BACKGROUND: Severe osteoarthritis (OA) has been identified as a risk factor for inferior outcomes following high tibial osteotomy (HTO). PURPOSE: To investigate the effectiveness of HTO in patients with advanced OA, particularly those with Kellgren-Lawrence (KL) grade 4 (KL4), and to compare clinical outcomes based on OA severity and the effect of postoperative alignment in each group. STUDY DESIGN: Cohort study
Level of evidence, 3. METHODS: A retrospective review was conducted on patients who underwent biplanar medial opening-wedge HTO from 2010 to 2022, with a follow-up period of 2 to 5 years. Patients were divided into 2 groups based on preoperative KL grades: non-KL4 and KL4. Clinical outcomes were compared using patient-reported outcome (PRO) measures: pain visual analog scale (VAS), Lysholm Knee Score, and Knee injury and Osteoarthritis Outcome Score (KOOS) between the groups. Subgroup analyses were conducted to ascertain whether outcomes differed based on postoperative weightbearing line (WBL) ratio within each group. RESULTS: Out of 324 patients, 141 were eligible: 110 in the non-KL4 group and 31 in the KL4 group, with a mean follow-up of 37.5 months (overall mean age, 56.9 years
mean body mass index, 26.9 kg/m CONCLUSION: HTO can yield comparable clinical outcomes in KL4 OA patients to those with lower-grade OA. However, achieving sufficient valgus alignment (WBL ratio >
62.2%-67.3%) correlates with less residual pain in the short- to midterm follow-up in high-grade OA patients.