Effect of alendronate sodium plus vitamin D3 tablets on knee joint structure and osteoarthritis pain: a multi-center, randomized, double-blind, placebo-controlled study protocol

Background: Osteoarthritis (OA) is a major cause of pain and disability worldwide. Despite the relatively high burden of the disease, the currently available non-surgical treatment options are directed towards symptomatic relief. Therefore, we propose the use of alendronate as a disease modifying agent to help slow and prevent OA. In addition, this study will utilize Whole-Organ Magnetic Resonance Imaging Score (WORMS) to evaluate the structural integrity of cartilage in the study population. High-quality evidence, limited to a few well-conducted randomized trials, highlights contradictory results on the effect of bisphosphonates on knee function and progression of OA. Therefore, a placebo-controlled, randomized trial is needed to evaluate the combined effect of alendronate and vit D on the structure of cartilage utilizing the WORMS score and its ability to treat knee pain in OA patients. Methods: This multicenter, randomized, double-blinded, placebo-controlled study will evaluate the efficacy and safety of alendronate in early OA. Patients will undergo a 1:1 double-blinded randomization to receive a one-year course of either alendronate sodium vitamin D-3 or placebo. The primary outcome is to compare WORMS score of knee joint at 6 and 12 months between both groups. Secondary endpoints will include WORMS score at 24 months, knee pain, radiographic progression of OA, severity of OA, quality of life, and serum inflammatory biomarkers at different assessment timepoints. To detect a 2.2% difference in cartilage loss between both groups with power of 80%, a sample size of 60 (30 per group) is proposed. Discussion: This trial will give helpful and high-quality evidence regarding the potential therapeutic role of alendronate sodium vitamin D3, as compared to placebo, in the management of patients with knee OA regarding its role on cartilage loss, radiographic progression of OA, severity of OA, knee pain, quality of life, and inflammatory biomarkers. If proven effective, this intervention would be a great option for providing beneficial outcomes with a reduced cost in this patient population.