In Hong Kong, over 3000 cases of Anterior Cruciate Ligament Reconstruction (ACLR) are operated annually to restore knee stability. Despite recovery of knee passive laxity and muscle strength, dynamic knee stability is often not restored. In additional to muscle strength, muscle elasticity and muscle coordination may also play an important role in knee stability. However, there is no evidence regarding the changes in muscle elasticity after ACLR and its contribution to dynamic knee stability. This study is a cross-sectional study designed to compare the the difference in muscle strength, muscle elasticity and muscle coordination of quadriceps and hamstring muscle in 30 ACLR patients and investigate its relationship with knee biomechanics during single leg hop landing. Patient selection was base on medical records and subjective knee functional scores. Patient enrollment and informed consent was conducted first. Muscle strength was measured by isokinetic muscle testing(Biodex) at two speeds. Muscle elasticity was assessed by ultrasound shear wave elastography. Muscle coordination evaluated by electromyography(EMG) and knee biomechanics including kinematics and kinetics was measured by 3D motion analysis system(VICON) and all the assessments were done in CUHK-ORT Sports Injury Research Laboratory in the Prince of Wales Hospital, Hong Kong. All data was collected and analyzed by qualified personnel.
This project aims to compare the difference in muscle strength, muscle elasticity and muscle coordination of quadriceps and hamstring muscle and their association with knee biomechanics during single leg hop landing in patients with anterior cruciate ligament reconstruction.