Aso K, et al. - Assuming the role of subchondral bone and the osteochondral junction in osteoarthritis (OA) knee pain, researchers investigated osteochondral pathologies specifically associated with symptomatic human knee OA. From 2 groups of subjects (n = 31 per group), they matched medial tibial plateau samples for macroscopic chondropathy scores. They obtained specimens of the medial tibial plateau from the symptomatic chondropathy group while they underwent total knee replacement for OA knee pain. Subjects who died of unrelated illness (specimens were obtained at postmortem examination) and who had not previously sought help for knee pain comprised the asymptomatic chondropathy group. The analysis revealed that symptomatic knee OA was associated with subchondral pathology, irrespective of chondropathy and synovitis. Key features associated with bone pain in knee OA seemed to comprise increased nerve growth factor expression in osteochondral channels and increased osteoclast density.