering from moderate to end stage osteoarthritis, with several studies showing either no improvement or minor improvement at six months, and no improvement at two years. [4,45-48].

In 2016, a study by Cohen, et al., evaluated the combined treatment of subchondroplasty and arthroscopy in the knee in 66 patients who initially presented for TKA consultation [4]. Pain was significantly decreased and function significantly improved in all groups, including at both 6 and 24 months post-op. Notably, there was a 70% 2-year joint preservation survivorship. Patients who ultimately received TKA were significantly older and were more likely to have had a history of prior meniscectomy. A follow-up study from Brazil also noted positive results, with improvement on both VAS and knee injury and osteoarthritis outcome scores (KOOS) at 24 weeks postoperatively [14]. Longer-term outcomes of treatment with CaP in post-traumatic, impact-induced BMLs in a medial femoral condyle canine model have also shown symptomatic and functional benefits for up to two years [41].

The effect on TKA

Logically, the next question to address is whether the technique of treating BML using CaP bone substitutes affects outcomes in patients who fail this joint preserving technique and require knee replacement. It has previously been reported that the complexity of knee arthroplasty increases in patients who have had previous knee surgery, resulting in the potential for more complications and poorer outcomes [49-52]. In 2016, Yoo, et al., evaluated the effect of prior BML treatment on the complexity and outcomes of future knee arthroplasty procedures [53]. A total of 22 patients who had undergone prior arthroscopic repair of BMLs were demographically matched in a 1:2 ratio to a group of controls undergoing knee arthroplasty, either unicompartmental knee arthroplasty (UKA) or total knee arthroplasty (TKA). Patients were followed up for an average of 23.5 months (ranging from 12-52 months), with no significant differences identified between the groups. There were no cases of intra-operative UKA conversion to TKA, no differences in surgical complications or technical challenges between groups, and no cases of non-standard primary components required. Additionally, on intraoperative inspection of the CaP bone substitute, it was reported to be consistently well incorporated without signs of compromise or inconsistencies from the subchondral bone. Based on their findings, Yoo, et al., concluded that previous treatment of BMLs using CaP bone substitute did not compromise knee arthroplasty outcomes or surgical performance.

Functional/Subjective outcomes in the knee

Functional and subjective outcomes have been generally favorable following subchondroplasty. In 2018, a literature review of 8 articles and 164 total patients treated with CaP injection for BMLs in the femoral condyles or tibial plateau noted significant improvement in symptoms, few complications, and return to activity at an average of three months [42]. Of the articles reviewed, only a single paper reported a subgroup of patients who experienced poor outcomes from the procedure. Chatterjee, et al., identified an inverse relationship between the subjective postoperative Tegner-Lysholm knee scoring scale and preoperative Kellgren-Lawrence osteoarthritis grade [54]. In other words, a correlation was identified between poorer subjective outcomes and more severe preoperative osteoarthritis. Despite this, other studies have failed to report similar correlation between OA grade and outcomes. As such, future prospective studies would be valuable in confirming this finding.

Described use in the Foot and Ankle

At this time, the literature regarding treatment of BMLs using flowable calcium phosphate (CaP) has been primarily directed to cases in the knee. However, due to the need for joint-sparing procedures for ankle osteoarthritis and for the treatment of symptomatic BMLs, there has been growing interest in its application in the foot and ankle. Since subchondroplasty was first introduced into the field of foot and ankle surgery in 2015, more than six thousand foot and ankle subchondroplasty procedures have been performed [55]. The first reported subchondroplasty procedures performed in the foot and ankle were from Miller, et al., [56]. Two cases were reported, the first in a 48 year old male with complaints of chronic left ankle pain and instability, and the second in a 28 year old male with chronic ankle pain following a fibular non-union. In both cases, the patients exhibited talar BMLs on MRI that were recalcitrant to conservative treatments. Each patient underwent a subchondroplasty procedure, combined with other indicated procedures. The first patient was able to return to full activity at 12 weeks post-operatively, while the second sustained a tibial fracture due to a syncopal event at 13 weeks post-op. Miller, et al., reported minimal subjective pain in both cases at 10-month follow-up with no activity restrictions.

Shortly thereafter in 2018, Chan, et al., reported an 11-patient retrospective cohort study of symptomatic talar osteochondral defects (OCDs) treated with subchondroplasty with bone marrow aspirate concentrate (BMAC) injection [57]. In this cohort, the mean talar OCD size was 1.3 cm x 1.4 cm. All subjective outcomes improved from preoperative baseline to final one year follow-up, including visual analog pain scale and Foot and Ankle Outcome Score, with 10 out of the 11 patients reporting they would undergo the procedure again. There was a single reported complication in the cohort, with a talar neck stress fracture at bone-BSM interface after the patient had previously experienced full resolution of symptoms. All patients, except for the aforementioned complication, returned to full activity between three and nine weeks postoperatively.

Barp, et al., published two case reports, including a 25 year-old male tennis player and a 53 year-old female, treated with percutaneous injection of CaP into the 2nd metatarsal head (Frieberg’s infraction) and cuboid (stress fracture), respectively. Both patients were allowed protected weightbearing as tolerated at one week postoperatively, returned to full activity without pain at four weeks, and remained free of related complaints at final follow-up at one and three years, respectively [58].

BMLs in the foot have also been found to be associated with plantar fasciitis, specifically patients requiring surgical intervention [59]. This may have significant clinical implications. In a report by Bernhard, et al., a single case of recalcitrant plantar fasciitis was shown to have a concomitant calcaneal BML on MRI [60]. This patient was treated with repeat plantar fasciotomy and CaP injection of the BML, successfully resulting in full return to activity and pain-free follow-up at 3 and 10 months.


Perhaps due to the minimally invasive nature of the procedure, few complications of subchondroplasty have been reported in the literature. While rare, the surgeon should be aware of the following potential complications: pain secondary to overfilling with CaP, intra- or extra-articular extravasation of CaP, deep vein thrombosis of the operative limb, subsequent soft tissue or bone infection, stress fracture at the bone-BSM interface, and avascular necrosis [8,57,61].

Pain secondary to overfilling with CaP has been identified as the most common complication of the subchondroplasty procedure, and has been described clinically as a disproportionate pain which often resolves completely within 72 hours postoperatively [42]. Over-pressurization and failure to completely fill a BML have both been associated with poorer outcomes in the orthopedic knee literature and are highly preventable with increased surgeon experience [62]. A single case of osteomyelitis secondary to subchondroplasty in the medial femoral condyle was reported by Dold, et al. In their report, the authors considered that this procedure may have a predisposition for infectious complications due to direct seeding and the hydrophilic nature of CaP, which can result in prolonged wound drainage, poor healing, and eventual sinus tract formation [61]. In a series of 11 patients receiving CaP injection in the talus for painful osteochondral defects, Chan, et al., reported a single complication in a patient with a BMI of 34 kg/m² who experienced a talar neck stress fracture at the bone-BSM interface [57].


Overall, subchondroplasty for the treatment of BMLs has led to promising outcomes and infrequent complications. The range of potential applications of the technique is constantly expanding, with increasing use in the treatment of foot and ankle pathology. Additional studies may help clarify the potential benefits in the setting of osteoarthritis of the foot and ankle, including the procedures potential in delaying and/or preventing total ankle arthroplasty.


  1. Pelucacci LM, LaPorta GA. 2018. Subchondroplasty: treatment of bone marrow lesions in the lower extremity. Clin Pod Med Surg 35: 367-371.
  2. Saltzman BM, Riboh JC. 2018. Subchondral bone and the osteochondral unit: basic science and clinical applications in sports medicine. Sports Health, 10(5): 412-418.
  3. Duan CY, Espinoza Orias AA, Shott S, et al. In vivo measurement of the subchondral bone thickness of lumbar facet joint using magnetic resonance imaging. Osteoarthritis and cartilage / OARS, Osteoarthritis Research Society. 2011;19(1):96–102.
  4. Cohen SB, Sharkey PF. 2016. Subchondroplasty for treating bone marrow lesions. J Knee Surg, 29: 555-563.
  5. Roemer FW, Neogi T, Nevitt MC, et al. Subchondral bone marrow lesions are highly associated with, and predict subchondral bone attrition longitudinally: the MOST study. Osteoarthritis Cartilage 2010;18:47-53.
  6. Farr J, Cohen SB. Expanding applications of the subchondroplasty procedure for the treatment of bone marrow lesions observed on magnetic resonance imaging. Oper Tech Sports Med 2013; 21:138–143.
  7. Van Dijk CN, et al. 2010. Osteochondral defects in the ankle: why painful? Knee Surg Sports Traumatol Arthro, 18: 570-580.
  8. Ng A, et al. 2017. Advances in ankle cartilage repair. Clin Pod Med Surg, 34: 471-487.
  9. Eriksen EF, Ringe JD. Bone marrow lesions: a universal bone response to injury? Rheumatol Int 2012;32(3):575–84.
  10. Arnoldi CC, Djurhuus JC, Heerfordt J, Karle A. Intraosseous phlebography, intraosseous pressure measurements and 99m Tc-polyphosphate scintigraphy in patients with various painful conditions in the hip and knee. Acta Orthop Scand. 1980;51:19-28.
  11. Zanetti M, et al. 2000. Bone marrow edema pattern in osteoarthritic knees: correlation between MR imaging and histologic findings. Radiology, 215: 835–840.
  12. Hunter DJ, Gerstenfeld L, Bishop G, et al. Bone marrow lesions from osteoarthritis knees are characterized by sclerotic bone that is less well mineralized. Arthritis Res Ther 11:R11, 2009.
  13. Taljanovic MS, Graham AR, Benjamin JB, et al. Bone marrow edema pattern in advanced hip osteoarthritis: quantitative assessment with magnetic resonance imaging and correlation with clinical examination, radiographic findings, and histopathology. Skeletal Radiol 37:423-431, 2008.
  14. Bonadio MB, et al. 2017. Subchondroplasty for treating bone marrow lesions in the knee: initial experience. Revista Brasileira de Ortopedia, 52(3): 325-330.
  15. Colon DA, et al. 2015. Assessment of the injection behavior of commercially available bone BSM’s for subchondroplasty procedures. The Knee, 22: 597-603.
  16. Wluka AE, et al. 2008. Bone marrow lesions predict progression of cartilage defects and loss of cartilage volume in healthy middle aged adults without knee pain over 2 years. Rheum, 47(9): 1392-1396.
  17. Felson DT, Chaisson CE, Hill CL, et al. The association of bone marrow lesions with pain in knee osteoarthritis. Ann Intern Med 2001;134:541-549.
  18. Link TM, Steinbach LS, Ghosh S, et al. Osteoarthritis: MR imaging findings in different stages of disease and correlation with clinical findings. Radiology. 2003;226:373-381.
  19. Sharkey PF, Cohen SB, Leinberry CF, Parvizi J. Subchondral bone marrow lesions associated with knee osteoarthritis. Am J Orthop. 2012;41(9):413-417.
  20. Felson DT, Niu J, Guermazi A, et al. Correlation of the development of knee pain with enlarging bone marrow lesions on magnetic resonance imaging. Arthritis Rheum 2007; 56:2986–2992.
  21. Kijowski R, Stanton P, Fine J, De Smet A. Subchondral bone marrow edema in patients with degeneration of the articular cartilage of the knee joint. Radiology. 2006;238:943-949.
  22. Kraeutler MJ, Kaenkumchorn T, Pascual-Garrido C, et al. Peculiarities in ankle cartilage. Cartilage 2017;8(1):12–8.
  23. Millington SA, Grabner M, Wozelka Mag R, et al. Quantification of ankle articular cartilage topography and thickness using a high resolution stereophotography system. Osteoarthritis Cartilage 2007;15:205–11.
  24. Shepherd DE, Seedhom BB. Thickness of human articular cartilage in joints of the lower limb. Ann Rheum Dis 1999;58:27–34.
  25. Hood CR, Miller JR. 2016. The triad of osteobiology: rehydrating calcium phosphate with bone marrow aspirate concentrate for the treatment of bone marrow lesions. Foot Ankle Online, 9(1): 11.
  26. Block JE. The role and effectiveness of bone marrow in osseous regeneration. Med Hypotheses. 2005;65(4):740-747. doi:10.1016/j.mehy.2005.04.026.
  27. Sampson S, Botto-van Bemden A, Aufiero D. Autologous bone marrow concentrate: review and application of a novel intra-articular orthobiologic for cartilage disease. Physician Sport Med. 2013;41(3):718. doi:10.1007/s13398-014-0173-7.2.
  28. Ishihara A, Helbig HJ, Sanchez-Hodge RB, Wellman ML, Landrigan MD, Bertone AL. Performance of a gravitational marrow separator, multidirectional bone marrow aspiration needle, and repeated bone marrow collections on the production of concentrated bone marrow and separation of mesenchymal stem cells in horses. Am J Vet Res. 2013;74(6):854-863.
  29. Khan WS, Rayan F, Dhinsa BS, Marsh D. An osteoconductive, osteoinductive, and osteogenic tissue-engineered product for trauma and orthopaedic surgery: how far are we? Stem Cells Int. 2012:1-7. doi:10.1155/2012/236231.
  30. Intini G, Andreana S, Intini FE, Buhite RJ, Bobek LA. Calcium sulfate and platelet-rich plasma make a novel osteoinductive biomaterial for bone regeneration. J Transl Med. 2007;5(13):1-13. doi:10.1186/1479-58765-13.
  31. Torres K, Lopes A, Lopes M, et al. The benefit of a human bone marrow stem cells concentrate in addition to an inorganic scaffold for bone regeneration: an in vitro study. Biomed Res Int. 2015;2015:1-10. doi:10.1155/2015/240698.
  32. Tshamala M, Bree H Van, Animals D. Osteoinductive properties of the bone marrow–myth or reality. Vet Comp Orthop Traumatol. 2006;19(3):133-141.
  33. Agten CA, et al. 2016. Subchondroplasty: what the radiologist needs to know. Amer J Rad, 207: 1257-1262.
  34. Nevalainen MT, et al. 2016. MRI findings of subchondroplasty of the knee: a two-case report. Clin Imaging, 40: 241-243.
  35. Bonadio MB, et al. 2017. Bone marrow lesion: image, clinical presentation, and treatment. Magn Res Insights, 10: 1-6.
  36. Lecouvet FE, van de Berg BC, Maldague BE, et al. Early irreversible osteonecrosis versus transient lesions of the femoral condyles: prognostic value of subchondral bone and marrow changes on MR imaging. AJR Am J Roentgenol. 1998;170:71–77.
  37. Zhao J, et al. 2010. Longitudinal assessment of bone marrow edema-like lesions and cartilage degeneration in osteoarthritis using 3 T MR T1rho quantification. Skeletal Radiol, 39: 523-531.
  38. Barr C, Bauer JS, Malfair D, et al. MR imaging of the ankle at 3 Tesla and 1.5 Tesla: protocol optimization and application to cartilage, ligament and tendon pathology in cadaver specimens. Eur Radiol. 2007;17(6):1518-1528.
  39. Hembree WC, Wittstein JR, Vinson EN, et al. Magnetic resonance imaging features of osteochondral lesions of the talus. Foot Ankle Int. 2012;33(7):591-597.
  40. Nakasa T, et al. 2018. Evaluation of articular cartilage injury using computed tomography with axial traction in the ankle joint. Foot Ankle Int’l, 39(9): 1120-1127.
  41. Brimmo OA, et al. 2018. Subchondroplasty for the treatment of post-traumatic bone marrow lesions of the medial femoral condyle in a pre-clinical canine model. J Ortho Res, 36: 2709-2717.
  42. Astur DC, et al. 2018. Evaluation and management of subchondral calcium phosphate injection technique to treat bone marrow lesion. Cartilage: 1-7.
  43. Tanamas SK, Wluka AE, Pelletier JP, et al. Bone marrow lesions in people with knee osteoarthritis predict progression of disease and joint replacement: a longitudinal study. Rheumatology (Oxford) 2010;49(12):2413–2419.
  44. Scher C, Craig J, Nelson F. Bone marrow edema in the knee in osteoarthrosis and association with total knee arthroplasty within a three-year follow-up. Skeletal Radiol 2008;37(7):609–617.
  45. Kröner AH, Berger CE, Kluger R, Oberhauser G, Bock P, Engel A. Influence of high tibial osteotomy on bone marrow edema in the knee. Clin Orthop Relat Res 2007;454(454):155–162.
  46. Moseley JB, O’Malley K, Petersen NJ, et al. A controlled trial of arthroscopic surgery for osteoarthritis of the knee. N Engl J Med 2002;347(2):81–88 15.
  47. Kirkley A, Birmingham TB, Litchfield RB, et al. A randomized trial of arthroscopic surgery for osteoarthritis of the knee. N Engl J Med 2008;359(11):1097–1107, 16.
  48. Thorlund JB, Juhl CB, Roos EM, Lohmander LS. Arthroscopic surgery for degenerative knee: systematic review and metaanalysis of benefits and harms. BMJ 2015;350:h2747.
  49. Lizaur-Ultrilla A, Collados-Maestre I, Miralles-Munoz FA, et al. Total knee arthroplasty for osteoarthritis secondary to fracture of the tibial plateau. A prospective matched cohort study. J Arthroplasty 2015;30:1328.
  50. Klit J. Results of total joint arthroplasty and joint preserving surgery in younger patients evaluated by alternative outcome measures. Dan Med J 2014;61(4):B4836.
  51. Bastos Filho R, Magnussen RA, Duthon V, et al. Total knee arthroplasty after high tibial osteotomy: a comparison of opening and closing wedge osteotomy. Int Orthop 2013;37(3):427.
  52. Haslam P, Armstrong M, Geutjens G, et al. Total knee arthroplasty after failed high tibial osteotomy long-term follow-up of matched groups. J Arthroplasty 2007;22(2)245.
  53. Yoo JY, et al. 2016. Knee arthroplasty after subchondroplasty: early results, complications, and technical challenges. J Arthroplasty, 31: 2188-2192.
  54. Chatterjee D, McGee A, Strauss E, Youm T, Jazrawi L. Subchondral calcium phosphate is ineffective for bone marrow edema lesions in adults with advanced osteoarthritis. Clin Orthop Relat Res 2015; 473: 2334–2342.
  55. McWilliams GD, et al. 2019. Subchondroplasty of the ankle and hindfoot for treatment of osteochondral lesions and stress fractures. Foot Ankle Spec, doi:
  56. Miller JR, Dunn KW. 2015. Subchondroplasty of the ankle: a novel technique. Foot Ankle Online, 8(1):7.
  57. Chan JJ, et al. 2018. Safety and effectiveness of talus subchondroplasty and bone marrow aspirate concentrate for the treatment of osteochondral defects of the talus. Ortho, 41(5): 734-737.
  58. Barp EA, et al. 2019. Subchondroplasty of the foot: two case reports. JFAS, 58: 989-994.
  59. Grasel RP, Schweitzer ME, Kovalovich AM, Karasick D, Wapner K, Hecht P, Wander D. MR imaging of plantar fasciitis: Edema, tears, and occult marrow abnormalities correlated with outcome. AJR Am J Roentgenol 173:699–701, 1999.
  60. Bernhard K, et al. 2018. Surgical treatment of bone marrow lesion associated with recurrent plantar fasciitis: a case report describing an innovative technique using subchondroplasty. JFAS, 57: 811-815.
  61. Dold AP, et al. 2017. Osteomyelitis after calcium phosphate subchondroplasty. Bulletin Hosp Joint Disease, 75(4): 282-285.
  62. Saltzman BM, Oliver-Welsh L, Yanke AB, Cole BJ. Subchondroplasty. In: Miller MD, Cole BJ, Cosgarea A, Owens BD, Browne JA, eds. Operative Techniques: Knee Surgery. 2nd ed. Philadelphia, PA: Elsevier; 2018:152-156.



A 12-month review of patients with advanced metatarsophalangeal joint osteoarthritis undergoing synthetic cartilage hemi implant arthroplasty

by James Lee Harmer FCPodS, MSc, BSc (Hons)1*; Anthony John Maher FCPodS, MSc, BSc (Hons)2 

The Foot and Ankle Online Journal 13 (1): 3

The aim of this study was to present patient reported outcomes (PROMS) and complications at 6 and 12 months following metatarsophalangeal joint (MTPJ) hemiarthroplasty with a synthetic cartilage hemi implant in patients with advanced MTPJ arthritic degeneration treated by a surgery team in the English National Health Service. Over a 12-month period between January 2016 and February 2017 a total of 20 patients underwent MTPJ hemiarthroplasty with a synthetic cartilage hemi implant. Patients were reviewed at both 6 and 12 months. All outcome data were collected using the PASCOM-10 audit database, an online resource which is able to report clinical and patient reported outcomes for selected cohorts. At 6 months, 65% of patients felt that their original complaint was now better or much better, while 4 patients (20%) felt their foot condition had deteriorated. At 12 months, 60% of patients felt better or much better and only 1 patient (5%) reported a deterioration in their foot condition. At 6 months 80% of patients felt that their original expectations from before surgery had been met or partly met and 95% reported they would be prepared to have surgery performed under the same conditions again; this reduced to 75% and 80% respectively by 12 months. The most common complication was joint pain and stiffness (60%) at 6 months, and 25% of the cohort had the implant revised to a joint destructive procedure by 12 months. Initial results for the synthetic cartilage hemi implant arthroplasty for the surgical treatment of advanced MTPJ arthritic degeneration were disappointing and did not compare well with previous studies. Although validated PROMS demonstrate a subtle improvement in health related quality of life and patient satisfaction at 6 months and 12 months, the results were not convincing and both complication and revision rates were high. 

Keywords: metatarsophalangeal, osteoarthritis, implant arthroplasty

ISSN 1941-6806
doi: 10.3827/faoj.2018.1301.0003

1 – Specialist Registrar in Podiatric Surgery, Nottinghamshire Healthcare NHS Foundation Trust, Department of Podiatric Surgery, Park House Health Centre.
2 – Consultant Podiatric Surgeon, Nottinghamshire Healthcare NHS Foundation Trust, Department of Podiatric Surgery, Park House Health Centre. 
* – Corresponding author: james.harmer@nottshc.nhs.uk

Historically arthrodesis for advanced arthritis of the 1st metatarsal phalangeal joint (MTPJ) was considered as the gold standard, with good reduction in pain and high patient satisfaction levels reported [1]. However, sacrificing the range of motion of the MTPJ following arthrodesis is not ideal, it can restrict footwear, interfere with activities that require joint motion, can lead to transfer metatarsalgia, and arthritic degeneration in adjacent joints [2]. A desire to preserve joint motion has prompted the development of several joint implants, unfortunately many have not lived up to expectations and have demonstrated high rates of failure as a result of loosening, malalignment, dislocation, subsidence, implant fragmentation, and bone loss [3-4]. The advancement of technology has led to the introduction of novel new implants one of which is the Cartiva® synthetic cartilage hemi implant arthroplasty (SCHIA) (Cartiva® Wright Medical Group N.V.). This is a polyvinyl alcohol (PVA) hydrogel MTPJ hemi implant. PVA has been used with great success in several different medical devices but it is particularly useful as a joint implant material as its viscoelasticity and tensile strength are very similar to healthy human articular cartilage [5-8]. 

Initial outcomes for the SCHIA appear promising, Buamhauer and colleagues in an industry funded prospective, randomised, multi-centred, clinical trial named ‘the Motion study’ followed 202 patients at two years and found the implant to be equivalent to 1st MTPJ arthrodesis for advanced hallux rigidus with the added advantage of maintaining dorsiflexion, reducing pain and having few safety concerns [9]. The study used 2:1 randomised allocation in favor of the implant group, 23% of the arthrodesis control group withdrew after initially consenting to randomisation, 152 implant patients and only 50 arthrodesis patients started the trail with a further 4% lost to follow-up by the end of the study. Although unfortunate, this disproportionate ratio of patients between the two groups may bias the results in favor of the implant group. A total of 11% of patients in the implant group underwent revision surgery with 9.2% of the implants failing and having to be converted to a 1st MTPJ arthrodesis. The root cause of the implant failure was not determined or discussed. Although implant patients’ VAS pain scores improved by >30% at 1 and 2 years follow-up these scores were higher than the MTPJ arthrodesis group at all time points, though not statistically significant. 

In a subset of 27 first MTPJ SCHIA patients followed up at five years, Daniel et al., showed an impressive 96% implant survivorship with only one implant having to be removed and converted to arthrodesis [10]. They also demonstrated continued improvements in function and pain scores over the five-year period compared to baseline scores for those patients with retained implants. Postoperative radiographs evaluation showed no bone loss, loosening or wear of the implant, and patient tolerance and satisfaction were high. They conclude that the SCHIA was a viable alternative to first MTPJ arthrodesis in the treatment of patients with advanced hallux rigidus, however generalizability of these results is limited, as only the first 43% of patients from the original RCT were evaluated, and no control group was included to compare results against. More recently the group have published their complete multi-centred midterm results for the SCHIA. They found that clinical and safety outcomes observed at two years were maintained at 5.8 years [11]. It is difficult to determine the relevance of these results as over 15% of patients were removed from the trial following revision to arthrodesis and it is unclear how a further 12% of patients progressed as they were lost to follow-up, hence results for almost a third of the original cohort were absent from the 5-year study.

Although not quite as common and certainly not as well covered in the literature as hallux rigidus lesser MTPJ degenerative joint disease can be equally debilitating and just as challenging for surgeons to treat [12]. Etiology can follow a similar course as a consequence of trauma, either acute or repetitive, and can lead to an interruption in the blood supply commonly affecting the 2nd metatarsal head, but any metatarsal can be affected resulting in avascular necrosis better known as Freiberg’s Infraction [12,13]. Freiberg’s is characterised radiographically by fissuring and fracture of the articular cartilage, leading to collapse and flattening of the metatarsal head, and finally resulting in severe arthritic degeneration of the joint, as described by Smillie in 1914 [13]. Surgical management is driven by the stage of the deformity and presence of arthritic degeneration. In advanced lesser MTPJ arthritic degeneration surgeons tend to shy away from arthrodesis and prefer to opt to maintain joint function with either excisional arthroplasty or implant arthroplasty [12]. The SCHIA is available in several sizes and although it has not received clearance in the USA for use in joints other than the 1st MTPJ, there is potential for it to be used as an alternative surgical option for advanced lesser MTPJ degeneration [14].    

The initial results from the MOTION study look promising, however further studies are still required to help substantiate their findings. The purpose of this study was to present patient reported outcomes and complications at 6 and 12 months following MTPJ SCHIA in patients with advanced MTPJ arthritic degeneration treated by a foot surgery team in the English National Health Service.  


A retrospective case series review of patients and their records was carried out at 6 and 12 months following MTPJ SCHIA. All patients over the age of 18 and who underwent surgery with the synthetic cartilage implant to address painful moderate to severe arthritic degeneration of an MTPJ, were included in the study. Patients with early MTPJ arthritic degeneration with minimal cartilage loss or those who had not previously received conservative care, or had marked transverse plane deformity were not offered surgery with the SCHIA. Over a 12-month period (Between January 2016 and February 2017) a total of 20 patients underwent MTPJ SCHIA. Surgical technique for SCHIA in the 1st MTPJ has previously been described in the literature [4,15].  Our surgical technique for implanting lesser MTPJ synthetic cartilage implants was no different except for the mobilisation of the sesamoid apparatus required in 1st MTPJ’s, all surgeries were combined with a dorsal joint cheilectomy. Surgeries were carried out under local anaesthesia with an ankle tourniquet by one of the department’s three surgeons. All patients were fit and healthy at the time of surgery and classed as either American Society of Anesthesiologists (ASA) 1 or ASA 2 [16] (Table 1). Mean Body Mass Index (BMI) was 27.9 ranging from (18.7 – 39.1) a third of the cohort had a BMI above 30. 

All patients underwent preoperative x-ray evaluation, patients diagnosed with hallux rigidus had their joint degeneration graded using the Coughlin and Shurnas classification system for hallux rigidus [17]. Patients diagnosed with lesser MTPJ degenerative disease were graded according to the Smillie classification system for Freiberg’s infraction [13] (Table 1). Subsequently seventeen 1st MTPJ, two 2nd MTPJ and one 3rd MTPJ hemi-arthroplasties were performed using a size appropriate synthetic cartilage implant. As long as wounds were healed patients returned to supportive footwear at two weeks and started a post-operative physiotherapy programme of 1st MTPJ strengthening and range of motion exercises.   Patients returned to the clinic on request and were reviewed by the authors at 6 months and 12 months following their surgical procedures. Governance approval for the study design was sought from Nottinghamshire Healthcare NHS Foundation Trust Research and Development Department.

All outcome data were collected using the PASCOM-10 audit database, an online resource which is able to report clinical and patient reported outcomes for selected cohorts [18]. PASCOM-10 benefits from the inclusion of a patient satisfaction questionnaire, the PSQ-10 [16]. For the measurement of patient-reported outcomes, PASCOM-10 uses the Manchester Oxford Foot/Ankle Questionnaire (MOXFQ), which is a validated measure of health-related quality of life (HRQOL) [19]. The MOXFQ assesses patient outcomes across 3 domains; pain, walking/standing, and social interaction with a maximum score of 100 in each domain. High scores signify poor HRQOL [20]. The PASCOM-10 system includes a reporting package, which was used to extract summary descriptive data for the cohort, this was then transferred into Microsoft Excel for further analysis. Descriptive statistics are presented throughout for demographic and outcome data. 

Minimal clinically important change (MCIC) scores were interrogated for all MOXFQ domains at each postoperative measurement point (6 months and 12 months). MCIC is an anchor based estimate of score change where a patient notices an actual, rather than statistical improvement in their foot health status. In the context of foot surgery, Dawson et al. [21] determined the MCIC estimate to be a 13-point score change across each of the 3 domains. 


All 20 patients completed preoperative MOXFQ questionnaires, 19 patients returned at six months and 18 patients returned at 12 months to complete postoperative MOXFQ, and patient satisfaction PSQ-10 questionnaires. Two patients (10%) were lost to follow-up at 12 months but the remaining 18 patients did return for a final review at a mean 18.95 months (range 11- 24 months). Only one case was a revision procedure following moderate 1st MTPJ degeneration after a hallux valgus correction with scarf and Akin osteotomies. MOXFQ scores improved at 6 months and a further improvement was recorded at 12 months across all three domains compared to baseline scores (See Figure 1). The MOXFQ score change at both 6 and 12 months exceeded the threshold for MCIC demonstrating an actual improvement in patients HRQOL (See Table 2). 

Demographics Measure Number Percentage %
ASA 1 8 40
ASA2 12 60
Female 17 85
Male 3 15
Mean Age 51 years
Age Range 35-72
Joint involvement Hallux Rigidus stage 2* 8 47
Hallux Rigidus stage 3* 8 47
Hallux Rigidus stage 4* 1 6
Lesser Metatarsal II** 2 67
IV** 1 33

Table 1 Patients diagnosed with lesser MTPJ degenerative disease were graded according to the Smillie classification system for Freiberg’s infraction. *Hallux Rigidus Classification (0-IV) Coughlin & Shurnas (2003). **Lesser Metatarsal – Smillie Classification (I-V).

Domain Pre-op 6/12 


Score change 12/12 


Score Change Minimal clinical important difference
Walking 67 47 20 33 34 16
Pain 80 45 35 32 48 12
Social  60 33 27 20 40 24
Mean PSQ-10 76 78

Table 2 Six- and 12-month follow-up: Summary of Mean MOXFQ and PSQ10 Scores.

Sequelae Number Percentage %
6 Months
Joint Pain & Stiffness 12 60
Swelling 2 10
Transfer Metatarsalgia 1 5
Implant failure revised to joint destructive procedure  3

1st MTPJ Arthrodesis

1st MTPJ Primus Implant

2nd MTPJ Interplex Rod

12 Months 
Joint restriction 4 20
Joint Pain & Stiffness 5 25
Implant failure revised to joint destructive procedure  2

1st MTPJ Arthrodesis 


Table 3 Six- and 12-month complications.

Figure 1 MOXFQ scores improved at 6 months and a further improvement was recorded at 12 months across all three domains compared to baseline scores.

Table 2, illustrates patient satisfaction scores recorded using the PSQ10 questionnaire at both 6 and 12 months, scores did meet the benchmark suggested for UK podiatric surgery of 75 and above [22]. Further descriptive data from the PSQ10 questionnaires demonstrated that at 6 months post operation, 65% of patients felt that their original complaint was now better or much better, while 4 patients (20%) felt their foot condition had deteriorated. At 12 months, 60% of patients felt better or much better and only 1 patient (5%) reported a deterioration in their foot condition. At 6 months 80% of patients felt that their original expectations from before surgery had been met or partly met and 95% reported they would be prepared to have surgery performed under the same conditions again, this reduced to 75% and 80% respectively by 12 months.

Within the first six months following surgery 12 patients, 60% of the cohort, had returned complaining of joint pain and stiffness and subsequently underwent MUA with intra-articular corticosteroid injection. Marked swelling was noted in two patients (10%), and one patient (5%) developed transfer metatarsalgia, there were no episodes of suspected or proven post-operative infection (See Table 3). Three implants failed and had to be revised to a joint destructive procedure in the first 6 months, this equated to 15% of the cohort and by 12 months the revision rate had risen to 25% a significantly higher figure than reported by the MOTION study. A further 25% of patients continued to experience pain and stiffness within the joint, and only 20% noticed an improvement in joint ROM at 12 months. Table 3 details the full list of complications recorded at 6 and 12 months following surgery.


In our study population, initial results for SCHIA in the surgical treatment of advanced MTPJ arthritic degeneration were suboptimal and not as good as previous studies stating positive outcomes in over 90% of patients [9-12]. Although validated PROMS demonstrate a subtle improvement in HRQOL and patient satisfaction at 6 months and 12 months, our results were not convincing and both complication and revision rates were high compared to the MOTION study group [9-11]. To our knowledge this is the first study to indicate suboptimal results for the SCHIA. 

Level I evidence from Baumhauer et al., demonstrated extremely promising results for the SCHIA. They found that clinical outcomes of pain, function and safety were equivalent to the gold standard 1st MTP joint arthrodesis, for treating advanced hallux rigidus at two-year follow-up, with the added advantage of improving joint dorsiflexion [9]. Two subsequent studies carried out by the MOTION study group showed these positive outcome scores were consistently maintained at 5.8 years when compared with those observed at two years [9-11]. The improvements from baseline exceeded the MCID for each outcome measure for the vast majority of patients at 5.8 years (90.5%-97.2%) [11]. 

It is difficult to directly compare our results to the previous studies as the study design, methodology and outcomes are dissimilar, however, it is still apparent that our early outcomes for SCHIA did not fare as well as the original study [9]. Within the first six months following surgery 12 patients (60% of the cohort) returned complaining of joint pain and stiffness and subsequently underwent MUA with an intra-articular corticosteroid injection. In a recent retrospective study of 60 patients undergoing 64 SCHIA’s for the management of stage 2-4 hallux rigidus yielded an overall neutral patient satisfaction, mild pain and dysfunction at an average follow up of 15.2 months [23]. Over half of their cohort had at least one injection of corticosteroid for joint pain postoperatively at 2 or more months after surgery, for a total of 79 injections and 82% of injections were given within the first year. As a consequence of our initial results we now routinely counsel patients about the risk of persistent pain and swelling and the potential need for a manipulation under anaesthetic with intra-articular corticosteroid injection within the first 6 months of surgery. 

The MOTION study noted few safety concerns at 2 or 5 years, with overall survivorship of the SCHIA reported to be 84.9% at 5.8 years [11]. Our study noted a lower implant survivorship of 75% at 12 months. Surgical revision rate was therefore high in-comparison with 25% of the cohort having the implant removed and converted to a joint destructive procedure as a result of persistent or recurrent joint pain and stiffness.

A 9.2% surgical revision rate and conversion to a 1st MTPJ arthrodesis at 24 months was reported by the MOTION study. Daniel et al., showed an impressive 96% implant survivorship with only one implant having to be removed and converted to arthrodesis [10]. It should be noted that this was a small subgroup of patients taken from the MOTION study followed up at 5 years, and therefore may not be a true representation of the original cohort. Glazebrook et al., did publish the complete midterm results for the MOTION study and, although there was a loss to follow-up of 17%, they reported a more realistic implant survivorship of 84.9% by 5.8 years [11]. Cassinelli et al., also found excellent implant survivorship of 92%, however they had a reoperation rate of 20% in their short-term follow-up study [23]. A third of patients underwent magnetic resonance imaging (MRI) postoperatively due to persistent pain. Revision surgery included implant removal and conversion to arthrodesis (5 patients), lysis of adhesions (4 patients), Moberg osteotomy (1 patient), and implant exchange with bone grafting for impinging soft tissue or implant subsidence (3 patients). It was not made clear if postoperative MRI imaging was helpful in determining if reoperation was necessary and whether it played a part in deciding whether to retain or remove the implant, but it is clear that this would have added a further expense to an already expensive procedure. A longer-term follow-up of these patients would be useful to evaluate the reoperation success rate and to determine how implant removal and arthrodesis compared with the less aggressive procedures, including implant exchange. All of our revision surgeries involved a joint destructive procedure of either MTPJ arthrodesis or total implant arthroplasty, intraoperatively in all cases the implant was found to have subsided below the cortical bone of the metatarsal head with resultant bony contact between the proximal phalanx and metatarsal head. Due to the advanced arthritic degeneration and the fact that the SCHIA had already failed, we felt that a joint destructive procedure would yield the most reliable surgical outcome for these patients.

Rothermel et al., carried out a systematic review of the available literature and compared the cost of SCHIA and 1st MTPJ arthrodesis. The total direct cost of MTPJ arthrodesis was $3632, using a conservative failure rate of 9.2% with subsequent conversion to MTPJ arthrodesis, the total cost of SCHIA was $4565. They concluded that significantly higher inclusive costs were associated with the SCHIA, and sensitivity analysis revealed that MTPJ fusion was more cost-effective even if the failure rate increased to 15% and SCHIA failure rate was 0% [24].

Other than secondary surgeries carried out for implant failure, the original prospective randomised study does not provide any other information on postoperative complications, nor does it give an explanation for implant failure [9]. Cassinelli et al., thought that implant failure was largely a result of the implant subsiding, they recommended only using SCHIA in patients with adequate bone stock and that leaving the implant prominent may reduce the risk of subsidence [23]. Given our study demographics that included 85% women with a mean age of 51, hence a high portion of our cohort were at high-risk of osteoporosis. This may offer some explanation for the high rate of implant subsidence and our high implant failure rate compared to other studies with a lower female to male ratio and age comparison [9-11]. 

In our study, all patients underwent six-month postoperative x-ray evaluation, typical findings showed marked narrowing of the joint space, proximal impaction of the synthetic cartilage implant into the head of the metatarsal and there was significant arthritic involvement of the sesamoid apparatus. Daniels et al., reviewed 23 of the 27 patients radiographs at five-year follow-up. They reported no signs of implant loosening or subsidence and no evidence of implant wear. Radiographs did show signs of further arthritic joint degeneration compared to baseline films, however none required further surgery [10].    

One of the main reasons patients choose a joint implant procedure over an arthrodesis is to maintain or improve function and joint ROM [2,3,4,8,9,10,11,25]. The MOTION study demonstrated a mean improvement of 27.3% in 1st MTPJ dorsiflexion at 24 months, these improvements in dorsiflexion were maintained at 5.8 years following surgery compared to baseline results [9-11]. In our study 60% of patients noticed an improvement in symptoms at 12 months, however only 20% of patients noticed an improvement in joint ROM, 80% had no improvement or a deterioration in joint ROM with the SCHIA. Cassinelli et al., reported that 14% of patients noticed a restriction in 1st MTPJ ROM postoperatively and were provided with a dynamic splinting device to aid postoperative rehabilitation and improve joint ROM. A further 19% were found to have restricted 1st MTPJ ROM intraoperatively and in these patients in addition to releasing the sesamoids they also added a Moberg dorsiflexion osteotomy of the proximal phalanx in an attempt to restore normal MTPJ ROM and kinematics, none of these patients complained of restricted joint ROM at short-term follow-up [23]. 

Another explanation for our suboptimal results may at least in some part be due to technical error. We feel that whilst being described as a joint resurfacing implant, in actual fact the synthetic cartilage implant has more of a buffer effect and if the Implant is inserted too deep within the metatarsal head there is a greater risk of subsidence due to the softer trabecular bone found in the metatarsal diaphysis. Leaving the Implant significantly prouder will not only reduce the risk of subsidence, as stated by Cassinelli et al., but also distend the joint and increase the implants buffer effect. We found that SCHIA limited the size of the dorsal metatarsal head exostectomy that could be taken, subsequently dorsal joint impingement was more likely, leading to reduced joint dorsiflexion and increased pain at end range of motion. Reducing the size of the implant or placing the implant more plantarly within the metatarsal head may address this issue, further studies on implant position and subsidence are needed. Finally, in advanced hallux rigidus, the sesamoids are often involved, showing significant hypertrophy on x-rays and clinically being ankylosed to the base of the metatarsal head, causing joint pain and stiffness. In our experience despite releasing the sesamoids intraoperatively, SCHIA does not address the sesamoid apparatus and continued plantar joint pain and stiffness was a recurrent issue in our cohort at 6 and 12 month follow-up. 

Limitations of this study lie with its single center retrospective design, small sample size, and short- term follow up, which undermines the reliability of these results. Due to the small cohort of patients we were unable to perform any statistical analysis and instead used descriptive analysis. The low patient numbers were because we quickly stopped using SCHIA to treat advanced arthritic degeneration of the MTPJ’s, as a consequence of cost and suboptimal results noted at early follow-up. We are unable to comment regarding mid to long-term results and perhaps patient satisfaction rates, complications and revision rates may all improve with time in our study population and measures have already been put in place to follow these patients up at 3 and 5 years. 

We acknowledge that combining the outcomes of the 1st MTPJ and lesser MTPJs may be a methodological error, as they are different pathologies and there is no equivalent of the 1st MTPJ sesamoid apparatus in the lesser MTPJs and, moreover, it is not typically salvageable by arthrodesis. However, reviewing the conditions separately would have reduced the numbers in the study further and we do not believe that combining the results in this case has detracted from the purpose of this study, which was to present our initial experience including patient reported outcomes and complications relating to MTPJ SCHIA. 

In conclusion, our initial results for the SCHIA were suboptimal, complication and revision rates were high and did not compare well with previous results published by the MOTION study group. From our experience, we would recommend judicious use of the SCHIA in the surgical treatment of patients with advanced MTPJ arthritic degeneration. We feel that further work around patient selection, implant positioning and subsidence is necessary. 


  1. Maher AJ, Metcalfe SA. First MTP joint arthrodesis for the treatment of hallux rigidus: results of 29 consecutive cases using the foot health status questionnaire validated measurement tool. Foot (Edinb). 2008;18(3):123-30
  2. Goldberg A, Singh D, Glazebrook M, Blundell CM, De Vries G, Le IL, Nielsen D, Pedersen ME, Sakellariou A, Solan M, Younger AS, Daniels TR, Baumhauer JF. Association between patient factors and outcome of synthetic cartilage implant hemiarthroplasty vs first metatarsophalangeal joint arthrodesis in advanced hallux rigidus: Foot Ankle Int. 2017;38(11):1199-1206
  3. Yee G, Lau J. Current concepts: hallux rigidus. Foot Ankle Int. 2008;29(6):637-646
  4. Younger ASE, Baumhauer JF. Polyvinyl alcohol hydrogel hemiarthroplasty of the great toe: Technique and indications: Tech Foot Ankle Surg. 2013;12(3):164-169
  5. Baker MI, Walsh SP, Schwartz Z, Boyan BD. A review of polyvinyl alcohol and its uses in cartilage and orthopedic applications. J Biomed Mater Res Part B Appl Biomater. 2012; 100(5):1451-1457
  6. Baumbauer JF, marcolongo M. The science behind wear testing for great toe implants for hallux rigidus. Foot Ankle Clin. 2016;21(4):891-902
  7. Noguchi T, Yamamuro T, Oka M, et al. Poly(vinyl alcohol) hydrogel as an artificial articular cartilage: evaluation of biocompatibility. J Appl Biomater. 1991;2(2):101-107
  8. Kobayashi M, Hyu HS. Development and evaluation of polyvinyl alcohol-hydrogels as an artificial articular cartilage for orthopaedic implants. Materials. 2010;3(1):2753-2771  
  9. Baumhauer JF, Singh D, Glazebrook M, Blundell C, De Vries G, Le ILD, Nielson D, Pedersen ME, Sakellariou, A, Solan M, Wansbrough G, Younder ASE, Daniels T. Prospective, Randomised, Multi-centered Clinical Trial Assessing Safety and Efficacy of a Synthetic Cartilage Implant Versus First Metatarsophalangeal Arthrodesis in Advanced Hallux Rigidus: Foot Ankle Int. 2016;37(5):457-469
  10. Daniels TR, Younger ASE, Penner MJ, Wing KJ, Miniaci-Coxhead SL, Pinsker E, Glazebrook M. Midterm outcomes of polyvinyl alcohol hydrogel hemiarthroplasty of the first metatarsophalangeal joint in advanced hallux rigidus: Foot Ankle Int. 2017; 38(3):243-247 
  11. Glazebrook M, Blundell CM, O’Dowd D, Singh D, de Vries G, Le IL, Neilson D, Pedersen M E, Sakellariou A, Solan M, Wansbrough G, Younger AS, Baumhauer JF, Daniels TR. Midterm Outcomes of a synthetic Cartilage Implant for the First Metatarsophalangeal joint in advanced hallux Rigidus.Foot Ankle Int. 2018;1-10
  12. Schade V L. Surgical Management of Freiberg’s Infraction. Foot Ankle Spec. 2015;8 (6): 498-519
  13. Smillie IS. Freiberg’s Infraction. Proc R Soc Med. Jan 1967;60(1):29-31
  14. De Cesar Netto C, et al. The use of polyvinyl alcohol hydrogel implants in the lesser metatarsal heads. Is it safely doable? A cadaveric study, Foot Ankle Surg (2019), https://doi.org/10.1016/j.fas.2018.12.009 
  15. Younger AS, Baumnauer JF, Glazebrook M. Polyvinyl alcohol hemiarthropathy for first metatarsophalangeal joint arthritis. current Orthopaedic Practice. 2013; 24(5):493 – 49
  16. Daabiss M. American Society of Anaesthesiologists physical status classification. Indian J Anaesth. 2011;2:111-115 College of Podiatry. PASCOM 10 – The Podiatry Audit Tool. 2016. http://www. pascom-10.com/. Accessed December 17th, 2018. 
  17. Coughlin MJ, Shurnas PS. Hallux rigidus grading and long-term results of operative treatment. J Bone Joint Surg Am. 2003;85-A(11): 2072-2088
  18. Rudge G, Tollafield D. A critical assessment of a new evaluation tool for podiatric surgical outcome analysis. Br J Podiatry. 2003;6:109-119. 
  19. Dawson J, Coffey J, Doll H, et al. A patient- based questionnaire to assess outcomes
of foot surgery: validation in the context
of surgery for hallux valgus. Qual Life Res. 2006;15:1211-1222. 
  20. Maher AJ, Kilmartin TE. An analysis of Euroqol EQ-5D and Manchester Oxford Foot Questionnaire scores six months following podiatric surgery. J Foot Ankle Res. 2012;5:17. 
  21. Dawson J, Boller I, Doll H, et al. Minimally important change was estimated for the Manchester-Oxford Foot Questionnaire after foot/ankle surgery. J Clin Epidemiol. 2014;67:697-705. 
  22. Maher & Wilkinson. Clinical Audit Report: Doncaster Podiatric Surgery Service. Podiatry Now. 2011;14(11):20-25.
  23. Cassinelli SP, Chen NP, Charlton TP, Thordarson DB. Early Outcomes and Complications of Synthetic Cartilage Implant for Treatment of Hallux Rigidus in the United States. Foot Ankle Int.2019; 13 (6):1-9
  24. Rothermel SD, King JL, Tupinio MT, Kempland CW, Juliano PJ, Aynardi MC. Cost Comparison of Synthetic Hydrogel Implant and First Metatarsophalangeal Joint Arthrodesis. Foot Ankle Spec.2019; 10 (6): 1-5
  25. Brodsky JW, ptaszek AJ, Morris SG. Salvage first MTP arthrodesis utilizing ICBG: clinical evaluation and outcome. Foot Ankle Int. 2000;21 (4):290-296

Radiographic changes in coronal alignment of the ankle joint immediately after primary total knee arthroplasty for varus knee osteoarthritis

by Ichiro Tonogai1*, Daisuke Hamada1, Koichi Sairyo1

The Foot and Ankle Online Journal 10 (2): 2

Objective: Total knee arthroplasty (TKA) is a common surgical procedure used to treat patients with high-grade varus knee osteoarthritis (OA). However, a change in alignment of the knee may cause radiographic problems in the ankle joint and secondary clinical complaints. The purpose of this study was to investigate radiographic changes in coronal alignment of the ankle joint immediately after primary TKA for varus knee OA.
Methods: In this study, 125 cases in 91 patients (30 case in 19 men, 95 cases in 72 women; mean age 74.2 years) who underwent TKA between 2009 and 2016 were enrolled. Weight-bearing  anterior-posterior (AP) radiographs of the lower extremity were taken preoperatively and 2 weeks after surgery. The hip-knee-ankle (HKA) angle, tibial plafond inclination (TPI), talar inclination (TI), and talar tilt (TT) were measured.
Results: Mean HKA, TPI, TI, and TT had decreased significantly by 2 weeks after surgery. Pearson correlation coefficient analysis showed that the change in HKA was correlated with changes in TPI and TI, the change in TPI was correlated with the changes in TI and TT, and the change in TI was correlated with the change in TT. Postoperative TT was significantly greater in the group with a preoperative HKA above 16° than in the group with a preoperative HKA below 16°. Postoperative TT was greater in the group with a postoperative HKA above 1.3° than in the group with a postoperative HKA below 1.3°.
Conclusion: Immediately after TKA for varus knee OA, correction of knee alignment had an impact on alignment of the ankle joint radiographically. Care is needed with regard to coronal alignment of the ankle joint when performing TKA in patients with an HKA above 16° and the target is HKA less than 1.3° during TKA.

Keywords: ankle joint, coronal alignment, total knee arthroplasty, varus, osteoarthritis

ISSN 1941-6806
doi: 10.3827/faoj.2017.1002.0002

1 – Department of Orthopedics, Institute of Biomedical Science, Tokushima University Graduate School, 3-18-15 Kuramoto, Tokushima 770-8503, Japan
* – Corresponding author: sairyokun@hotmail.com

Osteoarthritis (OA) of the knee is an orthopedic problem worldwide, and affects a large proportion of the elderly population [1, 2]. OA causes varus deformation in the knee joint, resulting in abnormal alignment in the coronal plane. Currently, total knee arthroplasty (TKA) is the procedure most commonly performed for varus knee OA [3-5] and has proven to be very successful in restoring the alignment of the lower extremities.

In TKA, it is desirable to have a line between the center of the femoral head and the center of the ankle through the center of the knee. Although the focus of TKA is on the knee joint [6-10], acute correction in the alignment of the knee joint during TKA can cause compensatory changes in neighboring joints, including the orientation of the ankle.

It has also been reported that foot and ankle problems might be a source of pain after TKA as a result of changes in alignment of the legs [11-14]. However, there is limited data on the impact of change in the mechanical axis of the lower extremity immediately after TKA.

The purpose of this study was to investigate radiographic changes in coronal alignment of the ankle joint immediately after TKA rather than during longer-term follow-up. Our hypothesis was that TKA for severe varus knee OA has an immediate rather than a delayed effect on coronal ankle joint alignment.


This retrospective study was approved by the Institutional Review Board at Tokushima University Hospital. The patients involved provided informed consent for this report. A total of 125 cases in 91 patients (30 cases in 19 men, 95 cases in 72 women) who underwent primary TKA for symptomatic varus knee OA between 2009 and 2016 were enrolled. The patients had a mean age of 74.2 ± 7.7 years and a mean body mass index of 29.2 ± 3.8 kg/m². Patients with a history or signs of previous ankle trauma or surgery, congenital or developmental deformities, or inflammatory arthritis were excluded.

To evaluate the coronal alignment of the ankle joint on weight-bearing AP radiographs of the lower extremity, the following parameters were measured preoperatively and 2 weeks after surgery: (1) hip-knee-ankle (HKA) angle, the angle between a line from the center of the femoral head to the center of the knee (mechanical axis of the femur) and a line from the center of the knee to the center of the ankle (mechanical axis of the tibia); (2) tibial plafond inclination (TPI), the angle between the tangent of the tibial plafond and the horizontal line; (3) talar inclination (TI), the angle between the tangent of the talar dome and the horizontal line; (4) talar tilt (TT), the angle between the tibial plafond and the talar dome, which was calculated from the difference between the TI and TPI (Figure 1A, 1B). A positive HKA angle indicated varus knee alignment and a negative angle indicated valgus knee alignment. Positive TPI and TI values, which indicate medial inclination, were used to define an angle opening to the medial aspect. Therefore, a medial angle was considered to indicate positive varus. A positive TT value, which indicated varus alignment of the ankle joint, was used to define an angle opening to the lateral aspect. Therefore, a lateral angle was considered to indicate positive varus. Measurements were made on three occasions by an independent orthopedic surgeon who was blinded to the patient’s clinical information and the purpose of the study. The average of the three measurements was calculated.

Figure 1 Radiographic parameters for evaluation of coronal alignment of the knee and ankle joint on standing whole-leg anteroposterior radiographs. A. (1) The hip-knee-ankle (HKA) angle is formed by a line from the center of the femoral head to the center of the knee and a line from the center of the knee to the center of the ankle. A positive angle indicates varus knee alignment. B. (2) The tibial plafond inclination is defined as the angle between the tangent of the tibial plafond line and the horizontal line. A positive value indicates medial inclination. (3) Talar inclination is defined as between the tangent of the upper talus and the horizontal line. A positive value indicates medial inclination. (4) Talar tilt is defined as the angle between the tibial plafond inclination and the talar inclination. A positive value indicates varus alignment of the ankle joint. The dashed line indicates the ground.

Statistical analysis

All statistical analysis was performed using SPSS software ver. 24.0 (SPSS Inc, Chicago, IL). All data are reported as the mean ± standard deviation. Paired t-tests were used to evaluate changes in values between before and after surgery. The radiologic indices of the two groups were statistically analyzed using the independent t-test. Pearson correlation coefficients were used to determine the relationship between changes in HKA, TPI, TI, and TT after TKA. Continuous variables were compared between the two groups using the Mann-Whitney U test. A p-value < 0.05 was considered to be statistically significant.


Preoperatively, 11 of 125 cases (8.8%) showed TPI (+), TI (+), and TT (-), indicating negative valgus TT (medial tilt), and 114 of 125 (91.2%) showed TPI (+), TI (+), and TT (+), indicating positive varus TT (lateral tilt). The orientation of the ankle joint became more parallel with the ground after TKA. Postoperatively, 17 of 125 cases (13.6%) showed a TPI (+), TI (+), and TT (-) pattern, 72 of 125 (57.6%) showed a TPI (+), TI (+), and TT (+) pattern, 7 of 125 (5.6%) showed a TPI 0, TI 0, and TT 0 pattern, 12 of 125 (9.6%) showed a TPI (-), TI (-), and TT (+) pattern, and 17 of 125 (13.6%) showed a TPI (-), TI (-), and TT (-) pattern (Table 1).


n (%)


n (%)

TPI (+), TI (+), TT (-) 11 (8.8%) 17 (13.6%)
TPI (+), TI (+), TT (+) 114 (91.2%) 72 (57.6%)
TPI 0, TI 0, TT 0 0 7 (5.6%)
TPI (-), TI (-), TT (+) 0 12 (9.6%)
TPI (-), TI (-), TT (-) 0 17 (13.6%)

Table 1 Preoperative and postoperative TPI, TI, and TT.

The mean HKA decreased from 15.4° ± 5.9° preoperatively to 1.2° ± 2.1° at 2 weeks postoperatively. The medial inclination of the distal tibial joint surface and the upper talus decreased after TKA. The mean TPI decreased from 11.0° ± 5.0° preoperatively to 2.8° ± 4.5° after postoperatively, and the mean TI and mean TT decreased from 13.4° ± 5.8° to 3.6° ± 5.3° and from 2.2° ± 2.4° to 0.8° ± 1.8°, respectively. HKA, TPI, TI, and TT decreased significantly between preoperatively and 2 weeks postoperatively (p < 0.05 for all four parameters; Table 2). Pearson correlation coefficient analysis showed that the change in HKA was correlated with the change in TPI (r = 0.500, p < 0.05) and TI (r = 0.480, p < 0.05), the change in TPI was correlated with the changes in TI (r = 0.870, p < 0.05) and TT (r = 0.260, p < 0.05), and the change in TI was correlated with the change in TT (r = 0.285, p < 0.05; Table 3).

  Preoperative Postoperative

(2 weeks after TKA)

Correction P value
HKA 15.4º ± 5.9º 1.2º ± 2.1º 14.4º ± 5.9º *P < 0.05
TPI 11.0º ± 5.0º 2.8º ± 4.5º 8.4º ± 5.1º *P < 0.05
TI 13.4º ± 5.8º 3.6º ± 5.3º 10.0º ± 5.0º *P < 0.05
TT 2.2º ± 2.4º 0.8º ± 1.8º 1.5º ± 1.9º *P < 0.05

*A statistically significant difference between preoperatively and postoperatively. Abbreviations: HKA, hip-knee-ankle; TPI, tibial plafond inclination; TI, talar inclination; TT, talar tilt

Table 2 Corrective changes in HKA, TPI, TI, and TT.

    r P value

of  HKA


of TPI

0.500 *P < 0.05

of  TI

0.480 *P < 0.05

of TT

0.065 P = 0.478

of  TPI


of TI

0.870 *P < 0.05

of TT

0.260 *P < 0.05

of TI


of TT

0.285 *P < 0.05

*Statistically significant difference between the two groups.

Table 3 Pearson correlation coefficient analysis of changes in HKA, TPI, TI, and TT.

Pearson correlation coefficient analysis also showed that the change in HKA was not correlated with the change in TT (r = 0.065, p = 0.478). However, the mean postoperative TT was significantly greater in the group with a preoperative HKA above 16° (HKA 20.4° ± 4.6°) than in the group with a preoperative HKA below 16° (HKA 11.2° ± 2.6°; TT 1.3° ± 1.9° and 0.7° ± 1.6°, respectively; p < 0.05; Table 4). The postoperative TT was greater in the group with a postoperative HKA above 1.3° (mean HKA 3.1° ± 1.3°) than in the group with a postoperative HKA below 1.3° (HKA -0.4° ± 1.3°; TT 1.4° ± 1.7° and 0.6° ±1.7°, respectively; p < 0.05; Table 5).


HKA ≥ 16º


HKA < 16º

P value
Number of feet n = 55 (44.0%) n = 70 (56.0%)


20.4º ± 4.6º 11.2º ± 2.6º  


1.3º ± 1.9º 0.7º ± 1.6º *P < 0.05

*A statistically significant difference between the two groups.

Table 4 Correlation between postoperative TT and preoperative HKA in the group with HKA 16° and the group with HKA < 16°.


HKA ≥ 1.3º


HKA < 1.3º

P value
Number of feet n = 57 (45.6%) n = 68 (54.4%)


3.1º ± 1.3º -0.4º ± 1.3º  


1.4º ± 1.7º 0.6º ± 1.7º *P < 0.05

*A statistically significant difference between the two groups (*P < 0.005).

Table 5 Correlation between postoperative TT and postoperative HKA in the group with HKA 1.3° and the group with HKA < 1.3°.


Preoperatively, the ankle joint orientation line (TPI and TI) in all cases in this study was varus with respect to the ground line. Postoperatively, the ankle joint orientation line was close to parallel with the ground line and the TT was decreased. The change in alignment of the knee joint had a significant effect on alignment of the ankle immediately after TKA, rather than having a delayed effect seen only during long-term follow-up. However, in many cases, the medial inclination of TPI and TI and varus TT remained 2 weeks after surgery.

In our study, postoperative TT was significantly greater in the group of cases with a preoperative HKA above 16° (n = 55, 44.0%) than in the group with a preoperative HKA below 16° (n = 70, 56.0%). This finding indicates that the group with a preoperative HKA above 16° was significantly more likely to continue to have a positive TT (varus ankle joint) even after TKA. The postoperative TT was greater in the group with a postoperative HKA above 1.3° (n = 57, 45.6%) than in the group with a postoperative HKA below 1.3° (n = 68, 54.4%). Our study showed that the group with postoperative HKA above 1.3° was also significantly more likely to continue to have a positive TT (varus ankle joint) even after TKA. Therefore, we recommend a cautious approach to coronal ankle joint alignment when performing TKA for severe varus knee OA, especially when the HKA is above 16°. Gursu et al. reported that leaving residual varus in the knee could be considered in order to prevent malalignment of the ankle joint [14], but we suggest aiming for an HKA below 1.3° during TKA.

An important strength of this study is its large sample size when compared with other studies. It is very difficult to retain such a sample size for the duration of a study. The outcomes evaluated in our study provide important information regarding alignment of the ankle joint immediately after TKA. To our knowledge, this is the first report to demonstrate that TKA for severe varus OA knee has an effect on coronal alignment of the ankle joint immediately rather than gradually.

One limitation of this study was that subtalar joint mobility was not investigated and radiologic assessment of hindfoot alignment was not performed. Alignment of the hindfoot changes when alignment of the knee joint changes [15, 16]. Most of the compensation for angular deformity of the knee joint occurs in the subtalar joint [17]. When varus knee with limited subtalar joint motion loses the compensatory function of the subtalar joint, varus deformity of the knee is compensated by valgus alignment of the ankle joint [12, 17, 18]. In this study, 11 of 125 cases (8.8%) showed varus of the ankle joint, which means a TPI (+), TI (+), and TT (-) pattern. In these cases, subsequent foot/ankle pain or disability may occur after TKA because the subtalar joint may not be able to reorient itself after knee realignment because of rigid hindfoot deformity.

Another limitation was that the results were based only on radiologic assessment two weeks after TKA without clinical assessment. It is possible that realignment of the knee joint effects symptoms in the ankle joint after TKA [19-24]. Moreover, the acute change in alignment of the ankle joint, together with the changes in the biomechanics of the ankle joint, changes the contact area of the tibiotalar joint and consequently contributes to increasing pressure on articular cartilage and accelerated degeneration of the ankle joint [25]. When degenerative changes and angular deformities of the knee are severe, a varus deformity is usually three-dimensional and associated with flexion contracture of the knee, and the varus angle measured on radiographs may not be a true varus angle [26, 27].

In conclusion, the change in alignment of the knee joint by TKA for varus knee OA influenced the alignment of the ankle joint immediately after surgery in this study. Examination and assessment are required not only at the knee joint but also at the ankle joint before TKA. More careful follow-up of the ankle after TKA should be considered when TKA is performed in patients with HKA above 16° and the aim should be to keep HKA below 1.3° during the procedure.


Conflicts of Interest and Source of Funding

No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. No funds were obtained in support of this study.

Funding declaration: No funds were obtained in support of this study.

Conflict of interest declaration: No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.


  1. Blazek K, Favre J, Asay J, Erhart-Hledik J, Andriacchi T. Age and obesity alter the relationship between femoral articular cartilage thickness and ambulatory loads in individuals without osteoarthritis. J Orthop Res. 2013;32(3):394–402.
  2. Prieto-Alhambra D, Judge A, Javaid MK, Cooper C, Diez-Perez A, Arden NK. Incidence and risk factors for clinically diagnosed knee, hip and hand osteoarthritis: influences of age, gender and osteoarthritis affecting other joints. Ann Rheum Dis. 2014;73(9):1659–64.
  3. Harding P, Holland AE, Delany C, Hinman RS. Do activity levels increase after total hip and knee arthroplasty? Clin Orthop Relat Res. 2013;472(5):1502–11.
  4. Chen JY, Yeo SJ, Yew AK, Tay DK, Chia SL, Lo NN, et al. The radiological outcomes of patient-specific instrumentation versus conventional total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc. 2014;22(3):630–5.
  5. Iacono F, Bruni D, Bignozzi S, Colle F, Marcacci M. Does total knee arthroplasty modify flexion axis of the knee? Knee Surg Sports Traumatol Arthrosc. 2014;22(8):1728–35.
  6. Daniilidis K, Tibesku C. Frontal plane alignment after total knee arthroplasty using patient-specific instruments. Int Orthop. 2013;37(1):45–50.
  7. Keyes BJ, Markel DC, Meneghini RM. Evaluation of limb alignment, component positioning, and function in primary total knee arthroplasty using a pinless navigation technique compared with conventional methods. J Knee Surg. 2013;26(2):127–32.
  8. Thienpont E, Paternostre F, Pietsch M, Hafez M, Howell S. Total knee arthroplasty with patient-specific instruments improves function and restores limb alignment in patients with extra-articular deformity. Knee. 2013;20(6):407–11.
  9. Paternostre F, Schwab PE, Thienpont E. The difference between weight-bearing and non-weight-bearing alignment inpatient-specific instrumentation planning. Knee Surg Sports Traumatol Arthrosc 2014;22(3):674–9.
  10. Luyckx T, Vanhoorebeeck F, Bellemans J. Should we aim at under correction when doing a total knee arthroplasty? Knee Surg Sports Traumatol Arthrosc 2015;23(6):1706–12.
  11. Tallroth K, Harilainen A, Kerttula L, Sayed R. Ankle osteoarthritis is associated with knee osteoarthritis. Conclusions based on mechanical axis radiographs. Arch Orthop Trauma Surg. 2008;128(6):555–60.
  12. Lee JH, Jeong BO. Radiologic changes of ankle joint after total knee arthroplasty. Foot Ankle Int. 2012;33(12):1087–92.
  13. Choi W, Yang JH, Park JH, Yun HH, Lee YI, Chae JE, et al. Changes in coronal alignment of the ankle joint after high tibial osteotomy. Knee Surg Sports Traumatol Arthrosc. December 19, 2015. doi: 10.1007/s00167-015-3890-3.
  14. Gursu S, Sofu H, Verdonk P, Sahin V. Effects of total knee arthroplasty on ankle alignment in patients with varus gonarthrosis: Do we sacrifice ankle to the knee? Knee Surg Sports Traumatol Arthrosc. 2016;24(8):2470–5.
  15. Chandler JT, Moskal JT. Evaluation of knee and hindfoot alignment before and after total knee arthroplasty: a prospective analysis. J Arthroplasty. 2004;19(2):211–6.
  16. Mullaji A, Shetty GM. Persistent hindfoot valgus causes lateral deviation of weightbearing axis after total knee arthroplasty. Clin Orthop Relat Res. 2011;469(4):1154–60.
  17. Norton AA, Callaghan JJ, Amendola A, Phisitkul P, Wongsak S, Liu SS, et al. Correlation of knee and hindfoot deformities in advanced knee OA: compensatory hindfoot alignment and where it occurs. Clin Orthop Relat Res. 2015;473(1):166–74.
  18. Takenaka T, Ikoma K, Ohashi S, Arai Y, Hara Y, Ueshima K, et al. Hindfoot alignment at one year after total knee arthroplasty. Knee Surg Sports Traumatol Arthrosc. 2016;24(8):2442–6.
  19. Tetsworth K, Paley D. Malalignment and degenerative arthropathy. Orthop Clin North Am. 1994;25(3):367–77.
  20. Cooke TD, Harrison L, Khan B, Scudamore A, Chaudhary MA. Analysis of limb alignment in the pathogenesis of osteoarthritis: a comparison of Saudi Arabian and Canadian cases. Rheumatol Int. 2002;22(4):160–4.
  21. Guichet JM, Javed A, Russell J, Saleh M. Effect of the foot on the mechanical alignment of the lower limbs. Clin Orthop Relat Res. 2003;415:193–201.
  22. Desmé D, Galand-Desmé S, Besse JL, Henner J, Moyen B, Lerat JL. [Axial lower limb alignment and knee geometry in patients with osteoarthritis of the knee]. Rev Chir Orthop Reparatrice Appar Mot. 2006;92(7):673–9. French.
  23. Mizuuchi H, Matsuda S, Miura H, Higaki H, Okazaki K, Iwamoto Y. The effect of ankle rotation on cutting of the tibia in total knee arthroplasty. J Bone Joint Surg Am. 2006;88(12):2632–6.
  24. Gao F, Ma J, Sun W, Guo W, Li Z, Wang W. The influence of knee malalignment on the ankle alignment in varus and valgus gonarthrosis based on radiographic measurement. Eur J Radiol. 2016;85(1):228–32.
  25. Tarr RR, Resnick CT, Wagner KS, Sarmiento A. Changes in tibiotalar joint contact areas following experimentally induced tibial angular deformities. Clin Orthop Relat Res. 1985;199:72–80.
  26. Cooke D, Scudamore A, Li J, Wyss U, Bryant T, Costigan P. Axial lower-limb alignment: comparison of knee geometry in normal volunteers and osteoarthritis patients. Osteoarthritis Cartilage. 1997;5(1):39–47.
  27. Hunt MA, Fowler PJ, Birmingham TB, Jenkyn TR, Giffin JR. Foot rotational effects on radiographic measures of lower limb alignment. Can J Surg. 2006;49(6):401–6.