title: Tibial tunnel defect size as a risk factor in growth arrest following paediatric transphyseal anterior cruciate ligament reconstruction: an anatomical study.
abstract: BACKGROUND
  There is ongoing controversy regarding growth disturbances in younger patients undergoing anterior cruciate ligament reconstructions. Animal models have shown that an injury of 7-9% of the physeal area is a risk factor for growth disturbances.
  
  
  METHODS
  A total of 39 magnetic resonance imaging studies of the knee were examined. The proximal tibial physeal area was determined using a calibrated 'region of interest' ligature encompassing the tibial physis in the axial plane. The potential defect left by commonly used drill sizes was calculated as a percentage of the physeal area.
  
  
  RESULTS
  A 7-mm drill leaves a mean defect of 1.45% physeal area (range: 1.11-1.89%, SD: 0.28, 95% CI: ±0.09), 8-mm drill leaves a 1.84% mean defect (range: 1.43-2.49%, SD: 0.38, 95% CI: ±0.12) and a 9-mm drill leaves a 2.30% mean defect (range: 1.83-3.19%, SD: 0.58, 95% CI: ±0.17). At 55°, 7-mm drill leaves a mean defect of 1.96% (range: 1.32-2.28%, SD: 0.37, 95% CI: ±0.12), 8-mm drill leaves a mean defect of 2.19% (range: 1.71-2.95%, SD: 0.46, 95% CI: ±0.14) and a 9-mm drill leaves a mean defect of 2.76% (range: 2.16-3.73%, SD: 0.58, 95% CI: ±0.18). There was a statistically significant difference in the tunnel area with a change of drill angle (7-mm drill P = 0.005, 8-mm drill P = 0.001, 9-mm drill P = 0.001).
  
  
  CONCLUSIONS
  On the basis of this study in the context of animal model and observational evidence, the area of physeal injury using drill tunnels for anterior cruciate ligament reconstruction would not appear to contribute to potential growth disturbances.
authors.affiliation: Department of Orthopaedic Surgery, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.
authors.forename: Hasitha
authors.initials: H
authors.lastname: Pananwala
authors.affiliation: Department of Orthopaedic Surgery, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.
authors.forename: Yaser
authors.initials: Y
authors.lastname: Jabbar
authors.affiliation: Department of Orthopaedic Surgery, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.
authors.forename: Leonora
authors.initials: L
authors.lastname: Mills
authors.affiliation: Department of Orthopaedic Surgery, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Symes
authors.affiliation: Department of Orthopaedic Surgery, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.
authors.forename: Haren
authors.initials: H
authors.lastname: Nandapalan
authors.affiliation: Department of Orthopaedic Surgery, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Sefton
authors.affiliation: Department of Orthopaedic Surgery, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.
authors.forename: Lasitha
authors.initials: L
authors.lastname: Delungahawatte
authors.affiliation: Department of Orthopaedic Surgery, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.
authors.forename: Quang
authors.initials: Q
authors.lastname: Dao
mesh_terms: D000293:Adolescent; D016118:Anterior Cruciate Ligament / Q000000981:diagnostic imaging*; D000070598:Anterior Cruciate Ligament Injuries / Q000175:diagnosis / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D013977:Tibia / Q000000981:diagnostic imaging / Q000254:growth & development*
keywords: anterior cruciate ligament; anterior cruciate ligament reconstructions; paediatric ACL injuries; paediatric ACL reconstructions; paediatric knee surgery; size of tibial tunnel; tunnel angle in paediatric ACL reconstructions