title: Does modern nail geometry affect positioning in the distal femur of elderly patients with hip fractures? A comparison of otherwise identical intramedullary nails with a 200 versus 150 cm radius of curvature.
abstract: OBJECTIVE
  To compare implant positioning in the distal femur between 2 cohorts of elderly patients treated for a hip fracture with a long 200- or 150-cm radius of curvature (ROC) cephalomedullary nail. We theorized that the 150-cm ROC nails would more closely approximate the femoral bow and result in fewer implant-related complications.
  
  
  METHODS
  Retrospective Comparative Study.
  
  
  METHODS
  Single Level II Trauma Center.
  
  
  METHODS
  Fifty-eight geriatric patients with a hip fracture (26 in 200-cm nail cohort and 32 in 150-cm nail cohort).
  
  
  METHODS
  Long cephalomedullary nailing using single hip fracture nail and instrumentation system (InterTAN) before and after transition from a 200- to 150-cm ROC long hip nail.
  
  
  METHODS
  Anteroposterior position of distal nail tip on intraoperative lateral radiograph (where 0.50 indicates midaxial, perfectly central placement) and implant-related complications (anterior cortical abutment, perforation, or fracture).
  
  
  RESULTS
  The average position of nails with a 150-cm ROC was closer to the midaxial line of the distal femur compared with 200-cm nails (0.63 vs. 0.55, P = 0.02). Only 1 of 26 (3.8%) 200-cm ROC nails was placed at the midaxial line and none were posterior, whereas 9 of 32 (28%) 150-cm ROC nails were positioned at or posterior to this line (P = 0.006). Only 1 nail with a 150-cm ROC abutted the distal femur's anterior cortex compared with 3 in the 200-cm cohort-including one that caused a fracture.
  
  
  CONCLUSIONS
  Femoral nails with a 150-cm ROC more closely approximate the femoral bow of geriatric hip fracture patients than 200-cm ROC nails, appearing less likely to cause complications such as anterior cortical abutment, perforation, or fracture.
  
  
  METHODS
  Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
authors.affiliation: Harris Methodist Fort Worth Hospital and John Peter Smith Orthopaedic Surgery Residency Program, Fort Worth, TX 76104, USA. ccollinge@msn.com
authors.forename: Cory A
authors.initials: CA
authors.lastname: Collinge
authors.forename: C P T Michael J
authors.initials: CP
authors.lastname: Beltran
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019544:Equipment Failure Analysis; D005260:Female; D005594:Fracture Fixation, Intramedullary / Q000009:adverse effects* / Q000295:instrumentation* / Q000379:methods; D006620:Hip Fractures / Q000150:complications / Q000000981:diagnostic imaging* / Q000601:surgery*; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging* / Q000209:etiology*; D007719:Knee Joint / Q000000981:diagnostic imaging*; D008297:Male; D011474:Prosthesis Design; D011859:Radiography; D012189:Retrospective Studies; D016896:Treatment Outcome