"Bimodal vs Unimodal High-Intensity Pulsed Electromagnetic Field Therapy in Older Adults With Knee Osteoarthritis"

Knee osteoarthritis (OA) is a highly prevalent and disabling condition in older adults. It often coexists with quadriceps muscle weakness, sarcopenia, and frailty, all of which contribute to pain, functional decline, and loss of independence. Pulsed electromagnetic field therapy (PEMF) has emerged as a non-invasive alternative for pain relief in OA, with growing interest in its application at both articular and muscular levels. High-intensity pulsed electromagnetic field (HI-PEMF) therapy-also known as the super inductive system-generates magnetic fields up to 2.5 Tesla, capable of stimulating both joint structures and skeletal muscle via deep tissue electric induction. HI-PEMF has shown promising results for pain reduction, anti-inflammatory modulation, and muscle bioactivation, particularly when applied over the quadriceps. This randomized, double-blind, parallel-assignment clinical trial aims to compare the effects of two HI-PEMF treatment modalities in older adults with moderate to severe knee OA (Kellgren-Lawrence grade II-IV): * Group A: HI-PEMF applied exclusively over the symptomatic knee. * Group 2: HI-PEMF applied both over the knee and the quadriceps (bimodal). Both groups will also perform a standardized home-based strengthening and mobility exercise program. A total of 64 participants (32 per group) will receive 9 sessions of HI-PEMF (2 per week for 5 weeks), using the BTL-6000 Super Inductive System. Outcomes will be assessed at baseline and post-intervention. The primary outcome is change in pain intensity using the Numeric Analog Scale (NAS). Secondary outcomes include functional tests (Timed Up and Go and 5-times Sit-to-Stand), and paracetamol use. Exploratory subgroup analyses will assess associations with frailty status (FRAIL), probable sarcopenia (SARC-F), and radiological OA grade. This study seeks to generate evidence on the potential synergistic benefits of combining articular and muscular HI-PEMF therapy in geriatric rehabilitation. It is designed for implementation in a public hospital setting in Mexico, with minimal risk and high feasibility. All procedures follow ethical guidelines and have received institutional review board approval.