title: Risk of tearing the intact anterior cruciate ligament in the contralateral knee and rupturing the anterior cruciate ligament graft during the first 2 years after anterior cruciate ligament reconstruction: a prospective MOON cohort study.
abstract: BACKGROUND
  The risk of tear of the intact anterior cruciate ligament in the contralateral knee after anterior cruciate ligament reconstruction of the opposite knee and the incidence of rupturing the anterior cruciate ligament graft during the first 2 years after surgery have not been extensively studied in a prospective manner. Clinicians have hypothesized that the opposite normal knee is at equal or increased risk compared with the risk of anterior cruciate ligament graft rupture in the operated knee.
  
  
  OBJECTIVE
  The risk of anterior cruciate ligament graft rupture and contralateral normal knee anterior cruciate ligament rupture at 2-year follow-up is equal.
  
  
  METHODS
  Cohort study; Level of evidence, 2.
  
  
  METHODS
  The Multicenter Orthopaedic Outcome Network (MOON) database of a prospective longitudinal cohort of anterior cruciate ligament reconstructions was used to determine the number of anterior cruciate ligament graft ruptures and tears of the intact anterior cruciate ligament in the contralateral knee at 2-year follow-up. Two-year follow-up consisted of a phone interview and review of operative reports.
  
  
  RESULTS
  Two-year data were obtained for 235 of 273 patients (86%). There were 14 ligament disruptions. Of these, 7 were tears of the intact anterior cruciate ligament in the contralateral knee (3.0%) and 7 were anterior cruciate ligament graft failures (3.0%).
  
  
  CONCLUSIONS
  The contralateral normal knee anterior cruciate ligament is at a similar risk of anterior cruciate ligament tear (3.0%) as the anterior cruciate ligament graft after primary anterior cruciate ligament reconstruction (3.0%).
authors: Department of Orthopaedic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St. Louis, Missouri 63110, USA. rwwright1@aol.com
authors: Rick W
authors: RW
authors: Wright
authors: Warren R
authors: WR
authors: Dunn
authors: Annunziato
authors: A
authors: Amendola
authors: Jack T
authors: JT
authors: Andrish
authors: John
authors: J
authors: Bergfeld
authors: Christopher C
authors: CC
authors: Kaeding
authors: Robert G
authors: RG
authors: Marx
authors: Eric C
authors: EC
authors: McCarty
authors: Richard D
authors: RD
authors: Parker
authors: Michelle
authors: M
authors: Wolcott
authors: Brian R
authors: BR
authors: Wolf
authors: Kurt P
authors: KP
authors: Spindler
mesh_terms: D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D002648:Child; D005260:Female; D006085:Graft Survival; D006801:Humans; D015994:Incidence; D007718:Knee Injuries / Q000601:surgery*; D008023:Ligaments, Articular / Q000293:injuries / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D019651:Plastic Surgery Procedures; D012008:Recurrence; D012307:Risk Factors; D012421:Rupture / Q000453:epidemiology; D013997:Time Factors