title: The effect of low intensity ultrasound and bioabsorbable self-reinforced poly-L-lactide screw fixation on bone in lateral malleolar fractures.
abstract: BACKGROUND
  There are no previous reports of low intensity pulsed ultrasound therapy in connection with bioabsorbable fracture fixation. In this randomised, prospective, double-blind and placebo-controlled study, the effects of ultrasound on bone mineral density and bone healing were examined in lateral malleolar fractures fixed with a bioabsorbable self-reinforced poly-L-lactide screw (SR-PLLA).
  
  
  METHODS
  Thirty adult patients with SR-PLLA screw-fixed lateral malleolar fracture underwent ultrasound therapy 20 min daily for 6 weeks. Half of the patients were provided randomly with a sham ultrasound device. Bone mineral density and bone healing were assessed by dual-energy X-ray absorptiometry (DXA) and by radiographs.
  
  
  RESULTS
  Bone mineral density of the fractured lateral malleolus tended to increase slightly during 12 weeks of follow-up. The increase was symmetrical and statistically non-significant between the ultrasound and non-ultrasound group. All the fractures healed uneventfully. The biocompatibility of the bioabsorbable SR-PLLA fixation device and low intensity pulsed ultrasound was good. Despite the slight tendency for more frequent callus formation in the ultrasound group, no statistically significant effect of low intensity pulsed ultrasound on lateral malleolar fracture healing could be observed.
  
  
  CONCLUSIONS
  It was not possible to observe any statistically significant effect of low intensity pulsed ultrasound on lateral malleolar fracture healing in this study. Further studies are needed to examine the role of ultrasound therapy in the healing of fractures treated with bioabsorbable fixation devices.
authors.affiliation: Department of Orthopaedics and Traumatology, Helsinki University Central Hospital, Topeliuksenkatu 5, 00260 Helsinki, Finland. lauri.handolin@hus.fi
authors.forename: Lauri
authors.initials: L
authors.lastname: Handolin
authors.forename: Veikko
authors.initials: V
authors.lastname: Kiljunen
authors.forename: Ilkka
authors.initials: I
authors.lastname: Arnala
authors.forename: Jarkko
authors.initials: J
authors.lastname: Pajarinen
authors.forename: Esa K
authors.initials: EK
authors.lastname: Partio
authors.forename: Pentti
authors.initials: P
authors.lastname: Rokkanen
mesh_terms: D020341:Absorbable Implants; D000328:Adult; D000368:Aged; D016512:Ankle Injuries / Q000000981:diagnostic imaging* / Q000601:surgery*; D015519:Bone Density / Q000502:physiology; D001863:Bone Screws; D004311:Double-Blind Method; D005260:Female; D005360:Fibula / Q000293:injuries; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D017102:Fracture Healing / Q000502:physiology; D050723:Fractures, Bone / Q000000981:diagnostic imaging* / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011091:Polyesters / Q000627:therapeutic use; D011446:Prospective Studies; D016896:Treatment Outcome; D014464:Ultrasonic Therapy; D014463:Ultrasonography
chemical_list: D011091:Polyesters; C033616:poly(lactide)