Feasibility within-subject RCT of neuromuscular electrical stimulation; an Intervention to Maintain and improve neuroMuscular function during period of Immobility (IMMI)

Introduction: Neuromuscular electrical stimulation (NMES) is a potentially effective intervention to improve outcomes after a fragility fracture, but its feasibility in this group has not been established.

Methods: A feasibility study was conducted in two phases: 1) in the hospital only, and 2) hospital, rehabilitation centres, and participants' homes. Patients with fragility fracture were randomised to receive NMES for 6 weeks/discharge either to the right or left leg, with the other leg serving as control. Patients who had no mobility issues had contraindications to NMES and were unable to give consent were excluded. NMES was applied to quadriceps and tibialis anterior muscles for 30 min, 3 days/week. Sessions were progressed to achieve 60 min, 5-7 days/week. Feasibility outcomes included participant characteristics, recruitment rate, tolerability, and number of NMES sessions. Clinical outcomes included muscle strength, and ADL at six months.

Results: Overall, 1052 patients were identified, of whom 113 (11%) were eligible, and 29 (3%) were recruited (median Clinical Frailty Score 3, median Barthel ADL score 93/100). The recruitment rate was 0.45/week in phase 1 and 0.9/week in phase 2. Fifty-three percent achieved the target of 24 NMES sessions. However, 5/29 withdrew due to intolerance of NMES. Leg muscle strength improved in both treated and untreated legs, with marginally greater improvement observed in the tibialis anterior of treated legs.

Conclusion: Although it would be feasible to evaluate the specific effect of NMES in fragility fracture patients in a multi-centre trial using home-based NMES, this would be possible only in a minority of mildly frail fragility fracture patients with little premorbid disability.