Abstract
Total knee arthroplasty (TKA) is becoming more prevalent as the average age of the general population increases and is generally considered to be a very effective and successful surgery. However, functional recovery post-surgery can often be less than optimal. Neuromuscular electrical stimulation (NMES) is a beneficial therapy proven to improve haemodynamics and muscle strength and may be of great benefit in improving functional recovery in the acute phase post-TKA. The objective of the study was to assess functional recovery in the period immediately following TKA and hospital discharge in response to a home-based NMES programme. Twenty-six TKA patients were randomized into a NMES stimulation or placebo-controlled group. All participants were given a research muscle stimulator to use at home post-discharge for 90 minutes per day over a period of 5 weeks. In the stimulation group, application of stimulation resulted in an electrically activated contraction of the soleus muscle. Patients in the placebo-controlled group received sensory stimulation only. Outcome measures were physical activity levels, joint range of motion and lower limb swelling, which were measured pre-surgery and on a weekly basis post-discharge up until the sixth post-surgical week. 90 minutes per day NMES stimulation significantly increased the Activity Time (P = 0.029 week 1 post-discharge) and the number of Stepping Bouts (P < 0.05 weeks 1 to 4 post-discharge) in the early post-discharge phase. While there was a trend towards a greater knee flexion with use of NMES, this did not reach statistical significance (P = 0.722). No effect of NMES was observed on swelling (P > 0.05 for all measures). Compliance to the NMES therapy was measured by an on-board SIM card in the NMES device, with a 95% and 94% time compliance rate for the stimulation and placebo-controlled groups respectively. The results of this study suggest that NMES may be very useful in improving functional recovery through increasing physical activity levels in the early post-TKA discharge phase. The results of this study warrant further investigation into the use of an optimized NMES protocol whereby improvements in knee range of motion and swelling may also be observed.
