UNASSIGNED: Conventional cephalomedullary nails (CMNs) are commonly employed for internal fixation in the treatment of reverse obliquity intertrochanteric (ROI) fractures. However, the limited effectiveness of conventional CMNs in addressing ROI fractures results in significant implant-related complications. To address challenges associated with internal fixation, a novel Proximal Femoral Bionic Nail (PFBN) has been developed.
UNASSIGNED: In this study, a finite element model was constructed using a normal femoral specimen, and biomechanical verification was conducted using the GOM non-contact optical strain measurement system. Four intramedullary fixation approaches-PFBN, Proximal Femoral Nail Antirotation InterTan nail (ITN), and Gamma nail (Gamma nail)-were employed to address three variations of ROI fractures (AO/OTA 31-A3). The biomechanical stability of the implant models was evaluated through the calculation of the von Mises stress contact pressure and displacement.
UNASSIGNED: Compared to conventional CMNs, the PFBN group demonstrated a 9.36%-59.32% reduction in the maximum VMS at the implant. The A3.3 ROI fracture (75% bone density) was the most unstable type of fracture. In comparison to conventional CMNs, PFBN demonstrated more stable data, including VMS values (implant: 506.33 MPa, proximal fracture fragment: 34.41 MPa), contact pressure (13.28 MPa), and displacement (17.59 mm).
UNASSIGNED: Compared to the PFNA, ITN, and GN, the PFBN exhibits improvements in stress concentration, stress conduction, and overall model stability in ROI fractures. The double triangle structure aligns better with the tissue structure and biomechanical properties of the proximal femur. Consequently, the PFBN has significant potential as a new fixation strategy for the clinical treatment of ROI fractures.

BACKGROUND: Dynamic hip screws (DHS) and proximal femoral nail anti-rotation (PFNA) were recommended for basicervical femoral neck fracture (BFNF), however, with high rate of postoperative femoral neck shortening. The proximal femoral bionic nail (PFBN) was designed to decrease the postoperative complications associated with DHS and PFNA. The aim of this study is to compare the biomechanical characters of DHS, PFNA, and PFBN for fixation of BFNF.
METHODS: Using finite element analysis, we created a three-dimensional model of the BFNF for this investigation. The PFBN group, the PFNA group and the DHS + DS group were our three test groups. For each fracture group, the von Mises stress and displacements of the femur and internal fixation components were measured under 2100 N axial loads.
RESULTS: The PFBN group demonstrated the lowest stress on the implants, significantly lower than the PFNA and DHS + DS groups. In terms of stress on the implants, the PFBN group exhibited the best performance, with the lowest stress concentration at 112.0 MPa, followed by the PFNA group at 124.8 MPa and the DHS + DS group at 149.8 MPa. The PFBA group demonstrated the smallest displacement at the fracture interface, measuring 0.21 mm, coupled with a fracture interface pressure of 17.41 MPa, signifying excellent stability.
CONCLUSIONS: Compared with DHS and PFNA, PFBN has advantages in stress distribution and biological stability. We believe the concept of triangle fixation will be helpful to reduce femoral neck shortening associated with DHS and PFNA and thus improve the prognosis of BFNF.

Intertrochanteric femoral fractures (IFF) are one of the most common traumatic conditions, but there are no established treatment methods for this condition due to implant failure and re-operation rates. The proximal femoral bionic nail (PFBN), which is a new design of the cephalomedullary nail, was developed by our team. The objective of this study was to assess the clinical and radiographic outcomes of PFBN in patients with unstable IFF.
From October 2020 to August 2021, 12 patients diagnosed with unstable IFF (31-A2, 3) were treated with PFBN at the Third Hospital of Hebei Medical University. We evaluated the clinical therapeutic effects of this treatment by measuring peri-operative indicators and post-operative complications. Clinical outcomes, specific radiographic parameters, and post-operative complications were collected and analyzed within the first post-operative year.
The average age of the patients was 72.4 ± 16.1 years (five males and seven females). The mean operation time was 90.4 ± 16.0 min, whereas the operation time of 31-A2 fractures (83.1 ± 12.2 min) was shorter than that of 31-A3 fractures (105.0 ± 12.9 min) (p < 0.05). The blood loss was 175 ml (range: 50 to 500 ml), and the length of hospitalization was 10.0 ± 1.9 days. The prognosis evaluation was assessed at three, six and 12 months after the operation; for these time points, the Harris hip scores were 69.6 ± 4.1, 77.8 ± 3.8, and 82.6 ± 4.6, respectively, and the Parker-Palmer scores were 5.3 (5.0, 7.0), 6.3 (5.3, 7.0), and 7.8 (7.0, 8.0), respectively.
PFBN has shown advantages in the treatment of unstable IFF (particularly in geriatric patients) and possesses both stability and safety. This innovative method may provide a new option for treating unstable IFFs.