Possible role of MRI-detected osteophytes as a predictive biomarker for development of osteoarthritis of the knee: A study using data from the Osteoarthritis Initiative

OBJECTIVE: To elucidate the possible role of MRI-detected osteophytes as a predictive imaging biomarker for knee osteoarthritis (KOA). DESIGN: Subjects (n ​= ​303) were selected according to the following inclusion criteria from the Osteoarthritis Initiative (OAI) data set: (1) ​< ​55 years old; (2) Western Ontario and McMaster Universities Arthritis Index pain score of 0; (3) Kellgren-Lawrence (KL) system grade 0 or 1; and (4) Complete MRI data set of the right knee. A pre-OA group (POA) consisted of subjects who developed KL grade 2 or more within 96 months, and a non-OA group (NOA) that remained KL 0 or 1 during that period. Baseline MRIs were assessed for osteophyte formation. Twenty-five locations were examined according to the MOAKS osteophyte score. Osteophytes at each location were assessed in terms of their predictive value for OA development. RESULTS: Thirty-two subjects were POA and 271 were NOA. Age, BMI, and sex did not differ between the two groups. In the POA group, the number of subjects with osteophytes tended to be higher at all 25 sites. Forward stepwise regression analysis revealed five locations - medial patella, lateral intra-condylar notch of the femur, lateral femoral condyle, tibial spine, and lateral posterior condyle - were important for the prediction of KOA development. Having more than two osteophytes at these five locations predicted KOA development with a sensitivity of 0.75 and specificity of 0.79. CONCLUSIONS: MRI-detected osteophytes could serve as a predictive biomarker of KOA development within 96 months after detection.