BACKGROUNDFew data are available concerning intercondylar notch dimensions in female nonathletes with knee osteoarthritis (OA) in plateau region. The aim of this study was to assess the relation of intercondylar notch morphology to anterior cruciate ligament (ACL) injuries in female nonathletes with knee OA aged 41-65 years from the Chinese Loess Plateau.

METHODSThe study was conducted on 330 patients with ACL injury (aged 31-65 years; 159 males, 171 females), 141 patients with OA (aged 31-65 years; 59 males, 82 females), and 89 female healthy controls (aged 41-65 years), and this evaluation included identifying the distribution of patients with OA or ACL injury and measuring the intercondylar notch width indexes (NWIs).

RESULTSThere was a significant rising trend in patients with OA (the Kellgren and Lawrence grade = 3) with ACL injury (OA-S + ACL) aged 41-65 years, especially in females. We found that the notches of OA-S + ACL had a smaller NWI compared with control and OA without ACL injury (OA-S-only, P = 0.000, 95% confidence interval [CI] = -0.059--0.030; P = 0.000, 95% CI = -0.049--0.016). A similar trend was found in notch shape index (NSI), but not in notch depth index and the cross-sectional area. The cutoff of NWI and NSI value was 0.26, and 0.65, and area under the receiver operating characteristic curve was 0.82, and 0.79, respectively. Further study displayed a significant correlation between a reduced NWI and NSI and OA-S + ACL (P = 0.000, χ2 = 14.012; P = 0.000, χ2 = 14.286).

CONCLUSIONA narrower intercondylar notch and a plateau environment are risk factors of predisposing female nonathletes with knee OA to ACL injury aged 41-65 years.