LAUSR

Background Femoral trochlear dysplasia (FTD) and meniscal tear are common knee disorders, yet there is lack of research investigating the correlation between them. We aimed to investigate the prevalence of FTD in young meniscal tear patients, and observe the main tear locations. Meanwhile, we explored the force distribution on meniscus by finite element analysis (FEA). Methods The magnetic resonance (MR) images of 422 young patients with meniscal tears confirmed by the arthroscopy (the meniscal tears group) and 412 young patients with a history of knee joint pain but without evidence of meniscal tears (the comparison group) were reviewed. The meniscal tears group underwent MR scans before the arthroscopy. FTD was diagnosed according to the Dejour classification. The prevalence of FTD in both groups and the main locations of meniscal tears were observed. The objective radiological parameters were measured in two groups. Multicollinearity testing was carried out, and variables with a variance inflation factor (VIF) value less than 10 were retained in the logistic regression analysis, and statistical difference defined as P<0.05. Last, FEA was performed on patients without FTD and with different types of FTD from the comparison group, respectively, and the biomechanical distribution was observed. Results The incidence of FTD was higher in the meniscal tears group than the comparison group (36.02% vs. 19.17%, P<0.001). Radiological parameters had statistical differences between two groups (P<0.001), and the high-grade FTD [odds ratio (OR) =0.278, P=0.043] was closely associated with meniscal tear. Tears most commonly occurred in the posterior horn of medial meniscus. The force distribution obtained by FEA was approximately consistent with the probability of meniscal tear locations. Conclusions The high-grade FTD was the independent predictor of meniscal tear. The posterior horn of medial meniscus was the most susceptible and this might be related to the increased stress on it confirmed by FEA.