TKA Patients with unsatisfying Knee Function Show Changes in Neuromotor Synergy Pattern but not Joint Biomechanics

Publication date: Available online 28 September 2017
Source:Journal of Electromyography and Kinesiology
Author(s): Marzieh M. Ardestani, Philip Malloy, Denis Nam, Aaron G. Rosenberg, Markus A. Wimmer
Nearly 20% of patients who have undergone total knee arthroplasty (TKA) report persistent poor knee function. This study explores the idea that, despite similar knee joint biomechanics, the neuro-motor synergies may be different between high-functional and low-functional TKA patients. We hypothesized that (1) high-functional TKA recruit a more complex neuro-motor synergy pattern compared to low-functional TKA and (2) high-functional TKA patients demonstrate more stride-to-stride variability (flexibility) in their synergies.Gait and electromyography (EMG) data were collected during level walking for three groups of participants: (i) high-functional TKA patients (n=13); (ii) low-functional TKA patients (n=13) and (iii) non-operative controls (n=18). Synergies were extracted from EMG data using non-negative matrix factorization. Analysis of variance and Spearman correlation analyses were used to investigate between-group differences in gait and neuro-motor synergies.Results showed that synergy patterns were different among the three groups. Control subjects used 5-6 independent neural commands to execute a gait cycle. High functional TKA patients used 4-5 independent neural commands while low-functional TKA patients relied on only 2-3 independent neural commands to execute a gait cycle. Furthermore, stride-to-stride variability of muscles' response to the neural commands was reduced up to 15% in low-functional TKAs compared to the other two groups.



http://ift.tt/2x0BKCd