Variable Volumes of Resected Bone Resulting From Different Total Ankle Arthroplasty Systems

Transfibular Total Ankle Arthroplasty: Clinical, Functional, and Radiographic Outcomes and Complications at a Minimum of 5-Year Follow-up

BACKGROUND

The Trabecular Metal Total Ankle Implant differs from other newer-generation implants in the transfibular approach, multiplanar external frame for alignment, tantalum trabecular metal interfaces, curved geometry, and shallow resection depths. The primary aim of this study was to report midterm clinical and radiographic results, as well as survivorship and adverse events at a minimum of 5-year follow-up.

METHODS

A total of 83 ankles (81 patients, average age 60.6 years old, 50.6% females) with average 6.3 years' (range, 5.0-10.1) follow-up were included. Postoperative patient-reported outcome measures (PROMs) included SF-12 physical (PCS) and mental component summary (MCS) scores, Ankle Osteoarthritis Scale (AOS), pain visual analog scale (VAS). Radiographic outcomes included postoperative range of motion (ROM) and coronal/sagittal alignment. Adverse events were reported using the Canadian Orthopaedic Foot and Ankle Society Reoperation Coding System (CROCS).

RESULTS

Preoperative tibiotalar coronal deformity included 27 valgus (10 degrees, range 2-20 degrees) and 25 varus ankles (-9 degrees, range -2 to -25 degrees), corrected to neutral postoperatively. Postoperative tibiopedal ROM was 17.8 degrees dorsiflexion and 21.8 degrees plantarflexion. Adverse events occurred at average 28.7 months, most commonly gutter debridement (n = 17, 16.7%) and subsequent operative treatment unrelated to metal components (n = 10, 12.0%). There were 2 cases (2.4%) of acute deep infection treated with irrigation and debridement, polyethylene exchange, and retention of metal components without recurrence of infection. There were no cases of fibular nonunion, septic or aseptic loosening, or implant subsidence. Postoperative PROMS included SF-12 PCS: 40.4; SF-12 MCS: 56.0; VAS: 2.3; AOS Pain: 17.0; and AOS Disability: 24.9. Overall implant survival, defined by retention of the metal components, was 100% at final follow-up.

CONCLUSION

At a minimum of 5 years, patients who underwent TM TAA reported minimal ankle pain and regained neutral ankle alignment and mobility, without septic or aseptic implant loosening. Although having certain limitations, this study suggests that TM TAA is a viable option for the treatment of end-stage ankle arthritis.

Survival and complications of transfibular trabecular metal total ankle replacement - A systematic review

BACKGROUND

In the past decade, the transfibular approach to Total Ankle Replacement (TAR) has emerged as an alternative to anterior approach with reduced bone resection. The purpose of this systematic review is to report survival, complications, and reoperation rates of transfibular TAR.

METHODS

We conducted a systematic search of studies that evaluated complications, reoperations, and survival of transfibular TAR following PRISMA guidelines across PubMed, Scopus and Web of Science.

RESULTS

Our review included data from 12 cohorts, comprising 919 patients across 7 countries, with an average age of 62 years (59% posttraumatic). Over an average follow-up period of 3 years, adverse events occurred in 23% of cases, with 18% requiring surgical reintervention, mostly due to hardware removal. The survival rate of the transfibular TAR metal components was 97% at the final follow-up.

CONCLUSION

Transfibular TAR demonstrates a 97% survival rate at a 3-year follow-up.

LEVEL OF EVIDENCE

Level II.

Outcomes of Lateral Transfibular Approach for Total Ankle Replacement

Total ankle replacement through a lateral transfibular approach with trabecular metal implants was introduced in 2012 and originally was advertised as a safer approach in terms of wound healing issues. Further studies showed no significant difference comparing anterior and lateral approach for infections and would healing issues, whereas the main advantage is deformity correction, acting on coronal, sagittal, and rotational deformities and on fibular length issues. It showed a survival rate of 97.7% at 5 years follow-up.

Comparison of Radiographic Talar Loosening Rates Between Salto-Talaris and INBONE II

BACKGROUND

Despite substantial increase in total ankle arthroplasty (TAA) nationwide, there are few studies comparing flat-cut vs chamfer-cut talar systems in TAA with regard to radiographic aseptic loosening rates of the implant.

METHODS

This retrospective study included 189 Salto-Talaris TAA and 132 INBONE II primary TAA with a minimum 1-year follow-up. Patient characteristics were obtained including gender, age at surgery, body mass index (BMI), smoking status, primary diagnosis, surgical time, and the presence of diabetes. Radiographic evidence for aseptic loosening was assessed. Statistical analysis was performed for comparison in outcomes between Salto-Talaris and INBONE II.

RESULTS

The mean age of the study population was 63.5 ± 9.8 years at surgery. Mean follow-up was 4.9 ± 3.0 years. Radiographic aseptic loosening of the tibial implant showed no significant difference between the 2 groups: Salto-Talaris, 18%, and INBONE II, 18.9% (P = .829). Aseptic loosening of the talar implant also showed no significant difference between the 2 groups: Salto-Talaris, 1.6%, and INBONE II, 1.5% (P = .959). No variables, including the implant type, were found to contribute to the aseptic loosening rate of either the tibia or talus.

CONCLUSION

In our cohort, we observed no difference in radiographic implant aseptic loosening between Salto-Talaris and INBONE II systems.

LEVEL OF EVIDENCE

Level IV, retrospective case series study.

Republication of "Perspectives in Treatments of End-Stage Ankle Arthritis Among Orthopaedic Surgeons: Analysis of an American Orthopaedic Foot & Ankle Society (AOFAS) Member Survey"

Background

This study aimed to assess the preferred operative treatment for patients over the age of 60 with end-stage ankle arthritis and perspectives on total ankle replacement (TAR) among American Orthopaedic Foot & Ankle Society (AOFAS) members. Associated factors were analyzed for potential contraindications among members with different levels of experience.

Method

A questionnaire containing 6 questions was designed and sent to 2056 members of the AOFAS. Responses were received from 467 orthopaedic surgeons practicing in the United States (76%), Canada (5%), and 26 other countries (20%). Participants were grouped for response comparisons according to country as well as experience level. Differences in contraindications were compared using χ2 tests or exact tests.

Results

Respondents practicing in the United States and surgeons who perform 11 or more TARs per year tended to recommend operative treatments favoring TAR and displayed recognition of its increasing role (P < .05). Overall, respondents felt that 41% of typical patients over 60 years old with end-stage arthritis would be best treated with TAR. Talus avascular necrosis, morbid obesity (body mass index >40 kg/m2), and poorly controlled diabetes with neuropathy were most recognized as the absolute contraindications to TAR. Surgeon's experience affected the consideration of these clinical factors as contraindications.

Conclusions

Total ankle replacement has a substantial and increasing role in the treatment of end-stage ankle arthritis in patients over the age of 60. Absolute and potential contraindications of the procedures were indicated from a cross-sectional survey of AOFAS members. Surgeons more experienced with total ankle replacement felt more comfortable employing it in a wider range of clinical settings.

Level of Evidence

Level III, therapeutic.

A combined FE-hybrid MCDM framework for improving the performance of the conical stem tibial design for TAR with the addition of pegs

BACKGROUND AND OBJECTIVES

The conical stemmed design of the tibial component for total ankle replacement (TAR) (example Mobility design) uses a single intramedullary stem for primary fixation. Tibial component loosening is a common mode of failure for TAR. Primary causes of loosening are lack of bone ingrowth due to excessive micromotion at the implant-bone interface and bone resorption due to stress shielding after implantation. The fixation feature of the conical stemmed design can be modified with the addition of small pegs to avoid loosening. The aim of the study is to select the improved design for conical stemmed TAR using a combined Finite Element (FE) hybrid Multi-Criteria Decision-Making (MCDM) framework.

METHODS

The geometry and material properties of the bone for FE modeling were extracted from the CT data. Thirty-two design alternatives with varying pegs in number (one, two, four, eight), location (anterior, posterior, medial, lateral, anterior-posterior, medial-lateral, equally spaced), and height (5 mm, 4 mm, 3 mm, 2 mm) were prepared. All models were analyzed for dorsiflexion, neutral, and plantarflexion loading. The proximal part of the tibia was fixed. The implant-bone interface coefficient of friction was taken as 0.5. The implant-bone micromotion, stress shielding, volume of bone resection, and surgical simplicity were the important criteria considered for evaluating the performance of TAR. The designs were compared using a hybrid MCDM method of WASPAS, TOPSIS, EDAS, and VIKOR. The weight calculations were based on fuzzy AHP and the final ranks on the Degree of Membership method.

RESULTS

The addition of pegs decreased the mean implant-bone micromotions and increased stress shielding. There was a marginal decrease in micromotion and a marginal increase in stress shielding when the peg heights were increased. The results of hybrid MCDM indicated that the most preferable alternative designs were two pegs of 4 mm height in the AP direction to the main stem, two pegs of 4 mm height in the ML direction, and one peg of 3 mm height in the A direction.

CONCLUSIONS

Outcomes of this study suggest that the addition of pegs can reduce the implant-bone micromotions. Modified three designs would be useful by considering implant-bone micromotions, stress shielding, volume of bone resection, and surgical simplicity.

Tibial Component Subsidence in a Total Ankle System Comparing Standard Technique Versus a Hybrid Technique

Total ankle arthroplasty (TAA) is a viable treatment option for end-stage ankle arthritis. However, implant survivorship remains an important consideration. Concerns regarding early component loosening with the low-profile tibial tray utilized by fourth-generation TAA systems have been raised in the literature. We have previously described our preliminary outcomes of a hybrid technique combining a stemmed intramedullary tibial component with a chamfer-cut talar component for TAA. A retrospective study comparing short-term outcomes of the tibial component between a standard fourth-generation TAA system versus our hybrid technique was performed. 46 patients with a minimum of 1-year follow up were included in the analyses. There were 25 subjects in the standard implant cohort utilizing a low-profile tibial tray, and 21 subjects in the hybrid group utilizing a stemmed intramedullary tibial component. No statistically significant difference between the demographics of each group was found. The rate of tibial component subsidence was 8% (n = 2) in the standard implant group, and 0% (n = 0) in the hybrid group, though this did not meet statistical significance (p = .49). Mean time to subsidence was 6 months, and revision rate due to tibial component subsidence was 2.1% (n = 1). Periprosthetic lucency was present on most recent follow-up radiographs in 32% and 9.5% of ankles in the standard and hybrid groups, respectively (p = .08). Despite prior concerns for tibial component subsidence with the standard fourth-generation system, we demonstrated low rates in both implant groups. Additional studies are needed to further explore factors that may predispose patients to early tibial component subsidence and resulting implant failure.

Feasibility and reliability of DEXA analysis after total ankle arthroplasty: A cadaver study

BACKGROUND

Although the outcomes of total ankle arthroplasty (TAA) have improved, unsolved problems such as stress shielding remain. Although dual energy X-ray absorptiometry (DEXA) is the "gold standard" for evaluation of these issues, it is rarely used in patients after TAA. This study aimed to establish a scan technique and to assess the mechanical changes in bone density caused by bone stock preparation.

METHODS

Eight fresh-frozen cadaver legs were investigated by DEXA before TAA, with implant in situ, and after implant removal. Scan surface, bone mineral content, and bone mineral density were analysed to assess mechanical bone mass changes.

RESULTS

We examined data for density changes by bone compression after TAA, and found "good" results for internal reliability but only "acceptable" results for external reliability.

CONCLUSIONS

The results were reliable and reproducible. Using the present data, mechanical and biological processes can be considered together to understand the postoperative phases of bone remodelling after TAA.

A Modification of the Fibular Osteotomy for Total Ankle Replacement Through the Lateral Transfibular Approach

BACKGROUND

One disadvantage of lateral transfibular total ankle arthroplasty is the rate of symptoms related to the implant and wound issues requiring implant removal in association with the traditional fibular osteotomy. In the present study, lateral total ankle arthroplasty involving the traditional short oblique fibular osteotomy was compared with arthroplasty involving a long oblique osteotomy (the Foot & Ankle Reconstruction Group osteotomy).

METHODS

We retrospectively reviewed all primary lateral total ankle arthroplasties that had been performed by a single surgeon from May 2013 to October 2016 and had a minimum of 2 years of follow-up. Clinical assessment included patient demographics, wound complications, the need for implant removal, the pain score on a visual analog scale, the American Orthopaedic Foot & Ankle Society score, and the Short Form-12 Mental and Physical Component Summary scores. Weight-bearing radiographs were used to assess tibiotalar alignment, implant alignment, and fibular osteotomy healing.

RESULTS

One hundred and fifty-nine total ankle arthroplasties were identified. The traditional short fibular osteotomy was used in 50 ankles, and the long oblique osteotomy was used in 109. The rate of survival of the tibial and talar components of the ankle replacements was 100%, and there were no osteotomy nonunions. There was improvement in all clinical parameters, with no significant difference between the 2 groups. Radiographs showed excellent arthroplasty alignment at all time points, with no significant difference between the groups. There was a significant difference in the rates of wound dehiscence (p = 0.011) and fibular implant removal (p < 0.0001), with the long oblique osteotomy having lower rates of both (2.8% and 2.8%, respectively) compared with the short oblique osteotomy (14% and 28%, respectively).

CONCLUSIONS

In total ankle arthroplasty, modification of the traditional short oblique fibular osteotomy to a long oblique configuration provided excellent 2-year survival rates with good clinical and radiographic outcomes and decreased rates of wound complications and symptoms related to the fibular implant.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Perspectives in Treatments of End-Stage Ankle Arthritis Among Orthopaedic Surgeons

Background:

This study aimed to assess the preferred operative treatment for patients over the age of 60 with end-stage ankle arthritis and perspectives on total ankle replacement (TAR) among American Orthopaedic Foot & Ankle Society (AOFAS) members. Associated factors were analyzed for potential contraindications among members with different levels of experience.

Method:

A questionnaire containing 6 questions was designed and sent to 2056 members of the AOFAS. Responses were received from 467 orthopaedic surgeons practicing in the United States (76%), Canada (5%), and 26 other countries (20%). Participants were grouped for response comparisons according to country as well as experience level. Differences in contraindications were compared using χ2 tests or exact tests.

Results:

Respondents practicing in the United States and surgeons who perform 11 or more TARs per year tended to recommend operative treatments favoring TAR and displayed recognition of its increasing role ( P < .05). Overall, respondents felt that 41% of typical patients over 60 years old with end-stage arthritis would be best treated with TAR. Talus avascular necrosis, morbid obesity (body mass index >40 kg/m2), and poorly controlled diabetes with neuropathy were most recognized as the absolute contraindications to TAR. Surgeon’s experience affected the consideration of these clinical factors as contraindications.

Conclusions:

Total ankle replacement has a substantial and increasing role in the treatment of end-stage ankle arthritis in patients over the age of 60. Absolute and potential contraindications of the procedures were indicated from a cross-sectional survey of AOFAS members. Surgeons more experienced with total ankle replacement felt more comfortable employing it in a wider range of clinical settings.

Level of Evidence:

Level III, therapeutic.

Early Clinical and Radiographic Outcomes of Trabecular Metal Total Ankle Replacement Using a Transfibular Approach

BACKGROUND

In the last 2 decades, total ankle replacement has gained greater acceptance as a treatment option in patients with end-stage ankle osteoarthritis. However, there is a lack of literature on total ankle replacement using a lateral transfibular approach. Therefore, we sought to report early clinical and radiographic results for a patient cohort treated with total ankle replacement using a lateral transfibular approach, performed by a single surgeon.

METHODS

From October 2012 to December 2014, 55 primary total ankle arthroplasties using the Zimmer Trabecular Metal Total Ankle implant were performed in 54 patients (29 male and 25 female; mean age, 67.0 years). Clinical assessment, including pain evaluation and measurement of ankle range of motion, was conducted preoperatively and at the latest follow-up. Weight-bearing radiographs were used to determine angular alignment of the tibial and talar components and to analyze the bone-implant interface. Intraoperative and postoperative complications, revision surgeries, and survivorship were evaluated.

RESULTS

Implant survival was 93% at 24 months of follow-up. There were 3 revisions of a tibial component due to aseptic loosening. In 10 of the 55 cases, a secondary procedure was performed during follow-up. The mean follow-up duration was 26.6 ± 4.2 months. No delayed union or nonunion was observed for fibular healing. The average visual analog scale (VAS) pain score decreased significantly, from 7.9 ± 1.3 to 0.8 ± 1.2. The average total range of motion increased significantly, from 22.9° ± 12.7° to 40.2° ± 11.8°.

CONCLUSIONS

Early results of total ankle replacement using the Zimmer trabecular metal implant and the lateral transfibular approach demonstrated improved patient-reported outcomes and increased ankle motion at a minimum follow-up of 2 years. In the 55 consecutive cases, the fibular osteotomy required for access to the ankle healed without complications. Painful early loosening due to lack of osseous ingrowth required revision in 3 of 55 cases.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.