title: Factors related to additional knee injuries after anterior cruciate ligament injury.
abstract: OBJECTIVE
  We reviewed 1,375 consecutive patients to determine whether patient gender, age at injury, or activity level at injury were related to the risk of additional knee injuries over time following anterior cruciate ligament (ACL) injury.
  
  
  METHODS
  Retrospective case series.
  
  
  METHODS
  Survival analysis was used to analyze the effect of each factor while statistically controlling for the effect of time from ACL injury to reconstruction.
  
  
  RESULTS
  The risk of meniscus injury was significantly higher among male subjects (odds ratio [OR] = 1.5, P < .001). When undergoing ACL reconstruction more than 6 months after injury, the risk of meniscus injury increased by 1.5 times for male subjects (P = .021) but increased by 3.4 times for female subjects (P < .001). The risk of meniscus injuries was significantly higher among patients undergoing ACL reconstruction more than 6 months after injury when compared with patients undergoing reconstruction within 2 weeks of injury (OR = 2.2, P < .001). The risk of articular cartilage lesions was significantly higher among patients undergoing ACL reconstruction more than 1 year after injury when compared with patients undergoing reconstruction within 2 weeks of injury (OR = 2.1, P < .001).
  
  
  CONCLUSIONS
  Men had a consistently higher occurrence rate of meniscus injuries than did women. The risk of meniscus injuries increased at a higher rate over time among women. The risk of meniscus injuries increases when ACL reconstruction is performed more than 6 months after injury. The risk of articular cartilage lesions increases when ACL reconstruction is performed more than 1 year after injury.
  
  
  METHODS
  Level IV, Case Series.
authors.affiliation: Joe W. King Orthopedic Institute, The University of Texas Medical School-Houston, Houston, Texas, USA. dano@jwkoi.com
authors.forename: Daniel P
authors.initials: DP
authors.lastname: O'Connor
authors.forename: Mitzi S
authors.initials: MS
authors.lastname: Laughlin
authors.forename: G William
authors.initials: GW
authors.lastname: Woods
mesh_terms: D000328:Adult; D000367:Age Factors; D000070598:Anterior Cruciate Ligament Injuries; D002358:Cartilage, Articular / Q000293:injuries; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000453:epidemiology / Q000209:etiology / Q000401:mortality / Q000503:physiopathology*; D008297:Male; D009043:Motor Activity; D016016:Proportional Hazards Models; D019651:Plastic Surgery Procedures / Q000379:methods; D012086:Reoperation / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012727:Sex Characteristics; D016019:Survival Analysis; D000070600:Tibial Meniscus Injuries; D013997:Time Factors