Background: Jones fractures of the 5th metatarsal are frequently associated with nonunion due to limited vascularization and repetitive mechanical stress. The aim of the study was to compare the biomechanical performance of T-plate and bicortical screw fixation using standardized 3D models. Methods: Three-dimensional models of the 5th metatarsal were generated from CT images and printed using PolyJet technology (Stratasys J5 DentaJet) using a rigid-elastic composite with properties similar to cortical and cancellous bone. Jones fractures were fixed with either a locked T-plate or a bicortical screw. The samples were tested under axial and oblique static loads (α = 0°, 90°, 180°) and for three values of interfragmentary distance (d = 0.1–1 mm), in a 3 × 2 factorial design. Results: The T-plate fixation recorded a maximum yield force (Fmax) of 149.78 ± 8.53 N (138–161 N), significantly higher compared to the bicortical screw −98.56 ± 2.58 N (96–101 N), (p < 0.05). The ductility index was higher for the plate, indicating a progressive transition to yield. The α and d factors significantly influenced the mechanical behavior, with the polynomial model explaining over 95% of the total variation. Discussion: The plate fixation demonstrated greater strength and superior biomechanical tolerance in imperfect reduction scenarios. The main limitation is the lack of fatigue testing and the inability of 3D models to reproduce the structural heterogeneity of human bone. Conclusions: Implant selection should be individualized based on fracture stability. 3D models provide a reproducible platform for comparative evaluation of osteosynthesis methods, but future studies should include cyclic loading and biological validation.

Background/Objectives: Avulsion fractures of the fifth metatarsal often require surgical fixation when displacement or instability is present. This study aimed to compare the biomechanical performance of hook-plate and bicortical screw fixation using anatomically accurate 3D-printed metatarsal models analyzed through digital image correlation (DIC). Methods: Multi-material 3D-printed specimens were subjected to simulated gait-phase loading (α = 0°, 90°, 180°), combined with three interfragmentary distances (d = 0.1, 0.5, 1 mm) following a replicated 3 × 3 factorial design (n = 27 per fixation method). Full-field strain and displacement maps were quantified using ARAMIS DIC. Results: Hook-plate fixation consistently produced lower maximum stresses compared with bicortical screws (reductions of 9–36 MPa across conditions). The highest stresses were observed for screw fixation at α = 90° and d = 0.1 mm (100.3 ± 1.5 MPa), while the lowest occurred for hook plates at α = 180° and d = 1 mm (33.3 ± 1.5 MPa). ANOVA confirmed significant α×d interactions (p < 0.01). Conclusions: Hook-plate fixation provided superior angular stability and suggested improved cyclic performance compared to bicortical screws, favoring early mobilization. The combined use of 3D printing and DIC represents a valuable framework for preclinical implant evaluation. These results provide useful insights for selecting the optimal fixation technique in clinical management of fifth metatarsal avulsion fractures.

The development of implantable neural interfaces is essential for enabling bidirectional communication between the nervous system and prosthetic devices, yet their evaluation still relies primarily on in vivo models which are costly, variable, and ethically constrained. Here, we report a bio-inspired artificial nerve simulator engineered as a reproducible ex vivo platform for pre-implantation testing of plug-type electrodes. The simulator is fabricated from a conductive hydrogel composite based on reduced graphene oxide (rGO), polyaniline (PANI), agarose, sucrose, and sodium chloride, with embedded conductive channels that replicate the fascicular organization and conductivity of peripheral nerves. The resulting construct exhibits impedance values of ~2.4–2.9 kΩ between electrode needles at 1 kHz, closely matching in vivo measurements (~2 kΩ) obtained in Sus scrofa domesticus nerve tissue. Its structural and electrical fidelity enables systematic evaluation of electrode–nerve contact properties, signal transmission, and insertion behavior under controlled conditions, while reducing reliance on animal experiments. This bio-inspired simulator offers a scalable and physiologically relevant testbed that bridges materials engineering and translational neuroprosthetics, accelerating the development of next-generation implantable neural interfaces.

This paper details the design, fabrication, and evaluation of three innovative mechatronic systems for simulating lower limb joint motion, with a focus on the hip, knee, and ankle, using 3D printing and advanced control techniques. Fabricated using CATIA V5 designs and Fused Deposition Modelling (FDM) technology, the models incorporate distinct actuation strategies: a rack-and-pinion mechanism, a streamlined planetary gear system, and an anatomically inspired pulley-cable system. In addition, comprehensive modelling and simulation of an exoskeleton mechanism were performed to establish critical functional parameters. Electronic control is realized via ATmega328p microcontroller coupled with DRV8825 drivers. The proposed electronic system offers improved reliability, customization and minimizes the wiring required in the mechatronic structure. The integration of simulation results, rigorous mechanical design, and precise electronic control demonstrates significant potential for applications in rehabilitation, training, and biomechanical research.

" The purpose of this paper was to evaluate the existence of the anterolateral ligament of the knee in the Romanian population. Multiple studies have investigated the anterolateral structures of the knee, but there is some inconsistency regarding the existence of the anterolateral ligament. Materials and methods: A cadaver dissection study was performed on 10 knees (5 left and 5 right), 3 males and 2 females Results: The anterolateral ligament was observed in all 10 knees. The mean length was 32±6mm, the width was 5.1±2 mm, and the thickness at the articular line was 1.1±5 mm. Conclusions: A 100% presence was found, with a slight difference from the length, width, and thickness in other countries, race not being a decisional factor in differences. Keywords: anterolateral ligament, anatomy, lateral collateral ligament, dissection "

Background/Objectives: This article brings forward a novel methodology for the intra-op approach of forearm amputation stumps to facilitate their subsequent wireless connection to a neural prosthesis. A neural prosthesis offers the amputee more motor functions compared to myoelectric prostheses, but the neural prosthesis must be connected to the patient’s stump nerves. Methods: An experimental animal study was conducted on 15 Wistar rats. Under anesthesia, the sciatic nerve was carefully dissected and preserved using a folding technique to maintain maximum length without tension. Nerves were repositioned with consideration for future use with biocompatible conduits. Morphometric measurements (nerve length, external diameter, fascicle count) were performed, followed by statistical analysis of length–diameter correlations. Results: The techniques show that the length of the nerves in the amputation stump can be preserved and integrated into the muscle masses with appropriate methods and biomaterials, which ensures the transmission of motor impulses to control the movements of a prosthesis. Fibrosis and mechanical injury have a lower risk of occurring with the nerves protected in the muscle mass. Through statistical analysis we find that sciatic nerve length and diameter have a positive correlation (r = 0.71, p = 0.003), supporting anatomic plausibility for human extrapolation of results. Conclusions: The amputation technique preserves much of the nerve length and viability and is simple to perform. Neural electrode implantation can be facilitated by folding the nerve within a large muscle mass and using biomaterial conduits. Better rehabilitation of the patient may occur with the use of a prosthesis equipped with more functions and superior control.