Association between measures of trochlear morphology and structural features of patellofemoral joint osteoarthritis on MRI: the MOST study.

The sulcus angle has been widely used in the literature as a measure of trochlear morphology. Recently, lateral trochlear inclination and trochlear angle have been reported as alternatives. The purpose of this study was to determine the association between measures of trochlear morphology and patellofemoral joint (PFJ) cartilage damage and bone marrow lesions (BMLs). Nine hundred seven knees were selected from the Multicenter Osteoarthritis Study, a cohort study of persons aged 50-79 years with or at risk for knee OA. Trochlear morphology was measured using lateral trochlear inclination, trochlear angle, and sulcus angle on axial MRI images; cartilage damage and BMLs were graded on MRI. We determined the association between quartiles of each trochlear morphology variable with the presence or absence of cartilage damage and BMLs in the PFJ using logistic regression. The strongest associations were seen with lateral trochlear inclination and lateral PFJ cartilage damage and BMLs, with knees in the lowest quartile (flattened lateral trochlea) having more than two times the odds of lateral cartilage damage and BMLs compared to those in the highest quartile (p < 0.0001). Lateral trochlear inclination may be the best method for assessment of trochlear morphology as it was strongly association with structural damage in the PFJ.