Impact of preoperative varus deformity severity on clinical and radiographic outcomes following total ankle arthroplasty.

BACKGROUND

The influence of preoperative varus deformity on outcomes following total ankle arthroplasty (TAA) remains controversial, and severe varus malalignment is traditionally regarded as a technical challenge that may compromise implant positioning.

PURPOSE: To compare clinical outcomes, radiographic correction, and complication rates after TAA stratified by the severity of preoperative varus deformity.

STUDY

DESIGN

Retrospective comparative study; Level III.

METHODS

We retrospectively reviewed 190 TAAs performed between June 2014 and June 2023 using a cementless, three-component mobile-bearing prosthesis. Ankles were categorized by preoperative coronal alignment into neutral (< 5°), mild-to-moderate varus (5° to < 15°), and severe varus (≥ 15°) groups. Outcomes included the American Orthopaedic Foot & Ankle Society (AOFAS) score, visual analog scale (VAS) pain score, ankle range of motion, five coronal-plane radiographic angles, complications, osteolysis, and reoperations. Three-group comparisons used analysis of variance or the Kruskal-Wallis test and the chi-square or Fisher exact test.

RESULTS

Of the 190 ankles, 61 were neutral, 91 mild-to-moderate varus, and 38 severe varus. Severe deformity required significantly more concomitant procedures, particularly lateral sliding calcaneal osteotomy and first tarsometatarsal arthrodesis. Despite this, radiographic correction was achieved in all groups. Clinical outcomes improved substantially, with AOFAS scores increasing from approximately 46-48 preoperatively to 87-91 postoperatively and VAS pain scores decreasing from 6.8-7.2 to 1.2-1.3. Complication, osteolysis, and reoperation rates were comparable among groups.

CONCLUSION

Although severe varus deformity often requires additional corrective procedures, TAA can provide comparable mid-term clinical outcomes and complication rates across deformity severities when appropriate surgical strategies are applied.