title: Effect of a functional knee brace on knee flexion and extension strength after anterior cruciate ligament reconstruction.
abstract: OBJECTIVE
  To investigate the effect of a knee brace on knee flexion and extension muscular strength of patients after anterior cruciate ligament (ACL) reconstruction and to evaluate whether the effect of the brace depends on patient symptoms and muscular strength.
  
  
  METHODS
  Repeated measures.
  
  
  METHODS
  A university-based outpatient orthopedic clinic and musculoskeletal assessment laboratory.
  
  
  METHODS
  Twenty-seven patients (14 women, 13 men; mean age, 28+/-11 y) having undergone arthroscopically assisted ACL reconstruction by using a semitendinosus and gracilis autograft.
  
  
  METHODS
  A custom-fit ACL functional knee brace.
  
  
  METHODS
  The brace effect was calculated as the change in peak torque observed with the brace, expressed as a percentage of peak torque observed without the brace, during isokinetic concentric knee flexion and extension movements performed at 90 degrees /s. Patient symptoms were quantified by using a disease-specific health-related quality of life questionnaire.
  
  
  RESULTS
  Knee flexion strength decreased significantly with the brace (mean brace effect=-7.3%, P<.05). The brace effect during knee flexion varied considerably (-52% to 47%) and was significantly related to peak torque observed without the brace (r=-.50, P<.01). All other comparisons and correlations were not significant.
  
  
  CONCLUSIONS
  These findings suggest that brace effects depend on patient strength. A brace may inhibit knee flexion strength of stronger patients, yet result in no change or even improvements in strength of weaker patients. Future research is required to further elucidate which patients may derive most benefit or detriment from bracing.
authors.affiliation: School of Physical Therapy, Faculty of Health Sciences, University of Western Ontario, London, Ont, Canada. tbirming@uwo.ca
authors.forename: Trevor B
authors.initials: TB
authors.lastname: Birmingham
authors.forename: John F
authors.initials: JF
authors.lastname: Kramer
authors.forename: Alexandra
authors.initials: A
authors.lastname: Kirkley
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D001696:Biomechanical Phenomena; D001915:Braces; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology* / Q000534:rehabilitation* / Q000601:surgery; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D016059:Range of Motion, Articular; D019651:Plastic Surgery Procedures