Radiotherapy for osteoarthritis-an analysis of 295 joints treated with a linear accelerator.

Osteoarthritis is a common disease, with a prevalence of symptomatic disease of 8.9%. One treatment option is radiotherapy. Most published samples were treated with an orthovoltage technique or with a telecobalt device. A lot of radiotherapy institutions are nowadays using linear accelerators for treatment of osteoarthritis. There is a discussion on whether the treatment results achieved with a linear accelerator are comparable to those with the orthovoltage technique. The aim of this study is to analyze the results of radiotherapy for osteoarthritis with a linear accelerator and compare the results with reference to different joints. The analysis was performed in patients of two German radiotherapy institutions and included 295 irradiated joints. Pain was documented with the numeric rating scale (NRS). Evaluation of the NRS was done before and directly after each radiation therapy course as well as for the follow-up of 24 months. The median age of the patients was 65 years, with 39.0% male and 61.0% female patients. Most frequently, osteoarthritis of the knee (34.6%) or the finger (15.9%) was treated. We could find a significant response to radiotherapy. Median pain for the whole sample was 7 on the NRS before radiotherapy, 4 after 6 weeks, and 3 after 12 and 24 months. The percentage of patients with 0 or 1 on the NRS was 33.8% 12 months after radiotherapy. All investigated subgroups had a significant reduction of pain. Radiotherapy of osteoarthritis with a linear accelerator is an effective treatment which is very well tolerated. All analyzed subgroups show a good response to radiotherapy for at least 24 months. Orthovoltage therapy seems to be superior to treatment with a linear accelerator in a case-related analysis of the published samples. Further investigations should be performed for a definitive answer to this question.