Relation of Patellofemoral Joint Alignment, Morphology, and Radiographic Osteoarthritis to Frequent Anterior Knee Pain: Data from the Multicenter Osteoarthritis Study

Objective Patellofemoral (PF) alignment and trochlear morphology are associated withPFosteoarthritis (OA) and knee pain, but whether they are associated with localized anterior knee pain is unknown, which is believed to be a symptom specific toPFjoint pathology. We therefore aimed to evaluate the relation ofPFalignment and morphology, as well asPFOAand tibiofemoralOA, to anterior knee pain. Methods The Multicenter Osteoarthritis Study is a cohort study of individuals with, or at risk for, kneeOA. We evaluated cross-sectional associations ofPFalignment, trochlear morphology, andPFand tibiofemoral radiographicOA, with localized anterior knee pain (defined with a pain map). We used 2 approaches: a within-person knee-matched evaluation of participants with unilateral anterior knee pain (conditional logistic regression), and a cohort approach comparing those with anterior knee pain to those without (binomial regression). Results With the within-person knee-matched approach (n = 110; 64% women, mean age 70 years, body mass index [BMI] 30.9),PFalignment, morphology, and tibiofemoralOAwere not associated with unilateral anterior knee pain. RadiographicPFOAwas associated with pain, odds ratio 5.3 (95% confidence interval [95%CI] 1.6-18.3). Using the cohort approach (n = 1,818; 7% of knees with anterior knee pain, 59% women, mean age 68 years,BMI30.4), results were similar: onlyPFOAwas associated with pain, with a prevalence ratio of 2.2 (95%CI1.4-3.4). Conclusion PFalignment and trochlear morphology were not associated with anterior knee pain in individuals with, or at risk for, kneeOA. RadiographicPFOA, however, was associated with pain, suggesting that features ofOA, more so than mechanical features, may contribute to localized symptoms.