title: The association of tibial slope and anterior cruciate ligament rupture in skeletally immature patients.
abstract: OBJECTIVE
  The purpose of our study was to investigate the relation between posterior tibial slope and anterior cruciate ligament (ACL) rupture in patients with open physes.
  
  
  METHODS
  A retrospective case-control study was performed comparing skeletally immature patients with an ACL rupture with an age-matched control group. Posterior tibial slope was measured on plain lateral radiographs in both groups by blinded readers, at 2 separate time intervals, using a previously examined and accepted technique.
  
  
  RESULTS
  Thirty-two patients were included in the study group (mean age, 13 years; age range, 9 to 17 years) and compared with 32 patients in the control group (mean age, 13 years; age range, 9 to 16 years). The mean posterior tibial slope in the ACL-injured population was 10.0° ± 3° versus 8.5° ± 3° in the control group (P = .0128). Statistical significance was seen in comparisons of slope measurements between the ACL-injured and control groups for 2 of the 3 readers (readers 1 and 3) at both time points (P = .0348 and P = .0051 for reader 1 and P = .0009 and P = .0059 for reader 3). Intrarater reliability proved superior with values correlating with moderate to good reliability, whereas inter-rater reliability values corresponded with fair to moderate reliability. The average posterior tibial slope was 9.5° (range, 3° to 14°) for female patients and 9.8° (range, 2° to 16°) for male patients.
  
  
  CONCLUSIONS
  On the basis of the results of this study, the data support the notion that a moderate association may exist between an increased posterior tibial slope and ACL injury in pediatric patients with open physes.
  
  
  METHODS
  Level III, case-control study.
authors.affiliation: Department of Orthopaedic Surgery, University of Connecticut Health Center, Farmington, Connecticut, U.S.A.. Electronic address: momalley@resident.uchc.edu.
authors.forename: Michael P
authors.initials: MP
authors.lastname: O'Malley
authors.affiliation: Elite Sports Medicine, Connecticut Children's Medical Center, Farmington, Connecticut, U.S.A.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Milewski
authors.affiliation: Center for Motion Analysis, Connecticut Children's Medical Center, Farmington, Connecticut, U.S.A.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Solomito
authors.affiliation: Department of Orthopaedic Surgery, University of Connecticut Health Center, Farmington, Connecticut, U.S.A.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Erwteman
authors.affiliation: Elite Sports Medicine, Connecticut Children's Medical Center, Farmington, Connecticut, U.S.A.
authors.forename: Carl W
authors.initials: CW
authors.lastname: Nissen
mesh_terms: D000293:Adolescent; D000070598:Anterior Cruciate Ligament Injuries; D016022:Case-Control Studies; D002648:Child; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D008297:Male; D015588:Observer Variation; D011859:Radiography; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012421:Rupture / Q000209:etiology; D013977:Tibia / Q000033:anatomy & histology* / Q000000981:diagnostic imaging