Summary

Low Frequency Pulsed Electromagnetic Fields (PEMFs) increase quadriceps strength in young healthy men and may be safely applied to patients following ACL reconstruction surgery.

Abstract

Introduction

Thigh muscle atrophy commonly occurs after ACL reconstruction surgery and can impair the recovery and rehabilitation process. As the thigh musculature is a major stabilizing influence in knee recovery, the loss of thigh muscle strength can negatively impact the rehabilitation outcome.

Methods

We developed a Pulsed Electromagnetic Field (PEMF) system to increase thigh muscle strength and to enhance the efficiency of rehabilitation therapy. In this first-in-man study, we tested the safety and performance of the system in 10 healthy volunteers, prior to clinical use. Male volunteers (n = 10) were exposed for 10 minutes a session to 1 mT PEMFs of our patented characteristics, once per week, for a total of 3 months. Subjects were treated in either their right (n = 5) or left thighs (n = 5). All subjects underwent a total of 6 PEMF exposure sessions. Quadriceps extension strength was tested with a digital dynamometer (Baseline ® Electronic Push-Pull Dynamometer) and leg circumference was measured with measuring tape. The mean of 3 (trial 1; right thigh treated) or 4 (trial 2; left thigh treated) attempts was recorded at baseline (prior 1st exposure) and end (post 6th exposure) of each trial period for all subjects. Data was analyzed for normality with a Shapiro-Wilk test, and a paired t-test was conducted for normally distributed data, while a Wilcoxon test was used for non-normally distributed data.

Results

Thigh strength increased significantly during the course of the study (pre: 51 ± 16.9lbs vs. post: 70.3 ± 34.61lbs, P = 0.02). Thigh circumference was unchanged in both groups (pre: 46.3 ± 5.1cm vs. post: 46.3 ± 4.4cm, P > 0.05). There were no local or systemic adverse reactions detected in the volunteers. The range of motion in the hip and knee joints of the treated limb was also preserved.

Conclusion

Our findings indicate that the PEMF system increases quadriceps muscle strength in young healthy men and may be safely applied to patients following ACL reconstruction surgery.