title: Are distal femoral traction pins intra-articular? A cadaveric study.
abstract: OBJECTIVE
  To examine the frequency of intra-articular placement of distal femoral traction pins and their proximity to the superficial femoral artery (SFA).
  
  
  METHODS
  Wires were placed in the distal femurs of 28 cadaveric knees at the adductor tubercle (ADT), the superior pole of the patella (SPP), and 2 cm proximal to SPP (SPP+2). A lateral fluoroscopic image was obtained after injection of radiopaque contrast to assess for joint penetration. Dissection was performed to confirm or refute fluoroscopic findings. The distance from each wire to the SFA was measured.
  
  
  RESULTS
  The percentage of intra-articular placement was higher (29%) at the ADT than the SPP+2 (0%) level. The mean (SD) distances from the ADT, SPP, and SPP+2 to the SFA were 7.4 (±1.8) cm, 5.7 (±1.7) cm, and 3.8 (±1.7) cm, respectively (P < 0.0001). None of the wires penetrated the femoral artery. The proportion of wires judged to be intra-articular was not statistically different whether judged by fluoroscopy or anatomic dissection (exact P = 1.0).
  
  
  CONCLUSIONS
  Wires placed at the level of the ADT are at risk for capsular penetration. Risk of major vascular injury with transmedullary placement at all levels seems to be minimal. The optimum position for distal femoral pins remains unknown, but aiming >0.7 cm proximal to the ADT may lower the risk of intra-articular placement. No difference was detected between fluoroscopic arthrography and gross dissection.
authors.affiliation: *Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA; Departments of †Oral and Maxillofacial Surgery, ‡School of Medicine; and §Orthopaedics and Rehabilitation, Oregon Health & Science University, Portland, OR.
authors.forename: Matthew
authors.initials: M
authors.lastname: McElvany
authors.forename: Brion
authors.initials: B
authors.lastname: Benninger
authors.forename: Sawyer
authors.initials: S
authors.lastname: Smith
authors.forename: Amer
authors.initials: A
authors.lastname: Mirza
authors.forename: Lynn
authors.initials: L
authors.lastname: Marshall
authors.forename: Darin
authors.initials: D
authors.lastname: Friess
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001858:Bone Nails; D002102:Cadaver; D004210:Dissection; D005260:Female; D005263:Femoral Artery / Q000000981:diagnostic imaging / Q000293:injuries; D005264:Femoral Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D005471:Fluoroscopy; D006801:Humans; D008297:Male; D008875:Middle Aged; D014143:Traction / Q000295:instrumentation*