title: Prevention of inaccurate targeting of proximal screws during reconstruction femoral nailing.
abstract: OBJECTIVE
  The purpose of this study was to identify the underlying cause by simulating the forces involved in a controlled laboratory setting, and then to illustrate some intraoperative tips on how to detect this malalignment and suggest solutions prevent this intraoperative complication.
  
  
  METHODS
  The Expert Asian Femoral Nail (A2FN) and Proximal Femoral Nail Antirotation (PFNA) reconstruction nail systems were evaluated to compare the characteristics of each nailing system and their reactions to soft tissue tension at the time of proximal reconstruction screw placement. Soft tissue tension was simulated by placing a fulcrum under the distal drill sleeve and exerting a load on the targeting device via the addition of weights. The occurrence and degree of guide malalignment were determined while gradually increasing the weight.
  
  
  RESULTS
  When soft tissue tension was simulated on the drill/guide sleeve of the A2FN, the drill sleeve deviated from the proximal screw hole proportionally to the weight applied and the K-wire guide passed outside of the nail at a weight of 7 kg. However, the drill sleeve of the PFNA was aligned exactly to the center of nail axis and the K-wire passed cleanly through the proximal locking hole regardless of weight applied.
  
  
  CONCLUSIONS
  Inaccurate guidance of the screw-targeting device can be caused by soft tissue tension. Thus, the authors recommend that careful attention be placed on minimizing soft tissue tension during proximal screw placement while using the targeting device of the A2FN system.
authors.affiliation: Department of Orthopaedic Surgery, Haeundae Paik Hospital, Inje University, College of Medicine, 1435, Jwa-dong, Haeundae-gu, Busan, 612-862, Republic of Korea.
authors.forename: Ji Wan
authors.initials: JW
authors.lastname: Kim
authors.affiliation: Department of Orthopaedic Surgery, Saint Louis University School of Medicine, 3635 Vista at Grand Blvd., St. Louis, MO, 63104, USA.
authors.forename: Derly O
authors.initials: DO
authors.lastname: Cuellar
authors.affiliation: Department of Orthopaedics, Denver Health Medical Center, University of Colorado, School of Medicine, 777 Bannock Street, Denver, CO, 80204, USA.
authors.forename: Jiandong
authors.initials: J
authors.lastname: Hao
authors.affiliation: Department of Orthopaedics, Denver Health Medical Center, University of Colorado, School of Medicine, 777 Bannock Street, Denver, CO, 80204, USA.
authors.forename: Benoit
authors.initials: B
authors.lastname: Herbert
authors.affiliation: Department of Orthopaedics, Denver Health Medical Center, University of Colorado, School of Medicine, 777 Bannock Street, Denver, CO, 80204, USA. Cyril.mauffrey@dhha.org.
authors.forename: Cyril
authors.initials: C
authors.lastname: Mauffrey
mesh_terms: D000063:Accidents, Traffic; D017760:Bone Malalignment / Q000601:surgery; D001863:Bone Screws; D005260:Female; D005593:Fracture Fixation, Internal / Q000295:instrumentation; D006620:Hip Fractures / Q000601:surgery*; D006801:Humans; D019300:Medical Errors / Q000517:prevention & control; D008875:Middle Aged; D008962:Models, Theoretical; D011183:Postoperative Complications / Q000209:etiology; D011474:Prosthesis Design
keywords: Complication; Femur; Reconstruction nail; Subtrochanteric fracture; Targeting device