title: Tunnel Enlargement and Coalition After Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction With Hamstring Tendon Autografts: A Computed Tomography Study.
abstract: BACKGROUND
  Tunnel enlargement and coalition following double-bundle anterior cruciate ligament (ACL) reconstruction with hamstring tendon autografts has not yet been sufficiently studied.
  
  
  OBJECTIVE
  The incidence and the degree of femoral tunnel enlargement will be significantly greater than those for tibial tunnel enlargement after anatomic double-bundle ACL reconstruction using hamstring tendon autografts. There will be no significant correlation between tunnel enlargement and coalition and the postoperative knee laxity.
  
  
  METHODS
  Case series; Level of evidence, 4.
  
  
  METHODS
  Thirty-nine patients who underwent anatomic double-bundle ACL reconstruction using semitendinosus and gracilis tendon autografts were followed up for 1 year after surgery. The grafts were simultaneously fixed at 10° of knee flexion with EndoButtons and spiked staples. All patients were examined with computed tomography and the standard clinical evaluation methods at 2 weeks and 1 year after surgery.
  
  
  RESULTS
  The degree of tunnel enlargement of the femoral anteromedial and posterolateral tunnels averaged 10% to 11% and 7% to 9%, respectively, while that of the tibial anteromedial and posterolateral tunnels averaged 3% to 7% and 1% to 6%. The degree and incidence of the anteromedial and posterolateral tunnel enlargement were significantly greater in the femur than in the tibia (P < .0335 and P < .0405, respectively). On the femoral and tibial intra-articular surface, tunnel outlet coalition was found in 5% and 77% of the knees, respectively, at 1 year after surgery. There was no significant correlation between tunnel enlargement and coalition and the clinical outcome.
  
  
  CONCLUSIONS
  The incidence and the degree of each tunnel enlargement in the femur were significantly greater than that in the tibia. However, the incidence of tunnel coalition in the femur was significantly less than that in the tibia after double-bundle ACL reconstruction with a transtibial technique. There was no significant correlation between tunnel enlargement and coalition and the clinical outcome.
  
  
  CONCLUSIONS
  The present study provides orthopaedic surgeons with important information on double-bundle ACL reconstruction with hamstring tendons.
authors.affiliation: Department of Sports Medicine and Joint Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kawaguchi
authors.affiliation: Department of Sports Medicine and Joint Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Kondo
authors.affiliation: Department of Sports Medicine and Joint Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Onodera
authors.affiliation: Department of Sports Medicine and Joint Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan.
authors.forename: Nobuto
authors.initials: N
authors.lastname: Kitamura
authors.affiliation: Department of Radiology, Hokkaido University Hospital, Sapporo, Hokkaido, Japan.
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Sasaki
authors.affiliation: Department of Orthopaedic Surgery, Yamanote-dori Yagi Hospital, Sapporo, Hokkaido, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Yagi
authors.affiliation: Department of Sports Medicine and Joint Surgery, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Yasuda
keywords: anterior cruciate ligament; clinical outcome; coalition; double-bundle reconstruction; hamstring tendon; tunnel enlargement