Effect of piroxicam on gait in patients with osteoarthritis of the knee.

OBJECTIVE To determine whether the use of a nonsteroidal antiinflammatory drug (NSAID) in patients with painful osteoarthritis (OA) of the knee would result in alterations in specific biomechanical parameters of gait. METHODS Eighteen patients with symptomatic knee OA and varus knee deformity underwent initial clinical evaluation for pain and activities of daily living, and assessment of parameters of gait utilizing a well-described computerized system. All patients were then treated with piroxicam at 20 mg once daily, and clinical and gait analyses were repeated after 4 weeks. RESULTS Fifteen of the 18 patients studied had a significant increase in the knee adduction moment after treatment. In the group as a whole there was a significant increase in knee adduction moment (mean percent body weight times height [%BWTH] 4.11 pretreatment versus 4.57 after 4 weeks of treatment; P < 0.01) and maximum quadriceps moment (mean %BWTH 2.13 pretreatment, 2.62 posttreatment; P < 0.01), as well as changes in other gait parameters that might be expected to be altered as a result of relief of pain. Sixteen of 18 patients experienced symptomatic relief, with a significant reduction in pain in the group as a whole after 4 weeks (P < 0.001). CONCLUSION NSAID treatment in patients with knee OA results in a reduction in symptomatic pain and an increase in loading of the knee. Whether the increased loading is due to the analgesic effects of the treatment is unknown, but if so, the development of agents capable of relieving pain while reducing loads at the knee may be desirable.