The Impact of Coronal Plane Deformity on Ankle Arthrodesis and Arthroplasty

Background: Ankle coronal plane deformity represents a complex 3-dimensional problem, and comparative data are lacking to guide treatment recommendations for optimal treatment of end-stage ankle arthritis with concomitant coronal plane deformity. Methods: In total, 224 patients treated for end-stage ankle arthritis were enrolled in an observational trial. Of 112 patients followed more than 2 years, 48 patients (19 arthrodesis, 29 arthroplasty) had coronal plane deformity and were compared to 64 patients without coronal plane deformity (18 arthrodesis, 46 arthroplasty) defined as greater than 10 degrees of varus or valgus. The arthroplasty implants used had different internal constraints to intracomponent coronal plane tilting. Patients completed Musculoskeletal Functional Assessment (MFA) and SF-36 preoperatively and at 3, 6, 12, 24, and 36 months postoperatively. Measures included change in SF-36 and MFA, as well as compared reoperation rates and pain scales. Results: For the groups with coronal plane ankle deformity, the median for the arthrodesis group was 19.0 degrees and the median for the arthroplasty group was 16.9 degrees. In the deformity cohort during the follow-up period, we had 7 major reoperations: 2 in the arthrodesis group and 5 in the arthroplasty group, all with the less constrained implant design. MFA, vitality, and social function of the SF-36 improved for all groups. Patients without preoperative deformities had greater improvement with fusion or replacement at both 2 and 3 years. There was no difference in improvement between those patients with coronal deformity who received arthroplasty vs arthrodesis. Conclusion: Patients with and without coronal plane deformity may benefit from ankle arthroplasty and arthrodesis, although greater improvements may be expected in those without preoperative deformity. In this study, at final follow-up of 3 years, overall we found no meaningful difference in patient-reported outcomes between the patients with preoperative coronal plane deformities whether they had a fusion or a replacement as treatment for end-stage ankle arthritis.