Effects of a knee extension constraint brace on lower extremity movements after ACL reconstruction.
BACKGROUND
Patients have high reinjury rates after ACL reconstruction. Small knee flexion angles and large peak posterior ground reaction forces in landing tasks increase ACL loading.


OBJECTIVE
We determined the effects of a knee extension constraint brace on knee flexion angle, peak posterior ground reaction force, and movement speed in functional activities of patients after ACL reconstruction.


METHODS
Six male and six female patients 3.5 to 6.5 months after ACL reconstruction participated in the study. Three-dimensional videographic and force plate data were collected while patients performed level walking, jogging, and stair descent wearing a knee extension constraint brace, wearing a nonconstraint brace, and not wearing a knee brace. Knee flexion angle at initial foot contact with the ground, peak posterior ground reaction force, and movement speed were compared across brace conditions and between genders.


RESULTS
Wearing the knee extension constraint brace increased the knee flexion angle at initial foot contact for each activity when compared with the other two brace conditions. Wearing the knee extension constraint brace also decreased peak posterior ground reaction force during walking but not during jogging and stair descent.


CONCLUSIONS
Although the knee extension constraint brace did not consistently reduce the peak posterior ground reaction force in all functional activities, it consistently increased knee flexion angle and should reduce ACL loading as suggested by previous studies. These results suggest the knee extension constraint brace has potential as a rehabilitation tool to alter lower extremity movement patterns of patients after ACL reconstruction to address high reinjury rates.
National Institutes of Health, Bethesda, MD, USA.
Christopher J
CJ
Stanley
R Alexander
RA
Creighton
Michael T
MT
Gross
William E
WE
Garrett
Bing
B
Yu
D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D001915:Braces; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology / Q000601:surgery*; D007866:Leg / Q000503:physiopathology*; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D016059:Range of Motion, Articular; D019651:Plastic Surgery Procedures / Q000379:methods*; D016896:Treatment Outcome; D055815:Young Adult