A biomechanical comparison of the antegrade inserted universal femoral nail with the retrograde inserted universal tibial nail for use in femoral shaft fractures

Comparative experimental study of the biomechanical properties of retrograde tibial nailing and distal tibia plate in distal tibia fracture

Objective: A biomechanical comparative analysis was conducted to evaluate the retrograde tibial nailing (RTN) and distal tibia plate techniques for the treatment of distal tibia fractures. Methods: Fourteen fresh adult tibia specimens were selected, consisting of seven males and seven females aged 34-55 years. The specimens were randomly divided into two groups (Group A and Group B) using a numerical table method, with seven specimens in each group. Group A underwent internal fixation of distal tibial fractures using RTN, while Group B received internal fixation using a plate. The axial compression properties of the specimens were tested in the neutral positions under pressures of 100, 200, 300, 400, and 500 N. Additionally, the torsional resistance of the two groups was assessed by subjecting the specimens to torques of 1.0, 2.0, 3.0, 4.0, and 5.0 N m. Results: At pressures of 400 and 500 N, the axial compression displacement in Group A (1.11 ± 0.06, 1.24 ± 0.05) mm was significantly smaller than that in Group B (1.21 ± 0.08, 1.37 ± 0.11) mm (p = 0.023, 0.019). Moreover, at a pressure of 500 N, the axial compression stiffness in Group A (389.24 ± 17.79) N/mm was significantly higher than that of the control group (362.37 ± 14.44) N/mm (p = 0.010). When subjected to torques of 4 and 5 N m, the torsion angle in Group A (2.97° ± 0.23°, 3.41° ± 0.17°) was significantly smaller compared to Group B (3.31° ± 0.28°, 3.76° ± 0.20°) (p = 0.035, 0.004). Furthermore, at a torque of 5 N m, the torsional stiffness in Group A (1.48 ± 0.07) N m/° was significantly higher than that in Group B (1.36 ± 0.06) N·m/° (p = 0.003). Conclusion: The results obtained from the study demonstrate that the biomechanical performance of RTN outperforms that of the distal tibial plate, providing valuable biomechanical data to support the clinical implementation of RTN.

Treatment of distal femur fractures with retrograde intramedullary nailing utilizing a tibial nail

Abstract Aim Retrograde intramedullary nailing for the treatment of femur fractures is a sound option due to its advantages including ease of implant placement and better control of the distal segment, especially in distal femur fractures. Unfortunately, retrograde femoral nails are not available in most developing countries or rural areas. The primary aim of the study is to investigate the outcomes of an alternative treatment of distal femur fracture with retrograde intramedullary nailing using a tibial nail. Material and Method Patients who had distal femur fractures and underwent retrograde intramedullary nailing with a tibial nail between January 2020 – March 2022 are retrospectively evaluated. Patients who were treated other than a tibial nail, aged below 18, had follow-up less than 6 months, multiple fractures, and open fractures were excluded. Patients’ demographics, time to union, and complications were recorded. Functional outcomes included visual analogue pain score (VAS), Lysholm score, Tegner activity scale, Knee Society Score (KSS), and Short Form-36 (SF36) on the latest follow-up. Results A total of 15 patients (11 male, 4 female) met the inclusion criteria and included in the study. The mean age of the patients was 42.9 ± 17.3 (range, 18 to 72) months. The mean follow-up period was 10.1 ± 5.2 (range, 6 to 18). There was no reduction loss and implant failure during follow-ups. One patient had nonunion. No intraoperative fracture occurred. Persistent knee pain was seen in a patient due to an intraarticular screw and removed arthroscopically. In the latest follow-up, the mean VAS was 0.73 ± 0.70 (range, 0 to2), the mean Tegner score was 5.0 ± 1.5 (range, 3 to 7), the mean Lysholm score was 90.9 ± 9.9(range, 64 to 100), the mean KSS was 86.6 ± 8.6 (range, 70 to 97), and the mean SF-36 score was 96.5 ± 4.7 (range, 87 to 100). Conclusion The results of this study suggest that a tibial nail with retrograde intramedullary nailing has good functional outcomes in the treatment of distal femur fractures. The tibial nail should be considered as an alternative treatment option where distal femoral nails are not available.

Retrograde nailing of a femoral supracondyle

Because standard femoral supracondylar nails have certain disadvantages, they are often replaced by traditional femoral or tibial locked nails. The purpose of this study was to make a biomechanical comparison between both types of traditional locked nails to determine which technique was more suitable for treating unstable femoral supracondylar fractures. Fourteen left Sawbones femurs (Pacific Research Laboratories, Vashon, Washington) were osteotomized in the femoral supracondylar area. One centimeter of the medial cortex in the proximal fragment was obliquely removed to simulate an unstable fracture without shortening. Seven specimens were treated with traditional retrograde dynamic femoral locked nails, and the other 7 with traditional retrograde dynamic tibial locked nails. All specimens were tested with a servohydraulic materials testing machine to compare their relative stability. Static compression, dynamic cyclic compression, and static compression to failure were tested. An extensometer was used to measure the displacement of fragments. Displacement between the fragments increased following the increment in loads in both nails. The load-displacement curve was nearly linear up to 1000 N for both nails. The femoral nail had a greater stiffness compared with the tibial nail at 100 and 200 N (P=.02 and P=.04, respectively) in static compression and at 700 to 1000 N (P=.01 in each case) in dynamic cyclic compression, as well as larger loads in static compression to failure (8663 vs 7547 N, respectively; P<.001). Clinically, a traditional femoral locked nail may be more suitable to replace a standard femoral supracondylar nail in a retrograde fashion to treat an unstable femoral supracondylar fracture.