A comparison of clinical outcomes and cartilage repair between opening wedge and closed wedge high tibial osteotomy procedures in patients with medial osteoarthritis of the knee

Abstract Background: The aim of the present study was to assess differences in clinical outcomes and postoperative cartilage repair between opening wedge high tibial osteotomy (OWHTO) and closed wedge HTO (CWHTO) for medial osteoarthritis (OA) of the knee. Methods: A total of 90 knees of 76 patients who underwent HTO were investigated. OWHTO was performed in 45 knees of 40 patients with a correction angle of 15° or less, and CWHTO was performed in 45 knees of 36 patients with a correction angle of greater than 15°. Initial arthroscopy was performed at the time of HTO, and a second-look arthroscopy was performed at the time of plate removal. Cartilage repair was classified into the following stages: Stage 1 (no reparative change); Stage 2 (partial coverage with white cartilaginous tissue); and Stage 3 (full coverage with white cartilaginous tissue). Clinical outcomes were assessed using Knee Society scores, and radiographic assessment was carried out by measuring the femorotibial angle (FTA). Results: Regarding preoperative OA grade, varus alignment, and function score, CWHTO patients showed more advanced OA status than OWHTO patients. Knee scores and function scores were significantly improved after surgery with both HTO procedures (P<0.05), with no significant difference between the two procedures. Cartilage repair of stage 2 or 3 was found in more than 80% of the subjects in the medial femoral condyle and more than 60% in the medial tibial condyle. However, there were no significant differences between the two HTO procedures. There was no relationship between clinical outcomes and postoperative cartilage status in both HTO procedures. Multivariate logistic regression analysis showed that preoperative International Cartilage Repair Society (ICRS) grade was the only factor affecting cartilage repair. Conclusions: CWHTO improved clinical outcomes and cartilage status as much as OWHTO. Although the effects of cartilage repair on clinical outcomes are unknown, HTO is an effective treatment option even for severe medial OA of the knee.