title: 130- versus 135-degree sliding hip screws and failure in pertrochanteric hip fractures.
abstract: BACKGROUND
  The fixed-angle sliding hip screw has become a popular method of fixation for pertrochanteric hip fractures. The tip-to-apex distance (TAD) concept was introduced by Baumgaertner et al. in 1995 and has subsequently become a decisive predictor of the successfulness of fixation. The 135-degree plate has become the most popular plate used for fracture fixation, although this has not been compared with lower angled plates (130 degree) in relation to TAD.
  
  
  METHODS
  We analysed 567 consecutive cases of dynamic hip screw (DePuy-Synthes) fixation to compare TAD in various angled plates and rate of failure.
  
  
  RESULTS
  The 130-degree plate has significantly lower mean TAD 19.3 mm versus 20.8 mm (P = 0.016). There were nine failures because of superior screw cut-out in the 135-degree plates and 0 failures in the 130-degree plates.
  
  
  CONCLUSIONS
  We believe the improved trajectory for lag screw placement using 130-degree angled plates leads to a lower TAD and improved fixation in pertrochanteric fractures.
authors.affiliation: Orthopaedics, Royal Perth Hospital, Perth, Western Australia, Australia.
authors.forename: Ross
authors.initials: R
authors.lastname: Radic
authors.forename: Piers J
authors.initials: PJ
authors.lastname: Yates
authors.forename: Tao Shan
authors.initials: TS
authors.lastname: Lim
authors.forename: Sally
authors.initials: S
authors.lastname: Burrows
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001860:Bone Plates; D001863:Bone Screws; D019544:Equipment Failure Analysis; D005260:Female; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods; D006620:Hip Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011475:Prosthesis Failure; D011859:Radiography
keywords: dynamic hip screw; hip fracture; sliding hip screw; tip-to-apex distance