1683 patients were randomized to assess the effect of strontium ranelate on radiological and clinical progression of knee osteoarthritis (OA). Patients received either strontium ranelate 1 g/day, 2 g/day, or placebo and were assessed over 3 years. Results revealed that treatment with strontium ranelate (1 and 2 g/day) was associated with a significant effect on structure in knee OA patients. Treatment with Strontium ranelate was associated with smaller degradations of joint space width compared to placebo. Additionally, a beneficial effect was observed on pain and function for patients receiving the treatment 2 g/day.