Impact of preoperative varus on ankle replacement survival

Abstract

Introduction: The severity of a foot or ankle deformity is a major prognostic factor for the success of ankle replacement. Varus deformity is at once the most arthrogenic and the most frequent.

Hypothesis: The severity of preoperative varus is a negative factor for ankle replacement survival.

Material and method: A retrospective study compared results in a continuous series of 57 Salto-Talaris® ankle replacements according to preoperative varus: 31 moderate (5-15̊) and 26 severe (> 15̊). Radiological and clinical assessment at a minimum 1 year focused on complications, revision and implant exchange and on AOFAS score, range of motion and tibiotalar angle at last follow-up.

Results: At a mean 2.4 years' follow-up, implant survival in the moderate and severe varus groups was respectively 83% and 92%. Postoperative AOFA score and range of motion improved significantly in both groups, without significant difference. Analysis of cumulative survival showed no significant intergroup difference.

Discussion: Severity of preoperative varus did not impact implant survival. Only postoperative alignment and stability emerged as survival factors. These results were related to the quality of associated procedures aiming to reduce deformity and to achieve ligament balance.

Level of evidence: IV, retrospective comparative study.

Keywords: Ligament balancing; Tibiotalar alignment; Total ankle arthroplasty; Total ankle replacement; Varus.