A new mechanical aiming device for the placement of distal interlocking screws in femoral nails

Abstract Although the free-hand technique remains the most popular method for distal interlocking screw insertion, a proximally mounted “radiation-independent” device which compensates for implant deformation has been developed. In 15 intact human cadaveric femora the same surgeon performed statically locked intramedullary nailing using the distal aiming system. Operation time, distal screw insertion, total radiation time and accuracy of the interlocking screw placement were measured using a radiation-independent distal aiming system. The average total operation time was 21.2 ± 8.6 min, and the average distal locking time (2 screws) was 7.1 ± 2.4 min. The total operation time and the distal locking time declined over the first 10 cases. These times did not significantly improve in the subsequent 5 procedures. The average total fluoroscopy time was 28.1 ± 16.6 s. None of the screw placements using the distal aiming device required the use of fluoroscopy. Drill-nail contact was absent in 5 drillings, mild in 9 drillings, moderate in 16 drillings, and severe in none. Measurement of screw damage showed in 55 of 60 measurements wear of less than 15 μm. There were no failures or major complications. A minor complication related to distal locking was observed in one specimen. This study suggests that distal interlocking screws can be placed successfully using a radiation-independent aiming arm-based system, which accounts for nail deformations. The distal aiming device (DAD) can be learned easily. The main advantages of the aiming arm include the elimination of radiation during distal interlocking and precise screw placement with little insertion-related hardware damage.

[1]  E J van der Merwe,et al.  Exposure of surgeons-in-training to radiation during intramedullary fixation of femoral shaft fractures. , 1992, South African medical journal = Suid-Afrikaanse tydskrif vir geneeskunde.

[2]  R. Gross,et al.  A simplified technique of distal femoral screw insertion for the Grosse-Kempf interlocking nail. , 1988, Clinical orthopaedics and related research.

[3]  S. Kelley,et al.  A Simple Technique for Insertion of Distal Screws into Interlocking Nails , 1995, Journal of orthopaedic trauma.

[4]  J. Dosch,et al.  Strahlungsmessungen bei Verriegelungsnagelungen , 1983 .

[5]  J. Benevenia,et al.  Distal screw targeting of interlocking nails. , 1989, Clinical Orthopaedics and Related Research.

[6]  M. Davis,et al.  Radiation exposure and associated risks to operating-room personnel during use of fluoroscopic guidance for selected orthopaedic surgical procedures. , 1983, The Journal of bone and joint surgery. American volume.

[7]  N. Goddard,et al.  A simple jig to ease the insertion of distal screws in intramedullary locking nails. , 1994, Injury.

[8]  S Stenzler,et al.  Exposure of the orthopaedic surgeon to radiation. , 1993, The Journal of bone and joint surgery. American volume.

[9]  Method for removal of the fractured stem in total hip replacement. , 1990 .

[10]  B. Browner,et al.  Radiation exposure to the surgeon during closed interlocking intramedullary nailing. , 1987, The Journal of bone and joint surgery. American volume.

[11]  A Grosse,et al.  Closed locked intramedullary nailing. Its application to comminuted fractures of the femur. , 1985, The Journal of bone and joint surgery. American volume.

[12]  I. Hudson.  Locking nailing: an aid to distal targetting. , 1989, Injury.

[13]  G. Berentey.  Neues Zielgerät für die distale Verriegelungsnagelung , 1983 .

[14]  C Krettek,et al.  The deformation of small diameter solid tibial nails with unreamed intramedullary insertion. , 1997, Journal of biomechanics.

[15]  K. Herzog.  Verlängerungsosteotomie unter Verwendung des percutan gezielt verriegelten Marknagels , 1951 .

[16]  H. Niederdellmann,et al.  Internal fixation of fractures. , 1978, International journal of oral surgery.

[17]  T. P. Barry.  Radiation Exposure to an Orthopedic Surgeon , 1984, Clinical orthopaedics and related research.

[18]  S A Riley,et al.  Radiation exposure from fluoroscopy during orthopedic surgical procedures. , 1989, Clinical orthopaedics and related research.

[19]  G. Grobler,et al.  Inserting the distal screws in a locked femoral nail. , 1991, The Journal of bone and joint surgery. British volume.

[20]  R. Langenberg.  [Interlocking nailing]. , 1986, Zeitschrift fur arztliche Fortbildung.

[21]  G. Beck,et al.  Die Operationstechnik der Verriegelungsnagelung , 1983 .

[22]  T D Bunker,et al.  Radiation dosage during AO locking femoral nailing. , 1988, Injury.

[23]  C Krettek,et al.  A new technique for the distal locking of solid AO unreamed tibial nails. , 1997, Journal of orthopaedic trauma.

[24]  D. Conlan.  Grosse and Kempf locked intramedullary nailing: an improved distal locking screw drill guide. , 1990, Journal of the Royal College of Surgeons of Edinburgh.