Changes in Quadriceps Muscular Activity in Patients After Total Knee Arthroplasty Compared to Healty Subjects

During Total Knee Arthroplasty (TKA), joint undergo considerable stress, which causes neuromuscular activation deficits of the quadriceps femoris muscle. The current phenomenon depends on a complex mechanism called Arthrogenic Muscle Inhibition (AMI). AMI has been studied only in sub-acute and chronic phase after TKA due to the invasive procedures employed in order to evaluate it; However, clinical observation and experimental studies suggest presence of this phenomenon also in the first postoperative days. The aim of the study is to investigate differences in quadriceps neuromuscular activity, in acute phase.

The study is a prospective observational study.15 healthy subjects and 15 patients scheduled for TKA will be recruited. Patients will be asked to perform three isokinetic taks in the same standardized biomechanical context in order to evaluate changes in quadriceps neuromuscular activity after surgery as primary outcome. Secondly, correlation between primary aim and pain perceived by the patient will be investigated. Moreover, patient's functional ability will be assessed using the Timed Up and Go Test (TUG). Data will be recorded the day before TKA, at one and three days after surgery.

At the end of data acquisition, normality and homogeneity of demographic variables will be assessed. Differences in the outcome measures will be investigated with the t student test (or with the related non-parametric tests) and by means of the mixed models repeated measures ANOVA test. Linear regression will be applied to evaluate any correlation between outcomes.