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The clinical and patient centered outcomes following surgical correction of tailor’s bunion in an acute hospital based podiatric surgery service

Posted on December 31, 2020 | Comments Off on The clinical and patient centered outcomes following surgical correction of tailor’s bunion in an acute hospital based podiatric surgery service

by Syarifah Wilson1*, BSc. MSc. MChS.; James Cowden1 BSc. MSc. MChS. FCPodS

The Foot and Ankle Online Journal 13 (4): 13

This paper presents the results of the clinical and patient reported outcomes of patients following fifth metatarsal scarf osteotomy performed for correction of tailor’s bunion deformities utilizing the Manchester Oxford Foot Questionnaire (MOXFQ), Patient Satisfaction Questionnaire-10 (PSQ-10) and radiographic analysis. The electronic records of 24 patients (25 feet) were reviewed retrospectively after they had undergone the procedure between 2014 and 2018. Student paired t-test was used to compare pre- and postoperative outcomes from the MOXFQ and fourth-fifth intermetatarsal angle (4-5 IMA) and fifth metatarsophalangeal joint angle (5-MTPA). Differences were considered statistically significant if the probability of the null hypothesis was less than 0.05. A 95% confidence interval was observed for MOXFQ and radiographic measurements. For PSQ-10, a thematic analysis was undertaken to identify patterns of important themes in question 1 responses data and a quantitative descriptive design was applied to question 2 to 10 numerical data scores. A significant reduction in all three MOXFQ domains was observed: scores of walking/standing (W/S) 54.7 to 20.2; pain (P) 60.4 to 22.2 and social interaction (SI) 50.4 to 6.7. A 95% confidence interval for the difference was given for MOXFQ scores: 22.786, 46.254 (W/S); 29.507, 46.893 (P) and, 34.534, 52.826 (SI). The mean preoperative 4-5 IMA was 11.6° and 5-MTPA measurement was 19.8°; the mean postoperative 4-5 IMA was 5.7° and 5-MTPA was 8.0°. The p-values for the W/S, P and SI differences and radiographic evaluations were <0.001. PSQ-10 scored 88.0 and 96% recorded ‘pain relief’ in patient’s expectation. There were 6 cases (24%) of surgical sequelae. This service review indicated high levels of patient satisfaction with the procedure and a relatively low number of complications. From a clinical point of view, it allows a greater amount of correction in transverse and sagittal planes variants and is inherently stable amenable to two screws fixation.

Keywords: tailor’s bunion, scarf osteotomy, MOXFQ, PASCOM-10, PSQ- 10

ISSN 1941-6806
doi: 10.3827/faoj.2020.1304.0013

1 – Sheffield Teaching Hospitals NHS Foundation Trust
* – Corresponding author: Syarifah.Wilson@nhs.net

Tailor’s bunion, also known as bunionette or digitus quintus varus, is a pathological deformity of the fifth metatarsophalangeal joint (MTPJ), characterised by a bony protuberance of the lateral aspect of the fifth metatarsal head [10]. The classification of tailor’s bunion by Coughlin in 1991 is based on standard weight-bearing radiographic measurements [8]. Coughlin [14] defined the three types of tailor’s bunion as:

  • Type 1: A lateral exostosis of the fifth metatarsal head (dumbbell-shaped)
  • Type 2: Lateral bowing of the distal aspect of the fifth metatarsal shaft
  • Type 3: Increased fourth-fifth intermetatarsal angle (4-5 IMA), of more than 10° for patients with symptomatic tailor’s bunion
  • Type 4: Added on by DiDomenico in 2013, describes patients with a combination of deformities; including 2 or more combinations of the above.

The pathophysiology of tailor’s bunion is multifactorial attributed to both its anatomical and biomechanical variations and therefore, understanding and characterising each component of the deformity is key to treating it successfully [24]. Although tailor’s bunion is not analogous to hallux abducto valgus (HAV) in its etiopathogenesis, both deformities can frequently occur concomitantly; known as splayfoot deformity [17,36]. However, the diagnosis of tailor’s bunion is often overlooked when patients present with HAV as their main complaint [13].

First line conservative treatments of the pathology include footwear alteration, use of orthoses, oral/topical analgesics and corticosteroid injection [43]. Surgical intervention may be considered if symptoms remain persistent despite conservative management and/or when the disease progresses to its more severe form. Different procedures have been suggested and reported for the tailor’s bunion with varying outcomes. Similar to the surgical management of HAV, osteotomies of the fifth metatarsal can be grouped into proximal, mid shaft or distal, depending on the severity of deformity [3]. Some of these corrective measures range from a simple lateral fifth metatarsal head exostectomy for early stages of the deformity to osteotomies and lastly, in cases of unreconstructable deformities may require a fifth metatarsal head resection [34,40].

As with any surgical procedure, there are advantages and disadvantages. For less severe tailor’s bunion deformities, distal osteotomies are beneficial and, owing to the increased blood supply at this location, have lesser risk of delayed and/or non-union [29]. In contrast, proximal osteotomies are effective in correcting deformities with a 4-5 IMA which exceeds 9° and provides greatest satisfaction score but disadvantages would include inherent instability of the location of the osteotomy, disruption of intra- and extraosseous blood supply of the metatarsal, and technical demand [43]. Similar to proximal osteotomies, diaphyseal osteotomies have also been found to achieve a greater 4-5 IMA correction and allows a triplanar correction [5]. Furthermore, diaphyseal osteotomies have more bone to bone surface thereby allowing fixation without compromising the vascular supply [5,25].

Procedure

Within the Sheffield Teaching Hospital National Health Services Foundation Trust (STH NHSFT) Department of Podiatric Surgery, the fifth metatarsal scarf osteotomy is routinely performed for the correction of tailor’s bunions of varying intermetatarsal angles. It is a diaphyseal osteotomy originally developed by Weil as the “Reverse scarf” and later popularised by Barouk [2,42]. The procedure in STH NHSFT was performed by three podiatric surgeons; a Consultant and two Registrars. The two Registrars had undertaken their surgical training with the Consultant and it is therefore hoped that this would minimise the commonly occurring variations in surgical approach/technique [32].

The surgical technique performed is similar to that described by Maher and Kilmartin (2010) whereby the osteotomy is fixed with two countersunk 2.0mm cortical screws (Figure 1) [25].

Figure 1 Pre- and postoperative demonstration of surgical technique.

Summary of Surgical Technique

  1. The procedure is carried out under regional anesthesia block with the use of an ankle tourniquet.
  2. A linear longitudinal skin incision is made down the lateral border of the fifth metatarsal, with a double elliptical incision over the fifth metatarsal head.
  3. Sharp and blunt dissection is undertaken maintaining hemostasis.
  4. Double elliptical lateral capsular incision is performed.
  5. The tissue is reflected from the dorsal and plantar metatarsal and the fifth MTPJ exposed.
  6. Lateral eminence is removed with a sagittal saw.
  7. A longitudinal cut to the metatarsal shaft is made with a slight dorsal inclination through both the lateral and medial cortices.
  8. A perpendicular cut is made transversely across the metatarsal dorsally at the distal end.
  9. An oblique cut is made transversely across the metatarsal plantarly at the proximal end.
  10. The metatarsal head is internally rotated about a proximal axis whilst preserving its length and temporarily held with a bone clamp.
  11. When satisfied with the position, two bicortical holes are drilled, countersunk and measured.
  12. Permanent fixation is applied utilizing two DePuy Synthes 2.0mm cortical screws.
  13. Stability is assessed versus distraction in all planes.
  14. Lateral overhang is removed with a sagittal saw.
  15. Deep tissue closure is undertaken with 3/0 vicryl and the skin with a 4/0 monocryl.
  16. Dressings are applied and postoperative shoe worn. Patients are allowed to partially ambulate on the heel of the operated foot with crutches for 2 weeks.
  17. Patients are reviewed at 2 weeks postoperatively for suture removal and transfer into supportive footwear.

Materials and Methods

This was a single-center retrospective service evaluation which reviewed the outcome of 24 patients (25 feet) who underwent a fifth metatarsal scarf metatarsal osteotomy between 2014 and 2018. This paper utilizes existing surgical audit data generated by and extracted from the Podiatric Audit of Surgery and Clinical Outcome Measurement (PASCOM-10). This online database is registered to the STH Podiatric Surgery Unit. Any PASCOM-10 reports with incomplete Manchester Oxford Foot Questionnaire (MOXFQ) and Patient Satisfaction Questionnaire (PSQ-10) data have been excluded.

The two functional outcome scoring instruments used within PASCOM-10 for this service evaluation were:

i) the MOXFQ; captured on the day of surgery and, at six months’ final check postoperative appointment.

ii) the PSQ-10, taken at the final six months follow up (no pre-treatment component for this domain).

Both MOXFQ and PSQ-10 are two powerful Patient Reported Outcome Measures (PROMs) instruments as they provide an insight into patient experiences of pain and foot function as well as an overall indication of the surgical outcomes [28]. The MOXFQ contains 16 items, each with five response options consisting of three underlying domains: Walking/Standing (W/S) (seven items), Pain (P) (five items), and Social Interaction (SI) (four items). Similar to a Likert scale, each item response is scored from 0 to 4; where the highest value denotes the most severe state and therefore, lower scores in each domain in the postoperative MOXFQ are indicative of positive patient outcomes [11]. The three domains scales have gone through extensive testing and have shown to have excellent psychometric properties in terms of reliability, validity and responsiveness, and is comparable to other known instruments such as American Orthopaedic Foot and Ankle Score (AOFAS) and Short-Form health survey questionnaire-36 [11,12].

In comparison to the MOXFQ, the PSQ-10 has yet to be formally tested for its validity, however, the instrument has been chosen for use in PASCOM-10 due to its reliability and repeatability [27,39]. The PSQ-10 asks patients a series of 10 questions relating to their experience of an episode of care. In question 1, it outlines the reason why the patient had sought treatment from the services. For this section of the questionnaire, there is no scoring attached and therefore, not included in the final scoring of the patient satisfaction. For question 2 to 10, these questions are in a fixed-response format with a maximum score of 100 to indicate satisfaction while scores below 70 are indicative of poor surgical outcomes and patient satisfaction [45].

A quantitative descriptive design was applied to the numerical data scores obtained from MOXFQ and PSQ-10 question 2 to 10 and radiographic evaluations. This allows for application of student paired t-test utilizing IBM Statistical Package for Social Sciences (SPSS) 24.0 to compare the MOXFQ as well as fifth MTPJ angle (5-MTPA) and 4-5 IMA measurements pre- and 6 months postoperative. The first question of the PSQ-10 is distinguished from the rest of the questionnaire as it incorporates a free text response space for patients to articulate their expectations from the treatment. Therefore, a qualitative approach was required for further analysis of the answers and to identify patterns of important themes in the responses data. Incorporation of this qualitative analysis of such statements contributes to the evaluation of the service [1].

Essential data collection on PASCOM-10 begins when patients are listed for surgical treatment. The start of an episode commences with a referral and finishes with a discharge [6]. Each patient may require multiple episodes recorded and, in the event of a revision surgery, a new treatment episode would be required. Should there be any postoperative events such as sequela i.e., complications, clinicians are required to record these data onto PASCOM-10 as part of their routine practice. The data metrics used for this study have all been obtained from patients exclusive to the STH Podiatric Surgical unit; who have all been informed of, and consented to their data being potentially used for educational or research purposes. Consenting patients would complete their MOXFQ and PSQ-10 forms before the data is transferred onto PASCOM-10. To ensure unsolicited answers are obtained, the questionnaires are generally completed in the outpatient waiting room following the consultation whereby they were listed for surgery.

For the MOXFQ scores, a hypothesis test was set up as the following below;

● H0 (null): There is no effect of the procedure on MOXFQ W/S,P and SI

● H1 (alternate): There is an effect of the procedure on MOXFQ W/S, P and SI

The decision to reject the null hypothesis (H0) or fail to reject was based on the p-value. Differences were considered statistically significant if the probability of the null hypothesis given the data was less than 0.05.

Figure 2 Pre- and postoperative A/P radiograph of fifth metatarsal scarf osteotomy with concurrent procedure scarf and Akin osteotomy.

A 95% confidence interval was observed for MOXFQ as it provides a statement on the level of confidence that the true value for a population lies within a specified range of values [38].

Radiographic Data Collection

Anteroposterior (A/P) weight-bearing radiographic measurements were obtained at pre- and postoperatively at 2 weeks. The radiographic evaluation, reviewed by the first author, compared the pre- and postoperative 5-MTPA and the 4-5 IMA. The 5-MTPA was measured by bisecting the fifth metatarsal shaft and the shaft of the fifth proximal phalanx and the 4-5 IMA was measured utilizing the traditional technique of bisecting the long axes of the fourth and fifth metatarsal shafts. These measurement techniques were preferred as they were found to be both reliable and reproducible in comparison to others such as the modified version by Fallat & Buckholz [16,37]. The average 4-5 IMA in normal patients has been reported to be 6.4 to 9.1 degrees and 8.7 to 10.8 degrees in symptomatic tailor’s bunion [9,30]. The 5-MTPA was determined to be 10.2° varus in normal feet and 16.6° varus in symptomatic tailor’s bunions [30].

It is recognised and accepted by the study that the preoperative x-ray films are weightbearing and the postoperative are non-weight bearing. This could lead to an inaccuracy in the angular improvement in the surgery which is one of the shortfall of this aspect of the study.

Results

At the time of surgery, as displayed on Table 1, the mean age was 44; range 19-74 years old (y/o). 21 (84%) patients were female, and 4 (16%) were male. The majority of the sample were females (N=21) with an average age of 43.6 y/o (1.dp) and a standard deviation (SD) of 17.9. There were 4 males who had the procedure with an average age of 44.5 y/o (1.dp) and SD of 24.3. An age range of 25-29 y/o showed to have the highest percentage (20%) of patients with 4 females and 1 male.

Age Range Male (N) Male (%) Female (N) Female (%) Total (N) Total (%)
15-19 0 0% 2 8% 2 8%
20-24 1 4% 1 4% 2 8%
25-29 1 4% 4 16% 5 20%
30-34 0 0% 1 4% 1 4%
35-39 0 0% 0 0% 0 0%
40-44 0 0% 3 12% 3 12%
45-49 0 0% 3 12% 3 12%
50-54 1 4% 2 8% 3 12%
55-59 0 0% 0 0% 0 0%
60-64 0 0% 2 8% 2 8%
65-69 0 0% 0 0% 0 0%
70-74 1 4% 3 12% 4 16%
Total 4 8% 21 84% 25 100%
Average 44.50

≈ 45

 43.62

≈ 44

 43.76

≈ 44

Table 1 Patient demographics.

Table 2 demonstrates that 5 patients underwent additional procedures at the same time as the tailor’s bunion repair. One patient (4%) had one concurrent procedure and 4 patients (16%) had two additional concurrent procedures. These additional procedures included HAV repair by scarf and Akin osteotomies; repair of lesser toes deformities: hammer toes by 2nd, 4th and 5th digit excisional arthroplasty and a Lapidus procedure for treatment of concurrent hypermobile HAV. Patients’ health status was summarised by the American Society of Anaesthesiologists (ASA). ASA grade 1 accounted for 80% of patients and ASA grade 2 accounted for the remaining 20% which suggests that the patients who had the procedure were generally normal and healthy with only mild systemic diseases.

Count (N) Count (%)
Total no. of procedures 25 100%
ASA Grade 1 20 80%
ASA Grade 2 5 20%
Patients receiving ≥ procedure 5 20%
Patient (s) receiving 1 concurrent procedure 1 4%
Patient (s) receiving 2 concurrent procedure 4 16%
Additional concurrent procedure (s):
scarf and Akin osteotomy 3 12%
Arthrodesis 1st MTPJ 1 4%
Excisional arthroplasty 2nd digit 2 8%
Excisional arthroplasty 4th digit 1 4%
Excisional arthroplasty 5th digit 1 4%
Lapidus 1st metatarsal-cuneiform joint 1 4%

Table 2 Summary of procedure (s) performed / ASA grades.

PASCOM-10 Surgical Treatment Event Count (N) Count (%)
Patients recorded as Discharged 18 72%
Patient not recorded as Discharged 7 28%
Total no. of sample 25 100%
No observed sequella 10 40%
Procedure related complications: (resolved and discharged in all cases) 6 24%
Thickened scar line or painful (SCR) Pain: Scar line hypertrophy / Keloid may not be painful 5 20%
Pain at site of surgery (PNSS): Surgical site beyond six weeks 1 4%
Non-related procedure complications 2 8%
Wound dehiscence recorded for Arthroplasty of 4th distal interphalangeal joint (IPJ) 1 4%
Iatrogenic: Surgery failed e.g recurrence, floating toe, hallux varus recorded for Athroplasty of 2nd proximal IPJ 1 4%
Total no. of patients who had complications 8 25%

Table 3 Surgical Sequelae recorded postoperative.

Any complications recorded at the end of postoperative period on PASCOM-10 is summarised in Table 3. 18 patients (72%) were discharged, of which, 10 (40%) had no postoperative sequelae; 6 (24%) patients had complications relating to the fifth metatarsal scarf osteotomy and; 2 (8%) patients had complications that were not related to the procedure. All 8 (32%) patients who presented with complications have been recorded as discharged. However, clinical decision status for 7 (28%) patients were not recorded thereby, it was unclear if these patients were discharged with or without any complications.

Responsiveness of MOXFQ

As shown on Table 4, the p-values (two-sided) for the W/S, P and SI differences are all <0.001. Therefore, in each domain, the authors have observed a highly significant pre-post difference. The null hypothesis of no effect can thus be rejected in all domains. In the W/S domain, the mean pre-MOXFQ score was 54.7 (SD 21.3), the post-MOXFQ score reduced to 20.2 (SD 27.6). For the P domain, score was reduced from 60.4 (SD 17.9) to 22.2 (SD 21.4) and in the SI category, 50.4 (SD 19.5) to 6.7 (SD 11.2) respectively. A 95% confidence interval for the difference was given by (22.786, 46.254) in W/S; (29.507, 46.893) in P and; (34.534, 52.826) in SI.

Responsiveness of PSQ-10

The mean PSQ-10 score in Table 5 for the cohort was 88.08 with the majority of patients (88%) scoring between 81 and 100 which suggests that good surgical outcomes can be achieved with the fifth metatarsal scarf osteotomy.

The majority of patients (96%) as shown in Table 6 recorded ‘pain relief’ in their response. ‘Improved mobility’ accounted for 16% and ‘better footwear’ 8%. ‘Improved cosmesis’ and ‘Others’ counts occurred less commonly, accounting for 4% respectively.

MOXFQ scores with associated difference scores, 95% confidence interval and p-values.
Domain Pre-mean Pre-SD Post-mean Post-SD Difference Mean Difference SD 95% Confidence interval P-value
W/S 54.68 21.268 20.16 27.559 34.520 28.427 (22.786, 46.254) <0.001
P 60.40 17.907 22.20 21.413 38.200 21.059 (29.507, 46.893) <0.001
SI 50.36 19.506 6.68 11.190 43.680 22.156 (34.534, 52.826) <0.001

Table 4 Summary of MOXFQ scores with associated difference scores, 95% confidence interval and p-values.

Figure 3 Pre/post op comparative MOXFQ distribution. The graph illustrates a significant improvement across the three MOXFQ domains of W/S,P and SI following the procedure. Higher scores in preoperative MOXFQ scores denote greater severity.

Band Count (N) Count (%)
1-10
11-20
21-30
31-40
41-50
51-60 1 4%
61-70
71-80 2 8%
81-90 7 28%
91-100 15 60%
Total sample size 25 100%
Mean PSQ-10 Scores 88.08

Table 5 PSQ-10 Score distribution.

Pain relief Improved mobility Better footwear Improved cosmesis Others
24 (96%) 4 (16%) 2 (8%) 1 (4%) 1 (4%)

Table 6 Total counts for each PSQ010 question 1 response (percentage of all themes).

Question 2-10 n. %
Qn. 2 Patient who stated the risks and possible complications of surgery have been explained to them prior to surgery 25 100%
Qn. 3 Patients who stated they know what to do should a problem arise after postoperatively 25 100%
Qn. 4 Patients who stated they have had problems postoperatively
No 17 68%
Yes, minor 6 24%
Yes, major 2 8%
Qn. 5 Patients who stated some postoperative pain but coped, and those who had minimal or no pain. 25 100%
Qn. 6 Patients who returned to footwear by 2 weeks 5 20%
Patients who returned to footwear by 4 weeks 11 44%
Patients who returned to footwear by 6 weeks 2 8%
Patients who returned to footwear by 8 weeks 4 16%
Patients who returned to footwear by 12 weeks 1 4%
Patients who returned to footwear by 6 months 2 8%
Qn. 7 Patients who described no discomfort or any occasional twinges from their original foot condition 20 80%
Qn. 8 Patients who described their foot condition was better or much better following surgery 24 96%
Patients who stated their foot condition deteriorated or a little worse following surgery 0 0%
Qn. 9 Patients who stated they would have the surgery again under the same conditions 22 88%
Qn. 10 Patients whose expectations were met or partly met 25 100%

Table 7 Summary of answers to key PSQ-10 question 2-10.

Radiographic Analysis

The results of the radiographic analysis for both 5-MTPA and 4-5 IMA are displayed in Table 9. The mean pre 5-MTPA measurement was 19.8 (SD 5.1), the post 5-MTPA measurement reduced to 8.0 (SD 3.1). For the mean 4-5 IMA measurement, it was reduced from 11.6 (SD 1.9) to 5.7 (SD 1.7). Post-operative mean scores of both 5-MTPA and 4-5 IMA fell within the normal angle range for non-pathological foot. A 95% confidence interval for the difference was given by (9.65338, 13.90662) in 5-MTPA and (4.72395, 6.88405) in 4-5 IMA. Improvement of both evaluated angles was highly statistically significant (p-values < 0.001).

Figure 5 Illustrates the significant improvement of the radiographic measurements for both 5- MTPA and 4-5 IMA postoperatively.

XRAY angles Pre-mean Pre-SD Post-mean Post-SD Difference Mean Difference Std.

Deviation

 95% Confidence interval P-value
5-MTPA 19.8120 5.05423 8.0320 3.13325 11.78000 5.15194 (9.65338,19.0662) <0.001
4-5 IMA 11.5520 1.94489 5.7480 1.69118 5.80400 2.61653 (4.72395, 6.88405) <0.001

Table 9 Radiological measurement scores with associated difference scores, 95% confidence interval and p-values.

Discussion

The prevalence of tailor’s bunion in the general population is still unknown, although existing literature suggests that the deformity mostly occurs in adults in their 40s and 50s and affects women more than men [35,36]. This is also reflected in the demographic data found in this study (Table 1); a vast majority of patients (84%) are female with an average age of 43.6 y/o (1.dp). Many studies have in fact found women are most likely to suffer with foot pain more than men as not only do they have higher familial tendency to development of structural forefoot deformities, but have also been observed to wear shoes that were too small for their feet [15,18,36]. Increased pressure from shoes over the prominence of the fifth metatarsal head can cause irritation, pain and development of skin lesions such as calluses and corns [35].

The results of the MOXFQ scores in this review showed significant improvement of more than 50% decrease postoperatively with the procedure in all three domains (W/S, P, SI). For the study population, the outcomes obtained demonstrated that the changes for the three MOXFQ domains are beyond the measurement error on a 95% confidence level hence can be interpreted as true changes. Furthermore, the score changes obtained have all exceeded Dawson’s estimated Minimal Clinically Important Differences (MCID) value of W/S, 12 in P and 24 in SI [11]. Scores exceeding the MCID are known to be clinically relevant [11]. This paper also found the procedure clinically effective with high levels of patient satisfaction and improved quality of life as reflected by a mean PSQ-10 score of 88.08 with the majority of patients (88%) scoring between 81 and 100. The high level of subjective satisfaction would be consistent with previous studies which also proved good results with the diaphyseal osteotomy procedure [3,19,22,25,41]. High patient satisfaction was further indicated by results of question 10 of the PSQ-10 where all the patients’ original expectations of surgery had been met or partly met; question 7 where 80% of patients described no discomfort or any occasional twinges from their original foot condition and question 8 where 24 (96%) patients described their foot condition as better or much better.

Patients scored highest for concerns relating to foot pain in comparison to other domains preoperatively on the MOXFQ. This correlates with their response on PSQ-10 question 1 taken at a 6 month postoperative review; where ‘pain relief’ accounted for 24 (96%) of patients’ expectation. This could be due to how services operate in the public sector; in that, cosmetic surgery is not routinely provided on the NHS and, indication for any surgical intervention is only warranted if the pathology presented is symptomatic [31]. While the interpretation of patients’ expectations can be challenging and varies depending on time, health and environmental factors [44]. The PROMs results obtained from this study are similar to other studies in that patients attending for foot surgery generally expect pain relief, followed by improved mobility and shoe fitting [26,44].

Acute postoperative pain is most commonly reported by patients following surgery [23]. Although this could deter patients from undergoing surgery again, 88% of patients from this study (Table 7) stated they would have the surgery again under the same conditions, should the need arise. Furthermore, question 5 of the PSQ-10 shows that 92% of patients reported no or minimal pain, with the remaining 8% reporting having some pain but were able to cope. This suggests that a combination of popliteal nerve block with a three day course of oral analgesia (paracetamol, non-steroidal anti-inflammatory drug (NSAID) and weak opioid) is well tolerated by patients with adequate effects.

From the 25 operated feet, there were no reported intra-operative complications and 6 cases of minor postoperative procedure associated complications. This was recorded on PASCOM-10 as ‘a scar line hypertrophy/keloid which may not be painful’ in 5 cases and pain in the surgical site beyond six weeks in 1 case. These findings now form a part of the consenting process for future patients undergoing this procedure. The two other cases of postoperative sequelae recorded were not a direct complication of the fifth metatarsal scarf, but rather of another procedure performed in the same episode. Overall, this paper recorded low complications which supports findings from systematic and meta-analysis study by Martijn, et al., [29] which reviewed complications arising from proximal, diaphyseal and distal osteotomies for correction of tailor’s bunion and found very low complication rates with diaphyseal osteotomies [29]. Some of the complications recorded on their study included hardware complications (i.e., removal of screws fixation, screw breakage/migrations), painful scar, delayed or non-union, infection and a revision surgery. None of these complications were recorded in this study. Other general postoperative complications such as deep vein thrombosis or pulmonary embolism were also not recorded.

When returning to normal footwear postoperatively, 5 patients returned at 2 weeks, 11 patients at 4 weeks, 2 patients at 6 weeks and 4 patients at 8 weeks, however, 1 patient required 12 weeks and 2 patients required 6 months. The total number of patients who returned by the eighth week was 22 (88%) suggesting the use of two countersunk screws provides sufficient stability thus enabling guarded weightbearing in normal footwear. Although there is currently no research which specifically looked into the mechanical strength of fifth metatarsal scarf osteotomies for correction of tailor’s bunion utilizing one or two screws, the positive results of this study is comparable to all the other studies which utilised screws in their diaphyseal osteotomies [3,19,22,25,41]. The procedure also allows for structural correction of increased 5-MTPA and 4-5 IMA. Radiographic analyses in this study revealed significant improvements in these angles which suggest the procedure has value in obtaining promising correction results in patients with widened 4-5 IMA. Despite the differing weight bearing status between pre- and postoperative films, the radiographic improvement findings are similar to other studies [3,19,22,25,41].

Finally, this review achieved 100% for question 2 of the PSQ-10 which asks patients if the risks and possible complications of surgery were explained to them preoperatively. This strongly indicates that there is a robust consenting process employed by the department – thereby protecting patients from unwanted medical intervention, and also safeguards their rights to autonomy, self-determination and inviolability [20]. This is also reflected on the Standards of Proficiency for podiatrist practicing podiatric surgery section 1.6; which recognizes the importance of delivering clear communication with patients and to ensure that they are fully informed of the proposed treatment benefits, risks and consequences [21]. Especially in the field of surgery, this information may be of relevance to patients’ decision making on the treatment choice and who they wish to seek treatment from [4].

Strengths and Limitations

This service review has a few limitations. It is retrospective in design which sits on the lower levels of evidence hierarchy [32]. It is also limited by a small study sample size as the cohort was determined by timeframes and tailor’s bunions are relatively uncommon compared to other foot and ankle pathologies and, as 28% patients’ final treatment episode on PASCOM-10 were missing thereby, risking a possibility of failing to pick up any complications and concerns. Lastly, the differing weight bearing status of pre- and postoperative films could lead to inaccuracy in radiographic tailor’s bunion angular evaluation following the surgery.

The authors believe that the study has taken a novel approach to evaluating diaphyseal osteotomy procedure by not just utilizing clinical outcomes and radiographic evaluations, but most importantly, has employed both MOXFQ and PSQ-10 functional outcomes instruments known for their sensitivity, reliability and validity when assessing PROMs [12]. In contrast to AOFAS, MOXFQ and PSQ-10 incorporate both subjective and objective components [11]. Furthermore, by using PASCOM-10, the data was easily extracted while keeping patient/service users’ information confidential. PASCOM-10 enables its users to collect anonymous or pseudo anonymous data related to the selected cohort of patients who underwent a specific procedure [7].

Conclusion

This service evaluation demonstrates that the fifth metatarsal scarf osteotomy provides good clinical outcomes, is able to address a range of angular deformity and has low complication rates associated with the procedure. The use of two screws for fixation potentially enhances stability of the osteotomy and allows for early mobilisation following the surgery.

It also highlights the key role of MOXFQ and PSQ-10 PROMs instruments when determining patient satisfaction with the services received alongside the clinical outcomes. It is important to recognise that the isolated use of objective clinical outcomes following surgery can overlook factors which are pertinent to patients and the contribution patients’ perspective can have in healthcare appraisal [12]. Therefore, it is in the interest of the surgical team to know how well they are meeting the needs of their patients in a meaningful way utilizing reliable and valid PROMs instruments to provide them with the information needed to assess the quality and outcome of care.

References

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A variant of screwless scarf osteotomy for hallux valgus: Clinical and radiographic outcomes

Posted on March 31, 2020 | Comments Off on A variant of screwless scarf osteotomy for hallux valgus: Clinical and radiographic outcomes

by Taoufik Cherrad1*, Hicham Bousbaä1, Mohammed Ouahidi2, Hassan Zejjari3, Jamal Louaste3, Larbi Amhajji4

The Foot and Ankle Online Journal 13 (1): 2

Scarf osteotomy is a versatile procedure for the correction of moderate and advanced hallux valgus. This technique has benefited from many improvements to allow translation and angulation correction of the deformity. We describe in our study a scarf variant without osteosynthesis material in which proximal fixation is made by interlocking and distal fixation with nonabsorbable suture. We retrospectively reviewed 33 feet in 30 patients with an average follow-up duration of 35 months (range: 4-60 months). On the latest follow up, 94 % of the patients were satisfied with the result. American Orthopaedic Foot and Ankle Society (AOFAS) score improved from 56/100 to 87/100. The average improvement of HV angle was from 35° to 12°. The intermetatarsal angle improved from 19° to 7°. The DMAA improved from 27° to 8°. Neither delayed union nor osteonecrosis were observed. This variant of screwless scarf technique gives very good results in severe Hallux valgus by safe and large translation authorizing rotation and supination with low iatrogenicity.

Keywords: hallux valgus, scarf osteotomy, screwless

ISSN 1941-6806
doi: 10.3827/faoj.2018.1301.0002

1 – Orthopaedic surgeon, Military Hospital Moulay Ismail Meknes (HMMIM). Morocco.
2 – Resident in Orthopedic Surgery and Traumatology, HMMIM. Morocco.
3 – Professor in Orthopedic Surgery and Traumatology, HMMIM. Morocco.
4 – Professor Head of the Department of Orthopedic Surgery and Traumatology, HMMIM. Morocco.
* – Corresponding author: taoufikcherrad@gmail.com

Hallux valgus (HV) is the main forefoot deformity. Non-operative treatment may relieve symptoms but the basis of management is surgery. The HV corrective surgery history is marked by various surgical techniques that currently enumerate over 150 procedures [1].

The scarf osteotomy is a powerful and mechanically stable procedure to correct moderate and severe forms of HV. This Z-shaped osteotomy of the first metatarsal was first proposed by Meyer [2]. Weil was the first to use the term ‘Scarf’ [3] and Barouk popularized it in Europe [4]. The scarf osteotomy is very versatile and stable, therefore it allows rotational and translation corrections. Originally this osteotomy was stabilized with two screws. Maestro proposed eliminating the proximal screw by locking the two fragments distally: a notch was created via a medial extension of the cephalic part of the osteotomy, the plantar fragment was displaced laterally, and the distal end of the proximal fragment was then fit into the notch (secondary cut and interlocking joint technique [5]. In 2012, Leemrijse et al optimized this technique to increase the potential range of translation. The procedure consists of distal locking and proximal stabilization without shortening. This was possible by impaction of a corticocancellous bone graft taken from the medial overhanging edge of the proximal fragment [6].

Our study presents the results of a retrospective series involving 33 feet (30 patients) operated for HV according to scarf technique without osteosynthesis material with proximal fixation by interlocking and distal fixation with nonabsorbable suture.

The aim of this study is to evaluate the safety, feasibility, and reproducibility of screwless scarf osteotomy by comparing our clinical and radiographic outcomes to the literature data.

Patients and methods

This is a retrospective study regarding 33 feet of HV from 30 patients treated with Scarf osteotomy without osteosynthesis material and followed in the orthopedic trauma surgery department of the military hospital Moulay Ismail Meknes between January 2014 and December 2018. The average follow-up duration was 35 months (range: 4-60 months). All subjects have given informed consent. Exclusion criteria were; HV treated with other operative techniques than scarf screwless, or a scarf procedure with internal fixation.

Twenty men and ten women had an average age of 37 years (range, 16-65 years) at the time of surgery. Six patients had bilateral HV and only 3 patients have been operated on the two sides by a screwless scarf.   

Pain with irritation at the bunion was present in 29 feet (88%). The unaesthetic deformity was a serious reason for consultation in 14 patients (47%). All of our patients had metatarsalgia and difficulty with shoes wear. Finally, 67% of our feet were Egyptian type (22 cases).

A standardised surgical technique was used in all cases. The foot was positioned on the operative table in spontaneous external rotation position, with a thigh tourniquet inflated to 300 mmHg.

The surgical procedure involves a standard medial incision over the first MTPJ and along the shaft of the first MT. Skin incision is done at the dorsal and plantar skin junction, avoiding to extend too far proximally and stopped distally at about 1 cm from the joint. The dorsal collateral sensitive nerve will be visible and protected. It is normally not necessary to visualise the collateral plantar nerve.

Figure 1 a: The medial capsulotomy with resection of the medial eminence. b: The sesamoid release by medial approach. c: The Z-shaped osteotomy.

After a medial capsulotomy, the medial eminence of the metatarsal head is removed (Figure 1a).

Then, by the same medial approach (Figure 1b). We release and reduce lateral sesamoid according to the Maestro approach; above and under the lateral collateral ligament (LCL) which is respected.

  • Above LCL: to free the extensor hallucis longus (EHL), the fibrous sling is cut.
  • Under LCL: the metatarso-sesamoïd ligament is cut principally with the lateral part of the conjoint ligament close to the base of the phalanx [7] 

The exposure of the plantar aspect of the metatarsal shaft by rugination must respect the soft tissue below the head for blood preservation.

Regarding the scarf osteotomy; the longitudinal section is made along the medial side of M1. The osteotomy begins proximally to 5 mm from the beginning of the proximal plantar exposure and on average at the junction of the dorsal two-thirds and plantar one-third of the shaft. It ends distally at the junction of the dorsal one-third and plantar two-thirds of the head just proximal to the cartilage of the joint (normally approximately 5mm from the joint surface). In the frontal plane, the osteotomy has an oblique direction downwards and outwards. The degree of dorsoplantar slope is chosen to obtain the desired amount of lowering. The saw is directed generally parallel to the metatarsal plantar surface of which has an average inclination from 40° relative to the horizontal; the focus is to respect the lateral beam from the dorsal fragment, which ensures the stability of the osteotomy. The longitudinal cut must be at least 2cm long to eliminate all risk of secondary displacement.

The distal transverse cut is done just behind the dorsal synovial recessus attachment which is respected. This cut is through the distal metaphysis (presence of spongiosa avoids the dorsal fragment to be fit into the distal fragment). The cephalic cut is dorsal and directed from within outward, proximally oblique and angled at 70°or 80° relative to longitudinal limb. If the distal transverse cut is perpendicular to the axis of the second metatarsal, pure translation is achieved and stabilization is required, either via a screw or via interlocking of the two fragments after a secondary cut, which shortens the first metatarsal bone. Finally the position and the obliquity of this distal cut give the osteotomy more stability (Figure 1c). 

The proximal transverse cut is performed, at an angle of 60° relative to the longitudinal limb and perpendicularly to the axis of the second metatarsal bone. A dovetail notch is then created at the proximal part of the plantar fragment to allow interlocking of the proximal plantar part of the osteotomy. This interlocking allows us not to use a proximal screw. This method is mainly used to acquire pure translation without correction of the distal metatarsal articular angle (DMAA). And, as Leemrijse et al recommended, when the DMAA must be corrected, a shorter osteotomy with a greater rotational effect is made and the proximal part of the cut is not impacted, to ensure marked proximal translation. 

After a complete Z cut, we translate easily the lower part of the plantar metatarsal associated with medial rotation which allows to correct the orientation of the metatarsophalangeal cartilage (DMAA).

Figure 2 a: Removal of medial overhanging bone. b: Reshaping and rotation of bony wedge. c: Superior view of screwless scarf osteotomy with a proximal fixation by impaction of bony wedge and distal fixation with nonabsorbable suture through a transosseous tunnel. 

Figure 3 Medial view of first metatarsal showing screwless scarf osteotomy with suture travelling through a transosseous tunnel in distal and proximal stabilisation by interlocking with impaction of the medial overhanging edge.

Once the desired displacement is obtained, the proximal fixation is done by interlocking from the proximal transverse cut, while the distal attachment is held temporarily by a modified Jospin forceps. The 10/10 Kirschner wire is then inserted from top to bottom which will lead the non-resorbable thread N°2 and allows the distal fixation by a transosseous suture under moderate tension avoiding shear of thread in the spongy bone. The medial overhanging wedge of bone is resected and impacted proximally, conferring perfect stability to the construct (Figure 2 and 3). The medial capsulorrhaphy is then performed to center the sesamoid bones which are released by the lateral side.

Figure 4 Postoperative strapping to be kept for 2 weeks.

Primary stability must be compatible with good mobility of the first metatarsophalangeal joint which enables it to maintain satisfying postoperative amplitude. Moreover one patient received an Akin osteotomy of P1 associated with Scarf osteotomy.

Postoperatively, strapping was kept for 2 weeks (Figure 4). Patients were allowed to walk with a Barouk boot for 6 weeks. At week 6, patients were able to walk and stand on the operated foot with full weight bearing.

Patients were assessed preoperatively and postoperatively for clinical and radiological parameters. The clinical evaluation included both subjective and objective assessment with American Orthopaedic Foot and Ankle Society (AOFAS) score. Radiological assessment included IMA (angle M1M2), HV angle (HVA: angle M1P1), DMAA (distal metaphyseal articular angle), angle M1M5 and situation of sesamoids. Measurements were taken with radiographs at weight-bearing dorsoplantar and lateral views.

Statistical analysis was performed using the paired z test to analyze the radiological parameters with the P value set at 0.05 to determine statistical differences.

For the situation of the sesamoids, we used the following classification [8]:

  • Grade 0: no dislocation;
  • Grade 1: lateral sesamoid beyond the lateral border of the first metatarsal;
  • Grade 2: the lateral sesamoid is fully apparent in 1st metatarsal space;
  • Grade 3: both sesamoid bones are located in the 1st metatarsal space.

Results

At the time of the latest follow up (mean: 35 months; range: 4-60 months), 94% of the cases were satisfied and very satisfied with the result (64% very satisfied and 30% satisfied), 6% were not satisfied. 

The average preoperative AOFAS score was 55 (range: 36-71), postoperative AOFAS score was 87 (range: 63-95), 

The average preoperative M1P1 angle of 35.06° (range: 24°-46°) improved to 12° (range: 2° to 22°) postoperatively (p < 0.001). The average reduction of M1P1 angle was 23.06 ° (66% from M1P1 angle

The average preoperative M1M2 angle of 19° (range: 12°- 28°) improved to 7.03° postoperatively (range: 4°-16°; p <0.001).The average reduction of the M1M2 angle was 11.96° (63% from M1M2 angle).

The average preoperative DMAA of 27.27 ° (range: 14 °- 32 °) improved to 8.3° postoperatively (range: 3°-16°; p <0.001).The average reduction of the DMAA was 18.96° (70% from DMAA angle).

Preoperatively the average value of the M1M5 angle was 32.51 ° (range: 20 ° to 42 °). While in postoperative, the average value of the angle M1M5 was 20.57 ° (12 ° to 32 °; p <0.001). The average reduction of the M1M5 angle was 11.93° (22% from DMAA angle).

In preoperatively, the grade 2 was predominant with 22 cases (66.67%) followed by grade 3 with 6 cases (18.18%) and finally the grade 1 with 5 cases (15.15%). 

Authors Procedures M1P1 Angle pre-operative M1P1 Angle post-operative M1M2 Angle

pre-operative

 M1M2 Angle

post-operative

 DMAA

pre-operative

 DMAA

post-operative
Jardé [12] (1996) Soft tissue +/- P1 33.3° 24.5° 14.2° 12°   – –
Coughlin & Carlson [13] (1999) Double osteotomy 34° 12° 15° 6° 23° 9°
Veri [14] (2001) Proximal osteotomy 37° 13° 16° 6° – –
Bauer [15] (2010) Reverdin-Isham Percutaneous Osteotomy 30° 15° 14° 11° 15° 7°
Mahadevan et al [16] (2016) Chevron 32.3° 14.3° 15.2 ° 5.8° 16.5° 8.5°
Our series  Screwless scarf osteotomy 35.06° 12° 19° 7° 27° 8°

Table 1 Anatomical results of several series using different techniques.

  Authors  Pre-operative

M1P1

 Post-operative

M1P1 

 Pre-operative

M1M2

 Post-operative

M1M2

 Pre-operative

DMAA

 Post-operative

DMAA 
Classical

Scarf 

 

 Gayet [17] 37° 21° 15° 10° – –
Crevoisier [18]   32° 17° 16° 10° 13° 10°
Freslon [8]  31.2° 17.5° 12.1° 7.5° 13.3° 11.1°
Lipscombe [19] 31.4° 11° 13° 6° – –
Law Kin-Wing [9] 37.9° 10° 16.1° 8.4° – –
Screwless

Scarf

 

 Leemrijse [6] 38.5° 10.6° 15.1° 8.7° 15.4° 5.4°
Dries Van Doninck [11] 27,9 ° 4,2° 13.5 ° 4.8° – –
Our series  35.06° 12° 19° 7° 27° 8°

Table 2 Radiographic outcomes in the Scarf osteotomy series of the literature.

Authors Year Technique Number of feet Follow-up  Satisfaction Preoperative AOFAS score Postoperative AOFAS score
Veri [14] 2001 Proximal metatarsal osteotomy 37 12.2 years 90% 37 92
Schneider[20] 2004 chevron 112 12.7 years – 46.5 88.8
Freslon [8] 2005 Scarf 123 4.8 years 84.6% – –
Bauer [15] 2009 Percutaneous Reverdin-Isham osteotomy 104 2 years 89% 49 87.5
Leemrijse [6] 2012 Screwless scarf 12 7.7 years 100% – 80
K.-W. Law [9] 2014 scarf 31 17 months 77% – 88
Raymond D. Pollock [21] 2016 Shortening scarf osteotomy 20 25 months 100% 29.2 82.2
Our series 2017 Screwless scarf  33 35.15 months 94% 55 87

Table 3 Comparison of the functional and objectives results of different series.

While in postoperative the grade 0 was found in 18 cases (54%), grade 1 in 13 cases (40%) and grade 2 in 2 patients (6%).

Complications were observed in three patients: Residual pain was reported in two patients (who have been disappointed), while the stiffness of the MP was objectified in one patient. No disorders of consolidation for osteotomy (delayed healing of bone, pseudarthrosis) were noted.

Discussion

Currently, foot surgery requires rapid functional recovery that cannot be conceived without a primary stability and solidity of an osteotomy. Scarf osteotomy is designed to be versatile, authorizing the restoration of multiplanar HV anomaly. It allows horizontal displacement, lengthening, rotation, elevation, and lowering of the MT head [9].

Various modifications of the traditional scarf osteotomy were proposed to improve the biomechanics and to reduce complications. This evolution is motivated by deficiencies and complications of chevron osteotomies, basal osteotomies and Lapidus arthrodesis and by the superiority of scarf osteotomy results compared to these techniques [10] (Table 1).

Many studies have focused on the surgical treatment of hallux valgus by Scarf osteotomy, with or without osteosynthesis material (Table 2). Maestro in 2007 [5] and Leemrijse in 2012 [6] were the first to use the Scarf osteotomy without internal fixation. Leemrijse et al. developed an original technique involving distal locking without shortening and proximal stabilisation by impaction of a cortical-cancellous bone graft [6], whereas in our technique the fixation was ensured  proximally by interlocking and distally by nonabsorbable suture. Compared to other series, our results lead to consider this procedure reliable for correction of the significant hallux valgus (Figure 5 and Tables 1-3).

The screwless scarf osteotomy is a diaphyseal-metaphyseal osteotomy which allows a very wide lateral translation; we don’t need more space for placing a screw which could limit our translation capacity. It also allows sufficient medial rotation to correct the DMAA [5, 6, and 11].

Figure 5 Example of correction of hallux valgus by screwless scarf osteotomy; a: preoperative. b: postoperative.

Figure 6 Scarf osteotomy without internal fixation with 45 days apart, a: preoperative anterior-posterior radiograph. b: Postoperative anterior-posterior radiograph. 

This surgical procedure has clear advantages [6, 11]: 

  • Fewer complications related to screw insertion mostly in porotic bones which can lead to  fragility fracture of  the 1st metatarsal
  • No loss of reduction due to the compressive effect of the screw 
  • Less risk for complications in case of  superficial infection 
  • Less cost because no screw is used

At last, the screwless technique provides high-quality remodeling at the osteotomy site, without stress shielding [6] (Figure 6). The mean follow-up of our series was 35.15 months which is a significant duration for a procedure whose practice is still recent. However, although this period is sufficient to consider the correction for granted, it would be interesting to pursue the follow up of these patients (as in the case of Leemrijse series [6]) to quantify the importance of late recurrence and whether corrections obtained with this procedure are superimposed in terms of efficiency in time to other techniques with an important follow up.

Conclusion

The screwless scarf osteotomy is the favored technique in moderate and severe hallux valgus, on the condition that technique fundamental principles are respected. The absence of screws allows a wide lateral translation and therefore reduces a considerable preoperative metatarsus varus.

Finally in our study, we confirm the efficiency of this recent technique in the treatment of HV with almost 94% excellent and good results in our series. The learning curve of this surgery remains long. Respect and application of various technical artifices is essential for the realization of this economic, reliable and biological procedure.

References

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  7. Maestro M. The ruled lateral release of the metatarsophalangeal and metatarso sesamoïd joint in hallux valgus by the medial approach. Poster EFAS Paris 23-25 octobre 1997.
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Can we recreate intraoperative weight bearing in hallux valgus surgery? A radiographic study using a reproducible technique of load bearing to simulate weight bearing

Posted on March 31, 2014 | Comments Off on Can we recreate intraoperative weight bearing in hallux valgus surgery? A radiographic study using a reproducible technique of load bearing to simulate weight bearing

by RS Ahluwalia1, C Elliott, MS Hennessy1, SR Platt1pdflrg

The Foot and Ankle Online Journal 7 (1): 2

Introduction: Correction of the hallux valgus angle, intermetatarsal angle and sesamoid subluxation in hallux valgus surgery is key to restoring normal joint biomechanics. This is difficult to judge accurately intraoperatively as the foot is not weight bearing. We examine the reproducibility of a simulated weight-bearing test on intraoperative images.
Methods: This is a prospective study of 20 patients undergoing a scarf osteotomy for hallux valgus. All patients were operated by one fellowship trained surgeon and were excluded if they had inflammatory arthropathy. At the time of surgery, two intraoperative images were taken after surgical correction. A standard positional anterior posterior (AP) image was taken followed by a reproducible simulated weight bearing view (i.e. load bearing view). A retrospective review of 6 week and 4-6 month weight bearing images was conducted to assess any measurable differences in a separate group of patients.
Results: The mean preoperative HVA was 30.7, IMA was 14.5, sesamoid position was 5.6. On completion of surgical correction the HVA was 6.6, IMA was 7.2 and sesamoid position was 1.8. On simulated weight bearing with an average of 131.2N (range 98.9-163.5N), the HVA was 8.9, IMA was 10.7 and sesamoid position was 2; this was a closer approximation to the 6-week weight bearing view in all indices recorded. No observed difference was noted between 6 week and 3-6 month weight bearing images.
Conclusions: We have found that our standardized simulated load bearing intraoperative view will yield reproducibility and is a good surrogate marker for the 6-week weight-bearing radiograph. We believe locking the ankle joint will avoid rotation of the foot and allow for an accurate evaluation of final correction (HVA, IMA, and sesamoid position) and aid meaningful evaluation of surgical technique. However, it does not represent a final united position therefore we could not recommend its use in isolation.

Keywords: hallux valgus, scarf osteotomy, basilar osteotomy, radiography, sesamoid

ISSN 1941-6806
doi: 10.3827/faoj.2014.0701.0002

Address correspondence to:1RS Ahluwalia
Email: Footsurgeon7@gmail.com

Hallux valgus is one of the most common chronic foot complaints [1]. Surgical correction involves a soft tissue release and reconstruction combined with an osteotomy.

The scarf osteotomy is a complex procedure and has many important steps with a learning curve. As a consequence the time taken to master the nuances of surgical technique may prove lengthy with the potential for difficulties and complications along the way [2]. Technical success is defined by correction of hallux valgus angle (HVA), intermetatarsal angle (IMA) and sesamoid position and patient satisfaction.

fig 1 Fig 2

Figure 1 and 2 This positional image taken with the foot pressed flat on the image intensifier housing of the C-arm for both positional (Figure 1 – top) and maximal ankle dorsiflexion views (Figure 2 – bottom).

Only one paper has evaluated the use of intraoperative radiography [3]; it highlighted the difficulty in obtaining standardized images. We have observed that non-weight bearing post-operative images show the position of implanted metal work and may provide a guide to correction but do not show absolute mechanical alignment.

figure 3

Figure 3 An illustration of how the load-bearing image was taken with the foot placed on the scale and then placed in to a talar neutral and ankle dorsiflexed. To assess actual force we placed a weight scale to record the crude reaction force produced on maximal dorsflexion of the foot pre- operatively.

We therefore hypothesize that a standardized intraoperative load bearing view could provide a better approximation to the final weight bearing correction. If this hypothesis were to be correct then one would expect this view to be an improvement on a non-weight bearing early intraoperative and postoperative image.

The purpose of this study was to compare the effects of an intraoperative simulated load bearing view to that of a simple foot positioning AP view to assess correction. Both images were then reviewed in comparison to the final weight-bearing image at 6 weeks. An assessment was made as to which of the two views better approximated the final weight-bearing image. A further assessment of adequacy of the 6-week view was made in comparison to 3 – 6 month weight bearing views.

fig 4 non loaded image faoj fig 4b loaded image FAOJ

Figure 4 example of positional (4a) vs. load bearing (4b) images taken in theatre where the soft tissue repair was revised to ensure adequate hallux valgus correction.

Materials and Methods

After internal ethical approval and appropriate consent; consecutive patients operated for hallux valgus were included, conducted by the fellowship-training surgeon (RSA). The operation performed in all cases was a scarf osteotomy plus or minus an Akin osteotomy. The patients were reviewed at 2 weeks postoperatively for a dressing change and wound check. They were seen again at 6 weeks for final weight bearing radiographs.

Intraoperative Radiographic Technique

Images were taken after fixation of the scarf osteotomy and medial capsular repair. All patients had a positional AP intraoperative image as per Elliot et al [3] standard technique. This positional image was taken with the foot placed flat on the image intensifier housing of the C-arm (Figure 1). To produce simulated weight bearing the foot was held in talar-neutral and the image intensifier was raised until maximal ankle dorsiflexion was achieved (Figure 2). In doing this, the simulated pressure was being maximally taken up by the forefoot.

To make an assessment of the force applied when the foot was in this position we placed a single weighing scale to record a maximal amount of reaction force produced on maximal dorsiflexion of the foot preoperatively (Figure 3). The force was calculated in Newtons. A surgeon not involved in the care of the patients made radiographic measurements of the radiographs (C.E.). The images were examined on our PACS system and the intermetatarsal angle (IMA), the hallux valgus angle (HVA), medial sesamoid position was recorded, using the 7 degrees of displacement described by Hardy and Clapham (positions 1–3 normal) [4].

A further retrospective analysis was undertaken by C.E. of 6-week weight bearing radiographs from our hallux valgus data base of patients whom had further radiographs taken at 12 – 24 weeks post-surgery. This additional analysis was done in order to assess the adequacy and validity of 6-week weight bearing radiographs as a surrogate marker for final radiographic outcome.

Statistical Analysis

To determine the accuracy of the fluoroscopy films we compared the two intraoperative images with each other and then finally with the 6-week postoperative radiographs. Further analysis of 6-week weight bearing radiographs and 12-24 week radiographs was undertaken separately. Statistical analysis was achieved with a paired t-test to evaluate the difference between measurement and a Shapiro-Wilk test to evaluate the distribution of measurements with p values less than 0.05 defined as significant.

Results

Twenty-two consecutive scarf osteotomies were undertaken for hallux valgus in 20 patients; 2 required an Akin osteotomy, all were included in final analysis. There were 18 females (2 bilateral cases) and 2 males with an average age of 56.2 years.

For the first 10 cases we measured the weight as surrogate for the reaction force produced on maximal dorsiflexion of the foot. We found that the mean pressure generated was 131.2N (range 98.9-163.5N; Table 1). Intraoperative images were taken on completion of surgical correction and on two separate occasions intraoperative images led the surgeon to make an alteration in the soft tissue tensioning to ensure sesamoid correction.

  HVA IMA Position Load
Preoperative 30.7°(26.2-33.7°) 14.5°(13.3-15.4°) 5.6(3-6) Body weight
Positional 6.6°(5.2-7.9°) 7.2°*(6.3-8.2°) 1.8*(1-2) 0N
Load Bearing 8.9°*(7.3-10.4°) 8.4°*(7.5-9.2°) 2°*(1-3) 131.2N(98.9-163.5)
Postoperative 10.9°*(10.1-11.6°) 8.8°*(7.9-9.7°) 2°*(1-3) Body weight

Table 1 Measurement of angles from images taken from time of surgery to follow up and the load applied at the time of imaging. Ranges are given as 95% confidence intervals around the mean for angles and force measurements, and for sesamoid position given as actual values. *Statistical analysis suggested no significant difference was found between these values at p<0.04, and p<0.03, respectively.

The preoperative radiographs showed the mean HVA was 30.7 (26.2-33.7), IMA was 14.5 (13.3-15.4) sesamoid position was 5.6 (mode 5; range 3-6). On completion of surgical correction the positional view showed the corrected HVA was 6.6 (5.2-7.9), IMA was 7.2 (6.3-8.2) and sesamoid position was 1.8 (mode 2; range 1-2). Our simulated load bearing with an average of 131.2N (98.9-163.5N) demonstrated an increase in the HVA to 8.9 (7.3-10.4), the IMA was 8.4 (7.5-9.2) and sesamoid position was 2 (mode 2; range 1-3) (see figure 4).

  HVA IMA Sesamoid Position
6-week weight bearing view 7.5°(6.2-9.9°) 9.6°(7.2-11.9°) 2(1-3)
3-6 month weight bearing view 7.9°(5.9-10.4°) 9.3°(7.1-12.6°) 2(1-3)

Table 2 Measurement of angles from 14 patients taken from 6-week and 12-24 week weight bearing radiographs after surgery.

Postoperative radiographs showed the mean HVA increased to 10.9 (10.1-11.6), IMA was 8.8 (7.9-9.7), and median sesamoid position 2 (mode 2; range 1-3) (Table 1). We observed that the simulated weight bearing views were a closer approximation to the 6-week weight bearing view in all indices recorded (p<0.05). They showed an improvement in the HVA angle and each individual angle measured. The sesamoid position was found to follow a normal distribution (p<0.05) for each image.

Our surgical database identified 14 patients whom underwent sequential bilateral foot surgery and consequently had 3 – 6 month post-operative weight bearing images of their original correction. The results showed an observed difference in HVA and IMA but no change in sesamoid position, from the 6- week weight-bearing image (Table 2). Ranges are given as 95% confidence intervals around the mean for angles.

We found that all populations fitted a normal distribution and there was no difference between HVA (p<0.03), IMA (p<0.05), and sesamoid position (p<0.02) in the radiographic views. Our results also bear out the fact that a positional view does not give a reliable measure of the final HVA as the null hypothesis could not be rejected. The observed difference in HVA and IMA were not significant.

Discussion

In the original paper by Elliot et al in 2011 [3] non-loading intraoperative radiographs were thought to be reliable and reproducible. However, there was a statistically significant increase in post-operative weight bearing HVA compared with the measurements made intraoperatively. This is important, as hallux valgus correction requires accurate assessment of the HVA angle. Whilst in their series the mean HVA was within normal limits the actual difference between intraoperative and post-operative image was 8.9 degrees and post-operative HVA measurements ranged from 4.5-13.6. This is of significance when it is taken into account that normal HVA is less than 15-20 degrees [1].

Our results show that simulated load bearing on the forefoot whilst the ankle is held in talar-neutral will give a closer approximation to the 6 week weight bearing view in all measurable indices – particularly the HVA than simple placement as suggested by Elliot et al [5].

Our standardized load bearing images require the patient to be able to flex the knee to 60 degrees, and require the hip to flex to 60 degrees and depend on the surgeons ability hold the foot at the ankle and the radiographer’s skill to simulate weight bearing. This achieved the constant end point of the patient’s maximal ankle dorsiflexion, which is a reliable and reproducible end point allowing the surgeon to lock the foot and preventing rotation leading to a semi oblique view. Our results suggest measurement pressures are highly variable (90-180N) unlike the constant end point of maximal ankle dorsiflexion that is dependent on patient ankle mobility. Loading of the forefoot soft tissues in this manor produced an average of 131.2N once the ankle is fully dorsiflexed. This is not anyway near the forces generated on weight bearing and would account for the measurable differences in angle measurements between the different image time points.

We infer that simulated weight bearing seems to allow loading of the medial capsular repair but not with the high pressures one would expect in a weight bearing view. However, our belief is that the range of motion in the ankle may well be the limiting factor in achieving more force but it may avoid rotation of the foot and getting a semi-oblique image during surgery when trying to simulate true weight bearing. Thus, leading to a more reproducible and accurate measure of HVA.

Further studies would be required to assess where the additional force generated on weight bearing may be taken up e.g. by the elastic nature of the tissues such as the intermetatarsal ligaments and dynamic forces acting on the first metatarsal conform to Hooke’s Law to prevent excessive separation of the first and second rays.

Our experience using intraoperative fluoroscopy revealed two separate occasions where the intraoperative images led the surgeon to make an alteration in the orientation or degree of sesamoid correction performed through improved soft tissue release and medial capsular reefing (sesamoid position 5 to 3). In the second case the osteotomy required a further lateral shift to correct the HVA (14.8 to 11.6).

The mean corrections in this study for HVA were within 1-3 degrees (HVA 9.7 vs. 9.9 and IMA 8.8 vs. 6.4) of previously published results from one senior author (M.S.H.) [6]. Thus, we would recommend intra-operative fluoroscopy as a useful aid in the early stages of learning the scarf osteotomy and the many steps to refine this technique [7]. Thus avoiding common procedural problems such as under correction, mal-rotation, metatarsal fracture, and troughing as well as a better appreciation of potential interphalangeus deformity [1,2,5].

Our unit has found that adequate surgical exposure leads to a satisfactory view of the sesamoids and the osteotomy site; providing adequate assessment of correction obtained from the osteotomy and soft tissue release and would not routinely use intraoperative imaging once the surgeon was appropriately skilled in the procedure.

We are aware that some surgeons do not request postoperative radiographs routinely after scarf osteotomy but instead rely on clinical indices [1,8,9]. Even though our results support the use of a reproducible simulated load bearing intraoperative image as a close approximation of actual hallux valgus correction, we could not recommend them as a surrogate for a final united position, and they should not be used in isolation.

References

1. Coetzee JC. Scarf osteotomy for hallux valgus repair: the dark side. Foot Ankle Int. 2003;24 (1): 29-33. –[Pubmed]
2. Smith AM, Alwan T, Davies MS. Perioperative complications of the Scarf osteotomy. Foot Ankle Int. 2003;24 (3): 222-7. – [Pubmed]
3. Elliot RR, Saxby TS, Whitehouse SL. Intraoperative imaging in hallux valgus surgery. Foot Ankle Surg. 2012;18 (1): 19-21. – [Pubmed]
4. Hardy RH, Clapham JC. Observations on hallux valgus; based on a controlled series. J Bone Joint Surg Br. 1951;33-B (3): 376-91. – [Pubmed]
5. Hammel E, Abi chala ML, Wagner T. [Complications of first ray osteotomies: a consecutive series of 475 feet with first metatarsal Scarf osteotomy and first phalanx osteotomy]. Rev Chir Orthop Reparatrice Appar Mot. 2007;93 (7): 710-9. – [Pubmed]
6. Prasad S, Lake A, Hannah H, Hennessy M. Scarf osteotomy for correction of hallux valgus: clinical and radiological evaluation. J Bone Joint Surg Br 2003;85-B no. SUPP III 248. Webpage
7. Weil LS. Scarf osteotomy for correction of hallux valgus. Historical perspective, surgical technique, and results. Foot Ankle Clin. 2000;5 (3): 559-80. – [Pubmed]
8. Dafydd M, Green N, Kadambande S. Are routine x-rays 6 weeks post scarf osteotomy for hallux valgus necessary? J Bone Joint Surg Br. 2012;94-B no. SUPP XLIII 9. – [Webpage]
9. Resch S, Ryd L, Stenström A et-al. Measuring hallux valgus: a comparison of conventional radiography and clinical parameters with regard to measurement accuracy. Foot Ankle Int. 1995;16 (5): 267-70. –[Pubmed]

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