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

We investigated whether cartilage composition and thickness and its change over time were associated with future intermittent and constant knee pain. 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. 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). 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.