Effect of High-Intensity Pulsed Electromagnetic Field Therapy as a Bimodal Intervention for Analgesia and Strengthening in Older Adults With Knee Osteoarthritis: A Randomized Double-Blind Controlled Clinical Trial
Trial Snapshot
- Phase
- Not Applicable
- Status
- Recruiting
- Enrollment
- 64
- Locations
- 2
- Primary Endpoint
- Change in pain intensity measured by the Numeric Analog Scale (NAS)
Study Overview
Brief Summary
This randomized, double-blind clinical trial aims to evaluate the effect of high-intensity pulsed electromagnetic field therapy (HI-PEMF) applied either exclusively on the knee joint or bimodally on the knee and quadriceps, in older adults with knee osteoarthritis. Both groups will also receive a structured home-based exercise program. The primary outcome is pain reduction, and secondary outcomes include functional performance.
Detailed Description
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.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Parallel
- Primary Purpose
- Treatment
- Masking
- Double (Participant, Outcomes Assessor)
Masking Description
Participants were informed that the intervention would be applied to the lower limb without specifying the anatomical region. The HI-PEMF equipment produces no perceptible sensations, aiding participant blinding. Outcome assessors were independent and unaware of group assignment. Care providers administering the intervention were not blinded.
Eligibility Criteria
- Ages
- 60 Years to — (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •Clinical and radiological diagnosis of knee OA grade I-IV
- •Pain ≥ 3 on Numeric Analog Scale for >6 months
- •Can walk (with/without aid)
- •Cognitive ability to follow instructions
- •Signed informed consent
- •Availability for 9 treatment sessions and home exercise
Exclusion Criteria
- •Prior total knee arthroplasty (unilateral or bilateral)
- •Neurological disorders affecting motor function or cognition (e.g., Parkinson's disease, stroke, moderate to severe dementia)
- •Active inflammatory rheumatic diseases (e.g., rheumatoid arthritis, lupus)
- •Presence of pacemakers, implantable defibrillators, or metallic implants near the treatment area
- •Current use of other physical therapy modalities for pain (e.g., electrotherapy, ultrasound, TENS) outside the study protocol
- •Participation in another clinical trial within the past 3 months
- •Current use of NSAIDs or systemic/local corticosteroids (including intra-articular injections)
- •Open wounds or active infections at the treatment site
- •Decompensated cardiac conditions or medical contraindication to exercise
- •Vestibular disorders that affect balance and interfere with functional assessments
- •Uncorrected visual impairment interfering with gait or balance (visual acuity worse than 20/60 in the better eye, assessed by Snellen chart)
- •Withdrawal Criteria:
- •Participants who complete fewer than 7 out of the 9 planned intervention sessions (i.e., less than 80% adherence)
- •Occurrence of serious adverse events related to the intervention that contraindicate continuation
- •Repeated non-compliance with the home exercise program, documented in at least two consecutive weekly follow-up reports
- •Voluntary withdrawal of consent at any time during the study
Arms & Interventions
Group A - Unimodal HI-PEMF
Participants in Group A will receive high-intensity pulsed electromagnetic field therapy (HI-PEMF) applied exclusively to the symptomatic knee (femorotibial joint) for 10 minutes per session, twice a week over 5 weeks, completing a total of 9 sessions. The intervention will use the "Chronic Pain" protocol of the BTL-6000 Super Inductive System. A standardized home-based exercise program will be provided to all participants.
Intervention: HI-PEMF - Knee (Chronic Pain Protocol) (Device)
Group A - Unimodal HI-PEMF
Participants in Group A will receive high-intensity pulsed electromagnetic field therapy (HI-PEMF) applied exclusively to the symptomatic knee (femorotibial joint) for 10 minutes per session, twice a week over 5 weeks, completing a total of 9 sessions. The intervention will use the "Chronic Pain" protocol of the BTL-6000 Super Inductive System. A standardized home-based exercise program will be provided to all participants.
Intervention: Home-Based Exercise Program (Behavioral)
Group B - Bimodal HI-PEMF
Participants in Group B will receive high-intensity pulsed electromagnetic field therapy (HI-PEMF) applied to both the symptomatic knee (femorotibial joint) and the quadriceps muscle (rectus femoris), with 10 minutes per site, twice a week over 5 weeks, completing a total of 9 sessions. The knee application will follow the "Chronic Pain" protocol, and the quadriceps application will follow the "Muscle Strengthening" protocol, both using the BTL-6000 Super Inductive System. A standardized home-based exercise program will be provided to all participants.
Intervention: HI-PEMF - Quadriceps (Muscle Strengthening Protocol) (Device)
Group B - Bimodal HI-PEMF
Participants in Group B will receive high-intensity pulsed electromagnetic field therapy (HI-PEMF) applied to both the symptomatic knee (femorotibial joint) and the quadriceps muscle (rectus femoris), with 10 minutes per site, twice a week over 5 weeks, completing a total of 9 sessions. The knee application will follow the "Chronic Pain" protocol, and the quadriceps application will follow the "Muscle Strengthening" protocol, both using the BTL-6000 Super Inductive System. A standardized home-based exercise program will be provided to all participants.
Intervention: Home-Based Exercise Program (Behavioral)
Outcomes
Primary Outcomes
Change in pain intensity measured by the Numeric Analog Scale (NAS)
Time Frame: Baseline, end of intervention (week 5), and 2-month follow-up
Pain intensity will be assessed using the 11-point Numeric Analog Scale (0 = no pain, 10 = worst possible pain), reported by the patient at rest and related to the most symptomatic knee. The primary endpoint is the change in NAS score from baseline to end of the 5-week intervention and at 2-month follow-up (approximately week 13). This will allow evaluation of both immediate and sustained effects of the intervention.
Secondary Outcomes
- Change in lower-limb functional strength measured by the 5-times Sit-to-Stand (5STS) test(Baseline, end of intervention (week 5), and 2-month follow-up)
- Change in lower-limb functional strength measured by the 5-times Sit-to-Stand (5STS) test(Baseline, end of intervention (week 5), and 2-month follow-up)
- Change in functional mobility measured by the Timed Up and Go (TUG) test(Baseline, end of intervention (week 5), and 2-month follow-up)
Investigators
Ana Lilia Villagrana Rodríguez
Physician Specialist, Department of Physical and Rehabilitation Medicine
Hospital Civil de Guadalajara