Reliability of Zebris Motion Analysis System in Healthy Athletes and Athletes with Anterior Cruciate Ligament Reconstruction

Background Reconstruction surgery is one of the treatment methods after an anterior cruciate ligament (ACL) injury especially in athletes. Reconstructed ACL is associated with altered joint biomechanics, abnormal muscle strength, gait disorder and decreased athletic performance. Abnormal walking pattern has been shown to be one of the functional consequences of ACL reconstruction. Objectives The aim of this study was to investigate the reliability of kinematic and spatiotemporal gait parameters after ACL reconstruction using Zebris ultrasound movement analysis system. Methods A sample of convenience including 20 healthy athletes and 20 athletes 4 to 6 months after ACL reconstruction participated. Subjects walked on a treadmill for one minute at preferred, high and low speeds and kinematic and spatio - temporal parameters including stride time, stride length, maximum knee flexion, maximum knee flexion velocity and maximum knee extension velocity are calculated. Results In the patient group, relative reliability measures for almost all parameters were high at low (ICC: 0.7 - 0.97), preferred and high speeds (ICC: 0.75 - 0.97). This was also true for the control group, were reliability for all parameters was high at low, preferred (ICC: 0.74 - 0.99) and high (ICC: 0.83 - 0.99) speeds, except for stride time of the left leg which showed moderate reliability. Additionally, at high speed, all parameters revealed very high reliability. Conclusions Zebris movement analysis system is a highly reliable instrument for the measurement of gait parameters at different speeds in healthy athletes and those after ACL reconstruction surgery. This implies its use in the assessment and treatment process of gait deficits in such a clinically important population.