title: Trajectories of Pain and Function after Primary Hip and Knee Arthroplasty: The ADAPT Cohort Study.
abstract: OBJECTIVE
  Pain and function improve dramatically in the first three months after hip and knee arthroplasty but the trajectory after three months is less well described. It is also unclear how pre-operative pain and function influence short- and long-term recovery. We explored the trajectory of change in function and pain until and beyond 3-months post-operatively and the influence of pre-operative self-reported symptoms.
  
  
  METHODS
  The study was a prospective cohort study of 164 patients undergoing primary hip (n = 80) or knee (n = 84) arthroplasty in the United Kingdom. Self-reported measures of pain and function using the Western Ontario and McMaster Universities Osteoarthritis index were collected pre-operatively and at 3 and 12 months post-operatively. Hip and knee arthroplasties were analysed separately, and patients were split into two groups: those with high or low symptoms pre-operatively. Multilevel regression models were used for each outcome (pain and function), and the trajectories of change were charted (0-3 months and 3-12 months).
  
  
  RESULTS
  Hip: Most improvement occurred within the first 3 months following hip surgery and patients with worse pre-operative scores had greater changes. The mean changes observed between 3 and twelve months were statistically insignificant. One year after surgery, patients with worse pre-operative scores had post-operative outcomes similar to those observed among patients with less severe pre-operative symptoms. Knee: Most improvement occurred in the first 3 months following knee surgery with no significant change thereafter. Despite greater mean change during the first three months, patients with worse pre-operative scores had not 'caught-up' with those with less severe pre-operative symptoms 12 months after their surgery.
  
  
  CONCLUSIONS
  Most symptomatic improvement occurred within the first 3 months after surgery with no significant change between 3-12 months. Further investigations are now required to determine if patients with severe symptoms at the time of their knee arthroplasty have a different pre-surgical history than those with less severe symptoms and if they could benefit from earlier surgical intervention and tailored rehabilitation to achieve better post-operative patient-reported outcomes.
authors.affiliation: Musculoskeletal Research Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom.
authors.forename: Erik
authors.initials: E
authors.lastname: Lenguerrand
authors.affiliation: Musculoskeletal Research Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom.
authors.forename: Vikki
authors.initials: V
authors.lastname: Wylde
authors.affiliation: Musculoskeletal Research Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom.
authors.forename: Rachael
authors.initials: R
authors.lastname: Gooberman-Hill
authors.affiliation: Musculoskeletal Research Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom.
authors.forename: Adrian
authors.initials: A
authors.lastname: Sayers
authors.affiliation: Musculoskeletal Research Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom.
authors.forename: Luke
authors.initials: L
authors.lastname: Brunton
authors.affiliation: Musculoskeletal Research Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Beswick
authors.affiliation: Medical School, University of Exeter, Exeter, United Kingdom.
authors.forename: Paul
authors.initials: P
authors.lastname: Dieppe
authors.affiliation: Musculoskeletal Research Unit, School of Clinical Sciences, University of Bristol, Bristol, United Kingdom.
authors.forename: Ashley W
authors.initials: AW
authors.lastname: Blom
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D019645:Arthroplasty, Replacement, Knee; D005260:Female; D006621:Hip Joint / Q000503:physiopathology*; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology / Q000601:surgery*; D020370:Osteoarthritis, Knee / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology / Q000601:surgery*; D010146:Pain / Q000150:complications* / Q000453:epidemiology; D010147:Pain Measurement; D011446:Prospective Studies; D020127:Recovery of Function; D057566:Self Report; D016896:Treatment Outcome; D006113:United Kingdom / Q000453:epidemiology