Patellofemoral osteoarthritis : characterizing knee alignment and morphology

Patellofemoral osteoarthritis (OA) is an under-recognized medical condition that may progress to generalized knee OA. It is highly prevalent and is associated with knee pain and disability. Patellofemoral alignment, tibiofemoral alignment or trochlear morphology may influence the prevalence, onset or worsening of patellofemoral OA. Therefore, my main objective in this dissertation was to use magnetic resonance (MR) imaging to quantify the relationships between knee alignment or morphology and prevalent patellofemoral OA. This dissertation is comprised of four studies. First, I systematically reviewed the associations among knee alignment or morphology with patellofemoral OA presence, severity, onset or worsening. Lateral patellar tilt, lateral displacement, patellar height, frontal plane knee alignment, and a shallow sulcus were all associated with OA prevalence and severity. Second, I examined the relationship between key alignment and morphology measures and early patellofemoral OA, one year following anterior cruciate ligament reconstruction. Lateral displacement and a shallow sulcus were associated with early patellofemoral OA. Third, I evaluated alignment and morphology in the Framingham community cohort, a population-based cohort. I established reference values in knees without patellofemoral OA or pain. I then evaluated dose-response patterns of the full sample. The odds of prevalent patellofemoral OA rose monotonically with greater lateral patellar displacement and a shallower sulcus. Odds rose for patellar tilt in both directions, i.e. increased medial or lateral tilt. Fourth, using an upright, open-bore MR scanner, I developed reproducible methods to evaluate three dimensional knee alignment in standing. I then examined differences in alignment from supine to standing positions, and differences in alignment in supine and standing in individuals with patellofemoral OA and matched controls. Key measures of malalignment were greater in standing then supine. In knees with patellofemoral OA, the patella was more laterally tilted, laterally displaced, and proximally displaced compared to controls, and the tibia was more externally rotated. Taken together, these studies suggest that knee alignment and trochlear morphology may influence the risk of patellofemoral OA.Medicine, Faculty ofExperimental Medicine, Division ofMedicine, Department ofGraduat