Next generation distal locking for intramedullary nails using an electromagnetic X-ray-radiation-free real-time navigation system.
BACKGROUND
Distal locking marks one challenging step during intramedullary nailing that can lead to an increased irradiation and prolonged operation times. The aim of this study was to evaluate the reliability and efficacy of an X-ray-radiation-free real-time navigation system for distal locking procedures.


METHODS
A prospective randomized cadaver study with 50 standard free-hand fluoroscopic-guided and 50 electromagnetic-guided distal locking procedures was performed. All procedures were timed using a stopwatch. Intraoperative fluoroscopy exposure time and absorbed radiation dose (mGy) readings were documented. All tibial nails were locked with two mediolateral and one anteroposterior screw. Successful distal locking was accomplished once correct placement of all three screws was confirmed.


RESULTS
Successful distal locking was achieved in 98 cases. No complications were encountered using the electromagnetic navigation system. Eight complications arose during free-hand fluoroscopic distal locking. Undetected secondary drill slippage on the ipsilateral cortex accounted for most problems followed by undetected intradrilling misdirection causing a fissural fracture of the contralateral cortex while screw insertion in one case. Compared with the free-hand fluoroscopic technique, electromagnetically navigated distal locking provides a median time benefit of 244 seconds without using ionizing radiation.


CONCLUSIONS
Compared with the standard free-hand fluoroscopic technique, the electromagnetic guidance system used in this study showed high reliability and was associated with less complications, took significantly less time, and used no radiation exposure for distal locking procedures.


METHODS
Therapeutic study, level II.
Department of Trauma, University Medical Centre Hamburg-Eppendorf, Hand and Reconstructive Surgery, Martinistrasse, Hamburg, Germany. mi.hoffmann@web.de
Michael
M
Hoffmann
Malte
M
Schröder
Wolfgang
W
Lehmann
Michael
M
Kammal
Johannes Maria
JM
Rueger
Andreas
A
Herrman Ruecker
D001858:Bone Nails; D002102:Cadaver; D004574:Electromagnetic Fields; D005471:Fluoroscopy; D005594:Fracture Fixation, Intramedullary / Q000379:methods*; D006801:Humans