Comparative Effectiveness of Continuous Versus Pulsed Long-Wave Diathermy in Patients with Knee Osteoarthritis: A Pilot Randomized Study

Abstract

Background: Knee osteoarthritis (OA) is a degenerative musculoskeletal disorder leading to chronic pain and disability. Long-wave diathermy (LWD) is used in physiotherapy practice, but comparative evidence between continuous (CLWD) and pulsed (PLWD) modes is scarce.
Objective: To compare the effects of CLWD versus PLWD combined with conventional physiotherapy on pain, range of motion (ROM), function, quality of life, inflammatory biomarker (IL-6), and gait in patients with knee OA.
Methods: Thirty patients with grade II–III knee OA were randomized into PLWD (n=15) and CLWD (n=15) groups. Both received identical conventional therapy (ultrasound, hot packs, quadriceps isometrics, hamstring stretching) for 8 weeks, 3 sessions/week. Outcomes included VAS, knee ROM, WOMAC subscales, WHOQOL-BREF, IL-6 levels, and gait parameters. The Shapiro–Wilk test was applied for normality; paired and independent t-tests were used for within- and between-group comparisons at α = 0.05.
Results: Both groups showed significant improvements (p < 0.05). CLWD produced greater reductions in VAS (-5.7 vs -4.6), IL-6 (-3.2 vs -2.0 pg/mL), and WOMAC domains, as well as larger gains in ROM (flexion: +18° vs +11°), WHOQOL domains (physical: +32 vs +22), and stride length (+20 cm vs +15 cm). Between-group differences were significant (p < 0.05).
Conclusion: Continuous LWD was more effective than pulsed LWD in reducing pain, improving function, enhancing quality of life, and lowering inflammation in knee OA. Larger multicenter RCTs are warranted.