Log: Biomed Central (BMC), subsidiary of Springer Nature

Who: Gregory R. Roytman, Alim F. Ramji, Brian Beitler, Brad Yoo, Michael P. Leslie, Michael Baumgaertner, Steven Tommasini and Daniel H. Wiznia

Insight: The goal of femoral neck stabilization is to limit fracture morbidity and mortality. Of the three potential fixation methods (three percutaneous screws, the Synthes Femoral Neck System, and one dynamic hip screw), each requires guidewire placement of the implant(s) into the femoral neck and head. Consistent and precise positioning of these systems is paramount to reducing surgical times, effectively stabilizing fractures and reducing complications. To help expedite surgery and achieve ideal implant positioning in the geriatric population, we have developed and validated a surgical planning methodology using 3D modeling and printing technology.

Using image processing software, 3D surgical models were generated by placing guidewires in a virtual osteoporotic proximal femur saw bone model. Three unique drill guides were created to achieve the optimal position for implant placement for each of the three different implant systems, and the guides were 3D printed. Subsequently, a trauma-trained orthopedic surgeon used the 3D-printed guides to position 2.8 mm diameter drill-tip guidewires in five osteoporotic sawbones for each of three systems (fifteen sawbones in total). Computed tomography (CT) scans were then taken of each of the saw bones with the implants in place. 3D model renderings of the CT scans were created using image processing techniques and the displacement and angular deviations at the entry of the guidewire to the optimal saw bone model were measured.

Of the three percutaneous screw guide wires, the mean displacement was 3.19 ± 0.12 mm and the mean angular deviation was 4.10 ± 0.17o. The Femoral Neck System guidewires had a mean displacement of 1.59 ± 0.18 mm and a mean angular deviation of 2.81 ± 0.64o. The dynamic hip screw had a mean displacement of 1.03 ± 0.19 mm and a mean angular deviation of 2.59 ± 0.39o.

The use of custom 3D-printed drill guides to aid in guidewire positioning has proven to be accurate for all three types of surgical strategies. Guides that are used to place more than one guide wire may have lower positioning accuracy because the guide may move during multiple wire insertions. We believe that point-of-care custom drill guides provide an accurate intraoperative method for positioning implants in the femoral neck.