Matilde Rodriguez
Research Mentor: Riann Smith
Mentor Department: School of Kinesiology, Kinesiology
Author(s): Matilde Rodriguez, Alfred Crone, Riann Palmieri-Smith
Session: Session 5 (2:00 PM – 2:50 PM)
Presentation Type: Poster 119
Abstract
Evaluating the Variability of Knee Loading during Gait After ACL Reconstruction Background: After anterior cruciate ligament reconstruction (ACLR), individuals demonstrate a 10–40% reduction in ACL peak knee extension moments (pKEM) during gait. This underloading is associated with functional limitations, increased re-injury risk, and post-traumatic osteoarthritis. Therefore, pKEM symmetry can be used as an inclusion criterion for clinical trials targeting underloading after ACLR and can also be considered as a successful benchmark after ACLR. However, between-day variability of pKEM symmetry is unclear. If variability is high, for example, individuals may present as symmetrical one day, but not another leading to erroneous conclusions about their loading status. We hypothesized that pKEM and pKEM symmetry after ACLR would show low between-day variability, but classification using a 90% threshold would show limited agreement. Methods: Thirty individuals post-ACLR (age 21.6±5.6 years; 6.44±1.3 months post-op) completed two treadmill sessions separated by =48 hours (8.6±7.8 days). Participants walked at a self-selected speed for two minutes per session. Data was collected using an instrumented treadmill (2000Hz) synchronized with 12-camera motion capture system (200Hz). Peak KEM were calculated using inverse dynamics during early stance (0–30%). Intraclass correlation coefficients (ICC 3,1 ) assessed between-day reliability for ACL pKEM, non-ACL pKEM moment, and pKEM symmetry (ACL/non-ACL*100). Cohen’s kappa assessed between-day agreement for pass/fail symmetry classification (fail<90%, pass=90%). Results/Conclusion: Reliability was good-to-excellent for ACL pKEM (ICC=0.791), non-ACL pKEM (ICC=0.907), and symmetry (ICC=0.886). However, pass/fail agreement was slight (?=0.133), indicating potential misclassification across sessions, likely due to ongoing neuromuscular adaptation post-ACLR.
