Effect of Prior Knee Arthroscopy on Midterm Outcomes After Medial Opening-Wedge High Tibial Osteotomy: A Propensity Score-Matched Analysis.

Background: Knee arthroscopy is frequently performed to improve joint function and relieve pain. However, there is no consensus regarding the effect of prior arthroscopy on outcomes following medial opening-wedge high tibial osteotomy (MOWHTO). Purpose: To compare midterm clinical outcomes and survival rates after MOWHTO between patients with and without a history of knee arthroscopy. Study Design: Cohort study; Level of evidence, 3. Methods: We enrolled patients who underwent MOWHTO between March 2008 and February 2017 and had ≥4 years of follow-up. Patients who had undergone knee arthroscopy were included in an arthroscopy group, and those who had not were included as controls. After propensity score matching based on age, sex, body mass index, and lesion size, 80 patients in each group were included. Clinical outcomes were assessed using the Knee injury and Osteoarthritis Outcome Score (KOOS), 36-Item Short Form Health Survey, and Tegner Activity Scale. Furthermore, survival rates and relevant risk factors that affected joint survivorship were analyzed, wherein conversion to total knee arthroplasty was considered the endpoint. Results: Although the pre- to postoperative improvement in clinical outcomes did not differ significantly between the groups, there were significant between-group differences in final postoperative scores on the KOOS-Activities of Daily Living (arthroscopy vs control, 78.1 ± 10.6 vs 81.0 ± 9.8; Conclusion: Although patients with prior arthroscopy had some inferior patient-reported outcome scores after MOWHTO, the overall clinical improvements were similar in the arthroscopy and control groups.