Development and Validation of Clinically Feasible Methods to Assess Landing Mechanics in Patients Following Anterior Cruciate Ligament Reconstruction

Patients returning to sport after anterior cruciate ligament (ACL) reconstruction surgery currently have a high risk for sustaining a second ACL injury and having early signs of knee osteoarthritis. Assessing lower extremity kinetics and kinematics during landing can provide information about a patient's risk for sustaining a second ACL injury and having further joint trauma. However, currently accepted methods to assess kinetics and kinematics are not feasible to use in most non-research settings as they are expensive, time consuming, and take up a lot of space. The goal of this project was to identify methods to assess landing mechanics which are reliable and feasible to use in non-research settings. First, we found that the loadsol®, a wireless force sensing shoe insole, is valid relative to embedded force plates and repeatable between days for assessing kinetics and kinetic symmetry during bilateral and unilateral landing tasks. Second, we developed a new method to collect continuous kinematic data using a low-cost videocamera, disposable markers, and an automated point tracking program. This method was validated against a 3D motion capture system for measuring a fixed angle and for measuring sagittal plane running kinematics. Third, we found that the new video analysis method is valid relative to 3D motion capture and is repeatable between days for assessing frontal and sagittal plane knee kinematics during landing. Finally, we used the loadsol® and automated 2D video analysis to assess landing mechanics in both patients following ACL reconstruction and healthy uninjured control participants in a non-research setting. We found that, relative to controls, patients following ACL reconstruction had reduced kinetic symmetry during bilateral landing, where they offloaded their surgical limb and relied more heavily on their non-surgical limb. Additionally, patients following ACL reconstruction had reduced knee flexion range of motion symmetry during unilateral landing, where they had reduced knee flexion when landing on their surgical limb. Collectively, these projects developed methods to quantitatively assess landing mechanics that are feasible to use in non-research settings, documented the validity and between-day repeatability of these methods, and demonstrated that they could be used to identify kinetic and kinematic deficits in patients following ACL reconstruction. This project is an important step toward being able to assess landing mechanics in patients recovering from an ACL reconstruction.