title: Bioabsorbable screw fixation for the treatment of ankle fractures.
abstract: BACKGROUND
  Self-reinforced poly(L/dL)lactide 70:30 (SR-PLA70) retains its strength in bone for 24 weeks, whereas self-reinforced poly-L-lactide (SR-PLLA) retains its strength for over 36 weeks. In this prospective randomized study, bioabsorbable 4.5-mm SR-PLA70 screws were compared with SR-PLLA screws in the treatment of displaced ankle fractures in adults.
  
  
  METHODS
  Sixty-two patients with ankle fractures needing operative treatment were randomized into two groups. Comminuted fractures needing plating were excluded. In total 54 of 62 patients were followed up for 1 year by clinical evaluation, radiographs, and Olerud-Molander score.
  
  
  RESULTS
  The study groups differed significantly only in the mean duration of sick leave (SR-PLA70, 60 days; SR-PLLA, 65 days; P = 0.02). At the 1-year follow-up, syndesmotic ossification was more common in the SR-PLA70 group (5 versus 1 patient, not significant). Radiologically, the screw channel had not disappeared in any of the patients by the 1-year follow-up.
  
  
  CONCLUSIONS
  Both implant types proved to have good biocompatibility. SR-PLA70 and SR-PLLA screws are suitable in selected cases for the fixation of ankle fractures, but the mechanical stability of the fixation has to be carefully monitored perioperatively.
authors.affiliation: Department of Orthopaedics and Traumatology, Kuopio University Hospital, P.O. Box 1777, FIN-70211, Kuopio, Finland.
authors.forename: Antti
authors.initials: A
authors.lastname: Joukainen
authors.forename: Esa K
authors.initials: EK
authors.lastname: Partio
authors.forename: Pekka
authors.initials: P
authors.lastname: Waris
authors.forename: Jaakko
authors.initials: J
authors.lastname: Joukainen
authors.forename: Heikki
authors.initials: H
authors.lastname: Kröger
authors.forename: Pertti
authors.initials: P
authors.lastname: Törmälä
authors.forename: Pentti
authors.initials: P
authors.lastname: Rokkanen
mesh_terms: D020341:Absorbable Implants; D000293:Adolescent; D000328:Adult; D000368:Aged; D016512:Ankle Injuries / Q000000981:diagnostic imaging / Q000601:surgery*; D001863:Bone Screws; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D019344:Lactic Acid / Q000031:analogs & derivatives*; D008297:Male; D008875:Middle Aged; D011091:Polyesters; D011108:Polymers; D011859:Radiography; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D011091:Polyesters; D011108:Polymers; C445939:polylevolactic acid; D019344:Lactic Acid; C033616:poly(lactide)