Outcomes of Posterior Arthroscopic Reduction and Internal Fixation (PARIF) for the Posterior Malleolar Fragment in Trimalleolar Ankle Fractures

CATEGORY: Arthroscopy; Trauma INTRODUCTION/PURPOSE: The treatment of posterior malleolar fractures within a trimalleolar ankle fracture pattern can be challenging to manage. Due to anatomical constraints that inhibit visualization of the articular surface, reduction of the posterior malleolus relies on cortical read and/or intraoperative fluoroscopy. Posterior ankle arthroscopy is a tool that may address this shortfall by providing a means to assess the intra-articular and syndesmotic reductions, while removing any loose bodies. The purpose of this study was to determine the radiographic and patient reported outcomes of posterior arthroscopic reduction and internal fixation (PARIF) for the posterior malleolar fragment in trimalleolar ankle fractures. METHODS: From November 2015 to May 2019, we prospectively enrolled consecutive trimalleolar ankle fractures that underwent PARIF for the posterior malleolar fragment by a single surgeon. Patient demographics, surgical details, and fracture characteristics, as determined by computed tomography (CT) scan, were obtained. At final follow-up the main outcome measures collected were: The Foot and Ankle Disability Index (FADI), American Orthopaedic Foot & Ankle Society (AOFAS) ankle score, Olerud and Molander Ankle Score (OSMA), the Visual Analog Score (VAS), and surgical complications. Preoperative and postoperative CT scans were interpreted and compared by two blinded musculoskeletal radiologists for articular congruity, syndesmosis congruity, and presence of loose bodies. RESULTS: A total of 29 trimalleolar ankle fractures were treated with PARIF, including 15 fracture-dislocations. Mean patient age was 36 (range, 19-69) years. Mean prone tourniquet time was 58 (range, 35-79) minutes. Preoperative CT scans demonstrated intra-articular loose bodies in 53% of fractures and syndesmosis incongruity in 80% of fractures. Postoperative CT scans showed one ankle with a retained loose body and residual syndesmosis incongruity in 17% of fractures. 100% of fractures healed and demonstrated intra-articular reduction within 2mm. There were 2 complications (hardware irritation and sural nerve numbness). 2-year patient reported outcomes were available in 13 patients. These included mean VAS 1 (range 0-4), mean AOFAS score 84 (range, 63-100), mean FADI 85 (range, 59-100), and mean OSMA 76 (range, 40-100). CONCLUSION: Posterior ankle arthroscopic reduction and internal fixation (PARIF) is a safe and effective option for management of posterior malleolar fractures. The technique results in improved intra-articular and syndesmosis congruity, while removing loose bodies. Future studies are needed that compare this technique with current practices.