Low-Dose Radiation Therapy (LDRT) for Osteoarthritis: A Retrospective Study of 94 Patients and 136 Joints Treated

Purpose This retrospective study aims to examine the efficacy of low-dose radiation therapy (LDRT) delivered via a linear accelerator in patients with osteoarthritis, measuring pain relief across various joints. Methods and Materials A total of 94 patients and a total of 136 affected joints were treated with LDRT between January 2023 and May 2025 at a radiation therapy institute. Each patient received 6 treatments of 0.5 Gy every other day, totaling 3 Gy over the course of 2 weeks. Pain was documented using the numeric rating scale (NRS) before treatment (preradiation therapy) and at follow-up visits approximately 12 weeks posttreatment, with the von Pannewitz score also assessed at follow-up. Results The mean age of patients was 74.5 years, with 38% male and 62% female patients. The treated joints included 61 hands (45%), 46 knees (34%), 15 shoulders (11%), 8 hips (6%), and 6 feet (4%). The mean pain score before treatment was 7.30 ± 1.90, while after treatment it dropped to 2.58 ± 3.09 on the NRS scale (P < .0001). Using a minimal clinically important difference threshold of a ≥2-point reduction in NRS, 79% of patients achieved clinically meaningful pain improvement following LDRT. Age (P = .23), sex (P = .20), and joint size (P = .35) were not found to significantly affect treatment outcomes. Most patients received a single course of LDRT treatment, with only 3.7% of patients receiving a second treatment course. Conclusions The study indicates that LDRT may be a safe, noninvasive option for treating osteoarthritis-related pain and improving joint function. Well-powered randomized controlled trials, especially with an American cohort, are required in the future to confirm these findings.