Influence of preoperative medial meniscus extrusion and subchondral bone marrow edema on outcomes after medial opening wedge high tibial osteotomy.

OBJECTIVE

No studies have assessed the correlation between preoperative medial meniscus extrusion (MME) and subchondral bone marrow edema (BME) or which factor influences the outcomes after medial opening wedge high tibial osteotomy (MOWHTO). The present study aimed to determine the influence of preoperative MME and BME on outcomes after MOWHTO.

METHODS

This study included 151 patients between January 2019 and January 2022 with a mean follow-up of 3.2 years. MME was classified into 2 groups according to the presence of pathologic MME (≥ 3 mm). BME was graded into 4 groups according to the lesion volume based on the MRI Osteoarthritis Knee Score (MOAKS) criteria. Clinical outcomes were assessed with the Hospital for Special Surgery (HSS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Knee Society Score (KSS).

RESULTS

The mean ± standard deviation preoperative MME for all patients was 3.6 ± 1.9 mm. A total of 103 patients (68.2%) had pathologic MME. MME significantly increased with increasing BME grade. Those with pathologic MME showed significantly worse outcomes in terms of the WOMAC and KSS for pain and function and HSS score than those without pathologic MME at 1 and 2 years postoperatively (all p < 0.05). A total of 122 patients (80.8%) had BME. Among the 151 patients, 29 (19.2%), 61 (40.4%), 42 (27.8%), and 19 (12.6%) were classified as having an MOAKS of 0, 1, 2, and 3, respectively, with significant differences in the preoperative WOMAC and KSS for pain and function and HSS score among these 4 groups (all P < 0.001). However, there were no significant differences in these indices at 1 or 2 years postoperatively (all P > 0.05). Only MME correlated with worse clinical outcomes in univariate (p < 0.001) and multivariate (p < 0.001) analyses.

CONCLUSIONS

Short-term clinical outcomes were worse for patients with preoperative MME greater than 3 mm than for those with preoperative MME less than 3 mm. There were no correlations between preoperative subchondral BME severity and postoperative outcomes.