The Relationship between Meniscal Tears and Meniscal Position.

OBJECTIVE: To investigate how different types of meniscal tears predispose to different patterns of meniscal position in subjects with and without symptomatic knee osteoarthritis (OA).
METHODS: A cross-sectional analysis of 161 women participating in an observational study to evaluate knee OA progression was performed using baseline MRI data. Meniscal morphologic features were scored in three separate locations. Meniscal position measures were determined for extrusion and proportion of coverage. Analysis was performed using multiple linear regression models treating each tear type as an individual variable with a binary response.
RESULTS: Complex tears, cysts and maceration of the medial meniscus were associated with more medial (p=0.0004, p=0.004, p <0.0001, respectively) and anterior extrusion (p =0.03, p=0.03, p<0.0001, respectively) than normal menisci. Horizontal tears of the lateral meniscus had more lateral (p=0.005) and anterior extrusion (p<0.0001) than normal menisci. Anterior and body tears of the medial meniscus were associated with more anterior extrusion (p=0.0006, p=0.01, respectively), whereas meniscal body tears alone had more medial extrusion than normal menisci (p= 0.0002). Meniscal body tears of the lateral meniscus had more lateral extrusion than normal menisci (p=0.01).
CONCLUSION: Anterior horn and meniscal body tears and the more severe macerated and complex tear types predisposed to more medial meniscal extrusion. Laterally, only meniscal body and horizontal tears significantly affected extrusion, potentially reflecting a lower overall prevalence of lateral meniscal tears. These results may have important implications in identifying tear types associated with more meniscal dysfunction, with the ultimate goal of identifying those at greatest risk for knee OA progression.