Patient-Reported Outcome Measures and Radiological Outcomes in Mobile-Bearing Total Ankle Arthroplasty With Varus or Valgus Deformity.

BACKGROUND

There is increasing evidence that varus deformity does not negatively affect total ankle arthroplasty (TAA) outcomes, but there is a sparsity of evidence for valgus deformity. We present our outcomes using a mobile-bearing prosthesis for neutral, varus, and valgus ankles.

METHODS

This is a retrospective cohort study of consecutive cases identified from a local joint registry. In total, 230 cases were classified based on preoperative radiographs as neutral (152 cases), varus greater than 10 degrees (60 cases), or valgus greater than 10 degrees (18 cases). Tibiotalar angle was again measured postoperatively and at final follow-up (mean follow-up of 55.9 months). A total of 164 cases had adequate patient-reported outcome measures data (Foot and Ankle Outcome Score, Short Form-36 [SF-36] scores, and patient satisfaction) for analysis (mean follow-up of 61.6 months). The groups were similar for body mass index and length of follow-up, but neutral ankles were younger (P = .021).

RESULTS

Baseline scores were equal except SF-36 physical health, with valgus ankles scoring lowest (P = .045). Valgus ankles had better postoperative pain (P = .025) and function (P = .012) than neutral. Pre- to postoperative change did not reach statistical significance except physical health, in which valgus performed best (P = .039). Mean final angle for all groups was less than 5 degrees. There was no significant difference in revision rates.

CONCLUSION

Our study is consistent with previous evidence that varus deformity does not affect outcome in TAA. In addition, in our cohort, outcomes were satisfactory with valgus alignment. Postoperative coronal radiological alignment was affected by preoperative deformity but within acceptable limits. Coronal plane deformity did not negatively affect radiological or clinical outcomes in TAA.

LEVEL OF EVIDENCE: Level III, retrospective comparative study.