Clinical Outcomes Following Total Ankle Arthroplasty without Concomitant Osteotomy in Ankles with Severe Preoperative Varus Deformity: Comparison to Ankles with Preoperative Neutral Alignment

Abstract

Background:It remains controversial whether satisfactory outcomes can be obtained following total ankle arthroplasty (TAA) without osteotomy in patients with severe varus ankle deformities. The purpose of this study was to examine outcomes following TAA without concomitant osteotomies in patients with severe varus ankle alignment by comparing them with patients with neutral alignment. Methods: Fifty-three ankles of 51 patients (71.4 ± 5.6 years old) who underwent TAA using an insert with a medial wall (TNK ankle prosthesis)were examined (mean follow-up: 36.8±17.8 months). The patients were allocated into two groups according to the preoperative talar tilt (TT) angle: the neutral group (preoperative TT angle < 9°; n=37) andthe varus group (preoperative TT angle > 10°; n=16). Outcome measures, including the Japanese Society for Surgery of the Foot (JSSF) scale, Self-Administered Foot Evaluation Questionnaire (SAFE-Q), the ankle range of motion, and radiographic parameters, were assessed prior to the surgery and at the final follow-up.Results:Significant improvements were observed in clinical and radiographical outcomes in both groups after surgery. The postoperative JSSF scale and the subscalescores of pain and shoes in the SAFE-Q were not significantly different between the groups, while subscale scores of function, social, and health in the SAFE-Q were greater in the varus group compared to the neutral group at the final follow-up (P < 0.05). Radiographic parameters, including TT angle and tibial axis-medial malleolus (TMM) angle improved postoperatively and were not significantly differentbetween the neutral group (TT angle, 0.5 ±0.7°;TMM angle, 16.0 ± 4.6°) and the varus group (TT angle, 0.4 ± 0.7°;TMM angle, 17.0 ± 5.3°) at the final follow-up. To achieve neutral alignment, adjunctive procedures, such as deltoid ligament release, were required more often in the varus group, but no concomitant osteotomies were performed. Conclusions:Outcomes after TAA using the TNK ankle prosthesis were favorable in patients with severe varus ankle alignment and in those with neutral ankle alignment without concomitant osteotomy. Satisfactory outcomes could be achieved in patients with severe varus ankle alignment after TAA using the TNK ankle prosthesis without concomitant osteotomy.