Robotic distal locking of intramedullary nailing: Technical description and cadaveric testing.

Interlocked intramedullary nailing is the treatment of choice for femoral shaft fractures. However, distal locking is a technically challenging part of the procedure that can result in distal femoral malrotation and high radiation exposure. We have tested a robotic procedure for robotic distal locking based on the computation of a drilling trajectory on two calibrated fluoroscopic images. Twenty distal holes were attempted in ten cadaveric femur specimens. Successful screw hole drilling was achieved at the first attempt in each of the ten specimens (20 drill holes in total). No failures were recorded. The average total number of images needed was 6.5 +/- 3.6. The average computation time was 16.5+/- 16.0 seconds. Robotic distal locking was feasible in this test and can be integrated into a fully robotic intramedullary nailing procedure.

Comparison of helicopter and ground emergency medical service: a retrospective analysis of a German rescue helicopter base.

BACKGROUND: In consideration of rising cost pressure in the German health care system, the usefulness of helicopter emergency medical service (HEMS) in terms of time- and cost-effectiveness is controversially discussed. The aim of the present study was to investigate whether HEMS is associated with significantly decreased arrival and transportation times compared to ground EMS. METHODS: In a retrospective study, we evaluated 1,548 primary emergency missions for time sensitive diagnoses (multiple trauma, traumatic brain and burn injury, heart-attack, stroke, and pediatric emergency) performed by a German HEMS using the medical database, NADIN, of the German Air Rescue Service. Arrival and transportation times were compared to calculated ground EMS times. RESULTS: HEMS showed significantly reduced arrival times at the scene in case of heart-attack, stroke and pediatric emergencies. In contrast, HEMS and ground EMS showed comparable arrival times in patients with multiple trauma, traumatic brain and burn injury due to an increased flight distance. HEMS showed a significantly decreased transportation time to the closest centre capable of specialist care in all diagnosis groups (p<0.001). CONCLUSIONS: The results of the present study indicate the time-effectiveness of German air ambulance services with significantly decreased transportation times.

Progress towards intra-operative measurement of femoral antetorsion.

Rotational malalignment following intramedullary nailing is a well-recognised problem. The threshold for clinically relevant malrotation has been established to be in the region of 15° whereas the incidence of significant malrotation following femoral nailing ranges from 22 to 43 percent. Many studies have been performed to address this issue with the major challenge acknowledged to be intraoperative control of femoral anteversion. In the current study, the investigators developed and analysed a novel method to estimate the femoral antetorsion based on computed tomography (CT) data. They hypothesized that this method would be intra-operatively feasible and repeatable without further radiation. CT scans (n=166) of femoral neck fractures performed between 2005 and 2010 were evaluated. Twenty patients had a femoral neck fracture and thus were excluded. Every femoral neck was measured according the method described by Jend et al. and the current authors. In contrast to the Jend method, the current authors described femoral antetorsion as the angle between the ventral cortex of the femoral neck and the posterior condylar line. To determine this angle, the axial cuts from computed tomography data were studied. In order to maximise measurement consistencty among cases, the axial cut which displayed the intertrochanteric crest was selected. Mean femoral antetorsion is 12.15°±10.04° according to Jend et al. In comparison, a mean angle of 12.61°±11.16° was demonstrated in the current study. The absolute difference in measuring the femoral neck angle when these different methods are compared was 4.44°. Statistically, there is no significant difference between the mean results for femoral antetorsion. The advantage of the method proposed in the current study, is the opportunity to enter the ventral femoral cortex during the surgical procedure without disturbing the process of femoral nailing. Thus, the surgeon can avail of continuous control of femoral rotation intra-operatively.

Factors influencing neck anteversion during femoral nailing: a retrospective analysis of 220 torsion-difference CTs.

BACKGROUND: Rotational malalignment is a well-known complication following intramedullary nailing of femoral shaft fractures. The hypothesis of this study is that various modifiable factors, such as position on the surgical table or nailing technique, influence the incidence of torsional abnormalities. METHODS: For this retrospective study, we analysed the data of 220 consecutive patients with femoral shaft fractures and postoperative torsion-difference computed tomographies (CTs), performed from 2001 to 2009 in our institution. Mean age of the patients was 33±15 years. Average delay to surgery was 8±11 days. The average postoperative neck anteversion difference between both sides was 11±8°. A p value <0.05 was considered to be statistically significant. RESULTS: The average postoperative neck anteversion difference between both sides was not significantly affected from the position of the patient on the surgical table (supine or lateral, p=0.698), the delay till surgery (p=0.989), the nailing technique (antegrade or retrograde, p=0.793; reamed or unreamed, p=0.930), the type of the implant (p=0.885) and the experience of the surgeon (p=0.055). Furthermore, the learning curve regarding this complication was long and not predictable. CONCLUSIONS: We could not identify any risk factors that are associated with an increased incidence of torsional deformities, and thus our hypothesis could not be confirmed. The inability to identify such risk factors renders the prevention of this complication particularly problematic. The invention of new techniques for better intra-operative control of the torsion is probably the only solution to further reduce the incidence of postoperative malrotational deformities.