B. Könemann

A mechanical distal aiming device for distal locking in femoral nails.

Although the free hand technique remains the most popular method for distal interlocking screw insertion, proximally mounted radiation independent devices that compensate for implant deformation recently have been developed for the femur. However, the benefits of such systems have not been determined. This study prospectively compared the duration of the nailing procedure, the length of radiation time, and the accuracy of interlocking screw placement when using a radiation independent distal aiming system with those using the free hand technique. In 20 paired intact anatomic specimen femurs, one surgeon experienced only in the free hand technique performed statically locked intramedullary nailing using the two methods. For the aiming system and free hand technique, respectively, the total operation time was 19.1 +/- 8.4 minutes versus 20.9 +/- 11.3 minutes, the distal locking time was 6.6 +/- 2.4 minutes versus 4.8 +/- 1.5 minutes, the total fluoroscopy time was 23 +/- 17 seconds versus 69 +/- 34 seconds, and the distal locking fluoroscopy time was 0 versus 37 +/- 15.5 seconds. There were no failures in either group. Drill nail contact and distal screw damage were greater with the free hand technique. This study suggests that the main advantages of the aiming arm compared with the free hand technique include the elimination of radiation during distal interlocking and more precise screw placement with decreased insertion related hardware damage.

Experimental Study of distal interlocking of a solid Tibial nail : Radiation-independent distal aiming device (DAD) versus freehand technique (FHT)

OBJECTIVES Recently, radiation-independent aiming devices for the tibia that compensate for insertion-related implant deformation have been developed, but the benefits of such systems have not been determined. This study prospectively evaluated the duration of the nailing procedure, the length of radiation time, and the accuracy of interlocking screw placement when using a radiation-independent distal aiming device (DAD) versus the freehand technique (FHT). MATERIALS AND METHODS In an oblique cadaveric tibial fracture, a surgeon inexperienced in both techniques (DAD and FHT) performed statically locked intramedullary nailing. RESULTS For the DAD and the FHT, respectively, the total operation time was 25.4 +/- 11.3 (mean +/- standard deviation) versus 30.9 +/- 14.3 minutes (p = 0.029), the distal locking time was 16.7 +/- 8.6 versus 21.9 +/- 10.5 minutes (p = 0.004), the total fluoroscopy time was 9 +/- 5 versus 93 +/- 34 seconds (p < 0.0001), the distal locking fluoroscopy time was zero versus 88 +/- 33 seconds (p < 0.0001), and the screw wear was -0.7 +/- 5.2 versus 26.8 +/- 31.6 micrometers (p = 0.001). The failure rate was 1.6 percent (one of sixty screws) in both groups. CONCLUSION These results suggest that the DAD can eliminate the need for radiation during placement of distal interlocking screws.

A new technique for the distal locking of solid AO unreamed tibial nails

Proximally mounted distal aiming systems have failed primarily because of nail deformation during insertion. A mechanical aiming device for the insertion of distal locking screws for solid unreamed AO tibial nails was developed and was tested in twenty unreamed solid tibial nailing procedures in a video-documented prospective clinical study. The rate of accurate screw placement, time expended, complications, and outcome for each patient were recorded. Distal locking was performed successfully in all cases without image intensification. Although a high percentage (55%) of fractures were open, the total mean operative time was 108 minutes (range, 60 to 180 minutes) and the mean time for distal locking (three screws) was 15.5 minutes (range, 8.0 to 39.0 minutes). Notable drill-nail contact occurred in 15 percent of the distal screws placed, demonstrating accurate aiming and drilling. There were no major intra- or postoperative complications related to the distal aiming system.

Vergleich eines durchleuchtungsfreien mechanischen Zielsystems und einer Freihandtechnik fur die Plazierung von distalen Verriegelungsschrauben von Tibianageln

Summary. Recently, radiation-independent aiming devices for the tibia which compensate for insertion-related implant deformation have been developed, but the benefits of such systems have not been determined. This study prospectively evaluated the duration of the nailing procedure, the length of radiation time, and the accuracy of interlocking screw placement with a radiation-independent distal aiming system and the free-hand technique. In an oblique cadaveric tibial fracture, a surgeon inexperienced with either technique performed a statically locked intramedullary nailing. For the aiming system and free-hand technique respectively, the total operation time was 25.4 ± 11.3 vs 30.9 ± 14.3 min (P = 0.029), the distal locking time was 16.7 ± 8.6 vs 21.9 ± 10.5 min (P = 0.004), the total fluoroscopy time was 9 ± 5 vs 93 ± 34 s (P < 0.0001), the distal locking fluorscopy time was 0 versus 88 ± 33 s (P < 0.0001), and the screw destruction was −0.7 ± 5.2 vs 26.8 ± 31.6 μm (P = 0.001). The failure rate was 1.6 % (1 of 60 screws) in both groups. These results suggest that aiming devices can eliminate the need for radiation during distal interlocking screw placement.Zusammenfassung. Seit kurzem stehen röntgendurchleuchtungsunabhängige, mechanische Zielsysteme für die distale Verriegelung von ungeschlitzten Tibiamarknägeln zur Verfügung, die die insertionsbedingte Nageldeformation kompensieren. Vergleichende Untersuchungen über Vor- und Nachteile dieser Systeme sind bisher noch nicht durchgeführt worden. Die vorliegende Studie untersuchte Operationsdauer, Länge der Durchleuchtungszeit und Präzision der Schraubenplazierung mit einem strahlenunabhängigen, mechanischen Zielsystem und einer Freihandtechnik (strahlentransparentes Winkelgetriebe). Von einem mit beiden Techniken unerfahrenen Chirurgen wurden am Frakturmodell der Tibia (Schrägosteotomie) an humanen Ganzkörperpräparaten im Rechts-Links-Vergleich Unterschenkelmarknagelungen mit statischer Verriegelung durchgeführt. Für das distale Zielgerät bzw. für die Freihandtechnik betrug die Gesamtoperationszeit 25,4 ± 11,3 vs. 30,9 ± 14,3 min (p = 0,029), die distale Verriegelungszeit 16,7 ± 8,6 vs. 21,9 ± 10,5 min (p = 0,004), die gesamte Durchleuchtungszeit 9 ± 5 vs. 93 ± 34 s (p < 0,0001), die Durchleuchtungszeit für die distale Verriegelung 0 vs. 88 ± 33 s (p < 0,0001), und die Bolzendestruktion −0,7 ± 5,2 vs. 26,8 ± 31,6 μm (p = 0,001). Die Versagerquote betrug in beiden Gruppen je 1,6 % (1 von 60 Schrauben). Beide Techniken können von einem unerfahrenen Chirurgen gleich schnell erlernt werden. Der Hauptvorteil des röntgenstrahlenfreien, mechanischen distalen Zielgerätes ist die Vermeidung von Röntgenstrahlen während der distalen Verriegelung und die präzisere Schraubenplazierung mit einer geringeren insertionsbedingten Implantatbeschädigung.

Stabilisierung einer distalen Femurfraktur mit dem „Less Invasive Stabilization System“ (LISS) / Treatment of a Distal Femur Fracture Using the Less Invasive Stabilization System (LISS)

Bei dem im Video gezeigten Fall handelt es sich um einen 49jahrigen Patienten mit einer suprakondylaren Femurfraktur rechts, sowie Tibiakopffrakturen beidseits. Alle Frakturen wurden sekundar mit dem LISS (Less Invasive Stabilization System) versorgt. Dieses Video zeigt die Versorgung der distalen Femurfraktur inklusive Zugangsweg, Reposition, Implantateinbringung und Plazierung. Im besonderen wird auf die technischen Einzelheiten, die speziell fur das LISS beachtet werden mussen, eingegangen. Abschliesend wird auf die Weichteilsituation nach bereits erfolgter Implantatentfernung eingegangen und das Ergebnis der Versorgung dargestellt. Die Frakturbehandlung mit dem LISS zeigt in diesem Fall ein sehr gutes funktionelles und kosmetisches Ergebnis.