Total ankle arthroplasty and coronal plane deformities.

INTRODUCTION: There is no consensus regarding total ankle replacement (TAR) in case of arthritis associated with coronal plane deformities. The purpose of this study was to determine, based on clinical and radiographic outcomes, the technical requirements and additional procedures that should be performed in such indications.

HYPOTHESIS: Coronal deformities greater than 10° are not a contraindication to TAR if a stable and aligned ankle can be obtained after surgery.

MATERIALS AND METHODS: Of a total of 131 TAR, 21 were performed on coronal plane deformities greater than 10°. Only cases of osteoarthritis secondary to fracture or chronic instability were included. Inflammatory ankles were excluded. Twenty-one patients (15 men and 6 women), mean age 57 years old (±12) were reviewed retrospectively with a mean follow-up of 38 months (±26). Patients were divided into four groups, categorizing first, congruent and incongruent ankles, and second varus and valgus deformities. Associated procedures were performed from proximal to distal, correcting periarticular malunions first, ligament imbalances, associated deformities of the foot and equinus deformity. Revision arthrodesis and implant changes due to loosening or progressive instability were considered to be failures.

RESULTS: Surgery resulted in improved functional outcome and durable correction of the deformity, passing from 16.5° (±4.9) to 2.5° (±3.9) for varus, and from 16.7° (±5.6) to 1.4° (±2.1) for valgus. Six varus ankles required revision surgery for further corrections. Three incongruent ankles failed.

DISCUSSION: Correction of osteoarticular deformities and ligament imbalance in case of frontal deformities requires a significant number of associated procedures. Residual defects are detrimental to implant longevity and warrant further correction. Short-term results are satisfactory even for severe deformities, but require longer-term monitoring.

LEVEL OF EVIDENCE: Level IV. Retrospective study.