COMP and osteoarthritis, knee: Patients with medial compartment knee osteoarthritis (OA) also showed an immediate increase in COMP but continuously decreasing levels below pre-stress levels after the walking stress without differences to an age-matched asymptomatic control group.3 The change in COMP at 3.5 and 5.5 hours,4 in a collagen degradation marker C1,2C and in the synthesis marker CS846 5.5 hours after the stimulus5 predicted changes in articular cartilage thickness supporting the potential relevance of load-induced changes in blood markers in the progression of knee OA.