title: Biomechanical and clinical correlates of swing-phase knee flexion in individuals with spastic cerebral palsy who walk with flexed-knee gait.
abstract: OBJECTIVE
  To identify clinical and biomechanical parameters that influence swing-phase knee flexion and contribute to stiff-knee gait in individuals with spastic cerebral palsy (CP) and flexed-knee gait.
  
  
  METHODS
  Retrospective analysis of clinical data and gait kinematics collected from 2010 to 2013.
  
  
  METHODS
  Motion and gait analysis laboratory at a children's hospital.
  
  
  METHODS
  Individuals with spastic CP (N=34; 20 boys, 14 girls; mean age ± SD, 10.1±4.1y [range, 5-20y]; Gross Motor Function Classification System I-III) who walked with flexed-knee gait ≥20° at initial contact and had no prior surgery were included; the more-involved limb was analyzed.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  The magnitude and timing of peak knee flexion (PKF) during swing were analyzed with respect to clinical data, including passive range of motion and Selective Control Assessment of the Lower Extremity, and biomechanical data, including joint kinematics and hamstring, rectus femoris, and gastrocnemius muscle-tendon length during gait.
  
  
  RESULTS
  Data from participants demonstrated that achieving a higher magnitude of PKF during swing correlated with a higher maximum knee flexion velocity in swing (ρ=.582, P<0.001) and a longer maximum length of the rectus femoris (ρ=.491, P=.003). In contrast, attaining earlier timing of PKF during swing correlated with a higher knee flexion velocity at toe-off (ρ=-.576, P<.001), a longer maximum length of the gastrocnemius (ρ=-.355, P=.039), and a greater peak knee extension during single-limb support phase (ρ=-.354, P=.040).
  
  
  CONCLUSIONS
  Results indicate that the magnitude and timing of PKF during swing were independent, and their biomechanical correlates differed, suggesting important treatment implications for both stiff-knee and flexed-knee gait.
authors.affiliation: Department of Orthopaedic Surgery, Stanford University School of Medicine, Stanford, CA; Motion & Gait Analysis Laboratory, Lucile Packard Children's Hospital, Palo Alto, CA; Department and Research Institute of Rehabilitation Medicine, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Dong-Wook
authors.initials: DW
authors.lastname: Rha
authors.affiliation: Department of Orthopaedic Surgery, Stanford University School of Medicine, Stanford, CA; Motion & Gait Analysis Laboratory, Lucile Packard Children's Hospital, Palo Alto, CA; Department of Bioengineering, Stanford University, Stanford, CA. Electronic address: kcct@stanford.edu.
authors.forename: Katelyn
authors.initials: K
authors.lastname: Cahill-Rowley
authors.affiliation: Department of Orthopaedic Surgery, Stanford University School of Medicine, Stanford, CA; Motion & Gait Analysis Laboratory, Lucile Packard Children's Hospital, Palo Alto, CA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Young
authors.affiliation: Motion & Gait Analysis Laboratory, Lucile Packard Children's Hospital, Palo Alto, CA.
authors.forename: Leslie
authors.initials: L
authors.lastname: Torburn
authors.affiliation: Department of Orthopaedic Surgery, Stanford University School of Medicine, Stanford, CA; Motion & Gait Analysis Laboratory, Lucile Packard Children's Hospital, Palo Alto, CA; Department of Mechanical Engineering, Stanford University, Stanford, CA.
authors.forename: Katherine
authors.initials: K
authors.lastname: Stephenson
authors.affiliation: Department of Orthopaedic Surgery, Stanford University School of Medicine, Stanford, CA; Motion & Gait Analysis Laboratory, Lucile Packard Children's Hospital, Palo Alto, CA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Rose
mesh_terms: D000293:Adolescent; D001696:Biomechanical Phenomena; D002547:Cerebral Palsy / Q000503:physiopathology* / Q000534:rehabilitation*; D002648:Child; D002675:Child, Preschool; D005260:Female; D020233:Gait Disorders, Neurologic / Q000503:physiopathology* / Q000534:rehabilitation*; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D018482:Muscle, Skeletal / Q000503:physiopathology; D012189:Retrospective Studies; D055815:Young Adult
keywords: Cerebral palsy; Gait; Kinematics; Rehabilitation