Computer-assisted three-dimensional correlation between the femoral neck-shaft angle and the optimal entry point for antegrade nailing.

Optimal entry point for antegrade femoral intramedullary nailing (IMN) remains controversial in the current medical literature. The definition of an ideal entry point for femoral IMN would implicate a tenseless introduction of the implant into the canal with anatomical alignment of the bone fragments. This study was undertaken in order to investigate possible existing relationships between the true 3D geometric parameters of the femur and the location of the optimum entry point. A sample population of 22 cadaveric femurs was used (mean age=51.09+/-14.82 years). Computed-tomography sections every 0.5mm for the entire length of femurs were produced. These sections were subsequently reconstructed to generate solid computer models of the external anatomy and medullary canal of each femur. Solid models of all femurs were subjected to a series of geometrical manipulations and computations using standard computer-aided-design tools. In the sagittal plane, the optimum entry point always lied a few millimeters behind the femoral neck axis (mean=3.5+/-1.5mm). In the coronal plane the optimum entry point lied at a location dependent on the femoral neck-shaft angle. Linear regression on the data showed that the optimal entry point is clearly correlated to the true 3D femoral neck-shaft angle (R(2)=0.7310) and the projected femoral neck-shaft angle (R(2)=0.6289). Anatomical parameters of the proximal femur, such as the varus-valgus angulation, are key factors in the determination of optimal entry point for nailing. The clinical relevance of the results is that in varus hips (neck-shaft angle

Evaluation of the Stryker S2 IM Nail Distal Targeting Device for reduction of radiation exposure: a case series study.

Distal locking is one challenging step during intramedullary nailing of femoral shaft fractures that can lead to an increase of radiation exposure. In the present study, the authors describe a technique for the distal locking of femoral nails, implementing a new targeting device in an attempt to reduce radiation exposure and operational time. Over a 2-year period, 127 consecutive cases of femoral shaft fractures were included in the study. All cases were treated with nailing of femoral shaft fractures with an unslotted reamed antegrade femoral nail and distal locking was performed with the use of a proximally mounted aiming device. Mean duration of the procedure was 63.5 18.1 min while the duration for distal locking was 6.6 +/- 2.6 min. In all successful cases, exposure from intraoperative fluoroscopy was 17.2 +/- 7.4 s for the whole operative procedure, and for distal locking was 2 shots, 1.35 s (range, 0.9-2.2 s) and 1.9 mGy (range, 1.1-2.9 mGy). Five cases (3.9%) were unsuccessful, but overall no intraoperative complications were encountered from the application of this technique. The ability of the device to correspond to the level of nail deformation and to properly identify the distal holes, reduced exposure to radiation compared to other published reports, and should be considered as a valuable tool for distal locking of femoral fractures.

Distal locking of tibial nails : a new device to reduce radiation exposure.

UNLABELLED: The indications for intramedullary nailing have expanded to include most tibial shaft fractures. Nail design has improved since their first introduction, but distal locking remains a difficult part of the procedure, resulting in radiation exposure to the patient and the surgeon and increased operation time. To address these issues, we describe an alternative surgical technique using a newly designed distal targeting device that consists of a proximally mounted aiming arm, and we report the preliminary data from its use in all tibial shaft fractures amenable to surgery for a 2-year period. Sixty-three tibial shaft fractures were treated with this method. The mean duration of the distal locking was 6.5 minutes, and in all successful cases, radiation exposure for distal locking was two shots (one shot before targeting and another for the confirmation of proper screw insertion). Radiation exposure was on average 0.85 seconds (range, 0.4-1.2 seconds) and 1.4 mGy (range, 0.8-1.9 mGy). There were no major intraoperative complications related to the technique. The method has certain advantages and can reduce radiation exposure and operation time. Nonetheless, familiarity with the instrumentation is a prerequisite for accurate distal locking. LEVEL OF EVIDENCE: Level IV Therapeutic study.