Introduction and Aims: Many patients having total ankle replacement require correction of a coronal plane deformity. This study examines the pre-operative characteristics and short-term results of patients with a coronal plane deformity having total ankle replacement. It tests the hypotheses that the pre-operative deformity will be corrected and maintained at two years.

Method: Eighteen of 86 patients who underwent Scandinavian Total Ankle Replacement between February 1998 and April 2001 had a pre-operative coronal plane deformity ≥ 10° and at least two-year follow-up. The goal of intraoperative alignment was to place all components perpendicular to the plumb line of the body, and to have this position maintained by appropriate ligament balancing. The mean patient age was 62.2±13.2 years. The etiology of arthrosis included eight post-traumatic, five idiopathic, one rheumatoid, and four other. There were 10 men and eight women. Valgus measurements are > 90°. Congruent ankles have pre-operative talar and tibial alignment within 10 degrees.

Results: Ligament balancing consisting of lateral ligament reconstruction was performed in six patients and superficial deltoid release was performed in three patients. The eight ankles with pre-operative varus-congruent alignment improved both the talar and tibial alignment immediately post-operatively and at two-year follow-up (p< 0.05). There was only one ankle with valgus-congruent alignment precluding statistical testing. The six ankles with varus-incongruent alignment improved the talar alignment immediately post-operatively and at two-year follow-up (p< 0.05). The three ankles with valgus-incongruent alignment improved the talar alignment immediately post-operatively and at two-year follow-up (p< 0.05).

Ankles with an incongruent pre-operative deformity had a greater loss of correction of the talus between the immediate pre-operative period and two-year follow-up than patients with a congruent pre-operative deformity (3.9±2.8 degrees vs. 1.3±1.0 degrees loss of correction, p< 0.05). The valgus-incongruent group lost 2.3 degrees of correction from the immediate post-operative period to the two-year follow-up (p< 0.05). The varus-incongruent showed a trend to lose 4.0 degrees of correction from the immediate post-operative period to the two-year follow-up (p=0.065).

Conclusion: In patients with a pre-operative coronal plane deformity ≥ 10 degrees, alignment after ankle replacement improves toward a neutral axis in the postoperative period and at two-year follow-up. Ankles with incongruent pre-operative deformities have a greater loss of correction over the first two years than ankles with congruent pre-operative deformities.