Clinicoradiologic Outcomes of Medial Open-Wedge High-Tibial Osteotomy Are Equivalent in Bone-on-Bone and Non-Bone-on-Bone Medial Osteoarthritis

Abstract

Purpose: (1) To investigate whether patients with bone-on-bone (BOB) medial OA (Ahlback grade 2) had comparable clinical improvement to those with non-BOB arthritis with remaining joint space (Ahlback grades 0/1) after medial open-wedge high tibial osteotomy (MOWHTO); (2) to determine whether the radiological results differ between these 2 groups from 1 month postoperatively to last follow-up >= 2 years later. Methods: Data of 132 knees (40 males and 92 females) who underwent MOWHTO were retrospectively reviewed. Preoperative standing anteroposterior radiographs were evaluated according to the Ahlback classification. Patients with Ahlback grade <= 1 were classified as the non-BOB group (group I, n = 88; mean age, 50.5 +/- 6.3 years) and those with grade 2 as the bone-on-bone group (group II, n = 44; age, 51.6 +/- 5.3 years). Clinical outcomes were assessed using Hospital for Special Surgery (HSS) and Knee Society (KS) functional scores. Medial joint space width (JSW), medial proximal tibial angle (MPTA), and mechanical alignment were considered radiological parameters. Results: Preoperative clinical scores were significantly lower in patients with BOB arthritis (HSS score: group I, 73.5 +/- 10.7 versus group II, 69.2 +/- 9.1, P = .026; KS score: group I, 72.9 +/- 10.3 versus group II, 63.2 +/- 11.6 points, P < .001). However, HSS and KS functional scores improved in both groups without a significant difference at a mean follow-up of 3.4 +/- 2.5 and 4.1 +/- 3.1 years in groups I and II, respectively (HSS score: 89.2 +/- 9.5 versus 89.4 +/- 7.3 points, P = .258; KS functional score: 90.1 +/- 7.1 versus 87.8 +/- 8.9 points, P = .105). Preoperative and postoperative medial JSWs were narrower in group II, but the JSW opening was wider in group II at 1 month after surgery and was maintained until the last follow-up (preoperative, 3.0 +/- 0.9 versus 0.0 +/- 0.1 mm; 1 month, 3.1 +/- 1.0 versus 1.4 +/- 0.8; last follow-up, 3.0 +/- 1.0 versus 1.4 +/- 0.9 mm; P < .001). Conclusion: Patients with BOB medial OA achieved clinical outcomes comparable to those with remaining joint space after MOWHTO. The medial JSW showed a significant increase without OA progression during midterm follow-up in these patients. Therefore, MOWHTO can be an effective treatment choice for symptomatic improvement in middle-aged patients with severe medial OA, if there is no subchondral bone attrition. Level of Evidence: III, retrospective comparative study.