title: Can the outside-in half-tunnel technique reduce femoral tunnel widening in anterior cruciate ligament reconstruction? A CT study.
abstract: BACKGROUND
  There are different techniques for drilling the femoral tunnel in the anterior cruciate ligament reconstruction (ACLR), but their influence in the bone tunnel enlargement in unknown. The purpose of this study was to compare two different surgical techniques for evaluating femoral tunnel enlargement in ACLR. The hypothesis was that tunnel placement using the outside-in technique leads to less tunnel enlargement compared to the transtibial technique.
  
  
  METHODS
  Forty-four patients treated for ACLR between March 2013 and March 2014 were prospectively enrolled in this study. According to the surgical technique, subjects were assigned to Group A (Out-in) or Group B (Transtibial). All patients underwent CT examination in order to evaluate the femoral tunnel enlargement at four different levels. Moreover, all patients were evaluated with the Lachman test and pivot shift test, and the KT1000 arthrometer was used to measure the anterior laxity of the knee. A subjective evaluation was performed using the 2000 International Knee Documentation Committee Subjective Knee score, Lysholm knee score and Tegner activity scale. All patients were assessed after 24 months of follow-up.
  
  
  RESULTS
  At the final follow-up, there were statistically significant differences (p < 0.05) in femoral tunnel enlargement between the two groups at all four femoral levels in favor of the out-in group. No statistical significant differences were found in the objective and subjective clinical outcomes between the two groups (p > 0.05).
  
  
  CONCLUSIONS
  In ACLR with a suspension system, the outside-in technique leads to less enlargement of the femoral tunnel lower than the transtibial technique.
authors.affiliation: Orthopaedic Unit and "Kirk Kilgour" Sports Injury Centre, S. Andrea Hospital, University of Rome "La Sapienza", Via di Grottarossa 1035, 00189, Rome, RM, Italy.
authors.forename: Riccardo Maria
authors.initials: RM
authors.lastname: Lanzetti
authors.affiliation: Orthopaedic Unit and "Kirk Kilgour" Sports Injury Centre, S. Andrea Hospital, University of Rome "La Sapienza", Via di Grottarossa 1035, 00189, Rome, RM, Italy. domenico.lupariello@gmail.com.
authors.forename: Domenico
authors.initials: D
authors.lastname: Lupariello
authors.affiliation: Orthopaedic Unit and "Kirk Kilgour" Sports Injury Centre, S. Andrea Hospital, University of Rome "La Sapienza", Via di Grottarossa 1035, 00189, Rome, RM, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: De Carli
authors.affiliation: Orthopaedic Unit and "Kirk Kilgour" Sports Injury Centre, S. Andrea Hospital, University of Rome "La Sapienza", Via di Grottarossa 1035, 00189, Rome, RM, Italy.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Monaco
authors.affiliation: Orthopaedic Unit and "Kirk Kilgour" Sports Injury Centre, S. Andrea Hospital, University of Rome "La Sapienza", Via di Grottarossa 1035, 00189, Rome, RM, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Guzzini
authors.affiliation: Orthopaedic Unit and "Kirk Kilgour" Sports Injury Centre, S. Andrea Hospital, University of Rome "La Sapienza", Via di Grottarossa 1035, 00189, Rome, RM, Italy.
authors.forename: Mattia
authors.initials: M
authors.lastname: Fabbri
authors.affiliation: Orthopaedic Unit and "Kirk Kilgour" Sports Injury Centre, S. Andrea Hospital, University of Rome "La Sapienza", Via di Grottarossa 1035, 00189, Rome, RM, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Vadalà
authors.affiliation: Orthopaedic Unit and "Kirk Kilgour" Sports Injury Centre, S. Andrea Hospital, University of Rome "La Sapienza", Via di Grottarossa 1035, 00189, Rome, RM, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Ferretti
mesh_terms: D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries / Q000150:complications / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction / Q000009:adverse effects / Q000379:methods*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000601:surgery*; D005500:Follow-Up Studies; D006801:Humans; D007593:Joint Instability / Q000209:etiology; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000601:surgery; D065466:Lysholm Knee Score; D008297:Male; D010027:Osteotomy / Q000379:methods*; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Anterior cruciate ligament reconstruction; CT imaging; Drilling technique; Femoral tunnel enlargement