The purpose of the present study was to discuss the effects of risedronate on osteoarthritis (OA) of the knee by reviewing the existing literature. The literature was searched with PubMed, with respect to prospective, double-blind, randomized placebo-controlled trials (RCTs), using the following search terms: risedronate, knee, and osteoarthritis. Two RCTs met the criteria. A RCT (n = 231) showed that risedronate treatment (15 mg/day) for 1 year improved symptoms. A larger RCT (n = 1,896) showed that risedronate treatment (5 mg/day, 15 mg/day, 35 mg/week, and 50 mg/week) for 2 years did not improve signs or symptoms, nor did it alter radiological progression. However, a subanalysis study (n = 477) revealed that patients with marked cartilage loss preserved the structural integrity of subchondral bone by risedronate treatment (15 mg/day and 50 mg/week). Another subanalysis study (n = 1,885) revealed that C-terminal crosslinking telopeptide of type II collagen (CTX-II) decreased with risedronate treatment in a dose-dependent manner, and levels reached after 6 months were associated with radiological progression at 2 years. The results of these RCTs show that risedronate reduces the marker of cartilage degradation (CTX-II), which could contribute to attenuation of radiological progression of OA by preserving the structural integrity of subchondral bone. The review of the literature suggests that higher doses of risedronate (15 mg/day) strongly reduces the marker of cartilage degradation (CTX-II), which could contribute to attenuation of radiological progression of OA by preserving the structural integrity of subchondral bone.
Keywords: Osteoarthritis; bisphosphonate; knee; subchondral bone.