Comparing 2-Hz and 100-Hz Electroacupuncture for Postoperative Musculoskeletal Pain: Protocol for a 2 × 2 Prospective...

Area of Science:

• Pain Management
• Neuroscience
• Rehabilitation Medicine

Background:

• Postoperative pain significantly impacts recovery and quality of life after musculoskeletal surgery.
• Electroacupuncture is a potential adjunct therapy for pain relief, but optimal parameters remain unclear.

Purpose of the Study:

• To compare the analgesic effects of 2 Hz versus 100 Hz electroacupuncture at ST36 to SP9 acupoints.
• To estimate effect sizes and variability for future definitive trials on electroacupuncture in postoperative pain.

Main Methods:

• A single-center, prospective, randomized crossover trial involving 30 adults with postoperative musculoskeletal pain (NRS ≥ 4).
• Participants received two 15-minute sessions of bilateral ST36 to SP9 electroacupuncture at 2 Hz and 100 Hz, with a minimum 7-day washout period.
• A frequency-masked, active-comparator design was employed, with participants unaware of the stimulation frequency or sequence.

Main Results:

• Primary outcomes include changes in pain Numerical Rating Scale (NRS) scores at 15 minutes and 2 hours post-intervention.
• Secondary outcomes assess pain NRS scores at multiple time points, pain characteristics, and physiological measures (pulse rate variability, radial pulse tonometry, activity metrics).
• Recruitment began September 2025, with data collection concluding August 2026 and analysis in late 2026.

Conclusions:

• This trial protocol aims to provide crucial data on the relative analgesic responses to different electroacupuncture frequencies.
• The findings will guide the optimization of stimulation parameters and outcome measures for larger efficacy studies.
• This study does not include a sham or no-treatment control, thus it will not determine absolute efficacy or placebo effects.