title: The natural history of a bioabsorbable interference screw used for anterior cruciate ligament reconstruction with a 4-strand hamstring technique.
abstract: OBJECTIVE
  The purpose of this study was to assess radiologically the rate of absorption of the Arthrex poly L-lactide bioabsorbable interference screw (Arthrex, Naples, FL) used in anterior cruciate ligament reconstruction with a 4-strand hamstring technique.
  
  
  METHODS
  Case series.
  
  
  METHODS
  Eight sequential patients undergoing anterior cruciate ligament reconstruction with a 4-strand hamstring technique were assessed with magnetic resonance imaging (MRI) scans at 1, 2, and 4 years postoperatively.
  
  
  RESULTS
  There was no radiologic evidence of absorption of the screw on any of the scans. The MRI appearance remained essentially unchanged from 1 to 4 years with the exception of the presence of a small cyst in the tibial tunnel of one of the patients. No edema was seen associated with the tibial tunnel in any of our patients.
  
  
  CONCLUSIONS
  There are several quoted theoretical advantages to using bioabsorbable screws. The rate of absorption is dependent on material, weight, and degree of crystallization. In our series using an amorphous low crystallization poly L-lactide screw, there was no evidence of any progression to absorption 4 years after implantation. This may be because all series quoted to date look at absorption using a bone-patellar tendon-bone graft.
  
  
  METHODS
  Level IV.
authors.affiliation: North Sydney Orthopaedic Sports Medicine Centre, Sydney, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Radford
authors.forename: Jennie
authors.initials: J
authors.lastname: Noakes
authors.forename: John
authors.initials: J
authors.lastname: Read
authors.forename: David G
authors.initials: DG
authors.lastname: Wood
mesh_terms: D020341:Absorbable Implants; D016118:Anterior Cruciate Ligament / Q000473:pathology / Q000601:surgery*; D001863:Bone Screws; D016025:Bone Transplantation; D005500:Follow-Up Studies; D045888:Ganglion Cysts / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D010329:Patella / Q000601:surgery; D011091:Polyesters; D019651:Plastic Surgery Procedures / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013710:Tendons / Q000601:surgery; D013997:Time Factors
chemical_list: D011091:Polyesters; C033616:poly(lactide)