Post-operative function and muscle modules during gait at 6 and 24 months following total knee arthroplasty

The theory of muscle modules (or synergies) suggests that groups of muscles are activated synergistically via a common neural command [1]. While this idea has provided insight into the control of simple tasks like locomotion [2], the clinical relevance of this theory has only recently begun to be explored. For example, patients with higher function at one year following a cruciate-retaining (CR) total knee arthroplasty (TKA) displayed a higher number of muscle modules (n=4-5) compared to patients with lower function (n=2-3) [3]. This relationship between number of modules and function suggests that if muscle modules are able to change over time, it may be possible to develop module-focused clinical programs to improve patient function. The aim of this study was to determine muscle modules in patients with TKA during gait at 6 & 24 months post-operatively and to compare these modules to patient function. We hypothesized that (i) participants with a higher number of modules would demonstrate higher function and (ii) changes in patient function would be accompanied by changes in the number and characteristics of muscle modules