Do MRI features at baseline predict radiographic joint space narrowing in the medial compartment of the osteoarthritic knee 2 years later?

PURPOSE: The purpose of the study was to relate magnetic resonance imaging (MRI) features at baseline with radiographically determined joint space narrowing (JSN) in the medial compartment of the knee after 2 years in a group of patients with symptomatic osteoarthritis at multiple joint sites. MATERIALS AND METHODS: MRI of the knee and standardized radiographs were obtained at baseline and after 2 years in 186 patients (81% female; aged 43–76 years; mean 60 years). MRI was analyzed for bone marrow lesions, cysts, osteophytes, hyaline cartilage defects, joint effusion, and meniscal pathology in the medial compartment. Radiographs were scored semiquantitatively for JSN in the medial tibiofemoral joint using the Osteoarthritis Research Society International (OARSI) atlas. Radiological progression was defined as ≥1 grade increase. Associations between baseline magnetic resonance (MR) parameters and subsequent radiographic JSN changes were assessed using logistic regression. Relative risk (RR) was then calculated. RESULTS: Radiographic progression of JSN was observed in 17 (9.1%) of 186 patients. Eleven patients had a Kellgren and Lawrence (KL) score of ≥2. A significant association was observed between all patients and meniscal tears (RR 3.57; confidence interval (CI) 1.08–10.0) and meniscal subluxation (RR 2.73; CI 1.20–5.41), between KL < 2 and meniscal subluxation (RR 11.3; CI 2.49–29.49) and KL ≥ 2 and meniscus tears (RR 8.91; CI 1.13–22.84) and radiographic JSN 2 years later. Follow-up MR in 15 of 17 patients with progressive JSN showed only new meniscal abnormalities and no progression of cartilage loss. CONCLUSION: Meniscal pathology (tears and/or meniscal subluxation) was the only MRI parameter to be associated with subsequent radiographic progression of JSN in the medial tibiofemoral compartment on a radiograph 2 years later, as assessed by the OARSI score.