Evaluation of the Effects of Pulsed Electromagnetic Field on Inflammatory Knee Osteoarthritis

Double-blind, Randomized Controlled Pilot Study to Assess the Effect of Pulsed Electromagnetic Field on Inflammatory Knee Osteoarthritis

This study will assess the efficacy of pulsed electromagnetic field therapy in patients with inflammatory knee osteoarthritis confirmed by MRI-detected effusion-synovitis. Fifty participants will be randomly allocated into two groups. One group will receive active PEMF therapy at a specific optimized parameter twice a week for 8 weeks, while the other group will receive sham treatment using the same device without PEMF signal. The primary outcome is the change in WOMAC pain score, and secondary outcomes include knee function, stiffness, quality of life, and MRI-quantified structural changes.

Study Overview

• Status: Not yet recruiting
• Conditions: Knee Osteoarthritis (Knee OA)
• Intervention / Treatment: Device: Pulsed Electromagnetic Field (PEMF) Therapy; Device: Sham Pulsed Electromagnetic Field (PEMF) Treatments

Detailed Description

Knee osteoarthritis (KOA) is a leading cause of pain and disability, posing a significant socioeconomic burden. Current treatments often focus on pain relief with safety concerns, and no disease-modifying drugs are available. Pulsed electromagnetic field (PEMF) therapy is a non-invasive and safe physical modality with potential anti-inflammatory and analgesic effects. However, existing evidence for its efficacy in KOA is inconsistent, likely because KOA is a heterogeneous disease, and previous studies have not targeted specific subtypes. The inflammatory KOA subtype, identifiable via MRI, is the most prevalent and represents a critical target for precise intervention.

Methods This study is a double-blind, randomized, placebo-controlled pilot trial. Fifty patients with inflammatory KOA, confirmed by the presence of effusion-synovitis on MRI will be recruited. Participants will be randomly assigned to receive either active PEMF therapy at a specific, optimized parameter or sham treatment twice a week for 8 weeks. The primary outcome is the change in the WOMAC pain score at 3 months after treatment. Secondary outcomes include knee function and stiffness (WOMAC), quality of life (SF-12), and quantitatively assessed structural changes on MRI (e.g., effusion synovitis volume).

Expected Results The investigators anticipate that the group receiving active PEMF therapy will show a statistically significant and clinically important greater reduction in WOMAC pain scores compared to the sham treatment group.The investigators also expect to observe improvements in secondary outcomes, including better knee function and reduced signs of inflammation on MRI in the treatment group.

Conclusion This will be the first clinical trial to evaluate PEMF therapy specifically for the inflammatory subtype of KOA. Positive findings will provide crucial evidence for a novel, non-invasive, and precise therapeutic strategy for KOA management. This has the potential to improve patient care, alleviate the disease burden, and reduce healthcare costs.

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Ye LI; Phone Number: +85227664842; Email: ye-julie.li@polyu.edu.hk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Knee visual analogue scale (VAS) pain of <40 mm (0-100 mm)
2. Effusion-synovitis or Hoffa synovitis MRI semi-quantitative score of ≥2 (used to determine inflammatory subtype KOA);
3. Kellgren-Lawrence (KL) grade II and III
4. Patients can listen, speak, read, and understand Chinese; understand the pilot study's requirements and are willing to cooperate with the investigator in conducting the pilot study
5. Willing and able to provide written informed consent

Exclusion Criteria:

1. Other inflammatory arthritis (e.g., gout, reactive arthritis, rheumatoid arthritis, psoriatic arthritis, and seronegative spondyloarthropathy) and systemic lupus erythematosus.
2. Participants with usual KOA interventions/ treatments
3. History of knee trauma
4. Contraindications to MRI
5. Administration of intra-articular, intramuscular, and oral glucocorticoids within the last 4
6. Pregnancy and lactation

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: PEMF Therapy Intervention Patients with inflammatory KOA receive active PEMF therapy with optimized; Active Pulsed Electromagnetic Field (PEMF) Therapy Active PEMF therapy at specific optimized parameters, administered twice a week for 8 weeks	Device: Pulsed Electromagnetic Field (PEMF) Therapy; Assigned Interventions
Placebo Comparator: : Sham PEMF Treatment Patients with inflammatory KOA receive sham PEMF treatment (no effective elect; Sham Pulsed Electromagnetic Field (PEMF) Treatments treatment (matching device without active electromagnetic field) administered twice a week for 8 weeks	Device: Sham Pulsed Electromagnetic Field (PEMF) Treatments; Matching device without active electromagnetic field) administered twice a week for 8 weeks

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Feasibility outcome：adherence	Adherence will be calculated as the actual number of completed exercise days relative to the prescribed total.	3 months after treatment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Serum Levels of Inflammatory Markers and Adipokines	The serum concentrations of the following biomarker: Interleukin-6 (picograms per milliliter, pg/mL).	Baseline; 3 months after treatment
Western Ontario and McMaster Universities (WOMAC) pain score	The primary outcome will be the Western Ontario and McMaster Universities (WOMAC) pain score. This scale consists of 5 questions assessing knee joint pain, each scored on a 5-point Likert scale (0 = no pain, 4 = extreme pain). The total score of the pain subscale ranges from 0 to 20, with higher scores indicating a more severe degree of pain.	Baseline; 3 months after treatment
Measurement of biomarkers on MRI images of the knee	Cartilage defects (grades 0-4). A higher score indicates more severe pathology.	Baseline; 3 months after treatment
Ultrousound measurement	The severity of the following pathologies will be assessed via ultrasonography using semi-quantitative scoring systems: Synovitis(0-3), Osteophytes(0-3), Cartilage damage(0-3). A higher score indicates more severe pathology.	Baseline, 1and 3 months after treatment
Six-Minute Walk Distance	The total distance walked during the Six-Minute Walk Test, measured in meters (m).	Baseline;3 months after treatment
30-Second Chair Stand Test Repetitions	The maximum number of repetitions of rising fully from a standard-height chair without using arms, sitting back down, and fully rising again, completed within 30 seconds.	Baseline; 3 months after treatment]
Timed Up and Go Test Time	The time required to complete the Timed Up and Go Test (rising from a chair, walking 3 meters, turning around, walking back, and sitting down), measured in seconds (s).	Baseline; 3 months after treatment
12-Item Short Form Health Survey Score	Assesses overall health-related quality of life. This scale comprises 12 items, which are aggregated into summary scores for physical and mental health. The scores are transformed to a range of 0 to 100, with higher scores indicating better health status.	Baseline; 3 months after treatment
Patient Health Questionnaire-9 (PHQ-9) Score	Assesses the severity of depressive symptoms. This scale consists of 9 items, each scored from 0 to 3. The total score ranges from 0 to 27, with higher scores indicating more severe depressive symptoms.	Baseline; 3 months after treatment
Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Stiffness Subscale Score	Assesses the severity of knee stiffness. This subscale contains 2 items, each rated on a 5-point Likert scale (0 = none, 4 = extreme). The total subscale score ranges from 0 to 8, with higher scores indicating worse stiffness.	Baseline; 3 months after treatment
Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Physical Function Subscale Score	Assesses knee-related difficulty in performing daily activities. This subscale contains 17 items, each rated on a 5-point Likert scale (0 = none, 4 = extreme). The total subscale score ranges from 0 to 68, with higher scores indicating worse physical function.	Baseline; 3 months after treatment
Serum Levels of Interleukin-6	The serum concentrations of the following biomarkers will be measured: Interleukin-6 (picograms per milliliter, pg/mL)	Baseline; 3 months after treatment

Collaborators and Investigators

• Sponsor: The Hong Kong Polytechnic University
• Collaborators: Chinese University of Hong Kong; Zhujiang Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): February 15, 2026
• Primary Completion (Estimated): December 31, 2027
• Study Completion (Estimated): December 31, 2028

Study Registration Dates

• First Submitted: December 10, 2025
• First Submitted That Met QC Criteria: February 27, 2026
• First Posted (Actual): March 2, 2026

Study Record Updates

• Last Update Posted (Actual): March 2, 2026
• Last Update Submitted That Met QC Criteria: February 27, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Knee osteoarthritis; Pulsed electromagnetic field therapy; Inflammatory subtype
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Arthritis; Joint Diseases; Rheumatic Diseases; Osteoarthritis; Osteoarthritis, Knee; Therapeutics
• Other Study ID Numbers: HESEARS20231113002; 12231596 (Other Grant/Funding Number: Health and Medical Research Fund)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No