title: Incidence and trends of anterior cruciate ligament reconstruction in the United States.
abstract: BACKGROUND
  Anterior cruciate ligament (ACL) injury is among the most commonly studied injuries in orthopaedics. The previously reported incidence of ACL injury in the United States has varied considerably and is often based on expert opinion or single insurance databases.
  
  
  OBJECTIVE
  To determine the incidence of ACL reconstruction (ACLR) in the United States; to identify changes in this incidence between 1994 and 2006; to identify changes in the demographics of ACLR over the same time period with respect to location (inpatient vs outpatient), sex, and age; and to determine the most frequent concomitant procedures performed at the time of ACLR.
  
  
  METHODS
  Descriptive epidemiological study.
  
  
  METHODS
  International Classification of Diseases, 9th Revision (ICD-9) codes 844.2 and 717.83 were used to search the National Hospital Discharge Survey (NHDS) and the National Survey of Ambulatory Surgery (NSAS) for the diagnosis of ACL tear, and the procedure code 81.45 was used to search for ACLR. The incidence of ACLR in 1994 and 2006 was determined by use of US Census Data, and the results were then stratified based on patient age, sex, facility, concomitant diagnoses, and concomitant procedures.
  
  
  RESULTS
  The incidence of ACLR in the United States rose from 86,687 (95% CI, 51,844-121,530; 32.9 per 100,000 person-years) in 1994 to 129,836 (95% CI, 94,993-164,679; 43.5 per 100,000 person-years) in 2006 (P = .015). The number of ACLRs increased in patients younger than 20 years and those who were 40 years or older over this 12-year period. The incidence of ACLR in females significantly increased from 10.36 to 18.06 per 100,000 person-years between 1994 and 2006 (P = .0003), while that in males rose at a slower rate, with an incidence of 22.58 per 100,000 person-years in 1994 and 25.42 per 100,000 person-years in 2006. In 2006, 95% of ACLRs were performed in an outpatient setting, while in 1994 only 43% of ACLRs were performed in an outpatient setting. The most common concomitant procedures were partial meniscectomy and chondroplasty.
  
  
  CONCLUSIONS
  The incidence of ACLR increased between 1994 and 2006, particularly in females as well as those younger than 20 years and those 40 years or older. Research efforts as well as cost-saving measures may be best served by targeting prevention and outcomes measures in these groups. Surgeons should be aware that concomitant injury is common.
authors.affiliation: Regeneration Orthopaedics, St Louis, Missouri, USA Cartilage Restoration Center of St Louis, St Louis, Missouri, USA nathanmall@gmail.com.
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Mall
authors.affiliation: Department of Orthopaedics, Division of Sports Medicine, Rush University Medical Center, Chicago, Illinois, USA.
authors.forename: Peter N
authors.initials: PN
authors.lastname: Chalmers
authors.affiliation: Department of Anesthesia, Rush University Medical Center, Chicago, Illinois, USA.
authors.forename: Mario
authors.initials: M
authors.lastname: Moric
authors.affiliation: Regeneration Orthopaedics, St Louis, Missouri, USA Cartilage Restoration Center of St Louis, St Louis, Missouri, USA.
authors.forename: Miho J
authors.initials: MJ
authors.lastname: Tanaka
authors.affiliation: Department of Orthopaedics, Division of Sports Medicine, Rush University Medical Center, Chicago, Illinois, USA Cartilage Restoration Center at Rush, Chicago, Illinois, USA.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Cole
authors.affiliation: Department of Orthopaedics, Division of Sports Medicine, Rush University Medical Center, Chicago, Illinois, USA.
authors.forename: Bernard R
authors.initials: BR
authors.lastname: Bach
authors.affiliation: Regeneration Orthopaedics, St Louis, Missouri, USA Cartilage Restoration Center of St Louis, St Louis, Missouri, USA.
authors.forename: George A
authors.initials: GA
authors.lastname: Paletta
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000556:Ambulatory Surgical Procedures / Q000706:statistics & numerical data / Q000639:trends; D016118:Anterior Cruciate Ligament / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000706:statistics & numerical data* / Q000639:trends*; D001182:Arthroscopy / Q000706:statistics & numerical data; D005260:Female; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D038801:International Classification of Diseases; D008297:Male; D008592:Menisci, Tibial / Q000601:surgery; D008875:Middle Aged; D017678:Sex Distribution; D000070600:Tibial Meniscus Injuries; D014481:United States / Q000453:epidemiology; D055815:Young Adult
keywords: ACL reconstruction; age; incidence; sex