Surgical Outcome of Unfixed Controlled Medial Malleolar Breakage for a Balanced Total Ankle Replacement

Category: Ankle Arthritis; Ankle Introduction/Purpose: Ligament balancing is very important for successful TAR (total ankle replacement). However, regarding medial tightness the amount of medial ligament release seems to be uncertain. Furthermore, the risk of medial instability and vascular insult can be major concerns after extensive deep deltoid release. Thus, I hypothesized that medial malleolar breakage instead of deltoid release would result in similar stability and heal more predictably with less complications. Methods: Between December 2019 and December 2022, 18 patients underwent total ankle replacement with medial malleolar breakage for ligament balancing. There was 14 females, and the average age was 70.5 (53-84). Concomitant procedures such as Achilles tendon lengthening, lateral ligament repair, subtalar joint debridement and 1st metatarsal osteotomy were added to get a stable and plantigrade foot. When there was still medial tightness after thorough spur resection and anterior part of superficial deltoid release, subcortical osteotomy was made around the medial malleolous instead of deep deltoid release. Then controlled valgus force was driven till a pop sound came out. No fixative was applied for broken bone. The surgery was finished only when coronal plane stability of the TAR was achieved. Short leg walking cast was applied for 3 to 4 weeks, and then range of motion exercise and tolerable weight bearing was allowed in a walking boot for another 4 weeks. Results: All patients were followed for more than 6 months after the index surgery. AOFAS (American Orthopedic Foot and Ankle Surgery) ankle-hindfoot score improved from average 36.2(10-60) to 72.7(50-90), and all returned to their daily activity. There was no major complication such as coronal plane instability or dislocation, deep infection and aseptic loosening. Two patients experienced minor wound dehiscence which have been healed, and another 3 patients suffered from superficial peroneal nerve irritation. Conclusion: Unfixed controlled medial malleolar breakage during TAR for varus ankle arthritis showed good results with few morbidities. However, longer term follow up is necessary to determine its clinical usefulness definitely.