DO PERIPROSTHETIC FRACTURES CHANGE THE OUTCOME IN THE MOBILITY TOTAL ANKLE REPLACEMENT

Introduction The standard practice of uncomplicated total ankle replacement (TAR) involves postoperative immobilisation. Periprosthetic fracture is a well-recognised complication following ankle arthroplasty . It occurs predominantly as a stress reaction on the medial tibial metaphysis during the postoperative rehabilitation period. Occasionally it occurs during surgery. We present fractures from a single-centre series of Mobility TARs. Materials and Methods We have 133 TARs with 3 to 48 months9 follow-up. 28 patients were excluded for the following reasons: other major procedure performed concurrently (osteotomy or tendon transfer), custom prosthesis, revision surgery, fusion conversions, or patients involved in a separate RCT (n = 16). We do not routinely immobilise patients postoperatively but allow partial to full weight-bearing as able. Outcome scores were compared to those without fractures. Results 105 patients were included in the study. Nine (8.6%) patients sustained a periprosthetic fracture with no history of significant trauma. One of these was intraoperative; this was a posterior tibial fracture noticed on postoperative radiographs. The remainder (n = 8) were tibial metaphyseal stress fractures, all occurring within the first three months, most (n = 6) within six weeks. One occurred on the sixth post-op day and was managed in cast. Seven were asymptomatic at diagnosis and managed nonoperatively; one was fixed at three months due to radiological medial migration of the talus and one was fixed at seven months due to progression to symptomatic non-union. The remainder united. Between those with and without fractures, there was no significant difference in age (mean 61.4 vs. 62.1, p = 0.387), diagnosis leading to arthroplasty (OA, RA, PTOA), or outcome scores (12 months: 83 vs. 78, p = 0.237) Conclusion Periprosthetic fracture remains a significant complication of total ankle arthroplasty . However, in our series, they do not lead to increased morbidity or worse outcome scores than patients without fractures and most can be managed nonoperatively.