To investigate the relationship between tenderness and the MR findings of patellofemoral articular cartilage abnormalities.

We investigated 64 patients, 70 knee joints, who had symptoms of knee pain. We evaluated the correlation between the tenderness and the MR grades at each tender point of the patellar and calculated the sensitivity, specificity and accuracy of the tenderness on the basis of MR imaging.

The sensitivity, specificity and accuracy of the tenderness were 49.0% (99/202), 83.8% (279/333), 70.6% (378/535), respectively. The tenderness and the MR grades were moderately correlated in the patellofemoral joint as a whole (r=0.41, p<0.01), and tenderness was substantially correlated with MR grade in the femoral trochlear articular surface (r=0.33, p<0.01) and moderately correlated in the patellar articular surface (r=0.47, p<0.01) with MR grades.

That of tenderness represents the condition of the articular cartilage of the patellar better than that of the femoral trochlear.