Total ankle replacement in patients with significant pre-operative deformity of the hindfoot

TLDR

Adequate correction of alignment and instability is crucial in ankle replacement. The study performed 123 total ankle replacements in 111 patients, comparing those with hindfoot deformity ≤10° to those with 11–30° over a mean four‑year follow‑up. Despite a 14.6% failure rate, survival was similar between groups, but group B achieved better functional scores; most failures were due to gross instability that lateral ligament reconstruction did not correct, yet ankle replacement remains safe for deformities up to 30°.

Abstract

We carried out 123 consecutive total ankle replacements in 111 patients with a mean follow-up of four years (2 to 8). Patients with a hindfoot deformity of up to 10 degrees (group A, 91 ankles) were compared with those with a deformity of 11 degrees to 30 degrees (group B, 32 ankles). There were 18 failures (14.6%), with no significant difference in survival between groups A and B. The clinical outcome as measured by the post-operative American Orthopaedic Foot and Ankle Surgeons score was significantly better in group B (p = 0.036). There was no difference between the groups regarding the post-operative range of movement and complications. Correction of the hindfoot deformity was achieved to within 5 degrees of neutral in 27 ankles (84%) of group B patients. However, gross instability was the most common mode of failure in group B. This was not adequately corrected by reconstruction of the lateral ligament. Total ankle replacement can safely be performed in patients with a hindfoot deformity of up to 30 degrees . The importance of adequate correction of alignment and instability is highlighted.