Postural stability and regulation before and after anterior cruciate ligament reconstruction – A two years longitudinal study

Abstract Objectives To evaluate postural regulation and stability among patients who underwent anterior cruciate ligament reconstruction (ACLR) and rehabilitation over a two-year follow-up period. Design Longitudinal; Setting Biomechanics laboratory; Participants 30 ACLR patients (32.0 ± 12.2 years, 14 males) with isolated ACL rupture. Main outcome measures Postural regulation was tested before ACLR, as well as at six-weeks, twelve-weeks, six-months, one-year and two-years post-ACLR and standardized rehabilitation. Postural regulation was measured for stability indicator (ST), weight distribution index (WDI), synchronization (foot coordination) and sway intensities (postural subsystems). Results Significant time effects (pre-vs. two-years postoperative) were found for WDI (η p 2  = 0.466), synchronization (η p 2  = 0.368), mediolateral weight distribution (η p 2  = 0.349), ST (η p 2  = 0.205), visual/nigrostriatal systems (η p 2  = 0.179) and peripheral-vestibular system (η p 2  = 0.102). The largest difference (preoperative: η p 2  = 0.180) to the matched sample was calculated for WDI. The most significant differences to the matched sample were observed for ST (preoperative: η p 2  = 0.126; six-weeks postoperative: η p 2  = 0.103) and WDI (preoperative: η p 2  = 0.180; six-weeks postoperative: η p 2  = 0.174). Conclusion ACLR and rehabilitation influence postural subsystems, postural stability, weight distribution and foot synchronization. Normalization of mediolateral weight distribution requires one year following ACLR. The ACLR leads to a suppression of the somatosensory and cerebellar system which was compensated by a higher activity of the visual and nigrostriatal systems.