To evaluate the function of anterior cruciate ligament (ACL) more accurately in patients with knee osteoarthritis through the imaging information of anteroposterior and lateral knee X-ray.

156 patients admitted to hospital with knee osteoarthritis from October 2021 to December 2023 were retrospectively selected. ACL function was verified during surgery and the patients were divided into functional and non-functional ACL groups. The wear depth and deepest position of the tibial plateau, the wear depth of anterior and posterior the tibial plateau in 1/3 position, and the distribution of knee osteophytic features in the anteroposterior and lateral knee X-ray of the two groups were compared, and the influence of imaging variables on the judgment of ACL function was analyzed by binary Logistic regression.

A total of 156 patients were included in this study, with 59 males (37.8%) and 97 females (62.2%). According to the results of ACL function verification in 156 patients with knee osteoarthritis, they were divided into functional group (85 cases) and non-functional group (71 cases). In the functional group, the deepest wear position in the posterior was 30.6%, and in the non-functional group, the deepest wear position in the posterior was 71.8%. D=1.7(1.3, 2.1)mm, d₁=1.2(0.8, 1.6)mm and d₂=0.8(0.5, 1.1)mm in functional group, D=2.3(1.8, 2.8)mm, d₁=1.5(1.1, 2.1)mm and d₂=1.8(1.0, 2.3)mm in non-functional group; The proportions of osteophytes in tibial plateau and intercondylar fossa were 45.9% and 38.8% in functional group, 73.2% and 83.1% in non-functional group, respectively. The proportion of the functional group with K-L grade Ⅳ was 30.6%, and the proportion of the non-functional group with K-L grade Ⅳ was 62.0% The deepest wear in front of the tibial plateau and the absence of osteophyte between the condyles are protective factors for judging ACL function, while the wear depth in the posterior 1/3 of the tibial plateau is a risk factor for affecting ACL function.

The patients with ACL dysfunction showed increased wear of the medial tibial plateau on X-ray, and the wear was mainly posterior, accompanied by the proliferation of osteophyte in tibial plateau and intercondylar fossa. The location of the deepest wear of the tibial plateau, the wear in the posterior 1/3 of the tibial plateau, and the intercondylar osteophyte proliferation can help accurately judge ACL function.