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J Rehabil Med 2019; 51: 821–827 REVIEW ARTICLE EFFECTS OF PULSED ELECTROMAGNETIC FIELD THERAPY ON PAIN, STIFFNESS AND PHYSICAL FUNCTION IN PATIENTS WITH KNEE OSTEOARTHRITIS: A SYSTEMATIC REVIEW AND META-ANALYSIS OF RANDOMIZED CONTROLLED TRIALS Li CHEN, MD, PhD*, Xin DUAN, MD, PhD*, Fei XING, MD, Guoming LIU, MD, Min GONG, MD, Lang LI, MD, Ran CHEN, MD and Zhou XIANG, MD, PhD From the Department of Orthopedics and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan, China. *These authors contributed equally to this work. Objective: To evaluate the efficacy of classical pul- sed electromagnetic field therapy on patients with knee osteoarthritis. Methods: The databases PubMed, EMBASE, Web of Science and Cochrane Library were searched for re- levant studies. Randomized controlled trials com- paring classical pulsed electromagnetic field with placebo for patients with knee osteoarthritis were included. Data for primary outcomes, including pain, stiffness and physical function, were extracted. Data from 8 randomized controlled trials involving 421 patients were pooled. Results: Pulsed electromagnetic field therapy had an effect on improving physical function (weighted mean difference; WMD  = −5.28, 95% confidence in- terval; 95% CI −9.45 to −1.11, p  = 0.01), but sho- wed no advantage in the reduction of Western On- tario and McMaster Universities Osteoarthritis Index (WOMAC) total score (WMD  = −7.80, 95% CI −16.08 to 0.47, p  = 0.06), WOMAC pain score (WMD  = −1.06, 95% CI −2.30 to 0.17, p  = 0.09), visual analogue sca- le pain score (WMD=−0.88, 95% CI −2.06 to 0.31, p  = 0.15) or WOMAC stiffness score (WMD  = −0.50, 95% CI −1.09 to 0.09, p  = 0.1). Conclusion: Pulsed electromagnetic field therapy is beneficial for improving physical function despite having no advantage in treating pain and stiffness. Further randomized controlled trials are needed to confirm these findings and determine the optimal parameters and treatment regimen for pulsed elec- tromagnetic field therapy. Key words: pulsed electromagnetic field; knee osteoarthritis; systematic review; meta-analysis; randomized controlled trial. Accepted Sep 25, 2019; Epub ahead of print Oct 4, 2019 J Rehabil Med 2019; 51: 821–827 Correspondence address: Zhou Xiang, Department of Orthopedics and National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan, China, 610041, China. E-mail: [email protected] O steoarthritis (OA) is one of the most common joint strain diseases, and it is generally considered that ageing, obesity, strain and trauma play important roles in the development of OA (1). The main pathological features of OA are degeneration of articular cartilage LAY ABSTRACT Knee osteoarthritis is currently one of the most common joint diseases worldwide. Pulsed electromagnetic field therapy has become popular among patients with knee osteoarthritis in recent years. However, the efficacy of this therapy on joint pain, joint stiffness and physical function is regarded as controversial in published clinical trials and systematic reviews. Several new randomized controlled studies on this subject have been published recently. The aim of this systematic review and meta- analysis is therefore to assess the efficacy of classical pulsed electromagnetic field therapy on patients with knee osteoarthritis, according to the methodology set out in the Cochrane Handbook for Systematic Reviews of Interventions. The results show that, despite showing no advantage in the management of pain and stiffness, pulsed electromagnetic field therapy is beneficial for im- proving clinical symptoms, such as physical function of the knee joint; thus it may be recommended as a supp- lementary therapy option for knee osteoarthritis. This review provides some evidence to help resolve current controversies about the efficacy of pulsed electromag- netic field therapy for knee osteoarthritis. and reactive hyperplasia of the articular margin and subchondral bone, which can result in chronic pain, stiffness and physical disability (2). In general, OA occurs mainly in weight-bearing areas, such as the knees, hips and spine, with knee OA having the highest prevalence among middle-aged and elderly people (3). At present, the main aims of conservative therapy for knee OA are to relieve pain and enhance joint mobility using treatments such as oral medication, intra-articular drug injection and physiotherapy (4). Although total knee arthroplasty has proved an effective method of treating knee OA, it is not suitable for all patients. In addition, total knee arthroplasty cannot be a permanent solution because patients often need reoperation within 20 years (5). Therefore, it is necessary to validate effective treatments that are beneficial in relieving pain, improving physical function, and blocking the process of joint destruction, so as to delay or avoid surgical options. Since the 1970s, pulsed electromagnetic field (PEMF) therapy has provided an alternative approach to treating This is an open access article under the CC BY-NC license. www.medicaljournals.se/jrm Journal Compilation © 2019 Foundation of Rehabilitation Information. ISSN 1650-1977 doi: 10.2340/16501977-2613