Associations of clinical measures and structural knee magnetic resonance imaging findings with knee symptoms in a birth cohort of 33-year-old adults.

Objective: To investigate the associations between knee magnetic resonance imaging (MRI) findings, knee joint symptoms and related health factors in a random subpopulation of 33-year-olds from the Northern Finland 1986 Birth Cohort. Method: Subjects with questionnaire, knee MRI, and clinical symptom data, were included in this study (n = 284, 60.9 % females, age 33.7 years). Knee MRI data was graded using the MRI Osteoarthritis Knee Score (MOAKS) system. Symptoms were evaluated using the Visual Analogue Scale (VAS) version of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and participants with VAS >3 in any WOMAC sub-question were considered symptomatic. Results: 12.2 % (74.3 % females) of the study population were symptomatic, and were more likely to have a higher BMI, adverse lipid profile and a family history of knee OA. Advanced MRI findings were sparse. Most MRI findings, such as bone marrow lesions (BMLs) and osteophytes, were more prevalent and severe in symptomatic participants. In adjusted regression analyses, BMLs in the medial femoral compartment and osteophytes in the lateral tibial and medial femoral compartments, patellar tendon signal and joint effusion were associated with knee symptoms. Conclusion: Several MRI findings, most notably medial femoral BMLs, osteophytes, patellar tendinopathy and joint effusion were associated with knee symptoms. Of other factors, sex, family history and clinical factors such as body composition are associated with knee joint symptomatology from early adulthood.