To Investigate the Effect of PEMF for Knee OA Patients

Pulsed Electromagnetic Fields (PEMF) in Knee Osteoarthritis: a Double-blind, Placebo-controlled, Randomised Clinical Trial

Health care costs are increasing alarmingly, which will impose an overwhelming economic burden to an aging society like that of Hong Kong. For example, degenerative musculoskeletal disorders such as osteoarthritis (OA) present a grand challenge with its high prevalence (>40% in the elderly suffered from knee OA). Knee osteoarthritis (OA) is the most common form of arthritis, and around 2 million population worldwide suffer from this disorder. OA is a debilitating progressive disease with typical pathological progress such as cartilage degeneration, inflammation, joint width narrowing and developing osteophytes. The main system of knee OA is acute pain leading to loss of mobility. There is no effective treatment to cure or stop the progression of OA. For now, the main method is to alleviate the pain and symptoms, including control weight, exercise, physical treatment and intake of NSAIDs/ paracetamol.

Pulsed electromagnetic field (PEMF) treatment has shown to enhance cell activity related to tissue healing, delay bone and cartilage degeneration and give beneficial effects such as relief in pain, anti-inflammation and reduce swelling. In clinic, PEMF treatment has been reported to be safe, and has been proved to reduce the usage of NSAIDs and pain in patients with knee OA.

This study aims to investigate the effectiveness of PEMF therapy on for patients with knee OA.

Study Overview

• Status: Completed
• Conditions: Knee Osteoarthritis
• Intervention / Treatment: Device: PEMF treatment; Device: Placebo treatment

• Study Type: Interventional
• Enrollment (Actual): 60
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Hong Kong
  • Sha Tin, Hong Kong
    • Prince of Wales Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 46 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Primary osteoarthritis of knee
• VAS score ≥ 4
• Grade 2 and 3 osteoarthritis (Kellgren-Lawrence criteria)
• No alleviation of symptoms after ≥ 3 months of nonsurgical treatment
• No acute knee injuries in both limbs in the past 3 months
• No muscle strain in both limbs in the past 3 months
• Voluntarily agreed to participate and signed the informed consent form

Exclusion Criteria:

• Skin diseases around the target knee joint
• Severe pain in other areas affects the diagnosis of function and symptoms of knee joints
• Injection in target knee within 3 months of enrolment
• Inflammatory joint disease (e.g., rheumatic inflammation)
• Infectious joint disease (e.g., septic arthritis)
• Pregnant or breastfeeding
• Patient with a pacemaker, an implantable defibrillator, neurosurgical clips, a neurostimulator, cochlear implant, a stent, an insulin pump
• Physical inability to undertake testing procedures
• Inability to give informed consent

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Mild-to-moderate Knee OA PEMF Treatment; Patients with Mild-to-moderate Knee OA will accept PEMF treatment	Device: PEMF treatment; Patient will receive a PEMF treatment. The involved leg will be exposed to PEMF for 30 minutes per session, and the treatment regime will run three times a week for eight weeks, summing up 24 sessions of PEMF exposure in total.
Placebo Comparator: Mild-to-moderate Knee OA Placebo Treatment; Patients with Mild-to-moderate Knee OA will accept placebo treatment	Device: Placebo treatment; Patient will receive a placebo treatment. The involved leg will be exposed to placebo treatment for 30 minutes per session, and the treatment regime will run three times a week for eight weeks, summing up 24 sessions of placebo exposure in total.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Muscle power	The isometric strength of the knee flexors and extensors was measured by a handheld dynamometer (MicroFET2, Hoggan Scientific, United States)	Baseline (pre-treatment), 2 months (immediate post-treatment), 8 months (6 months post-treatment), and 14 months (12 months post-treatment)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sonography	The femoral cartilage thickness in the affected knee was evaluated by ultrasound imaging (Aixplorer Ultimate, SuperSonic Imagine, France)	Baseline (pre-treatment), 2 months (immediate post-treatment), 8 months (6 months post-treatment), and 14 months (12 months post-treatment)
Dual-energy X-ray absorptiometry (DXA)	The lean muscle mass of the affected leg was assessed through the DXA scan (Horizon, Hologic, United States)	Baseline (pre-treatment), 2 months (immediate post-treatment), 8 months (6 months post-treatment), and 14 months (12 months post-treatment)
6-meter timed walking test	The gait speed was calculated	Baseline (pre-treatment), 2 months (immediate post-treatment), 8 months (6 months post-treatment), and 14 months (12 months post-treatment)
30-second chair stand test	The total number of stands completed within this timeframe was documented	Baseline (pre-treatment), 2 months (immediate post-treatment), 8 months (6 months post-treatment), and 14 months (12 months post-treatment)
X-ray Radiography	Standing X-rays assessed eligibility based on the Kellgren-Lawrence system and minimum joint space width.	Baseline (pre-treatment), 2 months (immediate post-treatment), and 14 months (12 months post-treatment)
WOMAC	The WOMAC questionnaire includes 24 questions divided into three subscales: pain, stiffness, and physical function. The total score varies from 0 to 96, where a higher score signifies more severe symptoms.	Baseline (pre-treatment), 2 months (immediate post-treatment), 8 months (6 months post-treatment), and 14 months (12 months post-treatment)

Collaborators and Investigators

• Sponsor: Chinese University of Hong Kong

Study record dates

Study Major Dates

• Study Start (Actual): July 5, 2022
• Primary Completion (Actual): August 31, 2024
• Study Completion (Actual): August 31, 2024

Study Registration Dates

• First Submitted: June 19, 2022
• First Submitted That Met QC Criteria: June 28, 2022
• First Posted (Actual): July 5, 2022

Study Record Updates

• Last Update Posted (Actual): May 6, 2025
• Last Update Submitted That Met QC Criteria: May 2, 2025
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Arthritis; Joint Diseases; Rheumatic Diseases; Osteoarthritis; Osteoarthritis, Knee
• Other Study ID Numbers: 2022.242

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No