title: Distal locking using an electromagnetic field-guided computer-based real-time system for orthopaedic trauma patients.
abstract: OBJECTIVE
  To compare the efficacy of distal interlocking during intramedullary nailing using a freehand technique versus an electromagnetic field real-time system (EFRTS).
  
  
  METHODS
  A prospective, randomized controlled trial.
  
  
  METHODS
  Level I academic trauma center.
  
  
  METHODS
  Patients older than 18 years who sustained a femoral or tibial shaft fracture amenable to antegrade intramedullary nailing were prospectively enrolled between August 2010 and November 2011. Exclusion criteria included injuries requiring retrograde nailing and open wounds near the location of the distal interlocks (distal third of the femur, knee, or distal tibia).
  
  
  METHODS
  Each patient had 2 distal interlocking screws placed: one using the freehand method and the other using EFRTS.
  
  
  METHODS
  Techniques were compared on procedural time and number of interlocking screw misses. Two time points were measured: time 1 (time to find perfect circles/time from wand placement to drill initiation) and time 2 (drill initiation until completion of interlocking placement).
  
  
  RESULTS
  Twenty-four tibia and 24 femur fractures were studied. EFRTS proved faster at times 1 and 2 (P < 0.0001 and P < 0.0002) and total time (P < 0.0001). This difference was larger for junior residents, though reached statistical significance for senior residents. Senior residents were faster with the freehand technique compared with junior residents (P < 0.004), but the 2 were similar using EFRTS (P = 0.41). The number of misses was higher with free hand compared with EFRTS (P = 0.02).
  
  
  CONCLUSIONS
  These results suggest that EFRTS is faster than the traditional freehand technique and results in fewer screw misses.
  
  
  METHODS
  Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.
authors: Department of Orthopaedic Surgery, Wake Forest Baptist Medical Center, Winston-Salem, NC 27157, USA.
authors: Maxwell K
authors: MK
authors: Langfitt
authors: Jason J
authors: JJ
authors: Halvorson
authors: Aaron T
authors: AT
authors: Scott
authors: Beth P
authors: BP
authors: Smith
authors: Gregory B
authors: GB
authors: Russell
authors: Riyaz H
authors: RH
authors: Jinnah
authors: Anna N
authors: AN
authors: Miller
authors: Eben A
authors: EA
authors: Carroll
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003199:Computer Systems; D004574:Electromagnetic Fields; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005264:Femoral Fractures / Q000175:diagnosis* / Q000601:surgery*; D005594:Fracture Fixation, Intramedullary / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D008875:Middle Aged; D061646:Operative Time; D011446:Prospective Studies; D025321:Surgery, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D013978:Tibial Fractures / Q000175:diagnosis* / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult