Page 58 - Demo

Chapter 356method of Boeth et al.6 One system was reconstructed in the femoral segment (parent system) and one in the tibial segment (child system). The motion of each coordinate system was consistent with the movement of the respective segment. Anterior tibial translation was quantified in millimetres using the relative movement of the centre of rotation of the tibial coordinate system relative to the centre of rotation of the femoral coordinate system in the local tibial coordinate system. Tibial rotation was quantified by the angle between the two axes of rotation, as described by Keizer and Otten.21 Flexion/extension, varus/valgus angles were obtained using scalar products as in the equations explained by Robertson et al.38Statistical analysisStatistical analysis was performed using SSPS (v23; IBM Corp, Armonk, NY, USA). Since we had a small sample size, determining the distribution of the rTR was important for choosing appropriate statistical tests. A ShapiroWilk test was performed and did not show evidence of non-normality. Based on this outcome, and after visual examination of the QQ plot, we decided to use parametric tests. Means were calculated for each subject over the trials to obtain one value for each kinematic parameter per task. If at least two successful trials were available for a kinematic variable, the variable was included in analysis. To compare means of a kinematic variable a paired t-test was used with a significance level of p<0.05. Three comparisons were made regarding the means of all kinematic data: • Comparison of the pre-operative ACL-deficient knee vs. the post-operative ACL reconstructed knee (different time, same knee)• Comparison of the pre-operative ACL-deficient knee vs. the pre-operative contralateral ACL-intact knee (same time, different knee) • Comparison of the post-operative ACL-reconstructed knee vs. the post-operative contralateral ACL-intact knee (same time, different knee)Mark Zee.indd 56 03-01-2024 08:56