Comparison of Intermediate to Long-Term Outcomes of Total Ankle Arthroplasty in Ankles with Preoperative Varus, Valgus, and Neutral Alignment

Abstract

Background: Preoperative ankle coronal malalignment has been considered as a risk factor for poor outcomes and failure after total ankle arthroplasty. The present study evaluated whether intermediate to long-term outcomes of total ankle arthroplasty in ankles with preoperative varus and valgus malalignment (5° to 20°) are comparable with those with neutral alignment (<5°).

Methods: We enrolled 144 consecutive ankles that underwent primary total ankle arthroplasty (140 patients) using a mobile-bearing HINTEGRA prosthesis with a minimum follow-up of 4 years; the mean overall follow-up duration was 89 months (51 to 145 months). We divided all patients into 3 groups according to the preoperative coronal plane tibiotalar angle: the varus group (59 ankles, 5° to 20° of varus), the valgus group (34 ankles, 5° to 20° of valgus), and the neutral group (51 ankles, <5°). Patients in each group showed similar characteristics in mean age, sex, body mass index, and follow-up period.

Results: The mean Ankle Osteoarthritis Scale pain and disability score, American Orthopaedic Foot & Ankle Society ankle-hindfoot score, Short Form-36 Physical Component Summary score, visual analog scale pain score, and ankle range of motion did not differ meaningfully among the 3 groups at the final follow-up. The final tibiotalar angle showed that the degree of coronal alignment of the varus group was significantly less corrected compared with the neutral group (p = 0.010). The varus group had significantly more concomitant procedures (42 procedures [71.2%]) compared with the neutral group (p = 0.003). The prevalence of major complications did not differ among the 3 groups (p = 0.124). The overall probability of implant survivorship was 91.1% (97.7% in the varus group, 81.1% in the valgus group, and 90.9% in the neutral group) at a mean follow-up of 7.3 years.

Conclusions: In the intermediate to long-term follow-up, mobile-bearing total ankle arthroplasty showed similarly good outcomes in patients with varus and valgus malalignment up to 20° compared with the neutral alignment group when neutrally aligned ankles were achieved postoperatively.

Level of evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.