title: Tibial tunnel widening after hamstring anterior cruciate ligament reconstructions: comparison between Rigidfix and Bio-TransFix.
abstract: BACKGROUND
  There is no study comparing tibial tunnel widening after hamstring anterior cruciate ligament (ACL) reconstructions between RigidFix(r) and Bio-TransFix(r).
  
  
  METHODS
  Hamstring ACL reconstructions using RigidFix(r) in 56 patients and Bio-TransFix(r) in 41 with a minimum of 2years postoperative evaluation were reviewed. Tibial fixation was performed using Intrafix in both groups. On the anterior-posterior (AP) and lateral radiographs, the diameter of the tibial tunnel was measured at proximal, middle, and distal positions. Postoperative laxity evaluations were performed using Lachman test, pivot-shift test, and instrumented laxity testing using the KT-1000 arthrometer.
  
  
  RESULTS
  On the AP and lateral radiographs, the average diameter of the tibial tunnel in the Bio-TransFix(r) group significantly increased after 6months compared to the immediate postoperative measurement (p=0.002 and p=0.002, respectively). However, the average diameter of the tibial tunnel in the RigidFix(r) group did not increase after 6months compared to the immediate postoperative measurement. Tunnel widening at 12months postoperatively in the Bio-TransFix(r) group was significantly more than that of the RigidFix(r) group on AP and lateral radiographs (p=0.012 and 0.016, respectively). Tunnel widening at 24months postoperatively showed a significant difference between the two groups (p=0.000 and 0.000, respectively). Fifteen patients (36.6%) in the Bio-TransFix(r) group and 15 patients (26.8%) in the RigidFix(r) group showed tunnel widening. There were no significant differences in results of the Lachman and pivot-shift tests, and mean KT-1000 measurement between the two groups.
  
  
  CONCLUSIONS
  The Bio-TransFix(r) group showed progressive tibial tunnel widening after 6months postoperatively but no clinical signs of instability.
  
  
  METHODS
  Level III.
authors: Department of Orthopaedic Surgery, Eulji Medical Center, 280-1, Hagye-1-dong, Nowon-gu, Seoul, 139-231, Republic of Korea. cnh2406@yahoo.com
authors: Nam-Hong
authors: NH
authors: Choi
authors: Soon-Young
authors: SY
authors: Yoo
authors: Brian N
authors: BN
authors: Victoroff
mesh_terms: D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000295:instrumentation*; D001863:Bone Screws; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000601:surgery*; D011184:Postoperative Period; D011474:Prosthesis Design; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D013977:Tibia / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult