title: Changes in landing mechanics in patients following anterior cruciate ligament reconstruction when wearing an extension constraint knee brace.
abstract: BACKGROUND
  Anterior cruciate ligament (ACL) reconstruction is associated with a high incidence of second tears (graft tears and contralateral ACL tears). These secondary tears have been attributed to asymmetrical lower extremity mechanics. Knee bracing is one potential intervention that can be used during rehabilitation that has the potential to normalize lower extremity asymmetry; however, little is known about the effect of bracing on movement asymmetry in patients following ACL reconstruction.
  
  
  OBJECTIVE
  Wearing a knee brace would increase knee joint flexion and joint symmetry. It was also expected that the joint mechanics would become more symmetrical in the braced condition.
  
  
  OBJECTIVE
  To examine how knee bracing affects knee joint function and symmetry over the course of rehabilitation in patients 6 months following ACL reconstruction.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Level 3.
  
  
  METHODS
  Twenty-three adolescent patients rehabilitating from ACL reconstruction surgery were recruited for the study. The subjects all underwent a motion analysis assessment during a stop-jump activity with and without a functional knee brace on the surgical side that resisted extension for 6 months following the ACL reconstruction surgery. Statistical analysis utilized a 2 × 2 (limb × brace) analysis of variance with a significant alpha level of 0.05.
  
  
  RESULTS
  Subjects had increased knee flexion on the surgical side when they were braced. The brace condition increased knee flexion velocity, decreased the initial knee flexion angle, and increased the ground reaction force and knee extension moment on both limbs. Side-to-side asymmetry was present across conditions for the vertical ground reaction force and knee extension moment.
  
  
  CONCLUSIONS
  Wearing a knee brace appears to increase lower extremity compliance and promotes normalized loading on the surgical side.
  
  
  CONCLUSIONS
  Knee extension constraint bracing in postoperative ACL patients may improve symmetry of lower extremity mechanics, which is potentially beneficial in progressing rehabilitation and reducing the incidence of second ACL tears.
authors.affiliation: Department of Community Health and Family Medicine, Doctor Division of Physical Therapy, Duke University, Durham, North Carolina ; Michael W. Kryzewski Human Performance Laboratory, Department of Orthopaedics, Duke University, Durham, North Carolina.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Butler
authors.affiliation: Michael W. Kryzewski Human Performance Laboratory, Department of Orthopaedics, Duke University, Durham, North Carolina.
authors.forename: Boyi
authors.initials: B
authors.lastname: Dai
authors.affiliation: Department of Orthopaedics, Duke University, Durham, North Carolina.
authors.forename: William E
authors.initials: WE
authors.lastname: Garrett
authors.affiliation: Michael W. Kryzewski Human Performance Laboratory, Department of Orthopaedics, Duke University, Durham, North Carolina ; Department of Orthopaedics, Duke University, Durham, North Carolina.
authors.forename: Robin M
authors.initials: RM
authors.lastname: Queen
keywords: biomechanics; function; jump; knee injury