title: Migration of EndoButton after anatomic double-bundle anterior cruciate ligament reconstruction.
abstract: OBJECTIVE
  The purpose of this study was to (1) assess the migration of EndoButtons (Smith & Nephew Endoscopy, Andover, MA) with or without tissue interposition by comparing the radiographs obtained immediately after anterior cruciate ligament (ACL) reconstruction and those obtained during the follow-up period and (2) investigate the effect of tissue interposition or migration of EndoButtons on the clinical outcomes.
  
  
  METHODS
  One hundred one patients underwent anatomic double-bundle ACL reconstruction with EndoButtons for femoral fixation. Anteroposterior and lateral radiographs were taken immediately postoperatively and at 1 week, 1 month, 3 months, and 1 year. The distance between the EndoButton and lateral femoral cortex was measured on the radiograph obtained immediately postoperatively, and more than 1 mm in distance was defined as positive tissue interposition. Moreover, the locations of the EndoButtons on the radiographs obtained at each follow-up visit were compared with those obtained immediately postoperatively, and EndoButton migration was considered to be present when the EndoButton had moved more than 1 mm or had rotated by more than 5°. The relations between clinical outcomes at 1 year and tissue interposition or migration of EndoButtons were also evaluated.
  
  
  RESULTS
  Tissue interposition was found for 51 EndoButtons and migration was observed for 71 EndoButtons, and there was a significant difference in the incidence of migration between anteromedial and posterolateral grafts. Of the 51 EndoButtons with tissue interposition, 32 migrated within 1 year, and 39 of 151 EndoButtons without tissue interposition migrated, whereas the EndoButtons with tissue interposition migrated significantly more frequently. On the other hand, there were no significant differences in clinical outcomes between the cases with or without tissue interposition and between the cases with or without EndoButton migration.
  
  
  CONCLUSIONS
  Tissue interposition between the EndoButton and femoral lateral cortex was found in 51 EndoButtons (25.2%) on the radiographs obtained immediately after ACL reconstruction, whereas EndoButtons with tissue interposition migrated more frequently than those without it 1 year after ACL reconstruction. However, neither tissue interposition nor migration of the EndoButton affected the clinical outcomes.
  
  
  METHODS
  Level IV, prognostic case series.
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan. ta-mae@umin.ac.jp
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Mae
authors.forename: Sanae
authors.initials: S
authors.lastname: Kuroda
authors.forename: Norinao
authors.initials: N
authors.lastname: Matsumoto
authors.forename: Minoru
authors.initials: M
authors.lastname: Yoneda
authors.forename: Ken
authors.initials: K
authors.lastname: Nakata
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshikawa
authors.forename: Konsei
authors.initials: K
authors.lastname: Shino
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016118:Anterior Cruciate Ligament / Q000000981:diagnostic imaging / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000295:instrumentation* / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D005548:Foreign-Body Migration / Q000000981:diagnostic imaging*; D006801:Humans; D016268:Internal Fixators; D007718:Knee Injuries / Q000601:surgery; D008297:Male; D008592:Menisci, Tibial / Q000601:surgery; D008875:Middle Aged; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D011475:Prosthesis Failure; D011859:Radiography; D012421:Rupture / Q000601:surgery; D000070600:Tibial Meniscus Injuries; D016896:Treatment Outcome; D055815:Young Adult