Objective    To investigate the correlation of anterior cruciate ligament (ACL) injury and intercondylar notch stenosis in osteoarthritis (OA) patients.  Methods     A total of 75 moderatesevere OA patients (≥45 years old) with K-L score of grade Ⅱ or above were selected from 1 107 in- and out-patients undergoing knee MR imaging in our hospital from 2011 to 2014. They were divided into 2 groups based on whether complicated with ACL injury

that is

simple OA group (n=40) and OA complicated with ACL injury group (n=35). According to the axial sequence in MR images

there were A

U and W shapes in the types of intercondylar notch. The notch width index (NWI) in the sequences of axial

coronal

and ACL attachment point at the femoral were measured respectively. The differences of intercondylar notch shape and 3 sequences of NWI were analyzed between the 2 groups. The cutoff values  of NWI in different sequences were calculated according to receiver operating characteristic (ROC) curve to determine intercondylar notch narrowing. Then the correlation of ACL injury and intercondylar notch stenosis was analyzed.  ResultsThe NWI in the sequences of axial

coronal

ACL attachment point at the femoral were NWI1=0.270±0.010

NWI2=0.252±0.012 and NWIA=0.262±0.016 in the simple OA group

and were NWI1=0.257±0011

NWI2=0.237±0.017 and NWIA=0.240±0.018 respectively in the OA complicated with ACL injury group

and significant differences were found between the 2 groups (P0.01). The proportion of type A was significantly larger in the latter than the former group (P0.05). ROC curve indicated that NWI10.263

NWI20.248 and NWIA0.254 were the cutoff values for the intercondylar notch narrowing of the 3 sequences. Among them

NWI1 was of the highest specificity

and NWIA was of the highest sensitivity.  ConclusionIntercondylar notch stenosis and type A shape may be the risk factors for moderatesevere OA patients complicated with ACL injury.