Abstract
BACKGROUND: Although both meniscus extrusion and changes in three-dimensional (3D) bone morphology are associated with the progression of knee osteoarthritis (KOA), it is currently unclear whether 3D bone morphology changes play a mediating role in the relationship between the medial meniscal extrusion (MME) and KOA progression. The aim of this study was thus to examine whether 3D bone morphology mediates the association between MME and the radiographic progression of KOA. METHODS: The participants in this study were drawn from the Osteoarthritis Initiative (OAI). The control group consisted of participants with an MME score <2 at baseline and 24 months, while the case group consisted of participants with an MME score ≥2 at baseline and 24 months. Radiological progression was defined as a reduction in the minimum width of the medial tibiofemoral joint space ≥0.7 mm. We analyzed the clinical covariates, 3D bone morphology at baseline and bone morphology changes at 24 months. Logistic regression was used to estimate the association between MME and the progression of KOA, and the mediating effect of bone morphology on the relationship between MME and KOA progression was estimated using multiple mediation analysis. RESULTS: A total of 537 participants were evaluated, including 216 cases and 321 controls. The participants in the case group exhibited more severe radiographic OA features. The progression rate of KOA was significantly higher in the case group than in the control group (61.11% vs. 34.89%; P<0.001). Multivariate regression analysis indicated a statistically significant correlation between MME and KOA progression (adjusted odds ratio =1.61; 95% confidence interval: 1.01-2.57; P=0.044). Changes in 3D bone morphology accounted for 31.2% of the total effect on KOA progression. CONCLUSIONS: Changes in 3D bone morphology mediate the association between MME and the progression of KOA.