Orthovoltage X-Ray Therapy Significantly Reduces Disability Risk In Knee Osteoarthritis Patients: A Decade-Long Cohort Study

Introduction — Osteoarthritis (OA) of the knee and hip joints affects 13% of the adult population in the Russian Federation. While medications can provide some relief from the pain associated with OA, they are often not enough. An alternative treatment option is orthovoltage radiation therapy (OVRT), which not only relieves pain, but can also help prevent disability. However, there is little evidence for the long-term effectiveness of OVRT. Objective — We compared the incidence of disability among patients with OA who received standard treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) in combination with the symptomatic slow-acting drugs for osteoarthritis (SYSADOA), or in combination with OVRT for knee OA in the setting of an open randomized controlled trial with long-term follow-up. Material and Methods — The sampling frame included patients with confirmed OA of the knee sensu Altman (1991), with radiographic grades of OA from 0 to 2 sensu Kellgren-Lawrence. A total of 292 patients were randomly distributed among two groups of equal sizes. The control group received combination therapy with NSAIDs and SYSADOA. In the experimental group, OVRT was additionally performed at a total dose of 4.5 Gy. Relationships between treatment regimen and time to disability were studied using actuarial analysis, Kaplan-Meier plots. Crude and adjusted hazard ratios (HR) with 95% confidence intervals (CI), as well as attributable fraction (AF) and population attributable fraction (PAF) were calculated. Results — The cumulative time at risk for disability was 2,304.9 person-years. In total, 9.5% of patients in the experimental group became disabled during the observation period vs. 17.8% in the control group. In the experimental group, the level of disability was lower (HR=0.49, 95% CI: 0.26-0.95). Differences became more pronounced after adjusting for sex, age, radiographic grade of OA, pain intensity, and duration of OA before treatment (HR=0.24, 95% CI: 0.11-0.48). AF and PAF were 49.9% and 25.8%, respectively. Conclusion — It has been shown that the introduction of OVRT in the treatment regimen can reduce the disability of patients with knee OA by almost 50%. One in four disability cases could be prevented if OVRT were used universally in the treatment of knee OA. Our results indicate that combining OVRT with standard care is a more effective approach to preventing disability in patients with knee OA than standard treatment alone.