Low-dose radiation therapy of no benefit in knee osteoarthritis
Low-dose radiation therapy (LDRT) falls short of producing substantial symptom improvements in patients with knee osteoarthritis (OA), a study has shown.
Researchers randomized 55 patients with knee OA aged ≥50 years to undergo LDRT (1 Gray per fraction; n=27) or sham treatment (n=28) six times in 2 weeks, stratified by pain (<8 vs ≥8/10). Patients had pain score ≥5/10 and nonresponse to analgesics and exercise therapy.
At 3 months after the intervention, the primary outcome of the proportion of Outcome Measures in Rheumatology Clinical Trials Osteoarthritis Research Society International (OMERACT-OARSI) responders did not significantly differ between the LDRT and sham groups (44 percent vs 43 percent; difference, 2 percent). Multivariable logistic regression yielded an odds ratio of 1.1 (95 percent CI, 0.4–3.2; p=0.9) for the LDRT vs sham group.
There were no differences in any other secondary outcomes investigated, including the inflammatory signs measured by imaging or inflammatory markers.
In terms of safety, the occurrence of both adverse events (AEs) and serious AEs (SAEs) was comparable for both groups. Colon carcinoma was diagnosed postintervention in two patients in the sham group, said not to be related to the intervention. One LDRT patient collapsed, one patient in the sham group had severe knee pain during and after the intervention, and one patient in the sham group experienced cold sensations in the lower index leg.
In light of the findings, researchers advised against the use of LDRT as treatment for knee OA. Further research is needed and should also focus on the quality of the scientific evidence of LDRT treatment for other benign (musculoskeletal) disorders, for which high-quality studies are also lacking.