title: Femoral neck shortening after internal fixation.
abstract: OBJECTIVE
  The aim of this study was to assess the factors affecting femoral neck shortening after internal fixation of femoral neck fractures.
  
  
  METHODS
  Eighty-six patients with femoral neck fractures were treated using three parallel cannulated screws between May 2004 and January 2011. The shortening of the femoral neck in the horizontal (X), vertical (Y), and along the resultant along the (Z) vector (X➝, Y➝, Z➝) was measured on anteroposterior radiographs corrected by screw diameter and analyzed using TraumaCad software. Age, gender, Garden classification, Garden's alignment index, Pauwels angle, Singh index, body mass index and weight-bearing time were also analyzed.
  
  
  RESULTS
  Follow-up duration was 8 to 36 months. Significant femoral neck shortening of the abductor lever arm (greater than 5 mm) was present in 33 of 86 (38.4%) patients. Average Harris score (HSS) was 90.05 ± 7.04 (range: 71 to 100). The 5 predictors for shortening greater than 5 mm in the multivariate logistic regression model were age, Singh index, Pauwels classification, Garden's alignment index and body mass index.
  
  
  CONCLUSIONS
  Femoral neck shortening associated with three parallel cannulated screws for fixation of femoral neck fractures is a common phenomenon. Femoral neck shortening after internal fixation is affected by multiple cofactors.
authors: Department of Orthopedics, Clinical School of The Second Military Medical University / Shanghai Pudong New Area Gongli Hospital, Shanghai, China.
authors: Yue
authors: Y
authors: Liu
authors: Zi Sheng
authors: ZS
authors: Ai
authors: Jin
authors: J
authors: Shao
authors: Tieyi
authors: T
authors: Yang
mesh_terms: D015992:Body Mass Index; D017760:Bone Malalignment / Q000209:etiology / Q000601:surgery*; D001863:Bone Screws; D005260:Female; D005265:Femoral Neck Fractures / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D005500:Follow-Up Studies; D005593:Fracture Fixation, Internal / Q000009:adverse effects* / Q000379:methods; D017102:Fracture Healing; D006801:Humans; D007870:Leg Length Inequality / Q000209:etiology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D016896:Treatment Outcome; D016474:Weight-Bearing