Effects of low dose rate radiotherapy on pain relief, performance score, and quality of life in patients with knee osteoarthritis; a double-blind sham-controlled randomized clinical trial

Introduction: Knee osteoarthritis (OA) is a prevalent chronic condition characterized by progressive damage to the articular cartilage, resulting in chronic pain, swelling, and reduced range of motion with a range of prevalence of 10-40%. This study aims to investigate the efficacy of low-dose radiation as a local treatment option for knee OA symptoms. Methods: In this prospective study, patients with confirmed OA and older than 65 years were randomly assigned to treatment and control groups. The protocol plan IRCT20160706028815N6 was registered in Iranian registry of clinical trials system. The treatment group received 3 Gy radiation over six fractions, while the control group continued routine treatment without radiation. The pain intensity and functional levels were assessed at pretreatment and each month following completion of therapy for six consecutive months by Visual Analog Scale (VAS) and the Lysholm 100-point Scale, respectively. Analgesic medication usage and performance status (PS) were also assessed. Results: The mean age of the patients was 77 years (range 72-89). All variables including VAS pain score, Lysholm scale, PS and analgesic consumption were improved following radiation from first month to the end of assessments (p value <0.01). Conclusion: Results showed significant pain score improvements and enhanced joint function with no adverse effects. Findings were compared with previous studies, revealing mixed conclusions on low dose radiation therapy (LDRT) efficacy. Mechanistic hypotheses suggest LDRT may modulate inflammatory pathways. The study suggests LDRT at 3 Gy could benefit knee osteoarthritis patients and calls for further research on mechanisms of action in early-stage osteoarthritis.