Ankle pain and orientation after high tibial osteotomy as a treatment of medial compartment knee osteoarthritis

Background: Ankle pain frequently occurs in patients with medial compartment knee osteoarthritis (OA), particularly in those with varus deformity. In these patients, an atypical alignment of the ankle joint line relative to the ground is often observed in the coronal plane. The purpose of this study was to evaluate changes in ankle pain and ankle joint orientation after high tibial osteotomy as a treatment of medial compartment knee OA. Methods: This prospective work was conducted on 100 patients, aged 40–55 years old, with symptomatic medial compartment knee OA associated with ankle pain, with a good range of motion and intact lateral compartment. All patients treated with high tibial osteotomy fixed by plate. Ankle pain was measured by visual analogue score (VAS) preoperatively and at 3 months, 6 months, 1 year, and 2 years postoperatively. The following parameters were assessed preoperatively and at 3 months postoperatively: the ankle joint line orientation (AJLO), medial proximal tibial angle (MPTA), and the hip-knee-ankle angle (HKA). Results: The ankle pain significantly improved postoperatively and at last follow-up after HTO; VAS significantly reduced from 5 (4–5) preoperatively to 2 (1–2) at last follow-up (P < 0.001). AJLO was substantially decreased from 9.58 ± 2.74° preoperative to 0.41 ± 1.88° postoperative (P < 0.001). MPTA increased significantly following surgery, from a preoperative value of 85.78 ± 1.84° to a postoperative value of 90.71 ± 1.58° (P < 0.001). Similarly, HKA improved significantly from −7.73 ± 1.50° preoperatively to 2.43 ± 0.88° postoperatively (P < 0.001). A positive correlation was found between ankle pain improvement via VAS and changes in AJLO, MPTA, and HKA (P < 0.05). Conclusion: In patients with medial unicompartmental knee OA associated with ankle pain, both ankle pain and ankle joint orientation improved following high tibial osteotomy.