title: Fixation of calcaneal avulsion fractures using screws with and without suture anchors: a biomechanical investigation.
abstract: BACKGROUND
  Lag screw fixation commonly is used to treat avulsion fractures of the posterior calcaneal tuberosity, but this method may not offer reliable fixation. This study compared the strength to failure of lag screws compared to lag screw fixation augmented with suture anchors in these fractures.
  
  
  METHODS
  The calcanei and Achilles tendons of 12 fresh lower extremity cadaver matched pairs were dissected and removed. An oblique osteotomy was created in the calcaneus, and two 4.0-mm lag screws were placed nearly perpendicular to the plane of the fracture in the dorsal aspect of the calcaneus with 30 degrees of divergence between them. In the contralateral specimen, the same procedure was done, but with two suture anchors placed 1.5 to 2 mm distal to the osteotomy. A zigzag suture technique through the Achilles tendon was used. The specimens were mounted and placed in a load frame for monotonic loading to failure. A paired Student t-test and a Pearson correlation were used to analyze the data (p <or= 0.05).
  
  
  RESULTS
  The specimens treated with lag screws alone failed at 251.3 (range 66 to 459) N whereas specimens repaired with lag screws and suture anchors failed at 441.6 (range 274 to 661; p = 0.01 N).
  
  
  CONCLUSIONS
  Suture anchor augmentation significantly improved the strength of screw fixation of the calcaneal posterior tuberosity avulsion fractures.
  
  
  CONCLUSIONS
  The use of suture anchor augmentation as described may improve the reliability of fixation in avulsion fractures of the posterior calcaneal tuberosity.
authors.affiliation: Department of Orthopaedics, Union Memorial Hospital, Baltimore, MD 21218, USA.
authors.forename: Gabriel E
authors.initials: GE
authors.lastname: Khazen
authors.forename: Adam N
authors.initials: AN
authors.lastname: Wilson
authors.forename: Sarmad
authors.initials: S
authors.lastname: Ashfaq
authors.forename: Brent G
authors.initials: BG
authors.lastname: Parks
authors.forename: Lew C
authors.initials: LC
authors.lastname: Schon
mesh_terms: D015519:Bone Density; D001863:Bone Screws; D002102:Cadaver; D002111:Calcaneus / Q000293:injuries / Q000601:surgery*; D019544:Equipment Failure Analysis; D005593:Fracture Fixation, Internal / Q000295:instrumentation / Q000379:methods*; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans; D008422:Materials Testing; D010027:Osteotomy; D011897:Random Allocation; D013314:Stress, Mechanical; D053441:Suture Anchors; D013536:Suture Techniques