Investigating the effects of percussion massage therapy on pain, functionality, muscle diameter, and proprioception in ındividuals with ACL reconstruction: a randomized controlled trial.

The short version

This single-blind randomized controlled trial with 24 adults recovering from anterior cruciate ligament (ACL) reconstruction explored whether percussion massage therapy (PMT) — handheld devices that deliver rapid, rhythmic vibration pulses to muscle, sometimes called massage guns — adds benefit when combined with a structured post-surgical exercise program. ACL reconstruction requires months of rehabilitation focused on restoring knee range of motion, strength, and proprioception (the body's sense of joint position, tested here as joint position sense), while managing pain that can otherwise limit progress. PMT has mostly been studied in healthy athletes; this trial asked whether it also helps people recovering from surgery. Twenty-four participants aged 18-40, all within eight weeks of hamstring-autograft ACL reconstruction, were randomly split into two equal groups of 12. Both groups followed the same progressive, three-phase neuromuscular exercise program, five days a week for six weeks (30 sessions total). The PMT group also received five minutes of percussion massage per muscle group (quadriceps, hamstrings) with a Hypervolt device at 40 Hz before each session. Researchers measured pain (Visual Analog Scale), knee function (WOMAC), balance (Berg Balance Scale), quality of life (SF-36), range of motion, joint position sense, and muscle thickness by ultrasound, before and after the six weeks. Both groups improved significantly across every outcome after six weeks (p<0.001), confirming that structured exercise alone works well after ACL reconstruction. But adding PMT produced significantly larger gains in several key areas: resting pain dropped further (5.75 versus 4.17 points on a 0-10 scale, p=0.004), activity pain dropped further (6.92 versus 5.50 points, p=0.003), knee function scores improved more (71.7 versus 46.1 points on WOMAC, p=0.002 — a large effect, Cohen's d=1.41), balance improved more (24.7 versus 15.5 points on the Berg scale, p=0.040), and knee-bending range of motion gained more (43.1 versus 30.2 degrees, p=0.048). Joint position sense at 60 degrees also improved more with PMT (p=0.023), though at 30 degrees the two groups were statistically similar. Muscle thickness gains and most quality-of-life measures were comparable between groups, suggesting PMT's edge lies mainly in pain relief, function, balance, and motion rather than muscle bulk. For people recovering from ACL surgery, these results suggest a few minutes of percussion massage before each exercise session may meaningfully speed up pain relief, functional recovery, and balance, with no adverse events reported. The trial is small (12 people per group) and single-site, the groups started with somewhat different baseline pain and muscle measurements, and there was no long-term follow-up, so the durability of these gains beyond six weeks is unknown. Larger trials testing different PMT frequencies and durations are needed before this becomes a standard rehabilitation recommendation.

Key findings

• In a small clinical trial of 24 adults recovering from ACL (anterior cruciate ligament) reconstruction surgery, adding percussion massage therapy (PMT, a handheld device that delivers rapid vibrating pulses to muscle, sometimes called a massage gun) to a structured exercise program led to significantly greater improvements in pain, knee function, and balance than exercise alone.
• Knee function, measured with the WOMAC index (a 0-96 point questionnaire where lower scores mean less pain and disability), improved by 71.7 points in the PMT group versus 46.1 points in the exercise-only group (p=0.002), a large difference.
• Pain at rest and during activity, rated on a 0-10 Visual Analog Scale, dropped further with PMT than with exercise alone (p=0.004 and p=0.003 respectively).
• Balance, measured with the Berg Balance Scale (a 0-56 point test of everyday balance tasks), and knee bending range of motion also improved more with PMT, and no adverse events were reported in either group.
• The trial was small (12 people per group) and did not follow participants beyond six weeks, so larger and longer studies are needed before PMT becomes a standard recommendation.

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