Is a biological marker for osteoarthritis within reach?

Identification of a biological marker for osteoarthritis is a important research priority. A good biological marker would be sensitive to changes in the severity of cartilage destruction. Data from the literature suggest that hyaluronate and cartilage oligomeric matrix protein are more likely to meet this criterion than keratan sulfate, cytokines, or phospholipase A2. Baseline hyaluronate levels and their increase during the first year of follow-up predicted radiographic changes in knee osteoarthritis, and baseline cartilage oligomeric matrix protein levels predicted radiological changes in hip osteoarthritis. Circulating metalloproteinase levels may also deserve to be investigated. Identification of a single predictive marker is probably an unrealistic goal. Current research is focusing on combinations of several markers capable of providing information on the extent of cartilage degradation and anabolism, on subchrondral bone metabolism, and on reactive changes in the synovial membrane.