title: Self-Reported Knee Instability Before and After Total Knee Replacement Surgery.
abstract: OBJECTIVE
  To determine the prevalence and burden of pain and activity limitations associated with retaining presurgery self-reported knee instability 6 months after total knee replacement (TKR) surgery and to identify early potentially modifiable risk factors for retaining knee instability in the operated knee after TKR surgery.
  
  
  METHODS
  A secondary analysis was performed using measures obtained from 390 participants undergoing primary unilateral TKR and participating in a randomized clinical trial. Self-reported knee instability was measured using 2 items from the Activities of Daily Living Scale of the Knee Outcome Survey. Outcome measures were knee pain (range 0-20) and physical function (range 0-68) on the Western Ontario and McMaster Universities Arthritis Index (WOMAC), stair-climb power, 50-foot walk time, knee range of motion, and isometric knee flexion and extension strength.
  
  
  RESULTS
  In this study, 72% of participants reported knee instability just prior to surgery, with 32% retaining instability in the operated knee 6 months after surgery. Participants retaining operated knee instability had significantly more knee pain and activity limitations 6 months after surgery, with mean ± SD WOMAC scores of 4.8 ± 3.7 and 17.5 ± 11.1, respectively, compared to participants without knee instability, with 2.9 ± 3.1 and 9.8 ± 9.2. The multivariable predictor model for retained knee instability included a high comorbidity score (>6), low stair-climb power (<150 watts), more pain in the operated knee (>7 of 20), and younger age (<60 years).
  
  
  CONCLUSIONS
  Self-reported knee instability is highly prevalent before and after TKR surgery and is associated with a considerable burden of pain and activity limitation in the operated knee. Increasing lower extremity muscle power may reduce the risk of retaining knee instability after TKR surgery.
authors: University of Sydney, Sydney, New South Wales, Australia.
authors: Genevieve
authors: G
authors: Fleeton
authors: University of Sydney, Sydney, New South Wales, Australia.
authors: Alison R
authors: AR
authors: Harmer
authors: University of Sydney, Sydney, New South Wales, Australia.
authors: Lillias
authors: L
authors: Nairn
authors: University of Sydney, Sydney, New South Wales, Australia.
authors: Jack
authors: J
authors: Crosbie
authors: University of Sydney, Sydney, New South Wales, Australia.
authors: Lyn
authors: L
authors: March
authors: Queensland University of Technology, Brisbane, Queensland, Australia.
authors: Ross
authors: R
authors: Crawford
authors: Reade, Centre for Rehabilitation and Rheumatology, Amsterdam, The Netherlands.
authors: Martin
authors: M
authors: van der Esch
authors: University of Sydney, Sydney, New South Wales, Australia.
authors: Marlene
authors: M
authors: Fransen
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D018771:Arthralgia / Q000175:diagnosis / Q000453:epidemiology; D053587:Arthrometry, Articular; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects; D001315:Australia / Q000453:epidemiology; D001696:Biomechanical Phenomena; D016009:Chi-Square Distribution; D004185:Disability Evaluation; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology / Q000601:surgery*; D007719:Knee Joint / Q000503:physiopathology / Q000601:surgery*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D010147:Pain Measurement; D010149:Postoperative Pain / Q000175:diagnosis / Q000453:epidemiology; D015995:Prevalence; D011446:Prospective Studies; D016059:Range of Motion, Articular; D020127:Recovery of Function; D012307:Risk Factors; D020377:Self Efficacy; D057566:Self Report; D013997:Time Factors; D016896:Treatment Outcome; D016138:Walking