Tag Archives: arthrosis of the ankle joint

Results of total ankle replacement in 71 patients with a follow-up period 6 month to 7 years

by Kirill S. Mikhaylov1*, Alexander Y. Kochish2, Aleksander A. Bulatov3, Evgeniy P. Sorokin

The Foot and Ankle Online Journal 13 (4): 1

The purpose of this study was to analyse the results of treatment in patients with arthritis of the ankle joint (AJ) based on analysis after surgery involving total ankle arthroplasty. We evaluated the efficiency of AJ replacement (71 patients). All patients were divided into two groups: prospective (6, 12 and 24 months) and retrospective (3, 5, and 7 years). The results were evaluated with the help of a visual analogue scale (VAS) and the 100-point AOFAS scale; we also performed X-ray examinations. With regard to AJ replacement, we identified a significant risk factor for the most frequent complication, which was aseptic instability of the implant components. Total ankle replacement (TAR) provides good or satisfactory treatment results in the vast majority of patients examined in the absence of complications: 100% on the VAS and 96% on the AOFAS scale after 2 years; 100% on both scales after 3 years; 92.3% on both scales after 5 years; and 85.7% on both scales after 7 years. At the same time, the dynamics of the various indicators studied were generally similar, but there were also some differences.

Keywords: ankle joint, arthrosis of the ankle joint, ankle arthroplasty, risk factors for poor treatment outcomes

ISSN 1941-6806
doi: 10.3827/faoj.2020.1304.0001

1 – PhD in Medical Sciences, Researcher, Vreden Russian Research Institute of Traumatology and Orthopaedics, St. Petersburg, Russia
2 – Professor, Vreden Russian Research Institute of Traumatology and Orthopaedics
3 – PhD in Medical Sciences, Vreden Russian Research Institute of Traumatology and Orthopaedics
4 – PhD in Medical Sciences, Researcher, Vreden Russian Research Institute of Traumatology and Orthopaedics
* – Corresponding author: web2@mail.ru


The improvement of methods of surgical treatment for patients with late stages of deforming arthrosis of the ankle joint (AJ) is one of the priority goals of modern traumatology and orthopaedics [1, 2]. Currently, patients with the specified pathology undergo two main types of surgery: the first is AJ arthrodesis, which has been used since the beginning of surgical orthopaedics, and the second is total ankle replacement (TAR), which has been used in clinical practice since the 1970s [3, 4] and quickly became an accepted method. According to the literature, both specified methods of surgical treatment have advantages and disadvantages and also show different results in the present day compared with the past. Therefore, the choice of one of these methods presents certain difficulties. Indications and contraindications for performing either of these surgeries are discussed in the following articles [5, 6, 7, 8, 9]. Surgeries of each type are quite often followed by complications and pathological states that substantially worsen the result of treatment in both the short- and long-term. In particular, after AJ fusion, patients often develop degenerate and dystrophic changes in joints of the middle part of the foot, and in addition, compensatory loads of the overlying large joints of the lower extremity lead to increased development of a pain syndrome [7].

Figure 1 a. Deformities of the bones forming the ankle joint in patients of the consequences of ankle joint injuries subgroup: a-radiographs of patient S, 53 years old, with the consequences of a fracture of the distal metaphysis of the tibia; b. X-ray of patient SH, 36 years old, with a consequence of fractures of both ankles.

Operations involving TAR increase the risk of future development of a number of pathological states, such as destruction of the established prosthesis designs, aseptic instability of their components and a deep periprosthesis infection [10, 11, 12]. Therefore, the introduction of TAR has been approached cautiously in clinical practice around the world. Indeed, according to the German register of operations, arthrodesis of the AJ is carried out approximately three times more often than its endoprosthesis replacement; the number of annually established endoprostheses of the AJ is about 1300 [13].

On the other hand, the relevant literature also has suggestions from some orthopaedists to greatly expand the indications for arthroplasty of the AJ [14, 15]. In particular, there are publications describing operations with the angles of varus or valgus deformations in this joint over 200 [16, 17, 18], at the site of tumoural damage of the tibia or talus [19], at defects of the talus [20] and also at the fracture of an earlier arthrodesis of the AJ [21, 22, 23]. The analysis of literature on this subject has convinced us that the comparative efficiency of ankle fusion and TAR operations, especially regarding long-term performance, and also risk factors for the development of a number of pathological states are insufficiently studied and need to be further investigated.

Materials and Methods

We performed an analysis of 71 patients who underwent TAR using three third-generation implants: Mobility (DePuy) 27, Hintegra (NewDeal) 37, and STAR (Waldemar Link) 7. The gender and age characteristics of patients are provided in Table 1 for comparison. Radiological examination showed that most patients had late-stage arthritis of the ankle and was based on the classification of Kellgren et al. [24]. It was found that 15 (21.1%) patients had stage II AJ arthrosis, 41 (57.8%) patients had stage III arthrosis, and 15 (21.1%) patients had stage IV arthrosis (Table 2).

It should be noted that pathological changes in the articular parts of the bones that form the AJ were found mainly in patients with the consequences of injuries to this joint. Thus, 10 (11.5%) patients had deformities of the distal metaphysis of the tibia after fractures (Figure 1 a) and 27 (51.9%) patients had ankle deformities (Figure 1 b), with 5 (9.6%) patients having significant deformities of the talus bone in this clinical subgroup. Among patients with AJ diseases that led to the development of deforming arthrosis, there were only two such observations: one patient (5.3%) with deformation of the distal metaphysis of the tibia and another (5.3%) with significant deformation of the talus bone.

For all patients, we carried out an objective and radiological inspection of the feet, including an X-ray analysis with the necessary projections, and patients also completed visual analogue scale (VAS) and American Orthopaedic Foot & Ankle Society (AOFAS) scores. Of note, all patients included in the research underwent surgery in the clinic by one team of surgeons in order to avoid differences in the result of treatment due to different operational techniques and equipment. It should be noted that, in general, all patients in the considered clinical group had VAS scores ranging from 6 to 10 and AOFAS scores ranging from 12 to 34, which corresponds to poor evaluation categories. In addition, they had pronounced restrictions on the amplitude of movement in the affected AJs (from 16° to 27°), which was significantly worse than normal indicators (on average 39±5°). All these changes are typical for the later stages of development of deforming ankle arthrosis (Table 3).

Average age (years) Sex Total
М F
48.1±4,2 29 (40.9%) 42 (59.1%) 71 (100%)

Table 1 Age and sex of patients of the first clinical group.

II III IV Total
n % n % n % n %
15 21.1 41 57.8 15 21.1 71 100

Table 2 Ankle arthrosis stages.

AOFAS VAS Movement amplitude
25.0±2.0 8.5±0.7 24.0±3.4°

Table 3 Preoperative clinical and functional indicators in patients.

Results

The most frequent reason for unsatisfactory treatment results from 6 months until 7 years after surgery was aseptic instability of components of the AJ. Therefore, special attention was paid in our work to the detection of significant risk factors of this emerging pathological state. We found that, in the prospective group of patients, radiological signs of instability of the established designs were observed 2 years after the surgery in 6 (19.4%) of 31 patients under clinical supervision. However, the presence of a severe pain syndrome and essential decrease in functionality, which necessitated carrying out a repeat operation (fusion), was reported only by one (3.2%) patient of the prospective group.

In the retrospective group from 3 to 7 years after treatment, radiological signs of instability of the components of the AJ were recorded for 16 (40%) of 40 observed patients. In addition, using VAS and AOFAS scores, patients with this complication had worse average values of these indicators (R<0.01) than other patients of the group. However, the revised procedures, including removal of unstable implants with subsequent biarticulate fusion of the ankle and subtalar joints were only carried out by interlocking intramedullary nails in 7 (43.8%) of 16 patients, as the other 9 patients preferred to keep the established endoprostheses. It should be particularly noted that these nine patients had only radiological signs of instability of the endoprosthetic components without essential migration of the bone bed, and they had a satisfactory functional result.

An example of a satisfactory functional result can be observed (Figure 2) 5 years after TAR with the presence of radiological signs of instability of the established construction. However, it is necessary to note that the patient did not demand a high functional load from the operated AJ.

Special attention in our research was paid to the detection of risk factors for developing aseptic instability of endoprostheses of the AJ. A search was carried out concerning two groups of factors noted in the relevant literature [4, 15, 17, 22, 25, 26, 27, 28]. The first group of risk factors included various deformations of the bones forming the AJ. The second group included the age of patients, related physical activity, and functional loads of the operated joints as significant factors. It should be noted that such analyses were carried out separately in the prospective group (31 patients) and in the retrospective group (40 patients). The results are presented in Tables 4 and 5.

The analysis showed that the risk of aseptic instability of the endoprosthetic components of the AJ during all periods of observation was clearly associated with previous fractures of the bones forming the joint. As can be seen, such fractures occurred in 5 of 6 patients with this pathological condition in the prospective group and in 13 of 16 patients in the retrospective group. In addition, we observed that the vast majority of these states (21 of 22 or 95.5%) occurred in patients under the age of 55 years. The proportion of patients with aseptic instability of the implant in the group of patients younger than 55 years was 34.4% (21 of 61) and only 10% (1 of 10) in the group of patients 55 years and older. It should also be noted that, in 19 (86.4%) of the 22 cases of aseptic instability of the endoprosthetic components, these patients performed activities involving high functional loads on the AJ in the postoperative period.

Analysis of the models installed as AJ implants in patients diagnosed with aseptic instability of the implant did not reveal any significant advantages for any one of the three used structures.

Figure 2 The result 5 years after total ankle replacement (left side) in a 42-year-old patient with the use of a Hintera implant (NewDeal). a) Radiological signs of instability of an endoprosthesis: the slight shift backwards of the tibial component and sagging of the talus component due to decreased height of the talus; b) Satisfactory functional result: 3 points on the VAS and 69 points on the AOFAS scale.

The third-generation implants studied implants had similar clinical effectiveness with respect to the development of the discussed pathological conditions. The analysis revealed the following significant risk factors of aseptic instability of the endoprosthetic components of the AJ: previous fractures of bones forming the joint, age of up to 55 years, and high functional load on the operated joints in the postoperative period.

Discussion

A comprehensive study of the results of ankle replacement of up to 7 years conducted in the prospective (31 people) and retrospective (40 people) subgroups of patients allowed us to make some generalizations presented in this section.

First of all, it was shown that operations with the AJ endoprosthesis in the absence of complications provided good or satisfactory treatment results in the vast majority of the examined patients: 100% on the VAS and 96% on the AOFAS scale after 2 years; 100% on both scales after 3 years; 92.3% on both scales after 5 years; and 85.7% after 7 years. At the same time, the dynamics of the various indicators studied were generally similar, but there were also some differences.

In particular, the severity of pain in the area of the operated joint, estimated by VAS, was minimal 2 years after the operation and gradually increased in the future, reaching a maximum by the 10-year follow-up. The functional capabilities of the AJs, determined on the AOFAS scale, reached the maximum average value 6 months after surgical treatment, remained at this level until 3 years, and then gradually decreased over the next 7 years of follow-up. Various indicators of gait biomechanics on the side of the operated joints gradually improved during the first 3 years after implantation of artificial AJs and then gradually deteriorated by the 7-year follow-up period. The amplitude of movements in the AJ (flexion/extension) increased after endoprosthesis on average only by 3–40° and reached the maximum average values, corresponding to about 75% of the norm, after 6 months. In the future, the volume of such movements gradually decreased and was an average of 46% of the norm 7 years after surgery.

However, it should be especially noted that, in the examined patients who did not show signs of aseptic instability of the established AJ components, the average values of almost all the studied parameters (except for the amplitude of movements) even 7 years after the performed operations were significantly better (P<0.05) than the corresponding preoperative values.

Anamnesis Age of patients, years Total
20–39 40–54
Change of a distal metaphysis of tibia 3 (50%) 3 (50%)
Fracture of ankle bones 1 (16,7%) 1 (16,7%)
Fracture of a collision bone 1 (16,7%) 1 (16,7%)
Deforming ankle joint arthrosis 1 (16,7%) 1 (16,7%)
Total 1 (16,7%) 5 (83,3%) 6 (100%)

Table 4 The anamnesis and age of patients who had aseptic instability of ankle joint endoprostheses 2 years after surgery.

Anamnesis Age of patients, years Total
20–39 40–54 55 and older
Change of a distal metaphysis of tibia 3 (18,8%) 3 (18,8%)
Fracture of ankle bones 2 (12,5%) 2 (12,5%) 4 (25%)
Fracture of a collision bone 6 (37,5%) 6 (37,5%)
Deforming ankle joint arthrosis 1 (6,3%) 1 (6,3%) 1(6,3%) 3 (18,7%)
Total 3 (18,8%) 12 (75%) 1(6,3%) 16 (100%)

Table 5 The anamnesis and age of patients who had aseptic instability of ankle joint endoprostheses from 3 to 7 years after surgery.

The above results of our research generally coincide with similar data in the literature. In particular, it is known that the analysis of the outcomes of the Hintegra (NewDeal) endoprosthesis in the period from 1 year to 5 years showed an increase in the AOFAS score on the average from 40.3 to 85.0 points [24]. Another publication presents the results of the Mobility (De Puy) endoprosthesis in 233 patients with an average follow-up period of 32.8 months [25]. It was noted that the function of the joints after the installation of this endoprosthesis improved on the AOFAS scale from an average of 48.2 to 84.1 points, and the pain syndrome on the VAS regressed from an average of 7.7 to 1.7 points. However, the volume of movement in the AJs that were operated on improved on average only by 2.1° (from 19.8° to 21.9°), which is quite consistent with the data we received.

A purposeful comparative analysis of our clinical data allowed us to conclude that, in the long-term postoperative period (3–7 years after the performed operations), there are no significant and reliable (P<0.05) differences in the values of clinical and functional indicators (according to the VAS and AOFAS scales) when using three different models of AJ implants: Hintegra (NewDeal), Mobility (De Puy) and STAR (Waldemar Link). Thus, it was shown that the third-generation implants studied have quite comparable clinical effectiveness in those patients who do not have aseptic loosening of the installed structures.

The analysis of models of installed AJ implants in patients with diagnosed aseptic instability of implants also did not reveal any significant advantage of any of the three designs used. However, in the prospective group, 2 years after surgery, instability of the Mobility (De Puy) endoprosthesis was observed in 3 (30%) of 10 cases, and a similar condition after installation of the Hintegra (New Deal) structure was recorded in 3 (14.3%) of 21 patients. Despite the revealed differences, in our opinion, these data are not enough to make a clear judgment about the advantages of one of these endoprosthetic models of over the other.

Our research has shown that aseptic instability of various components of AJ endoprostheses is a frequent unsatisfactory outcome of operations. In particular, it occurred in 6 (19.4%) of 31 patients of the prospective clinical subgroup by the 2-year follow-up period after surgical treatment. In the retrospective subgroup, 16 (40%) of 40 patients had this pathological condition in the long-term period (from 3 to 7 years) after surgical treatment. In our opinion, the proportion of patients with this condition in the retrospective clinical subgroup was so high, because patients with aseptic instability of implants purposefully went to the hospital, where they performed the primary implant of the AJ endoprosthesis. At the same time, patients with good clinical and functional results did not always agree to undergo additional examination in the long term after surgical treatment. It is likely that if the survey was not 40 patients, but all 116 patients operated on in RNIITO n.a. R. R. Vreden in 2003–2011, the proportion of patients with the discussed unsatisfactory outcomes would have been significantly lower.

The information we received generally coincided with those given by other researchers. Thus, according to various foreign authors, the percentage of patients with aseptic instability of AJ endoprosthetic components varies from 3% to 13.7% in the first 5 years after the surgery [26-27] and from 16% to 32% within 5 to 10 years after the surgery [28-29].

In a retrospective subgroup of our patients, the analysis of cases of aseptic instability of the components of the AJ endoprostheses showed that the largest number of them and, accordingly, the highest proportions of the number of examined patients were recorded within 3 years (5 cases or 17.2%) and 5 years (10 cases or 43.5%) after the performed operations. By the 7-year follow-up period, these indicators decreased (one case or 12.5%), and three patients examined after 10 years showed no signs of aseptic instability of the implants. In addition, it was noted that 3 years after the surgical treatment, X-rays of patients with the considered pathological condition showed signs of loosening only in the tibial components, and in later periods of observation (after 5 and 7 years), signs of instability of both the tibial and talus components were recorded. Thus, based on the data obtained, it can be assumed that usually the tibial components of endoprostheses are loosened first, and then, over time, instability also develops in the talus components of the implants.

It should be noted that the presence of radiographic signs of aseptic instability of AJ endoprosthesis, reducing the functionality of the operated joints (by AOFAS scale) and increasing pain intensity (by VAS), have significant individual differences. Therefore, patients with aseptic instability do not always agree to repeat the operation, which involves the removal of implants and arthrodesis of the AJ. In particular, such revision operations were performed only in 1 (16.7%) of 6 patients in the prospective subgroup and in 7 (43.8%) of 16 patients in the retrospective subgroup. Thus, most of our patients with aseptic instability of the components of the installed endoprosthesis preferred to keep the installed implants and refused arthrodesis of the AJ.

The facts described above indicate that X-ray signs of instability of AJ components do not always have pronounced clinical manifestations. In our opinion, this feature explains the large variation in the numbers of unsatisfactory results discussed in the publications of various authors. It should also be noted that our work took into account the X-ray signs of aseptic instability of the installed implants, which determined a fairly high percentage of patients with such negative results.

Special attention in our study was paid to determining the risk factors for the development of aseptic instability of AJ endoprostheses. The following factors were identified: technical errors in positioning the endoprosthetic components, the young age of patients (up to 55 years) and the associated high functional loads on the operated joints, as well as deformities of the tibial and talus bones that form the articular surfaces of the AJ that occurred as a result of previous injuries. Taking this into account, it is clear why the proportion of patients with the considered pathological condition was higher in the subgroup of patients with the consequences of ankle joint injuries (CAJI) than in the subgroup with diseases of this joint (DAJ). However, the analysis showed that the risk factor for developing this condition is not so much the presence of a history of AJ injuries as it is the existing deformities of the tibia and talus bones.

It should be noted that, according to the special literature, technical errors of implantation are considered an important cause of aseptic instability of AJ endoprostheses, which predetermine up to 15% of unsatisfactory results. Some authors noted that the positioning ratios of the tibial and talus components had a direct effect on the occurrence of pain and instability of implant components. Correct surgical technique and correct positioning of endoprosthetic components relative to the mechanical axis helped to increase the durability of the installed structures [30-32].

Some authors have developed their own classifications of the unsatisfactory results discussed. For example, Glazebrook and co-authors (2009) proposed dividing negative outcomes into high-value, moderate-value, and low-value outcomes. At the same time, infection in the area of surgical approach and aseptic instability of the prosthesis were highly significant; errors during implantation were moderately significant; and difficulties during the healing of postoperative wounds were insignificant. It should be noted that, due to the technical difficulties of installing AJ endoprostheses and ensuring good integration with bone tissue, the problem of aseptic instability of such implants has not yet been completely eliminated. It continues to be actual. The associated severe pain syndrome and reduced functionality are common causes of revision operations.

Also, it should be noted that there are publications in the special literature with indications of a direct link between the development of aseptic loosening of the AJ components and causes of pronounced deformities of the articular surfaces of the tibia and talus bones [33-34], as well as the young age and high physical activity of patients, which determine the increased functional workloads on the operated joints [35].

References

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  16. Schuberth JM, Christensen JC, Seidenstricker CL. Total ankle replacement with severe valgus deformity: technique and surgical strategy. J Foot Ankle Surg. 2017;56:618–27..
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  18. Reddy SC, Mann JA, Mann RA, et al. Correction of moderate to severe coronal plane deformity with the STAR ankle prosthesis. Foot Ankle Int. 2011;32:659–64. Erratum in: Foot Ankle Int. 2011 Sep;32(9):vi.
  19. Lampert C. Ankle joint prosthesis for bone defects. Orthopade. 2011;40:978–83. (In German).
  20. Mikhaylov KS, Emelyanov VG, Bulatov AA. Staged bilateral ankle arthroplasty for the treatment of patient with severe defect of the talus (case report). Traumatology and Orthopedics of Russia. 2013;(2):105–10. (In Russian)
  21. Atkinson HD, Daniels TR, Klejman S, et al. Pre- and postoperative gait analysis following conversion of tibiotalocalcaneal fusion to total ankle arthroplasty. Foot Ankle Int. 2010;31:927–32.
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  23. Hintermann B, Barg A, Knupp M, et al. Conversion of painful ankle arthrodesis to total ankle arthroplasty. Surgical technique. J Bone Joint Surg Am. 2010;92 Suppl 1 Pt 1:55–66.
  24. Hintermann, B. The HINTEGRA ankle: short- and mid-term results. Orthopade. – 2006. – Bd. 35, H. 5. – S. 533-545.
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Choice of surgical treatment for patients with arthrosis of the ankle joint

by Kirill S. Mikhaylov1, Vladimir G. Emelyanov2, Alexandr Yu Kochish3, Aleksandr A. Bulatov4

The Foot and Ankle Online Journal 11 (1): 3

The purpose of this study was to justify the algorithm of rational choice of surgical treatment in patients with arthrosis of the ankle joint, based on a comparative analysis of risk factors for poor results after surgery involving ankle fusion and ankle arthroplasty. We evaluated the efficiency of ankle fusion (63 patients) and ankle joint replacement (71 patients). All patients were divided into 2 groups – prospective (6, 12 and 24 months) and retrospective (3, 5, 7 and 10 years). The results were evaluated with the help of a visual analogue scale (VAS) and the 100-point AOFAS scale; we also performed X-ray examinations. The longest follow-up period was 10 years. We found that the desirable angles of ankle fusion ranging from 900– 950 could reduce the chance of the rapid progression of arthritis in the joints of the middle part of the foot. For ankle joint replacement we identified a significant risk factor for the most frequent complication, which was aseptic instability of the implant components. From the results of our analysis we suggest an algorithm of surgical treatment in patients with terminal stage arthrosis of the ankle joint.

Keywords: ankle joint, arthrosis of the ankle joint, ankle arthroplasty, ankle fusion, risk factors of poor treatment outcomes

ISSN 1941-6806
doi: 10.3827/faoj.2018.1101.0003

1 – Cand. Sci (Med), researcher, Vreden Russian Research Institute of Traumatology and Orthopaedics, Saint Petersburg, Russia.
2 – Cand. Sci (Med), head of traumatology and orthopaedics department № 19, Vreden Russian Research Institute of Traumatology and Orthopaedics.
3 – Dr. Sci. (Med), Professor, deputy director for research and academic affairs, Vreden Russian Research Institute of Traumatology and Orthopaedics.
4 – Cand. Sci (Med), Vreden Russian Research Institute of Traumatology and Orthopaedics, department № 19.
* – Corresponding author: web2@mail.ru


The improvement of methods of surgical treatment for patients with late stages of deforming arthrosis of the ankle joint is one of the priority goals of modern traumatology and orthopaedics [1,2]. Currently, patients with the specified pathology undergo two main types of surgery: the first is ankle joint arthrodesis which has been used since the beginning of surgical orthopedics and the second is total ankle replacement (TAR) which has been used in clinical practice since the 1970s [3,4] and quickly became an accepted method. According to the literature both specified methods of surgical treatment have advantages and disadvantages and also show different results in the present day compared with the past. Therefore the choice of one of these methods presents certain difficulties. Indications and contraindications for performing either of these surgeries are discussed in the following articles [5-9].

Surgeries of each type are quite often followed by complications and pathological states that substantially worsen the result of treatment in both the short and long term. In particular, after ankle joint fusion patients often develop degenerate and dystrophic changes in joints of the middle part of the foot and in addition, compensatory loads of the overlying large joints of the lower extremity lead to increased development of a pain syndrome [7]. Operations involving TAR increase the risk of future development of a number of pathological states such as destruction of the established prosthesis designs, aseptic instability of their components and a deep periprosthesis infection [10-12]. Therefore, introduction of TAR surgeries has been approached cautiously in clinical practice around the world. Indeed, according to the German register of operations, arthrodesis of the ankle joint is carried out approximately 3 times more often than its endoprosthesis replacement; the number of annually established endoprostheses of the ankle joint is about 1300 [13].

On the other hand, the relevant literature also has suggestions from some orthopaedists to greatly expand the indications for arthroplasty of the ankle joint [14,15]. In particular, there are publications describing operations with the angles of varus or valgus deformities in this joint over 20° [16-18], at the site of tumoral damage of the tibia or talus [19], at defects of a talus [20] and also at the fracture of an earlier arthrodesis of the ankle joint [21-23].

The analysis of literature on this subject has convinced us that the comparative efficiency of operations of an ankle fusion and TAR, especially regarding long-term performance, and also risk factors of the development of a number of pathological states, are insufficiently studied and need to be further investigated. Here, we have discussed the choice of a method of surgical treatment for patients with late stages of deforming arthrosis of the ankle joint based on the analysis of significant risk factors of unsatisfactory outcomes. The investigation of the practical importance of the above unresolved questions was one of the purposes of this study.

In addition, we attempted to justify an algorithm for the choice of a surgical treatment of patients with late stages of deforming ankle joint arthrosis, on the basis of a comparative analysis of risk factors for unsatisfactory outcomes after ankle fusion and TAR.

Materials and Methods

We performed an analysis of the most common noninfectious complications and unsatisfactory outcomes of treatment after these 2 surgeries to detect significant risk factors in 2 clinical groups of patients during the period from 2003 to 2014. The first of these groups (63 patients) underwent biarticulated arthrodesis of the talocrural and subtalar joints using the interlocked intramedullary nail. The second group (71 patients) underwent TAR using 3 implants of the third generation: Mobility (DePuy) 27, Hintegra (NewDeal) 37, and STAR (Waldemar Link) 7. Gender and age characteristics of patients of the 2 specified clinical groups are provided in Tables 1 for comparison.

Group Ave age (years) Sex Total
М F
1 53,8±5,8 30 (47,6%) 33 (52,4%) 63 (100%)
2 48,1±4,2 29 (40,9%) 42 (59,1%) 71 (100%)

Table 1 Age and sex of patients of the first clinical group.

Radiological examination was used to diagnose the deforming arthrosis of the talocrural and subtalar joints for all 63 patients of the first clinical group and was based on the classification of Kellgren et al [24]. At the same time we established that 7 (11.1%) patients had stage II with expressed pain syndrome, 31 (49.2%) patients had stage III and 25 (39.7%) patients had stage IV. Among patients of the second group, 15 (21,1%) patients had stage II, 41 (57,8%) patients had stage III and 15 (21,1%) patients had stage IV of arthrosis of the ankle joint.

Of note, the reasons for the deforming ankle joint arthrosis in patients of both clinical groups, including injuries and disease were similar, both in aetiology, and in share ratios; therefore correct comparisons could be made.

Taking into account how the results of the surgeries were assessed and the availability of information for unsatisfactory outcomes, patients of the first and second groups were allocated to 2 prospective (49 and 31 patients) and 2 retrospective (14 and 40 patients) subgroups. The corresponding examinations of patients in the prospective subgroups were conducted at 6, 12 and 24 months, and in the retrospective subgroups  after 3, 5, 7 and 10 years after treatment. For all patients, we carried out an objective and radiological inspection of the feet including an X-ray analysis with the necessary projections and patients also completed scores for VAS and AOFAS. Of note, all patients included in the research underwent surgery in the clinic by one team of surgeons in order to avoid differences in the result of treatment due to different operational techniques and equipment.

Results

In the prospective subgroup of the first clinical group 2 years after surgery for a biarticular arthrodesis of the ankle joint and subtalar joints, also AOFAS (less than 50 points) was recorded 9 (18.4%) the unsatisfactory results of the carried out treatment on scales VAS (more than 6 points). At the same time, for 3 patients unsatisfactory results were caused in the 12 months after treatment by an unsuccessful arthrodesis in the talocrural and subtalar joints that necessitated carrying out repeated arthrodesis. Also, 6 other patients with poor clinical and functional outcomes of treatment have been associated with a 2-year period of postoperative osteoarthritis in the joints of the middle part of the foot, accompanied by severe pain syndrome and dysfunction of the feet which had undergone surgery.

Additionally, the analysis of the angles of ankylosis of the ankle joint in the sagittal plane showed that 4 of these 6 patients had a pathological condition; this angle ranged from 101° to 105°, which is confirmed by the radiographs in Figure 1. The other 2 patients with this pathology showed that the corners angles of ankylosis of the ankle joint ranged from 96°–100° and had angles of 90°–95°; these unsatisfactory outcomes were not noted until 2 years after surgical treatment (Table 2).

Figure 1 The ankylosis of an ankle joint at an angle of 101°; arthrosis of joints of the middle part of the foot in an 82-year-old patient with pain syndrome (7 points on a scale VAS), 2 years after surgery.

The studied parameters Fusion angle The average for the group
90–95 96–100 101–105
VAS 2.5±0.4 2.6±0.3 2.8±0.3 2.6±0.3
AOFAS 77±3.5 75±3.6 70±3.6 74±3.5
Numbers of patients 7 (15.2%) 28 (60.9%) 11 (23.9%) 46 (100%)

Table 2 Outcomes in patients of the first clinical group 2 years after surgery, indicating the fusion angle.

In the analysis of the end result of treatment in the retrospective subgroup of the first clinical group, we found that 5 years after surgery of a biarticular arthrodesis the average scores for VAS and AOFAS were worse (R <0.05) for patients with the angle of an ankylosis of 101°–105°, in comparison with patients for whom this corner ranged from 90°–95°.

The analysis of treatment outcomes showed that in all circumstances the best clinical functional results for patients of the first clinical group were achieved with ankle joint ankylosis corners in the sagittal plane from 90°–95°, and the corresponding corners with values within 101°–105° were in fact significant risk factors for unsatisfactory treatment outcomes (Table 3).

Angle VAS AOFAS
Bad

7–10

Satisfactory

5–6

Good

2–4

Bad

1–50

Satisfactory

51–74

Good

75–100

90– 95 6 (13%) 1 (2,3%) 2 (4,3%) 5 (10,9%)
96–100 2 (4.3%) 24(52.2%) 2 (4.3%) 2 (4.3%) 24(52.2%) 2(4.3%)
101– 105 2 (4.3%) 7(15.2%) 2 (4.3%) 4 (8.7%) 7 (15.2%)
Total 4 (8.7%) 37(80.4%) 5(10.9%) 6 (13%) 33(71.7%) 7(15.2%)

Table 3 Qualitative index for 2-year treatment results using the AOFAS and VAS scales depending on the angle of fusion.

For patients of the second clinical group, the most frequent reason for unsatisfactory treatment results from 6 months until 10 years post-surgery was an aseptic instability of components of the installed ankle joint endoprostheses. Therefore, special attention was paid in our work to the detection of significant risk factors of this emerging pathological state. We found that in the prospective subgroup of patients radiological signs of instability of the established designs were observed 2 years after the surgery in 6 (19.4%) of 31 patients under clinical supervision. However, the presence of a severe pain syndrome and essential decrease in functionality which necessitated carrying out a repeat operation (fusion) was reported only by one (3.2%) patient of the prospective subgroup.

Figure 2 The result 5 years after total ankle replacement (left side) in a 42-year-old patient with use of a Hintera implant (NewDeal): a) radiological signs of instability of an endoprosthesis: the slight shift backwards of a tibial component and a sagging of a talus component due to decreased height of a talus; b) satisfactory functional result: 3 points on a VAS and 69 points on the AOFAS.

In the retrospective subgroup from 3 to 10 years after treatment radiological signs of instability of components of ankle joint endoprostheses of were recorded for 16 (40%) of 40 observed patients. In addition, using scores of VAS and AOFAS, patients with this complication had worse average values of these indicators (R <0.01), than other patients of the subgroup. However, the revised procedures including removal of unstable implants with the subsequent biarticulate fusion of the ankle and subtalar joints were only carried out by interlocking intramedullary nails in 7 (43.8%) of 16 patients, as the other 9 patients preferred to keep the established endoprostheses. It should be particularly noted that these 9 patients had only radiological signs of instability of the endoprosthetic components without their essential migration regarding bone bed, and they had a satisfactory functional result of treatment.

An example of a satisfactory functional result can be observed (Figure 2) 5 years after TAR with the presence of radiological signs of instability of the established construction. However, it is necessary to note that the patient did not demand a high functional load from the operated ankle joint.

Special attention in our research was paid to the detection of risk factors for developing aseptic instability of endoprostheses of the ankle joint. A search was carried out concerning 2 groups of the factors noted in the relevant literature [4,15,17,22,25,26,27,28]. The first group of risk factors included various deformations of the bones forming the ankle joint. The second group included the age of patients, the related physical activity, and also functional loads of the operated joints as significant factors. It should be noted that such analyses were carried out separately in the prospective subgroup (31 patients) and in the retrospective subgroup (40 patients). The results are presented in Tables 4 and 5.

Anamnesis Age of patients, years Total
20–39 40–54
Change of a distal metaphysis of tibia 3 (50%) 3 (50%)
Fracture of ankle bones 1 (16,7%) 1 (16,7%)
Fracture of a collision bone 1 (16,7%) 1 (16,7%)
Deforming ankle joint arthrosis 1 (16,7%) 1 (16,7%)
Total 1 (16,7%) 5 (83,3%) 6 (100%)

Table 4 The anamnesis and age of patients who had aseptic instability of ankle joint endoprostheses 2 years after surgery.

Anamnesis Age of patients, years Total
20–39 40–54 55 and older
Change of a distal metaphysis of tibia 3 (18,8%) 3 (18,8%)
Fracture of ankle bones 2 (12,5%) 2 (12,5%) 4 (25%)
Fracture of a collision bone 6 (37,5%) 6 (37,5%)
Deforming ankle joint arthrosis 1 (6,3%) 1 (6,3%) 1(6,3%) 3 (18,7%)
Total 3 (18,8%) 12 (75%) 1(6,3%) 16 (100%)

Table 5 The anamnesis and age of patients who had aseptic instability of ankle joint endoprostheses from 3 to 7 years after surgery.

The analysis showed that the risk of aseptic instability of endoprosthesis components of the ankle joint during all periods of observation was clearly associated with previous fractures of the bones forming the joint. As can be seen from Tables 3 and 4, such fractures occurred in 5 of 6 patients with this pathological condition in the prospective sub-group and in 13 of 16 patients in the retrospective subgroup. In addition, we observed that the vast majority of these states (21 of 22 or 95.5%) occurred in patients under the age of 55 years. The proportion of patients with aseptic instability of the implant in the subgroup of patients younger than 55 years was 34.4% (21 of 61) and in the subgroup of 55 years and older only 10% (1 of 10). It should also be noted that in 19 (86.4%) of the 22 cases of aseptic instability of endoprosthesis components, these patients performed activities involving high functional loads on the ankle joint in the postoperative period.

Analysis of the models installed as ankle joint implants in patients diagnosed with aseptic instability of the implant did not reveal any significant advantages for any 1 of the 3 used structures. Studied implants of the third generation have a similar clinical effectiveness with respect to the development of the discussed pathological conditions.

The analysis revealed the following significant risk factors of aseptic instability of endoprosthesis components of the ankle joint: previous fractures of bones forming the joint, an age of up to 55 years, and a high functional load on the operated joints in the postoperative period.

The results of our study and related data of specialized scientific publications helped to substantiate and propose the algorithm for choosing a rational method of surgical treatment of patients with terminal stages of deforming arthrosis of the ankle joint. The algorithm involves the separation of diagnostic procedures in 2 stages and in sequence, as shown in the diagram (Figure 3).

Figure 3 The algorithm for choosing the method of surgical treatment of patients with terminal stages of deforming arthrosis of the ankle joint.

At the beginning of the patient examination, we performed an assessment of the current stage of deforming arthrosis of the ankle joint. These data, along with the severity of pain, are crucial to the choice between conservative or surgical treatment of such patients. Particular attention should be given to the severity of the deformity. It is known that gross deformation of bones forming the ankle joint, in particular varus or valgus angles greater than 10°, practically excludes the possibility of adequately installing the endoprosthesis components and does not predict a long and successful outcome. Therefore, patients with these gross deformities of the ankle joint should be encouraged to undergo fusion of the affected joints.

Other patients with no such deformations can be considered as candidates for surgery involving endoprostheses of the ankle joint. However, it is advisable to assess the presence of risk factors for the development of pathological conditions that cause poor outcomes of surgical treatment such as aseptic instability of the endoprosthesis components. These factors, according to the proposed algorithm (Figure 3), should be evaluated at the second stage of selecting a rational method of surgical treatment. Among the risk factors for this pathology the age of the patients is very important. Therefore, it is recommended initially to divide all patients into 2 age groups: under 55 years and older (Figure 3).

When evaluating the older age group, patient history of bone fractures of the ankle joint should be specifically assessed. The surgery for replacement of the ankle joint is only recommended for patients without an identified history of fractures, and if there is such a history it is expedient to look for arthrosis of the affected joints. In the group aged under 55 years, the selection method for surgery should be generally performed in accordance with the same principles as that of the older patient group. However, the assessment of risk factors for the development of instability of installed implants needs to be performed more fully and carefully.

Therefore, within the presented algorithm (Figure 3). we propose initially to allocate the patients under the age of 55 years into 2 subgroups depending on the presence or absence of a history of fractures of the ankle joint. In the presence of such fractures, it is advisable to offer the patients arthrosis ankle joint. In their absence it is also important to rate their level of anticipated physical activity and consequently, possible future functional load on the operated joints. High physical load on the joints was defined in our studies as one of the important risk factors of aseptic instability of the endoprosthesis components of the ankle joint. Therefore, patients with high demands for future functional loads on the affected joints should be made aware that fusion of the ankle joint has a more reliable positive long-term outcome. In cases of expected moderate physical activity of the treated joints, arthroplasty of the ankle joint can be recommended even at a young age.

Discussion

We have analysed unsatisfactory results of surgical treatment of patients with terminal stages of deforming arthrosis of the ankle joint, and found a number of risk factors for their development. These factors were different and specific for each of the 2 main types of surgery. In our view, these factors can and should be considered primarily at the stage of diagnosis and while determining the severity of pathological changes in the affected ankle joint. This is important both for preoperative planning and during surgery involving fusion or TAR.

The most clinically significant pathology observed a year or more after arthroplasty of the ankle joint is aseptic instability of components of the installed implants. According to authors from other countries, the proportion of patients with this pathological condition varies from 3% to 13.7% in the first 5 years after surgery and from 16% to 32% in the period from 5 to 10 years after the treatment [26,29,30]. In our observations, the proportion of patients with radiographic signs of instability of the endoprosthesis components was 19.4% after 2 years and 40% after 3 to 10 years. However, severe clinical symptoms arising from this condition and requiring repeat surgery were observed much less frequently: 3.2% after 2 years and 17.5% in the later periods of observation. It should be noted that the proportion of patients with aseptic instability of the implants in our study were slightly higher because patients purposely went to a clinic, where endoprosthesis treatment for the ankle joint was undertaken. In addition, patients without this pathology did not always agree to be tested over a long-term period after surgical treatment. In a retrospective sub-group of patients (40 observations) analysis of cases of aseptic instability of the endoprosthesis components of the ankle joint showed that the greatest number of them (and accordingly the highest percentage of the number of patients) was recorded 3 years (5 cases or 17.2%) and 5 years (10 cases or 43.5%) after the operations were performed. After 7 years of observations, these figures decreased (about 1 case of 8 or 12.5%) and when 3 patients were examined after 10 years, signs of this pathological condition were absent.

Among the risk factors for the development of the aseptic instability and, consequently, unsatisfactory outcomes for ankle joint replacement, the proposed algorithm first took into account the severity of deformities in the affected ankle joint. In the literature a direct link between the development of aseptic instability of endoprostheses of the ankle joint and deformations of the articular surfaces of the tibia and talus, and also varus or valgus deviations of more than 100 have been reported [8,15,18,27,28]. In addition, many orthopaedists have reported a higher incidence of this pathology among people of a young age [4,22,25] and also in patients with increased functional load on the previously operated ankle joint, related to high physical activity [26,29]. These findings of other authors were fully confirmed in our study, in particular as illustrated by the data given in Tables 3 and 4. Therefore, all of these risk factors were considered significant and included in the algorithm.

In addition, our study identified opportunities to prevent some of the complications and pathological conditions that lead to poor results of surgical treatment, because of certain requirements during the 2 types of operations. In particular, we found that during surgery for ankle joint arthrodesis the aim should be to form an ankylosis with an angle in the sagittal plane of 90°–95°. If this is achieved, it is possible to prevent the rapid development of deforming arthrosis in the joints of the middle part of the foot, which often leads to decreased function and severe pain in the late postoperative period.

The algorithm presented in the present article is based on results of our own research and data from relevant literature. We have considered significant risk factors of the most frequent pathological states arising after surgeries of fusion and TAR and resulting in poor outcomes. At the same time we have shown that the desirable angles of an ankylosis of the ankle joint in the sagittal plane varying from 90°–95° can reduce the probability of rapid progression of arthrosis in joints of the middle part of the foot. For TAR surgery significant risk factors of development of the most frequent reason of unsatisfactory results of treatment (aseptic instability of the components of the installed designs) were revealed. If these are present, the algorithm assumes refusal of Total Ankle Replacement in favour of the more reliable surgery of ankle joint fusion. However, TAR can be indicated for patients aged 55 years and older and without anamnesis of fractures of the bones forming the ankle joint, and also for younger patients corresponding to these criteria but not expecting high loads on the operated joints.

We hope that practical use of the presented algorithm for selection of a method of surgical treatment will promote the prevention of a number of the pathological states predetermining the poor results of surgeries of both discussed types and will help to improve the outcomes of expeditious treatment.

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