Cartilage Status, Rather Than Chronologic Age, Determines the Outcomes of Open Wedge High Tibial Osteotomy: A Cartilage Status-Matched Cohort Study

Purpose: To evaluate the true effects of chronologic age on the clinical and radiologic outcomes of open wedge high tibial osteotomy (OWHTO) in a sample of patients who had been matched according to cartilage status in the medial and lateral compartments. Methods: The records of 107 OWHTO cases were reviewed. To evaluate potential differences in the outcomes according to age, the subjects were divided into 2 groups by the median age: older group and younger group. The Hospital for Special Surgery scores and Knee Society objective and functional scores before surgery and at the latest follow-up were compared between the groups. Then, the subjects in each group were matched 1:1 according to cartilage status in the medial and lateral compartments, which had been evaluated during arthroscopy prior to the osteotomy. The clinical scores were compared between the matched groups. The change in the medial joint space width (Delta JSW) from 6 to 12 months postoperatively to the latest follow-up was also compared before and after matching. Results: With a median age of 55 years, 44 and 63 cases were allocated into the older and younger groups, respectively. Prior to cartilage status matching, the latest Hospital for Special Surgery and Knee Society functional scores were significantly higher in the older group (P = .042 and P = .025, respectively). After matching, each group included 41 cases, and the differences in these clinical scores were no longer significant (P = .164 and P = .165, respectively). No difference in Delta JSW was observed between the groups, regardless of matching status (P = .901 before matching, P = .979 after matching). Conclusions: The clinical outcomes of OWHTO were affected by cartilage status, rather than by the chronologic age itself. No difference was observed in the radiologic outcome (Delta JSW) with respect to age. OWHTO should not be waived in treating elderly patients without highly advanced cartilage degeneration simply because of their chronologic ages.