title: Longitudinal Evaluation of Stair Walking Biomechanics in Patients with ACL Injury.
abstract: OBJECTIVE
  After anterior cruciate ligament (ACL) injury and reconstruction, abnormal biomechanics during daily tasks may have prominent and detrimental long-term consequences on knee joint health. The purpose of this study was to longitudinally evaluate hip and knee joint biomechanics during stair ascent and descent in patients with acute ACL injury and at return to activity after ACL reconstruction.
  
  
  METHODS
  Twenty individuals with unilateral ACL injury (age, 20.9 ± 4.4 yr; height, 172.4 ± 7.5 cm; mass, 76.2 ± 12.2 kg) that were scheduled to undergo surgical reconstruction were compared with 20 healthy matched controls (age, 21.7 ± 3.7 yr; height, 173.7 ± 9.9 cm; mass, 76.1 ± 19.7 kg). Lower extremity biomechanics were recorded using three-dimensional motion analysis during stair ascent and descent at two testing sessions (before surgery and at approximately 6 months after surgery or when they were allowed to return to unrestricted physical activity). Time between sessions for healthy participants was matched on the basis of the ACL group. Peak sagittal and frontal plane knee and hip joint angles and moments, joint angles at initial contact, and joint excursions across stance phase were evaluated.
  
  
  RESULTS
  The ACL-injured limb of patients experienced smaller knee extension moments than the uninjured limb and healthy controls during stair ascent and descent (P < 0.05) before and 6 months after ACL reconstruction. During stair ascent, ACL patients experienced more extended knee joint positions and less sagittal plane knee joint excursions, coupled with greater frontal plane hip joint excursions (P < 0.05).
  
  
  CONCLUSIONS
  Patients with ACL injury experience reductions in knee flexion angle and knee extension moments during stair walking. These alterations were observed both before and after reconstruction, suggesting that early gait retraining interventions may be beneficial in these patients.
authors.affiliation: 1Department of Kinesiology, University of Connecticut, Storrs, CT; 2Department of Rehabilitation Sciences, University of Kentucky, Lexington, KY; 3Biodynamics Research Laboratory, Department of Kinesiology, University of North Carolina at Charlotte, Charlotte, NC; 4Department of Rehabilitation Sciences, University of Toledo, Toledo, OH; 5Department of Orthopedic Surgery, University of Toledo, Toledo, OH; and 6Department of Exercise and Sports Science, University of North Carolina at Chapel Hill, Chapel Hill, NC.
authors.forename: Adam S
authors.initials: AS
authors.lastname: Lepley
authors.forename: Phillip A
authors.initials: PA
authors.lastname: Gribble
authors.forename: Abbey C
authors.initials: AC
authors.lastname: Thomas
authors.forename: Michael A
authors.initials: MA
authors.lastname: Tevald
authors.forename: David H
authors.initials: DH
authors.lastname: Sohn
authors.forename: Brian G
authors.initials: BG
authors.lastname: Pietrosimone
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction; D001696:Biomechanical Phenomena; D005260:Female; D005684:Gait / Q000502:physiology; D006621:Hip Joint / Q000503:physiopathology*; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology* / Q000601:surgery*; D007719:Knee Joint / Q000503:physiopathology*; D008137:Longitudinal Studies; D008297:Male; D016138:Walking / Q000502:physiology*; D055815:Young Adult