Early neuromuscular electrical stimulation to improve quadriceps muscle strength after total knee arthroplasty: a randomized controlled trial

Stevens-Lapsley JE, Balter JE, Wolfe P, Eckhoff DG, Kohrt WM · Physical Therapy

At 3.5 weeks the stimulation group was stronger in the quadriceps and hamstrings, performed better on function tests and had more active knee extension range. By 52 weeks the gap had narrowed but strength, functional performance and some self-reported measures still favoured stimulation. The authors call the effect most pronounced and clinically meaningful in the first month.

Population

Sixty-six patients aged 50 to 85 having a first single-knee replacement

Intervention

Neuromuscular electrical stimulation of the quadriceps started 48 hours after surgery, twice a day at maximum tolerable intensity for 15 contractions, added to standard rehabilitation

Comparator

Standard rehabilitation alone

Limitations

Author-reported: treatment volume was not matched, so the stimulation arm received more contact overall; testers were not blinded, though they worked from standardised scripts; and some patients hit the stimulator's maximum output and might have tolerated more. The joint has been replaced, so this is about muscle around a prosthesis and not about cartilage. Funded by the National Institute on Aging (K23AG029978), an American College of Rheumatology New Investigator Award, the Foundation for Physical Therapy and a Clinical and Translational Science Award — and, for the stimulators themselves and patient transport, a peer-reviewed grant from Empi Inc, a DJO Global company that makes them.