Goal

To identify mechanisms by which knee osteoarthritis develops and progresses, by examining the interaction of in vivo mechanical and biological factors in patients with medial compartment knee OA:

• MR imaging
• Analysis of cytokines present in the serum.

Major Findings

• In OA patients, the difference in serum COMP concentrations after a mechanical stimulus (mCOMP) at 3.5h and 5.5h post-activity are associated with cartilage thickness.
  • At baseline testing, patients who had higher mCOMP levels 3.5 hours after the walking activity had greater cartilage loss at the 5-year callback test.
• At baseline testing, in OA patients and control subjects:
  • Serum COMP concentrations increased immediately after the walking exercise.
  • Serum COMP concentrations decreased over 5.5 h after the exercise.
• The magnitude of increase in COMP concentration did not differ between groups and did not correlate with joint loads at baseline testing.

Representative Publications

• A relationship between mechanically-induced changes in serum cartilage oligomeric matrix protein (COMP) and changes in cartilage thickness after 5 years.
  Erhart-Hledik JC, Favre J, Asay JL, Smith RL, Giori NJ, Mündermann A, Andriacchi TP. Osteoarthritis Cartilage. 2012 Nov; 20:1309-15.
• Change in serum COMP concentration due to ambulatory load is not related to knee OA status.
  Mündermann A, King KB, Smith RL, Andriacchi TP. J Orthop Res. 2009 Nov;27(11): 1408-13.

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