Cruciate ligament integrity in osteoarthritis of the knee

To evaluate, using magnetic resonance imaging (MRI), the prevalence of anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) rupture in knees with symptomatic osteoarthritis (OA) compared with those without OA, and the relationship to pain and recalled injury.

MRI and plain radiography of the knee were performed in a group of 360 subjects with painful knee OA (cases; 66.7% male, mean age 67.1 years) and 73 without knee pain (controls; 57.5% male, mean age 66.1 years). MRIs were read for the presence or absence of complete or partial ACL or PCL tear. Subjects with knee pain were asked to quantify severity of pain on a visual analog scale and to report whether they could recall a significant knee injury (requiring use of a cane or crutches). We compared the prevalence of ACL and PCL rupture in those with and those without knee pain and also evaluated whether, in cases, there was any association with recalled knee injury.

The proportion of cases who had complete ACL rupture was 22.8%, compared with 2.7% of controls (P = 0.0004). PCL rupture was rare both in cases (0.6%) and in controls (0%). Cases with ACL rupture had more severe radiologic OA (P < 0.0001) and were more likely to have medial joint space narrowing (P < 0.0001) than cases with intact ACLs, but did not have higher pain scores. Among cases, only 47.9% of those with complete ACL tears reported a previous knee injury, compared with 25.9% of those without complete ACL tears (P = 0.003).

ACL rupture is more common among those with symptomatic knee OA compared with those without knee OA. Fewer than half of subjects with ACL rupture recall a knee injury, suggesting that this risk factor for knee OA is underrecognized.