Subtalar Distraction Arthrodesis for the Treatment of Subtalar Arthritis and Severe Hindfoot Deformity: A Systematic Review

Abstract

Category: Hindfoot; Trauma Introduction/Purpose: Subtalar distraction arthrodesis (SDA) was developed as a means of treating the symptoms of subtalar arthritis. Despite almost 30 years of research in this field, many controversies still exist regarding SDA. The objectives of this study were (1) to conduct a systematic review of clinical outcomes following SDA, (2) to assess the demographics, indications, and surgical technique used, (3) to assess the clinical and radiographic outcomes of this procedure and its role in improving function, (4) to provide treatment recommendations based on the best available literature, and (5) to identify knowledge deficits that require further investigation. Methods: MEDLINE and EMBASE were queried with an end date of January 1, 2018 using the keywords The keywords used for this search included ‘‘subtalar,’’ ‘‘talar,’’ ‘‘talus,’’ ‘‘bone,’’ ‘‘block,’’ ‘distraction,’ ‘arthrodesis,’ ‘fusion,’ ‘arthritis,’ ‘arthrosis,’ ‘calcaneus,’ ‘calcaneal,’ ‘fracture,’ ‘malunion,’ ‘deformity,’ and ‘‘clinical outcome,’’ alone and in various combinations using the Boolean operator ‘‘AND.’’ Data abstraction was performed by two independent reviewers. Inclusion criteria for the articles were (1) English language, (2) peer-reviewed clinical studies with evidence levels I to IV, (3) with at least five patients, (4) reporting clinical and/or radiographic outcomes of SDA. Data collected included: demographics, operative techniques, radiographic measures, clinical and functional outcomes, and complications. The level of evidence for each study was assessed according to the method described by Wright et al. Methods followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Results: Twenty-five studies matched the inclusion criteria (2 Level III and 23 Level IV studies) including 492 feet in 467 patients. The most common indication for SDA was late complications of calcaneus fractures. Many different operative techniques have been described, and there is no proven superiority of one method over the other. The most commonly reported complications were nonunion, hardware prominence, wound complications, and sural neuralgia. All studies showed both radiographic and clinical improvement at the last follow-up visit compared with the preoperative evaluation. Pooled results (12 studies, 237 patients) demonstrated improved American Orthopaedic Foot & Ankle Society ankle hindfoot scores with a weighted average of 33 points of improvement. Conclusion: Subtalar bone block arthrodesis provides good clinical results at short-term and midterm follow-up, with improvement in ankle function as well as acceptable complication and failure rates. These consistent clinical outcomes throughout the literature, despite different lengths of followup periods, suggest that the functional results do not deteriorate with time. Higher confidence recommendations for SDA require longer follow-up, clear indications and treatment protocols, standardized clinical and radiographic outcome measures, and direct comparison or stratification of results based on graft type and other operative techniques.