title: Characteristics of inpatient anterior cruciate ligament reconstructions and concomitant injuries.
abstract: OBJECTIVE
  The purpose of this epidemiologic study was to quantify the incidence, expense, and concomitant injuries for anterior cruciate ligament reconstruction (ACLR) procedures in the USA from 2003 to 2011 that required an inpatient stay. It was hypothesized that the relative reported rates of concomitant knee injuries would be greater with the MCL and menisci compared to all other concomitant knee injuries.
  
  
  METHODS
  The National Inpatient Sample from 2003 to 2011 was retrospectively sampled using ICD-9-CM codes to identify ACLR patients and to extrapolate national averages.
  
  
  RESULTS
  Between the years of 2003-2011, an average of 9,037 ± 1,728 inpatient hospitalization included ACLRs, of which 4,252 ± 1,824 were primarily due to the ACLR. Inpatient visits primarily due to ACLR involved an average hospitalization of 1.7 ± 0.2 days and cost $30,118 ± 9,066 per patient. Knee injuries that were commonly reported along with inpatient ACLRs included medial meniscus damage (18.1 %), lateral meniscus damage (16.8 %), collateral ligament repairs (12.3 %), and medial collateral ligament strains (6.9 %). Prevalence of meniscus injuries was consistent across years, but MCL-related injuries increased over time.
  
  
  CONCLUSIONS
  ACLR-related inpatient hospitalizations account for approximately 7.1 % of the total ACLRs performed annually in the USA. Inpatient ACLR procedures continue to decrease in frequency; however, the mean cost per patient increased. Meniscus and collateral ligament injuries were the most commonly reported concomitant knee injuries. The clinical relevance of this investigation is that it informs, on a large clinical cohort of patients, the current state of incidence and expense for ACLR surgeries in an inpatient setting.
  
  
  METHODS
  Prognostic, retrospective study, Level II.
authors.affiliation: Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, USA.|The Sports Health and Performance Institute, OSU Sports Medicine, The Ohio State University, Columbus, OH, USA.|Sports Medicine Biodynamics Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors.forename: Nathaniel A
authors.initials: NA
authors.lastname: Bates
authors.affiliation: Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, USA.|Sports Medicine Biodynamics Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors.forename: April L
authors.initials: AL
authors.lastname: McPherson
authors.affiliation: Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, USA.|Department of Environmental Health-Genomics, University of Cincinnati, Cincinnati, OH, USA.
authors.forename: Marepalli B
authors.initials: MB
authors.lastname: Rao
authors.affiliation: Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, USA.|Sports Medicine Biodynamics Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.|Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, OH, USA.|Department Orthopaedic Surgery, College of Medicine, University of Cincinnati, Cincinnati, OH, USA.|Athletic Training Division, School of Allied Medical Professions, The Ohio State University, Columbus, OH, USA.
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Myer
authors.affiliation: Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, USA. timothy.hewett@osumc.edu.|The Sports Health and Performance Institute, OSU Sports Medicine, The Ohio State University, Columbus, OH, USA. timothy.hewett@osumc.edu.|Sports Medicine Biodynamics Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA. timothy.hewett@osumc.edu.|Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, OH, USA. timothy.hewett@osumc.edu.|Departments of Physiology and Cell Biology, Orthopaedic Surgery, Family Medicine and Biomedical Engineering, The Ohio State University, 2050 Kenny Road, Suite 3100, Columbus, OH, 43221, USA. timothy.hewett@osumc.edu.
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Hewett
mesh_terms: D000293:Adolescent; D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries / Q000191:economics / Q000453:epidemiology* / Q000601:surgery; D059549:Anterior Cruciate Ligament Reconstruction / Q000191:economics / Q000706:statistics & numerical data*; D017885:Collateral Ligaments / Q000293:injuries* / Q000601:surgery; D016208:Databases, Factual; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D007718:Knee Injuries / Q000191:economics / Q000453:epidemiology* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012189:Retrospective Studies; D000070600:Tibial Meniscus Injuries / Q000191:economics / Q000453:epidemiology* / Q000601:surgery; D014481:United States / Q000453:epidemiology; D055815:Young Adult
keywords: Anterior cruciate ligament reconstruction; Expenditure; Incidence; Inpatient; Knee injury; Patient demographics