Restoration of Talar Height using a Modular Revision Prosthesis after Failed Total Ankle Arthroplasty

Abstract

Category: Ankle Arthritis Introduction/Purpose: Talar component subsidence is the most common indication for revision total ankle replacement. The management of talar bone loss and alteration in the ankle joint center of rotation is challenging following component subsidence. Unfortunately, ankle arthrodesis as a salvage procedure for failed ankle arthroplasty has been associated with high rates of nonunion and collapse. Equally unfortunate, there is paucity in the literature on revision total ankle arthroplasty. The purpose of this study was to report the early outcomes of revision total ankle replacement using a modular prosthesis and metal/cement augmentation to reconstitute talar height following catastrophic failure of the index total ankle arthroplasty. Methods: A retrospective review was performed on sixteen patients who underwent revision total ankle replacement for failed arthroplasty associated with talar component subsidence and subsequent talar bone loss. Demographic data, postoperative complications, index implant, and concomitant procedures were recorded. Radiographic measurements were performed at three time-points (preoperative, immediately postoperative, and most recent follow-up) to evaluate alignment of the prosthesis, talar height restoration, and range of motion. Results: Patient follow-up ranged from 9.3 –19.1 months, with a mean follow-up period of 12.2 months. The maximum preoperative and postoperative talar coronal misalignment was 16.2° and 3.5°, respectively. The mean preoperative and immediate postoperative talar height was 28.7 mm and 33.3 mm, respectively. There was a significant improvement in talar height of 4.6 mm after revision total ankle replacement (P<0.001). There was no difference in talar height between the immediate postoperative visit and latest follow-up visit (33.2 mm). The mean preoperative and postoperative radiographic arc of motion was 19.5° and 24.0°, respectively. Ten patients (62.5%) did not sustain complications post surgical. Three patients developed a superficial wound complication that healed without additional surgery. One patient required a transmetatarsal amputation. Other complications included neuritis and DVT. Conclusion: Revision ankle replacement using a modular prosthesis with metal/cement augmentation allows restoration of talar height. Though we recognize this data constitutes a very early follow up, this cohort has utilized the revision ankle implant with significant repetitive load after which older generation implants underwent secondary subsidence due to poor talar bone stock. Early outcomes demonstrate a predictable method to salvage catastrophic prosthesis failure associated with severe talar subsidence and deformity. The risk of postoperative complications, although moderate, is an acceptable alternative to lower limb amputation/arthrodesis. Further follow up is warranted to determine functional outcomes and longevity of revision implant systems.