Date of Paper/Work

3-2011

Degree Name

Doctor of Physical Therapy

Department

Physical Therapy

First Advisor

Jaynie Bjornaraa, PT, PhD, MPH, SCS, ATR, CSCS

Abstract

BACKGROUND AND PURPOSE:

The anterior cruciate ligament (ACL) is a commonly ruptured ligament among male and female athletes. Women are at a higher risk of ACL injuries compared to men. The leading cause of female ACL injuries has been identified as non-contact mechanisms. Several risk factors for injury among females that have been theorized include: quadriceps/hamstring activation pattern and force production, greater dynamic knee valgus, hormonal influenced laxity and anatomical gender variation. The purpose of this research was to analyze three dimensional (3D) kinetic and kinematic dynamic landing patterns at the knee between ACL reconstructed and healthy females and any interaction effects of visual disruption.

METHODS:

Seventeen healthy female subjects (25.3± 6 y) and 17 female subjects with an ACL reconstruction (26.5± 6.3 y) were studied. A 3D electromagnetic system measured knee position during a cutting maneuver from an athletic stance position. Anatomic boney landmarks on the occiput, sacrum, femur and tibia were digitized for capture. Subjects began on a force plate and were instructed to catch a ball and cut immediately left or right as indicated by a specific tone, which was randomized (40 trials). Vision was randomly disrupted via shutter glasses for either one second at the beginning of the cutting maneuver or was left intact for the duration of the movement. A two-way repeated measures ANOVA analyzed the differences between healthy and ACL reconstructed subjects and intact vision versus disrupted vision.

RESULTS:

The results indicate significant differences exist between subjects with ACL reconstruction and healthy subjects for flexion, adduction, and external rotation knee angles and extension, abduction, and internal rotation moments. Significant interactions of group and vision conditions also exist for flexion, adduction, and external rotation knee angles. Vision alone displayed no significant differences for all subjects.

CONCLUSION:

Years later, subjects with ACL reconstructions continue to display different knee kinematics and kinetics that could increase their risk for re-injury or injury of other leg. Furthermore, visual disturbances have significant effects on ACL reconstructed knee angles and moments when landing compared to healthy subjects. These results support continued movement related rehabilitation with visual disturbances for ACL reconstructed patients.

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