Residual deficits of knee and hip joint coordination and clinical performance after return to sports in athletes with anterior cruciate ligament reconstruction

Background Biomechanical changes and neuromuscular adaptations have been suggested as risk factors of secondary
injury in individuals after anterior cruciate ligament reconstruction (ACLr). To achieve a better understanding
of preventive mechanisms, movement quality is an important factor of consideration. Few studies have explored
time-series analysis during landing alongside clinical performance in injured and non-injured individuals. The purpose
of the study was to investigate the biomechanical risks of recurrent injury by comparing clinical and jump-landing
performance assessments between athletes with ACLr and healthy controls.
Method This study was observational study. Sixteen athletes with and without ACLr voluntarily participated in clinical
and laboratory measurements. Single-leg hop distance, isokinetic tests, landing error score, and limb symmetry
index (LSI) were included in clinical report. Lower limb movements were recorded to measure joint biomechanics
during multi-directional landings in motion analysis laboratory. Hip-knee angle and angular velocity were explored
using discrete time-point analysis, and a two-way mixed analysis of variance (2 × 4, group × jump-landing direction)
was used for statistical analysis. Time series and hip-knee coordination analyses were performed using statistical parametric
mapping and descriptive techniques.
Results Significantly lower single-leg hop distance was noted in ACLr group (158.10 cm) compared to control group
(178.38 cm). Although the hip and knee moments showed significant differences between four directions (p < 0.01),
no group effect was observed (p > 0.05). Statistical parametric mapping showed significant differences (p ≤ 0.05)
between groups for hip abduction and coordinate plot of hip and knee joints. Athletes with ACLr demonstrated
a higher velocity of hip adduction. Time-series analysis revealed differences in coordination between groups for frontal
hip and knee motion.
Conclusions Athletes with ACLr landed with poor hip adduction control and stiffer knee on the involved side. Multidirections
landing should be considered over the entire time series, which may facilitate improved movement quality
and return to sports in athletes with ACLr.