A large, multicentre, double-blind, randomised, controlled trial of strontium ranelate in patients with mild–moderate OA of the knee
followed 1683 patients from 98 centres across 18 countries over 3 years. Participants were randomised to either strontium ranelate in a dose of 1 g/day or 2 g/day or placebo. The primary endpoint was change in joint-space width measured radiographically at yearly intervals. Other endpoints included knee pain and WOMAC scores. Both doses of strontium ranelate reduced the loss of joint space significantly compared to placebo. The lead author explained in an interview for Medscape 1 that a reduction in joint-space loss of ≥0.5 mm is significant because a 0.5 mm loss increases the likelihood of joint replacement within 10 years 5-fold. 34% of patients taking 1 g of active treatment achieved a reduction in joint-space loss of ≥0.5 mm, and 44% of those taking 2 g. The authors claim that treatment with strontium ranelate could therefore lead to significant reductions in the need for joint replacement surgery. 2
While effective strategies to keep the population lean and active into their 70s, 80s and even 90s are probably a greater priority in preventing osteoarthritic progression, an effective drug treatment that reduced the need for joint replacement would be very welcome indeed. We need much more work to be done to substantiate these results and we will then need some long-term health economics studies before understanding the complete picture here.