Exploratory insights into novel prehabilitative neuromuscular exercise-conditioning in total knee arthroplasty

Abstract

Background: Contemporary strategies for prehabilitation and rehabilitation associated with total knee arthroplasty (TKA) surgery have focused on improving joint range-of-motion and function with less emphasis on neuromuscular performance beneficially affecting joint stability. Furthermore, prehabilitation protocols have been found to be too long and generic-in-effect to be considered suitable for routine clinical practice.

Methods: A pragmatic exploratory controlled trial was designed to investigate the efficacy of a novel, acute prehabilitative neuromuscular exercise-conditioning (APNEC) in patients electing TKA. Adults electing unilateral TKA were assessed and randomly allocated to exercise-conditioning (APNEC, n = 15) and usual care (Control, n = 14) from a specialised orthopaedic hospital, in the United Kingdom. APNEC prescribed nine stressful exercise-conditioning sessions for the knee extensors of the surgery leg, accrued over one week (3 sessions·week^-1; 36 exercise repetitions in total; machine, gravity-loaded) and directly compared with usual care (no exercise). Prescribed exercise stress ranged between 60%-100% of participant's daily voluntary strength capacity, encompassing purposefully brief muscular activations (≤ 1.5 s). Baseline and follow-up indices of neuromuscular performance focusing on muscle activation capacity (electromechanical delay [EMD], rate of force development [RFD] and peak force [PF]) were measured ipsilaterally using dynamometry and concomitant surface electromyography (m. rectus femoris_[RF] and m. vastus lateralis_[VL]).

Results: Group mean ipsilateral knee extensor muscular activation capacity (EMD_RF [F_(3,57) = 53.5; p < 0.001]; EMD_VL [F_(3,57) = 50.0; p < 0.001]; RFD [F_(3,57) = 10.5; p < 0.001]) and strength (PF [F_(3,57) = 16.4; p < 0.001]) were significantly increased following APNEC (Cohen's d, 0.5-1.8; 15% to 36% vs. baseline), but unchanged following no exercise control (per protocol, group by time interaction, factorial ANOVA, with repeated measures), with significant retention of gains at 1-week follow-up (p < 0.001).

Conclusions: The exploratory APNEC protocol elicited significant and clinically-relevant improvement and its retention in neuromuscular performance in patients awaiting TKA.

Trial registration: (date and number): clinicaltrial.gov: NCT03113032 (4/04/2017) and ISRCTN75779521 (3/5/2017).

Keywords: Exercise-conditioning; Joint replacement; Neuromuscular; Pre-surgery training; Sensorimotor; Total knee arthroplasty.

Fig. 1

Knee extensor machine and settings a side view b knee position 1–10; this also helped secure the 90◦ starting position of the knee. c front view d padded leg rest setting: Small, Medium, Large and Extra large; this position determined where the padded leg rest will place pressure on the shin and was normally placed above the ankle e back seat rest setting 1–10; this was normally positioned so that the back of the knee rested comfortably over the machine’s seat-edge, with the shin hanging perpendicularly to the ground

Fig. 2

APNEC exercise movement. Please see main text for full explanation

Fig. 3

Study’s flow-chart of participants within the study based on the CONSORT guidelines for longitudinal studies

Fig. 4

Group mean performance scores (± SD; APNEC, n = 9; Control, n = 12) assessed in the ipsilateral leg for muscle activation capacity (electromechanical delay [EMD]; rate of force development [RFD]) and knee extension strength (peak force [PF]) using dynamometry and concomitant surface electromyography (m. rectus femoris_[RF] and m. vastus lateralis_[VL])

Fig. 5

Patients’ individual improvement scores (APNEC, n = 9; Control, n = 12) for EMD (rectus femoris [_RF]) of the ipsilateral leg (undergoing surgery), from baseline to the end of APNEC (absolute gain in EMD_RF performance [vertical axis: ms] plotted relative to the corresponding mean score associated with baseline and T3 performances [horizontal axis: ms]). Minimal detectable change associated with random measurement error in EMD (MDC; Estimated as an upper 95% confidence limit at 4.5% of pooled group mean scores: 3.8 ms) is superimposed for comparison