Summary
Larger pre-operative BML volumes positively correlated with some post-operative KOOS subscales and with many delta KOOS subscales. Pre-operative large BML had no negative influence on post-operative clinical outcomes; hence, surgeons need not hesitate to perform MOWHTO in patients with large BMLs in the medial condyles.
Abstract
Purpose
There is insufficient evidence regarding the indications of MOWHTO in patients with large pre-operative bone marrow lesion (BML). To this end, this study evaluated modern medial open-wedge high tibial osteotomy (MOWHTO) clinical outcomes and bone marrow lesion (BML) scores and volumes. We hypothesized that BML volume is more associated with clinical outcomes of MOWHTO than qualitative BML evaluations, and that BML volume is correlated with the improvement of clinical outcomes.
Methods
Patients who underwent MOWHTO for osteoarthritis or spontaneous necrosis of the knee between 2018 and 2021 were enrolled retrospectively. Knee Injury and Osteoarthritis Outcome Score (KOOS) was recorded before the initial surgery and at plate removal surgery. Pre-operative BMLs were evaluated using three qualitative scoring systems, reflecting the maximum length, proportion, and intensity of the BML. For quantification, BMLs of the femur and tibia were separately defined as the area with a threshold more than the mean signal intensity plus wo standard deviations, using the corresponding lateral condyles as controls. BML volumes were then calculated by the integration of BML in each slice. Association between KOOS total/subscores and BML scores/volume was evaluated with Spearman’s correlation. Spearman’s correlation between BML volumes and Lysholm knee and Tegner activity scores were also calculated. Finally, multivariate linear regression analysis for the post-operative KOOS total was performed using a backward-stepwise approach to minimize the Akaike information criterion.
Results
Forty-three cases (24 females and 19 males, age:61.5 ± 7.4 years old) of MOWHTO were included in the final analysis. No significant correlations between qualitative BML scores and pre-operative, post-operative, and delta KOOS were found, except one BML score each which correlated with pre-operative KOOS sports or with post-operative KOOS ADL. Femoral BML volume did not correlate with pre-operative, post-operative or delta- KOOS total, but tibial BML volume weakly correlated with delta KOOS total (r = 0.33, p = 0.03). For KOOS subscales, femoral BML volume were correlated with post-operative KOOS ADL (r = 0.36, p = 0.02) and KOOS QOL (r = 0.50, p = 0.007), and tibial BML volume were correlated with post-operative KOOS ADL sports (r = 0.38, p = 0.01). Tibial BML volume was significantly correlated with all five delta KOOS scales (r = 0.37 to 0.51, p = 0.02 to 0.007), however, femoral BML volume was only correlated with delta KOOS QOL (r = 0.41, p = 0.009). The femoral and tibial BML volumes were moderately (r = 0.42, p = 0.006) and weakly (r = 0.36, p = 0.02) correlated with delta Lysholm knee scores, respectively, while BML volumes did not correlate with Tegner activity scores.
Conclusion
Larger pre-operative BML volumes positively correlated with some post-operative KOOS subscales and with many delta KOOS subscales. Pre-operative large BML had no negative influence on post-operative clinical outcomes; hence, surgeons need not hesitate to perform MOWHTO in patients with large BMLs in the medial condyles.