title: Mechanical complications of intertrochanteric hip fractures treated with trochanteric femoral nails.
abstract: BACKGROUND
  The Trochanteric Fixation Nail System (TFN) was designed with a helical blade to improve resistance to cutout. We evaluated the incidence, modes, and predictors of failure for intertrochanteric hip fractures treated with this device.
  
  
  METHODS
  A retrospective review of 341 intertrochanteric hip fractures treated with the TFN was conducted. Fractures were classified from the injury films using the Arbeitsgemeinschaft für Osteosynthesefragen/Orthopedic Trauma Association (AO/OTA) classification, and quality of reduction and hardware placement was evaluated on the initial postoperative films.
  
  
  RESULTS
  Two hundred twenty-three patients met inclusion criteria. The overall rate of mechanical complications was 20.5%. Twenty-one patients (9.4%) had excessive lateral migration of the helical blade (≥10 mm). Fifteen patients (6.7%) had blade migration in the head, including 7 patients (3.1%) with typical cutout and 8 patients (3.6%) with medial perforation without loss of reduction. Three patients (1.3%) sustained a femoral shaft fracture at the tip of the nail. The quality of calcar reduction was significantly predictive of all modes of failure (p < 0.05), except femoral shaft fracture at the nail tip.
  
  
  CONCLUSIONS
  The most common mechanical complication was lateral migration of the helical blade; however, this rarely led to a clinical problem. Medial migration of the blade in the head without loss of reduction was the second most frequent complication. We have identified a new complication associated with the TFN, that is, medial perforation without loss of reduction. Blade migration in the head was less frequent when blades were placed inferiorly with a tip-apex distance of at least 15 mm.
authors.affiliation: Department of Orthopaedics, Shanghai Sixth People's Hospital, Shanghai, China.
authors.forename: Wanjun
authors.initials: W
authors.lastname: Liu
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Zhou
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Weaver
authors.forename: Mark S
authors.initials: MS
authors.lastname: Vrahas
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D001858:Bone Nails / Q000009:adverse effects*; D005260:Female; D005269:Femur / Q000601:surgery; D005593:Fracture Fixation, Internal / Q000009:adverse effects / Q000295:instrumentation; D006620:Hip Fractures / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011475:Prosthesis Failure / Q000209:etiology*; D012086:Reoperation; D012189:Retrospective Studies