The positive benefits of negative movement patterns following total knee arthroplasty

Abstract

Introduction: Eccentric (negative) resistance exercise of the legs using specialized machines has been reported to be useful and often superior to standard exercise following total knee arthroplasty (TKA). Movements that utilize body mass and gravity as a mode of eccentric resistance exercise in a more pragmatic rehabilitation paradigm may also be useful in reversing chronic muscle impairments observed years following surgery. This study explores whether an eccentrically biased, body mass resistance exercise induces greater magnitude of sagittal plane extensor angular impulse of the support torque and individual net joint torque contributions during both squatting and lunging movement patterns 6 weeks following TKA. Methods: Cross-sectional laboratory-based study design including 10 patients following primary unilateral TKA (6.5 ± 0.8 weeks.). All patients completed 3 trials of the squat and lunge movement pattern under both a concentric and an eccentric condition. Extensor angular impulse of the support torque and net joint torque contributions were calculated by integrating the joint torque versus time curves. A Two-way analysis of covariance was conducted and contracts of clinical interest were computed using Wald posttest. P Values for all pairwise comparisons were adjusted for multiplicity using Bonferroni multiple comparison procedure. Results: The eccentric condition, compared to the concentric condition, displayed larger magnitude of extensor angular impulse during both the squat (P