title: Normalized knee-extension strength or leg-press power after fast-track total knee arthroplasty: which measure is most closely associated with performance-based and self-reported function?
abstract: OBJECTIVE
  To investigate which of the 2 muscle-impairment measures for the operated leg, normalized knee extension strength or leg press power, was most closely associated with performance-based and self-reported measures of function shortly after total knee arthroplasty (TKA).
  
  
  METHODS
  Cross-sectional, exploratory study.
  
  
  METHODS
  Laboratory at a regional hospital.
  
  
  METHODS
  Individuals (N=39) with an average age ± SD of 65.5±10.3 years, who all had unilateral TKA 28 days prior.
  
  
  METHODS
  None.
  
  
  METHODS
  The patients performed maximal isometric knee extensions and dynamic leg presses to determine their body-mass normalized knee extension strength and leg press power, respectively. The 10-meter fast speed walking- and 30-second chair stand tests were used to determine performance-based function, while the Western Ontario and McMaster Universities Osteoarthritis Index and Oxford Knee Scores were used to determine self-reported function.
  
  
  RESULTS
  Normalized leg press power was more closely associated with both performance-based (r=.82, P<.001) and self-reported (r=.48, P=.002) measures of function compared with normalized knee extension strength (r=.51, P=.001 and r=.39, P=.015, respectively).
  
  
  CONCLUSIONS
  Normalized leg press power was more closely associated with both performance-based and self-reported function early after TKA than normalized knee extension strength. It may be explained by the fact that performance-based measures of function are typically closed kinetic chain tasks, such as walking or rising from a chair, and self-reported measures of function typically include questions that address perceived difficulty with performing these same tasks.
authors.affiliation: Department of Occupational Therapy and Physiotherapy, Holstebro Regional Hospital, Holstebro, Denmark.
authors.forename: Peter K
authors.initials: PK
authors.lastname: Aalund
authors.forename: Kristian
authors.initials: K
authors.lastname: Larsen
authors.forename: Torben B
authors.initials: TB
authors.lastname: Hansen
authors.forename: Thomas
authors.initials: T
authors.lastname: Bandholm
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D053581:Muscle Strength Dynamometer; D017063:Outcome Assessment, Health Care / Q000379:methods*; D010147:Pain Measurement; D011184:Postoperative Period; D057566:Self Report; D011795:Surveys and Questionnaires