In middle-age overweight or obese women, signs of osteoarthritis (OA) on magnetic resonance imaging (MRI) in the tibiofemoral compartment was more strongly related to the development of incident radiographic and clinical knee OA compared with the presence of Kellgren and Lawrence Grade 1 (KLG1) classification, according to data from the Prevention of Knee Osteoarthritis in Overweight Females (PROOF) cohort study published in Seminars in Arthritis and Rheumatism.

The investigators sought to determine the predictive value of tibiofemoral MRI, patellofemoral MRI, and KLG1 for the incidence of clinical or radiographic knee OA at 2.5 years and 6.5 years follow-up in a cohort of high-risk patients. Data from the PROOF study were used, which included middle-age obese or overweight women without clinical knee OA as defined by American College of Rheumatology criteria and no radiographic signs (KLG <2) at baseline. Sensitivity, specificity, likelihood ratios, and pre- and post-test probabilities were calculated.

Baseline prevalence of KLG1 (42.9%) was greater than the prevalence of OA on tibiofemoral MRI (14.6%) and patellofemoral MRI (10.0%). Based on all diagnostic performance statistics, better prediction was reported for radiographic OA compared with clinical OA. For both outcomes and time points, the absolute difference between pre- and post-test probabilities was highest for signs of OA on tibiofemoral MRI.

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The association was statistically significant between the presence of OA on tibiofemoral MRI (odds ratio [OR], 10.4; 95% CI, 4.9-22.2) or the presence of OA on patellofemoral MRI (OR, 9.3; 95% CI, 4.1-21.4) at baseline and incident radiologic knee OA after 2.5 years. This association remained significant after 6.5 years for signs of OA on tibiofemoral MRI (OR, 14.2; 95% CI, 7.4-27.3) and for signs of OA on patellofemoral MRI (OR, 5.7; 95% CI, 2.8-11.3). With respect to KLG1, a significant association with incident radiologic knee OA was reported at 2.5 years (OR, 7.9; 95% CI, 2.7-23.2) and at 6.5 years (OR, 7.3; 95% CI, 3.5-15.4).

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The investigators concluded that in middle-age women who are overweight or obese, signs of OA on MRI in the tibiofemoral compartment are strongly associated with longitudinal incident radiographic and clinical OA. The investigators note that, given the higher baseline prevalence of KLG1 compared with tibiofemoral MRI and patellofemoral MRI, radiographic screening appears to be sufficient when selecting participants for a preventive trial.


Bijen CBM, Runhaar J, Rijkels-Otters JBM, Oei EHG, Bierma-Zeinstra SMA. Predictive value of early structural changes on radiographs and MRI for incident clinical and radiographic knee osteoarthritis in overweight and obese women [published online March 27, 2018].  Semin Arthritis Rheum. doi:10.1016/j.semarthrit.2018.02.015