Zhikuan Li, Lingpeng Jin, Zhen Chen, Ziqi Shang, Yue Geng, Siman Tian, Jiangtao Dong

Purpose: This systematic review and meta-analysis was conducted to investigate the effects of neuromuscular electrical stimulation (NMES) on quadriceps strength and knee function after anterior cruciate ligament (ACL) surgery.


Methods:

  • Study Selection: Included randomized controlled trials where NMES was part of the ACL surgery postoperative rehabilitation protocol and compared to standard physical therapy as the control group. Eleven studies met the inclusion criteria (N = 202 patients receiving NMES; N = 200 patients in control group).
  • Assessments: Quadriceps strength was measured using isometric or isokinetic tests. Knee function was assessed using the Lysholm score.


Results:

  • Meta-analysis analysis – Knee Function: Three studies were included in the meta-analysis to assess knee function using the Lysholm score. This analysis revealed no statistical difference in knee function between the NMES and control groups. However, there was a medium to high degree of heterogeneity. Other knee function assessments used in the studies, including the International Knee Documentation Committee, Knee Injury and Osteoarthritis Outcome Score-Activities of Daily Living, and the Knee Outcome Survey-Activities of Daily Living Scale did show some positive effect of NMES on knee function.
  • Meta-analysis – Muscle Strength: Nine studies were included in the meta-analysis to assess muscle strength. The analysis demonstrated that NMES combined with standard physical therapy significantly improves quadriceps strength when compared to physical therapy alone at both short (≤ 6 weeks) and long-term (> 6 week) follow-up.
  • Subgroup analysis –Timing of NMES: This analysis showed that starting physical rehabilitation with NMES earlier in the post-operative course (≤ 1 week post-surgery) resulted in better muscle strength recovery.


Conclusion:

  • NMES combined with standard physical therapy significantly enhances quadriceps muscle strength recovery after ACL surgery.
  • Starting NMES treatment earlier in the post-operative period yields better muscle strength recovery.

Citation:

Li Z, Jin L, Chen Z, et al. Effects of Neuromuscular Electrical Stimulation on Quadriceps Femoris Muscle Strength and Knee Joint Function in Patients After ACL Surgery: A Systematic Review and Meta-analysis of Randomized Controlled Trials. Orthop J Sports Med. 2025;13(1):23259671241275071. Published 2025 Jan 13. doi:10.1177/23259671241275071