Objectives Low-dose radiation therapy (LDRT) for benign disorders such as knee osteoarthritis (OA) is widely used in some parts of the world, despite absence of controlled studies. We evaluated the effect of LDRT on symptoms and inflammation in patients with knee OA.
Methods In this randomised, double-blinded, sham-controlled clinical trial (RCT), we recruited patients with knee OA (clinical ACR criteria) in the Netherlands, aged ≥50 years, pain score ≥5/10 and non-responding to analgesics and exercise therapy. Patients were randomised 1:1 to receive LDRT (1 Gray per fraction) or sham intervention six times in 2 weeks, stratified by pain (<8 versus ≥8/10). Primary outcome was the proportion of OMERACT-OARSI responders, 3 months postintervention. Secondary outcomes included pain, function and inflammatory signs assessed by ultrasound, MRI and serum inflammatory markers.
Results We randomly assigned 55 patients: 27 (49%) to LDRT and 28 (51%) to sham. At 3 months postintervention, 12/27 patients (44%; 95% CI 26% to 63%) in the LDRT vs 12/28 patients (43%; 95% CI 25% to 61%) in the sham group responded; difference 2% (95% CI 25% to 28%), OR adjusted for the stratifying variable was 1.1 (95% CI 0.4 to 3.2). Also, for clinical and any of the inflammatory signs, no differences were observed.
Conclusions We found no substantial beneficial effect on symptoms and inflammatory signs of LDRT in patients knee OA, compared with sham treatment. Therefore, based on this RCT and the absence of other high-quality evidence, we advise against the use of LDRT as treatment for knee OA.
Trial registration number NTR4574.
- randomised controlled clinical trial
- radiation therapy
- knee osteoarthritis
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Handling editor Josef S Smolen
Contributors FHJvdH and JWHL had the idea for the study. Study conception and design (EAMM, MJMM, MML-H, JWHL, AAdB, CHMvdE); inclusion and data collection (EAMM, MJMM, MML-H, SSB); literature search, data analysis, tables and figures (EAMM, MJMM) and interpretation of data (all authors); drafting of the manuscript (EAMM); critical revision of the manuscript for important intellectual content (all authors); final approval of the manuscript (all authors). All authors take responsibility for the integrity of the work and agreed to submit the article for publication.
Funding There was no external funding source for this study. The study costs were jointly covered by Sint Maartenskliniek and Radboud University Medical Center.
Disclaimer The corresponding author had full access to all the data in the study and had final responsibility for the decision to submit for publication.
Competing interests None declared.
Patient consent Not required.
Ethics approval The local Medical Ethics committee Arnhem-Nijmegen, the Netherlands approved the study (2014-275).
Provenance and peer review Not commissioned; externally peer reviewed.