Malleolar fracture after total ankle arthroplasty: a comparison of two designs.

There has been a resurgence in the treatment of end-stage tibiotalar arthritis with prosthetic replacement. This procedure has highlighted numerous complications including malleolar fracture. We wanted to determine the clinical relevance of malleolar fracture with the two most commonly used implants in the United States. We retrospectively compared the first 20 STAR with the first 25 Agility total ankle arthroplasties done by two surgeons. We examined the fracture rate, the timing, location, and treatment of the fracture, and the outcome in each group. In the Agility group, five fractures occurred, all intraoperatively. Four involved the medial malleolus and one involved the lateral malleolus. All fractures were fixed as implant stability was compromised. In the STAR group, there were four fractures. Two lateral malleoli fractured intraoperatively and were fixed. Two medial malleoli fractures occurred postoperatively and were treated nonoperatively. There was one medial malleolar nonunion in each group. The incidence of malleolar fracture was 20% in each group, comparable to results reported in relevant literature. We highlight some of the causes of malleolar fracture and describe our technique of prophylactic malleolar pinning to prevent this complication. Malleolar fracture is clinically relevant with the Agility and STAR implants and should be anticipated and prevented.