Knee Osteoarthritis, Osteoarthritis, Osteo Arthritis of the Knee, Gonarthrosis
Conditions
Keywords
High-Intensity Pulsed Electromagnetic Fields, HI-PEMF, Super Inductive System, Knee Osteoarthritis, Gonarthrosis, Geriatric Rehabilitation, Chronic Pain, Functional Mobility
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. 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
DEVICEHI-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.
DEVICEHI-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 perpendicular to the muscle belly, without skin contact, with the patient lying supine and a cushion under the knee for slight flexion.
BEHAVIORALHome-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.
Sponsors
Hospital Civil de Guadalajara
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, 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.
Intervention model description
Two-arm parallel design: Group A receives HI-PEMF applied to the knee only (unimodal), while Group B receives HI-PEMF applied to both the knee and quadriceps (bimodal). Both groups also perform the same home-based exercise program.
Eligibility
Sex/Gender
ALL
Age
60 Years to No maximum
Healthy volunteers
No
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in pain intensity measured by the Numeric Analog Scale (NAS) | 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
| Measure | Time frame | Description |
|---|---|---|
| Change in functional mobility measured by the Timed Up and Go (TUG) test | Baseline, end of intervention (week 5), and 2-month follow-up | Functional mobility will be assessed using the Timed Up and Go (TUG) test. Participants are instructed to stand up from a chair, walk 3 meters, turn around, return, and sit down. The total time (in seconds) will be recorded using a stopwatch. The outcome measure is the change in time from baseline to the end of the 5-week intervention and at 2-month follow-up. This assesses both short-term and sustained improvements in functional mobility. |
| 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 | Lower-limb functional strength will be assessed using the 5-times Sit-to-Stand (5STS) test. Participants will be instructed to rise from a standard chair and sit back down five times as quickly as possible without using their arms. The total time (in seconds) to complete the task will be recorded using a stopwatch. The outcome measure is the change in time from baseline to the end of the 5-week intervention and at 2-month follow-up. This evaluates improvements in functional lower-limb strength and endurance over time. |
Countries
Mexico
Outcome results
None listed