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

Official title

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

Overview

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.

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.

Interventions

• Device HI-PEMF - Knee (Chronic Pain Protocol)
  High-intensity pulsed electromagnetic field (HI-PEMF) therapy applied to the symptomatic knee using the "Chronic Pain" protocol of the BTL-6000 Super Inductive System, 10-minute duration per session, applied twice per week over 5 weeks (total of 9 sessions). The applicator is positioned 2-3 cm above the patella, without skin contact, with the patient seated or in supine position.
• Device HI-PEMF - Quadriceps (Muscle Strengthening Protocol)
  HI-PEMF therapy will be applied to both the symptomatic knee and the quadriceps muscle (rectus femoris). The knee application will follow the same procedure as in Group A, using the "Chronic Pain" protocol of the BTL-6000 Super Inductive System. In addition, the quadriceps will be treated using the "Muscle Strengthening" protocol. Each site will receive 10 minutes of therapy per session, twice per week over 5 weeks (total of 9 sessions). The applicator for the quadriceps will be positioned perpe
• Behavioral Home-Based Exercise Program
  Standardized home-based exercise program prescribed to both groups. It includes five exercises: isometric quadriceps contractions, straight leg raises, seated knee extensions, sit-to-stand from chair, and stationary marching. Participants are instructed to perform the exercises three times per week during the 5-week intervention. Printed instructions and a video guide are provided. Adherence is reinforced via weekly follow-up.

Primary outcome measures

• Change in pain intensity measured by the Numeric Analog Scale (NAS) [Time frame: Baseline, end of intervention (week 5), and 2-month follow-up]

Secondary outcome measures (2)

• Change in functional mobility measured by the Timed Up and Go (TUG) test [Time frame: 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 [Time frame: Baseline, end of intervention (week 5), and 2-month follow-up]

Eligibility criteria

Inclusion criteria

• Age ≥ 60
• 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

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Double blind

Primary purpose

Treatment

Study locations

Mexico · 1 center

• Hospital Civil de Guadalajara "Fray Antonio Alcalde" — Guadalajara

Publications

• Iannitti T, Fistetto G, Esposito A, Rottigni V, Palmieri B. Pulsed electromagnetic field therapy for management of osteoarthritis-related pain, stiffness and physical function: clinical experience in the elderly. Clin Interv Aging. 2013;8:1289-93. doi: 10.2147/CIA.S35926. Epub 2013 Sep 26. PMID 24106421
• Ong MT, Man GC, Lau LC, He X, Qiu J, Wang Q, Chow MC, Choi BC, Yu M, Yung PS. Effect of pulsed electromagnetic field as an intervention for patients with quadriceps weakness after anterior cruciate ligament reconstruction: a double-blinded, randomized-controlled trial. Trials. 2022 Sep 12;23(1):771. doi: 10.1186/s13063-022-06674-2. PMID 36096886
• Bagnato GL, Miceli G, Marino N, Sciortino D, Bagnato GF. Pulsed electromagnetic fields in knee osteoarthritis: a double blind, placebo-controlled, randomized clinical trial. Rheumatology (Oxford). 2016 Apr;55(4):755-62. doi: 10.1093/rheumatology/kev426. Epub 2015 Dec 24. PMID 26705327

Identifiers

NCT: NCT07198750 · CEI-151-25

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗