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.
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
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
50
Assigned Interventions
Matching device without active electromagnetic field) administered twice a week for 8 weeks
Feasibility outcome：adherence
Adherence will be calculated as the actual number of completed exercise days relative to the prescribed total.
Time frame: 3 months after treatment
Serum Levels of Inflammatory Markers and Adipokines
The serum concentrations of the following biomarker: Interleukin-6 (picograms per milliliter, pg/mL).
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: Baseline, 1and 3 months after treatment
Six-Minute Walk Distance
The total distance walked during the Six-Minute Walk Test, measured in meters (m).
Time frame: 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.
Time frame: 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).
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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)
Time frame: Baseline; 3 months after treatment
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