Relationship of urinary pyridinium crosslinks to disease extent and activity in osteoarthritis.

Urinary crosslinks, pyridinoline and deoxypyridinoline, have been shown to be elevated in RA and OA. This study confirmed this elevation, with levels in patients with predominantly knee OA higher than those with nodal OA and hip OA. Intra-articular corticosteroid injection was followed by a significant fall in urinary crosslinks, which was associated with a corresponding improvement in articular index and pain score, although there was no overall correlation between crosslink levels and the clinical indices studied. Collagen crosslinks may be of value as markers of disease activity in OA.