title: The epidemiology of revision anterior cruciate ligament reconstruction in Ontario, Canada.
abstract: BACKGROUND
  Knowledge of the rate of and risk factors for re-revision, reoperation, and readmission after revision anterior cruciate ligament reconstruction (ACLR) is limited.
  
  
  OBJECTIVE
  To determine the rate of and risk factors for re-revision, reoperation, and readmission after revision ACLR.
  
  
  METHODS
  Descriptive epidemiology study.
  
  
  METHODS
  All patients who underwent first revision ACLR in Ontario, Canada, from January 2004 to December 2010 were identified and followed until December 2012. Exclusions included age <16 years, previous osteotomy, or multiligament knee reconstruction. The main outcome was re-revision ACLR. Secondary outcomes included reoperation (irrigation and debridement [I&D], meniscectomy, manipulation under anesthesia, contralateral ACLR, and total knee arthroplasty) and readmission. Survival to re-revision was determined using the Kaplan-Meier approach. A Cox proportional hazards model or logistic regression were used to determine the influence of patient, surgical, and provider factors on outcomes. A post hoc analysis was performed to determine the influence of the aforementioned factors on postoperative infection risk.
  
  
  RESULTS
  Overall, 827 patients were included (median age, 30 years; 58.8% males). Single-stage revisions comprised 92.9% of cases, and a meniscal procedure (repair or debridement) was performed in 45.3% of cases. The re-revision rate at a mean follow-up of 4.8 ± 2.2 years was 4.4%, and the 5-year survival rate was 95.4%. The rates of I&D, meniscectomy, contralateral ACLR, and readmission were 0.8%, 3.1%, 3.4%, and 4.1%, respectively. Manipulation under anesthesia and total knee arthroplasty were rare. Young age significantly increased contralateral ACLR risk (risk decreased by 5.1% with each year of age >16 years; P = .02) but not re-revision ACLR risk. Low surgeon's annual volume of revision ACLR (<4 revisions/year: odds ratio, 1.2; P = .02) and male sex (odds ratio, 13.3; P = .01) significantly increased overall infection risk; male sex also influenced I&D risk.
  
  
  CONCLUSIONS
  Re-revision, reoperation, and readmission rates after revision ACLR were low, and the risk for I&D, infection, and contralateral ACLR were influenced by male sex, low surgeon volume, and young age, respectively.
  
  
  CONCLUSIONS
  This is the first study to determine morbidity rates and risk factors after revision ACLR, providing reference data from the general population.
authors.affiliation: University of Toronto Orthopaedic Sports Medicine Program (Women's College Hospital), Toronto, Ontario, Canada Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada timothy.leroux@mail.utoronto.ca.
authors.forename: Timothy
authors.initials: T
authors.lastname: Leroux
authors.affiliation: University of Toronto Orthopaedic Sports Medicine Program (Women's College Hospital), Toronto, Ontario, Canada Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Wasserstein
authors.affiliation: University of Toronto Orthopaedic Sports Medicine Program (Women's College Hospital), Toronto, Ontario, Canada.
authors.forename: Tim
authors.initials: T
authors.lastname: Dwyer
authors.affiliation: University of Toronto Orthopaedic Sports Medicine Program (Women's College Hospital), Toronto, Ontario, Canada Osteoarthritis Research Group, University Health Network (Toronto Western Hospital), University of Toronto, Toronto, Ontario, Canada.
authors.forename: Darrell J
authors.initials: DJ
authors.lastname: Ogilvie-Harris
authors.affiliation: University of Toronto Orthopaedic Sports Medicine Program (Women's College Hospital), Toronto, Ontario, Canada Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
authors.forename: Paul H
authors.initials: PH
authors.lastname: Marks
authors.affiliation: Division of Sports Medicine, Rush University Medical Center, Chicago, Illinois, USA.
authors.forename: Bernard R
authors.initials: BR
authors.lastname: Bach
authors.affiliation: University of Toronto Orthopaedic Sports Medicine Program (Women's College Hospital), Toronto, Ontario, Canada.
authors.forename: John B
authors.initials: JB
authors.lastname: Townley
authors.affiliation: Osteoarthritis Research Group, University Health Network (Toronto Western Hospital), University of Toronto, Toronto, Ontario, Canada.
authors.forename: Nizar
authors.initials: N
authors.lastname: Mahomed
authors.affiliation: University of Toronto Orthopaedic Sports Medicine Program (Women's College Hospital), Toronto, Ontario, Canada Osteoarthritis Research Group, University Health Network (Toronto Western Hospital), University of Toronto, Toronto, Ontario, Canada.
authors.forename: Jaskarndip
authors.initials: J
authors.lastname: Chahal
mesh_terms: D000328:Adult; D000367:Age Factors; D059549:Anterior Cruciate Ligament Reconstruction / Q000009:adverse effects / Q000706:statistics & numerical data*; D019645:Arthroplasty, Replacement, Knee / Q000706:statistics & numerical data; D015331:Cohort Studies; D003646:Debridement / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D008349:Manipulation, Orthopedic / Q000706:statistics & numerical data; D008592:Menisci, Tibial / Q000601:surgery; D009864:Ontario; D010359:Patient Readmission / Q000706:statistics & numerical data*; D016016:Proportional Hazards Models; D012086:Reoperation / Q000706:statistics & numerical data; D012307:Risk Factors; D024162:Second-Look Surgery / Q000706:statistics & numerical data; D012737:Sex Factors; D015996:Survival Rate; D007507:Therapeutic Irrigation / Q000706:statistics & numerical data; D055815:Young Adult
keywords: epidemiology; re-revision; readmission; reoperation; revision ACL reconstruction