No Benefit Found for Low-Dose Radiation Therapy for in Treatment of Knee Osteoarthritis

No significant effect has been demonstrated to support the use of low-dose radiation therapy (LDRT) compared with sham treatment for inflammatory signs and symptoms in patients with knee osteoarthritis (OA), according to the results of a randomized double-blinded sham-controlled superiority clinical study published in the Annals of the Rheumatic Diseases.

Patients with knee OA from the rheumatology outpatient clinic of the Sint Maarttensskliniek in Nijmegen, The Netherlands, were recruited for this study. Eligibility criteria included age ≥50 years, numeric rating scale pain score ≥5/10 in the index knee, and insufficient response to exercise therapy and analgesics. Patients were randomly assigned in a 1:1 ratio to receive LDRT or sham intervention 6 times over 2 weeks, which was stratified based on pain (<8 vs ≥8/10).

The primary study outcome was the percentage of Outcomes Measures in Rheumatology/Osteoarthritis Research Society International responders 3 months post-intervention. Secondary outcomes included pain, inflammatory signs, and function as assessed by ultrasound, magnetic resonance imaging, and serum inflammatory markers.

Of the 55 patients enrolled between October 2015 and February 2017, 27 were randomly assigned to receive LDRT and 28 were assigned to receive sham therapy. Overall, 28 patients were women and mean participant age was 65 ± 9 years.

At 3 months post-intervention, 44% of patients in the LDRT group (95% CI, 26%-63%) and 43% of patients in the sham treatment group (95% CI, 25%-61%) achieved the primary outcome, which resulted in a difference of 2% (95% CI, 25%-28%). Logistic regression for response after adjusting for the stratified variable (numeric rating scale score ≥8/10) generated similar results, with an odds ratio of 1.1 (95% CI, 0.4-3.2; P =.9). No differences were observed with respect to any inflammatory signs.

The investigators concluded that based on the results of this analysis and the absence of other high-quality evidence, they advise against the use of LDRT as treatment in patients with knee OA. With this treatment still being widely used in some parts of the world, future efforts should focus on deimplementaiton of LDRT by changing the beliefs of involved healthcare professionals regarding the efficacy of this therapy, since these beliefs are not based on scientific grounds.

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Reference

Mahler EAM, Minten MJ, Leseman-Hoogenboom MM, et al. Effectiveness of low-dose radiation therapy on symptoms in patients with knee osteoarthritis: a randomised, double-blinded, sham-controlled trial [published online October 26, 2018]. Ann Rheum Dis.  doi:10.1136/annrheumdis-2018-214104