title: Critical factors in cut-out complication after Gamma Nail treatment of proximal femoral fractures.
abstract: BACKGROUND
  The most common mechanical failure in the internal fixation of trochanteric hip fractures is the cut-out of the sliding screw through the femoral head. Several factors that influence this complication have been suggested, but there is no consensus as to the relative importance of each factor. The purpose of this study was to analyse the cut-out complication with respect to the following variables: patients' age, fracture type, fracture reduction, implant positioning and implant design.
  
  
  METHODS
  3066 consecutive patients were treated for trochanteric fractures with Gamma Nails between 1990 and 2002 at the Centre de Traumatologie et de l'Orthopedie (CTO), Strasbourg, France. Cut-out complications were identified by reviewing all available case notes and radiographs. Subsequently, the data were analysed by a single reviewer (AJB) with focus on the studied factors.
  
  
  RESULTS
  Seventy-one cut-out complications were found (2.3%) of the 3066 trochanteric fractures. Cut-out failure associated with avascular head necrosis, pathologic fracture, deep infection or secondary to prior failure of other implants were excluded from the study (14 cases). The remaining 57 cases (1.85%, median age 82.6, 79% females) were believed to have a biomechanical explanation for the cut-out failure. 41 patients had a basicervical or complex fracture type. A majority of cut-outs (43 hips, 75%) had a combination of the critical factors studied; non-anatomical reduction, non-optimal lag screw position and the characteristic fracture pattern found.
  
  
  CONCLUSIONS
  The primary cut-out rate of 1.85% was low compared with the literature. A typical cut-out complication in our study is represented by an unstable fracture involving the trochanteric and cervical regions or the combination of both, non-anatomical reduction and non-optimal screw position. Surgeons confronted with proximal femoral fractures should carefully scrutinize preoperative radiographs to assess the primary fracture geometry and fracture classification. To reduce the risk of a cut-out it is important to achieve both anatomical reduction and optimal lag screw position as these are the only two factors that can be controlled by the surgeon.
authors.affiliation: Department of Orthopaedics, Institute of Clinical Sciences at Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden. alicja.bojan@vgregion.se
authors.forename: Alicja J
authors.initials: AJ
authors.lastname: Bojan
authors.forename: Claudia
authors.initials: C
authors.lastname: Beimel
authors.forename: Gilbert
authors.initials: G
authors.lastname: Taglang
authors.forename: David
authors.initials: D
authors.lastname: Collin
authors.forename: Carl
authors.initials: C
authors.lastname: Ekholm
authors.forename: Anders
authors.initials: A
authors.lastname: Jönsson
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001858:Bone Nails; D001863:Bone Screws; D016009:Chi-Square Distribution; D005260:Female; D005593:Fracture Fixation, Internal / Q000009:adverse effects* / Q000295:instrumentation*; D005602:France; D006620:Hip Fractures / Q000145:classification / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000209:etiology*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome