title: Associations between inadequate knee function detected by KOOS and prospective graft failure in an anterior cruciate ligament-reconstructed knee.
abstract: OBJECTIVE
  First, to evaluate whether the 2 year post-operative Knee injury and Osteoarthritis Outcome Score (KOOS) in primary anterior cruciate ligament reconstructions (ACLRs) was significantly different between patients that did not go on to have a subsequent revision after the 2 year post-operative control and the ones that did. Second, to test whether the "clinically failure" value of KOOS quality of life (QoL) < 44 was indicative of a clinically relevant difference in the risk of subsequent revision ACLR.
  
  
  METHODS
  ACLRs reported to the Norwegian Knee Ligament Registry between June 2004 and December 2009. 5,517 primary ACLRs with at least 2-year follow-up with KOOS QoL before revision surgery.
  
  
  RESULTS
  There were clinically significant differences, adjusted and unadjusted, in both the KOOS Sport and Recreation and QoL subscales in patients with a later revision surgery compared to those that did not have a revision surgery. In adjusted models, the risk of later ACLR revision was 3.7 (95 % CI 2.2-6.0) higher in patients with a 2-year KOOS QoL < 44 compared to patients with a KOOS QoL ≥ 44. For every 10-point reduction in the KOOS QoL, a 33.6 % (95 % CI 21.2-47.5 %) higher risk for later ACLR revision was observed.
  
  
  CONCLUSIONS
  This study reveals an association between inadequate knee function, as measured by KOOS, and a prospective ACL-reconstructed graft failure.
  
  
  METHODS
  Prognostic study (prospective cohort study), Level II.
authors.affiliation: Oslo Sports Trauma Research Center, Norwegian School of Sport Sciences, Oslo, Norway, lars-petter.granan@nih.no.
authors.forename: Lars-Petter
authors.initials: LP
authors.lastname: Granan
authors.forename: Valborg
authors.initials: V
authors.lastname: Baste
authors.forename: Lars
authors.initials: L
authors.lastname: Engebretsen
authors.forename: Maria C S
authors.initials: MC
authors.lastname: Inacio
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology / Q000601:surgery*; D007719:Knee Joint / Q000503:physiopathology* / Q000601:surgery; D008297:Male; D018447:Medical Futility; D011446:Prospective Studies; D011788:Quality of Life; D016059:Range of Motion, Articular / Q000502:physiology*