Radiographic Progression of Patellofemoral Osteoarthritis Is Not Associated With Long‐Term Clinical Outcomes After Open‐Wedge High Tibial Osteotomy: A 10‐Year Minimum Follow‐Up

Purpose To evaluate the radiographic findings of the patellofemoral (PF) joint and the PF‐specific clinical outcomes after open‐wedge high tibial osteotomy for medial osteoarthritis (OA) in varus knees with a minimum 10‐year follow‐up. Methods Consecutive patients who underwent open‐wedge high tibial osteotomy for medial compartment knee OA or osteonecrosis between 2007 and 2014 with ≥10 years of follow‐up were retrospectively reviewed. Patients with incomplete radiographic data or missing scores were excluded. Knees were classified into PF OA progression and nonprogression groups according to changes in the Kellgren‐Lawrence grade from preoperative to final follow‐up. Progression was defined as an increase of at least 1 Kellgren‐Lawrence grade. Clinical outcomes were assessed using the Knee Injury and Osteoarthritis Outcome Score‐patellofemoral subscale and the Hospital for Special Surgery patella score. Outcomes were compared using Student's t ‐test or the Mann‐Whitney U test. Predictors of PF OA progression were analyzed by multivariate logistic regression. Survival analysis was performed with conversion to knee arthroplasty as the endpoint. Results A total of 168 knees were included. The mean follow‐up period was 12.2 years (range, 10.0‐16.9 years). The 10‐year survival rate was 91.3%, and no knees required conversion to knee arthroplasty for PF OA. PF OA progression was observed in 55.4% (93/168). There were no significant differences in the Knee Injury and Osteoarthritis Outcome Score‐patellofemoral subscale or Hospital for Special Surgery patella score between the groups (Knee Injury and Osteoarthritis Outcome Score‐patellofemoral subscale: 68.5 vs 69.8, P = .533; Hospital for Special Surgery patella score: 89.0 vs 91.0, P = .179). Multivariate logistic regression identified correction angle (odds ratio, 1.361; P = .004) and preoperative Kellgren‐Lawrence grade of the PF joint (odds ratio, 0.241; P = .002) as independent predictors of PF OA progression. Conclusions Although PF OA progressed after open‐wedge high tibial osteotomy, it did not adversely affect the long‐term clinical outcomes at a mean follow‐up of 12.2 years. Level of Evidence Level IV, retrospective cohort study.