Association between constant and intermittent knee pain and T2 values and cartilage thickness: data from the osteoarthritis initiative.

BACKGROUND: We investigated whether cartilage composition and thickness and its change over time were associated with future intermittent and constant knee pain. METHODS: Osteoarthritis Initiative participants with 3T MRI scans from baseline to 36-month visits were selected. Outcomes were Intermittent and Constant Osteoarthritis Pain (ICOAP) scores in the right knee at the 48-month visit (0 to 100 = highest pain). We measured T2 values and cartilage thickness in 5 regions in the right knee from baseline to 36-months using deep-learning-based segmentation. Associations between baseline and change in cartilage biomarkers with pain scores were tested using adjusted logistic and linear regression models. RESULTS: Of 3780 included participants, 1042(28%) had symptomatic knee OA in any knee at baseline. At 48 months, 1671(44%) had intermittent and 265(7%) constant pain in the right knee. Odds for having intermittent knee pain increased with longer baseline T2 values in medial and lateral femoral cartilage (OR[95%CI]: 1.05[1.02–1.08] and 1.06[1.03–1.09] for 1 ms longer) and thinner baseline patellar cartilage (0.65[0.53–0.81] for 1 mm thicker). Greater annual rates of patellar cartilage thinning were associated with higher odds of constant knee pain (93.4[7.66–1139] for 1 mm/yr greater). Among those with knee pain, greater annual rates of increase in medial and lateral tibial cartilage T2 led to more intermittent knee pain (percent change[95%CI]: 8.02[2.87–13.4] and 7.85[3.39–12.5] for 1 ms/yr greater). Thicker lateral tibial cartilage at baseline led to less constant knee pain (beta coeff.[95%CI]: -11.8[-19.8–3.76] for 1 mm thicker). CONCLUSIONS: Impaired femoral cartilage composition, indicated by longer T2 values, preceded intermittent knee pain found in early-stage OA. Constant knee pain characteristic for late-stage OA was related to greater cartilage thickness loss.