2015 ISAKOS Biennial Congress ePoster #1313

Test-Retest Reliability of Frontal Plane Knee Kinematics and Kinetics During Jump Landing in Patients After ACL Reconstruction

Sheila S. Gagnon, PhD (candidate), MSc, BKin, London, Ontario FINLAND
Trevor B. Birmingham, PT, PhD, London, Ontario CANADA
Alliya Remtulla, PhD (candidate), Markham, Ontario CANADA
Dianne M. Bryant, PhD, London, ON CANADA
J. Robert Giffin, MD, FRCSC, MBA, London, ON CANADA

Wolf Orthopaedic Biomechancis Laboratory, Fowler Kennedy Clinic, London, Ontario, CANADA

FDA Status Not Applicable

Summary: Intraclass correlation coefficients and standard errors of measurement indicated that the drop vertical jump, a functional task designed to evaluate dynamic knee valgus collapse and risk for ACL injury, has adequate test-retest reliability for use during rehabilitation after ACL reconstruction.

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Abstract:

The drop vertical jump (DVJ) is a functional task of neuromuscular function and dynamic stability of the knee, designed to evaluate dynamic knee valgus collapse, a risk factor for injury to the anterior cruciate ligament (ACL), and a focus for rehabilitation after ACL reconstruction. The objective of this study was to examine the test-retest reliability of frontal plane kinematics and kinetics using the DVJ in patients undergoing rehabilitation after ACL reconstruction. Methods: Fifteen patients (age: 22.8 ± 4.4 y) were tested on two separate days within 1 week approximately 6 months after primary ACL reconstruction. The surgical limb (7 right, 8 left) was evaluated using a 10-camera motion capture system, two force plates and inverse dynamics. Frontal plane kinematics and kinetics of the knee were evaluated at initial contact, peak, and for excursion (peak angle – initial contact angle). Results: Intraclass correlation coefficients (ICC2,1) (95% confidence intervals (CI)) were 0.81 (0.53, 0.93), 0.78 (0.47, 0.92), and 0.82 (0.56, 0.93) for knee abduction angle at initial contact, peak, and excursion, respectively. ICCs (95% CI) were 0.28 (-0.23, 0.67) and 0.90 (0.73, 0.96) for knee abduction moment at initial contact and peak, respectively. The standard errors of measurement (SEM) for kinematics were 2.21, 3.97, and 2.62 degrees for knee abduction angle at initial contact, peak, and excursion, respectively. The SEMs for kinetics were 0.11 and 0.13 Nm/kg for knee abduction moment at initial contact and peak, respectively. Conclusions: The present findings suggest poor-to-excellent test-retest reliability depending on the specific variables tested, with best reliability for knee abduction excursion (ICC = 0.82) and peak knee abduction moment (ICC = 0.90). The findings support the use of the DVJ as a tool to help evaluate progress throughout rehabilitation following ACL reconstruction.