The role of pulsed electromagnetic therapy after knee arthroplasty

Background: Pulsed electromagnetic field therapy (PEMF) is included in current clinical guidelines for postoperative rehabilitation after knee arthroplasty. However, its indications remain limited, primarily for managing pain during the early mobilization of the operated joint. Aim: To evaluate pain relief and clinical outcomes — including knee function, general health status, objective and subjective knee swelling assessment, nonsteroidal anti-inflammatory drug (NSAID) consumption, persistent pain, daily activity limitations, and complications — in patients undergoing unicompartmental knee arthroplasty (UKA) followed by PEMF therapy, compared with a control group receiving sham PEMF. Materials and methods: This prospective, randomized, placebo-controlled study included 72 patients who underwent medial UKA. Participants were randomized into either a control group (sham PEMF) or a treatment group receiving PEMF therapy. Patients in the treatment group were advised to use PEMF for 20 minutes, four times daily, for 60 days. Evaluations were conducted preoperatively and at 1, 2, 6, 12, and 36 months postoperatively. The control group followed the same schedule using sham PEMF. Clinical assessments included the Visual Analog Scale (VAS) for pain, the Oxford Knee Score (OKS), the Short Form-36 (SF-36) health survey, a questionnaire on subjective knee swelling, and an objective measurement of knee circumference. NSAID consumption was recorded at each follow-up visit. Results: VAS scores decreased in both groups over time, but statistically significant differences favoring the PEMF group were observed at 6 months (p=0.0143), 12 months (p=0.0004), and 36 months (p=0.0213). One month postoperatively, 73% of patients in the PEMF group and 91% in the control group used NSAIDs (p=0.0341). At 2 months, 14% of the PEMF group continued NSAID use, compared to 38% in the control group (p=0.0326). Objective knee circumference measurements showed statistically significant differences at 6 (p=0.0232), 12 (p=0.0016), and 36 months (p=0.0004), with better outcomes in the PEMF group. Subjective swelling assessment demonstrated statistically significant differences at 2 (p=0.0064), 6 (p=0.0005), 12 (p=0.00022), and 36 months (p=0.00031), again favoring the PEMF group. Finally, OKS scores were significantly higher in the PEMF group across all time points (1 month: p=0.0258; 2 months: p=0.0014; 6 months: p=0.0003; 12 months: p=0.0002; 36 months: p=0.0144). Conclusion: PEMF therapy significantly reduced pain, improved clinical outcomes, and decreased NSAID consumption following medial UKA compared with the control group.