Abstract
We evaluated the effect of the bisphosphonate, risedronate, on pain and cartilage metabolism in 33 patients with osteoarthritis of the knee, randomized into two groups. Group RC was treated with risedronate (2.5 mg/day) and calcium (900 mg/day); group C received calcium (900 mg/day) alone. Pain on exercise was estimated using a subjective visual rating scale (VRS) and an electroalgometric method of measuring decrease in skin impedance, previously shown to be indicative of pain. We measured urinary excretion of cartilage-specific collagen type II fragments as a marker of cartilage degradation. Multiple regression analysis revealed that pain alleviation as measured by skin impedance, but not VRS, was associated with a decrease in collagen fragment excretion. This suggests that, for pain evaluation, reduction in skin impedance may have a greater physiological basis compared with VRS-based evaluation. We consider that the chondroprotective and analgesic effects of risedronate may be related.