The Multicenter Osteoarthritis Study (MOST)

Knee osteoarthritis (OA) is a common chronic painful disorder that is the most frequent cause of mobility disability in aging adults. The prevalence of OA is increasing due to aging and increased rates of obesity. Currently there are few effective treatments for OA none of which slows disease progression.

MOST is one of the world’s longest running cohort studies of OA. Initially funded in 2001, the MOST study has been a major source of new knowledge about the course of OA and factors that affect it. Having published over 200 articles on pain and pain sensitivity, biomechanics, structural joint pathology, decline in function, and falls; results from the MOST study has provided insights into risk factors and consequences of this highly prevalent and disabling disease. The MOST study completed its 20th year in the field in December 2025.

The MOST study has an overall goal to advance our understanding of OA and its consequences in order to advance treatment approaches including stratified approaches. Current projects include: 1) examining the neurobiological mechanisms related to impaired exercise-induced hypoalgesia (temporary reduction in pain and sensitivity to pain that occurs with exercise) in people with knee OA, 2) identifying proteins in knee OA synovial fluid and plasma that are associated with pain and disease progression of OA, and 3) differentiating types of calcium crystals deposited in the knee to further understand the clinical and structural consequences of crystal deposition.

A complete list of measures available across all MOST visits can be found here (List of MOST Measures PDF).