title: Outcome of revision anterior cruciate ligament reconstruction: a systematic review.
abstract: BACKGROUND
  Revision anterior cruciate ligament (ACL) reconstruction is believed to have an inferior outcome compared with primary ACL reconstruction. The available literature on the outcome of revision ACL reconstruction is sparse compared with that for primary reconstruction. The purpose of this systematic review was to test the hypothesis that the outcome of revision ACL reconstruction compares unfavorably with the historical outcome of primary ACL reconstruction.
  
  
  METHODS
  A systematic review of studies evaluating the outcome of revision ACL reconstructions with a minimum of two years of follow-up was performed. Pooled data were collected when appropriate and a mixed-effect-model meta-analysis was performed for important outcome measures that were reported in several studies (objective graft failure, Lysholm score, International Knee Documentation Committee [IKDC] subjective score, and IKDC objective score). Objective failure was defined as repeat revision, a side-to-side difference of &gt;5 mm measured with use of a KT1000 arthrometer, or a pivot-shift grade of 2+ or 3+.
  
  
  RESULTS
  Twenty-one studies were included, and 863 of the 1004 patients in these studies had a minimum of two years of follow-up and were analyzed. The pooled mean age of the patients at the time of the revision procedure was 30.6 years, and 66% were male. Objective failure occurred in 13.7% ± 2.7% of the patients (95% confidence interval, 8.0% to 19.4%). The mean Lysholm score in 491 patients was 82.1 ± 3.3 (95% confidence interval, 74.6 to 89.5) according to a mixed-model meta-analysis. The mean IKDC subjective score in 202 patients was 74.8 ± 4.4 (95% confidence interval, 62.5 to 87.0).
  
  
  CONCLUSIONS
  Revision ACL reconstruction resulted in a worse outcome compared with primary ACL reconstruction. Patient-reported outcome scores were inferior to previously published results of primary ACL reconstruction, but these differences may not be clinically important. A dramatically elevated failure rate was noted after revision ACL reconstruction; this rate was nearly three to four times the failure rate in prospective series of primary ACL reconstructions.
authors.affiliation: Department of Orthopaedic Surgery, Washington University School of Medicine, 1 Barnes Hospital Plaza, Suite 11300 West Pavilion, St. Louis, MO 63110, USA. rwwright1@aol.com
authors.forename: Rick W
authors.initials: RW
authors.lastname: Wright
authors.forename: Corey S
authors.initials: CS
authors.lastname: Gill
authors.forename: Ling
authors.initials: L
authors.lastname: Chen
authors.forename: Robert H
authors.initials: RH
authors.lastname: Brophy
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Matava
authors.forename: Matthew V
authors.initials: MV
authors.lastname: Smith
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Mall
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D012086:Reoperation; D019737:Transplants; D016896:Treatment Outcome