Polyetheretherketone implants with hierarchical porous structure for boosted osseointegration

Hanna's Modified Sagittal Split Osteotomy (HSSO): An Alternative to Inverted L Osteotomy-Merging Function and Aesthetics for Enhanced Stability, Attractiveness, and Nerve Protection

Background: The current high standards in orthognathic surgery demand surgical solutions that are both ⁠ functionally ⁠ effective and aesthetically pleasing. Our approach offers one for enhanced stability, attractiveness, and nerve protection ⁠ with improved accessibility ⁠ in the majority of orthognathic scenarios ⁠ compared to an inverted L osteotomy. Methods: A case series is presented to illustrate the application and outcomes of HSSO, an optimised approach that combines the advantages of a transoral inverted L osteotomy with specific enhancements and increased versatility, ⁠ with accessibility and exposure similar to a BSSO. Results: HSSO as a completely transoral technique, demonstrate the ability to perform significant counterclockwise rotations of the mandible, eliminating the need for trocars or skin incisions. We experinced high postoperative stability when HSSO was performed in conjunction with a three-piece LeFort 1 osteotomy on a dynamic opposing arch. In comparison to an inverted L approach, we postulated that HSSO offers advantages in stability, due to the increased segmental overlap of the proximal and distal segments of the mandible. This approach is designed to enhance the safety of the inferior alveolar nerve compared to traditional sagittal split methods. Furthermore, HSSO represents an alternative to total joint replacement in select cases of idiopathic condylar resorption and is effective for correcting mandibular asymmetries while maintaining jawline aesthetics. This is achieved through the manipulation of the mandibular angle, ramus height, and inferior border without creating a step deformity in the soft tissue. Conclusions: The outcomes of HSSO highlight its capacity to deliver predictable, functional, and aesthetically pleasing results, offering a viable alternative to more traditional orthognathic techniques.

N-Halaminated spermidine-containing polymeric coating enables titanium to achieve dual functions of antibacterial and osseointegration

Titanium (Ti) and its alloys have been widely employed in the treatment of orthopedics and other hard tissue diseases. However, Ti-based implants are bioinert and suffer from bacterial infections and poor osseointegration in clinical applications. Herein, we successfully modified Ti with a porous N-halaminated spermidine-containing polymeric coating (Ti-SPD-Cl) through alkali-heat treatment, surface grafting and chlorination, and it has both excellent antibacterial and osteogenic abilities to significantly enhance osseointegration. The as-obtained Ti-SPD-Cl contains abundant N-Cl groups and demonstrates effective antibacterial ability against S. aureus and E. coli. Meanwhile, due to the presence of the spermidine component and construction of a porous hydrophilic surface, Ti-SPD-Cl is also beneficial for maintaining cell membrane homeostasis and promoting cell adhesion, exhibiting good biocompatibility and osteogenic ability. The rat osteomyelitis model demonstrates that Ti-SPD-Cl can effectively suppress bacterial infection and enhance bone-implant integration. Thus, Ti-SPD-Cl shows promising clinical applicability in the prevention of orthopedic implant infections and poor osseointegration.

Parametric Design of Porous Structure and Optimal Porosity Gradient Distribution Based on Root-Shaped Implants

Porous structures can reduce the elastic modulus of implants, decrease stress shielding, and avoid bone loss in the alveolar bone and aseptic loosening of implants; however, there is a mismatch between yield strength and elastic modulus as well as biocompatibility problems. This study aimed to investigate the parametric design method of porous root-shaped implants to reduce the stress-shielding effect and improve the biocompatibility and long-term stability and effectiveness of the implants. Firstly, the porous structure part was parametrically designed, and the control of porosity gradient distribution was achieved by using the fitting relationship between porosity and bias and the position function of bias. In addition, the optimal distribution law of the porous structure was explored through mechanical and hydrodynamic analyses of the porous structure. Finally, the biomechanical properties were verified using simulated implant-bone tissue interface micromotion values. The results showed that the effects of marginal and central porosity on yield strength were linear, with the elastic modulus decreasing from 18.9 to 10.1 GPa in the range of 20-35% for marginal porosity, with a maximum decrease of 46.6%; the changes in the central porosity had a more consistent effect on the elastic modulus, ranging from 18.9 to 15.3 GPa in the range of 50-90%, with a maximum downward shift of 19%. The central porosity had a more significant effect on permeability, ranging from 1.9 × 10-7 m2 to 4.9 × 10-7 m2 with a maximum enhancement of 61.2%. The analysis showed that the edge structure had a more substantial impact on the mechanical properties. The central structure could increase the permeability more effectively. Hence, the porous structure with reasonable gradient distribution had a better match between mechanical properties and flow properties. The simulated implantation results showed that the porous implant with proper porosity gradient distribution had better biomechanical properties.

Dual aldehyde cross-linked hyaluronic acid hydrogels loaded with PRP and NGF biofunctionalized PEEK interfaces to enhance osteogenesis and vascularization

Polyetheretherketone (PEEK) material has become a potential bone replacement material due to its elastic modulus, which is close to that of human bone, and stable chemical properties. However, its biological inertness has hindered its clinical application. To improve the biological inertia of PEEK material, a hyaluronic acid (HA) hydrogel coating loaded with platelet-rich plasma (PRP) and nerve growth factor (NGF) was constructed on the surface of PEEK material in this study. After the hybrid hydrogel coating was constructed, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), degradation tests, and enzyme-linked immunosorbent assays (ELISAs) were used to evaluate its characteristics and biological properties. The osteogenic and angiogenic potentials were also investigated in vitro and in vivo. Our results showed that the HA hydrogel loaded with RPP and NGF on the PEEK surface degraded slowly and could sustainably release various growth factors, including NGF. The results of in vitro tests showed that the hybrid hydrogel on the surface of PEEK effectively promoted osteogenesis and angiogenesis. The in vivo experiment also confirmed that the PEEK surface hydrogel could promote osseointegration of the implant and the integration of new bone and neovascularization. Our results suggest that the cross-linked hyaluronic acid hydrogel loaded with PRP and NGF can significantly improve the biological inertia of PEEK material, endowing PEEK material with good osteogenic and angiogenic ability.

Management of severe defects of humerus in combat patients injured in Russo-Ukrainian war

INTRODUCTION

Russo-Ukrainian war is associated with application of high-energy weapon, causing severe multifragmental injuries to the bones an associating with severe bone defects. The aim of the study was to evaluate various methods to treat combat patients with severe defects of humerus and to demonstrate the experience of orthopedic war surgeons in managing gunshot injuries to the humerus defects in the ongoing war.

PATIENTS AND METHODS

A 24 patients were active-duty military personnel of Armed Forces of Ukraine. These patients were diagnosed with severe humerus defects due to gunshot injury in battlefield zone in various areas of Ukraine. Data was collected within period between February, 24th 2022 till January, 01st 2023. The following approaches were applied to replace bone defect: preoperative 3D printing with polyetheretherketone (PEEK) as orthobiological material; closed reduction, percutaneous lag screw and Ilizarov external fixation; vascularized fibula grafting.

RESULTS

Data analyses of the segmental defects of humerus showed 5 cm defect in 3 (13 %) patients, from 5 to 10 cm in 4 (17 %) patients, over 10 cm in 17 (71 %) patients. Analyses were performed in these 17 (71 %) patients, showing 5 patients treated with 3D-printed PEEK implants, 6 patients with vascular-pedicle graft of fibula, 6 patients with closed reduction, percutaneous lag screw, Ilizarov external fixation. Osteomyelitis was diagnosed in one case (20 %) after the use of PEEK implants, requiring to remove both PEEK implant and metal implants followed by application of the antibiotic joint spacers and Ex-Fix fragments of the humerus. In our opinion, the osteomyelitis happened due to inadequate debridement of the wound and non-compliance with the conversion criteria (replacement of the fixation method). The mean length of hospital stay was 5.5 months for patients treated with 3D-printed PEEK implants.

CONCLUSIONS

Closed reduction, percutaneous lag screw and Ilizarov external fixation as well as vascularized fibula grafting are associated with good outcomes in management of the patients with severe humerus defect due to gunshot injury. 3D printing and PEEK implants could also be considered for the reconstructions of the humerus multifragmental fractures with a bone defect over 10 cm associated with gunshot injury due to high-energy weapon in the war settings.

A strategy for enhancing bioactivity and osseointegration with antibacterial effect by incorporating magnesium in polylactic acid based biodegradable orthopedic implant

Biodegradable orthopedic implants are essential for restoring the physiological structure and function of bone tissue while ensuring complete degradation after recovery. Polylactic acid (PLA), a biodegradable polymer, is considered a promising material due to its considerable mechanical properties and biocompatibility. However, further improvements are necessary to enhance the mechanical strength and bioactivity of PLA for reliable load-bearing orthopedic applications. In this study, a multifunctional PLA-based composite was fabricated by incorporating tricalcium phosphate (TCP) microspheres and magnesium (Mg) particles homogenously at a volume fraction of 40 %. This approach aims to enhance mechanical strength, accelerate pore generation, and improve biological and antibacterial performance. Mg content was incorporated into the composite at varying values of 1, 3, and 5 vol% (referred to as PLA/TCP-1 Mg, PLA/TCP-3 Mg, and PLA/TCP-5 Mg, respectively). The compressive strength and stiffness were significantly enhanced in all composites, reaching 87.7, 85.9, and 84.1 MPa, and 2.7, 3.0, and 3.1 GPa, respectively. The degradation test indicated faster elimination of the reinforcers as the Mg content increased, resulting in accelerated pore generation to induce enhanced osseointegration. Because PLA/TCP-3 Mg and PLA/TCP-5 Mg exhibited cracks in the PLA matrix due to rapid corrosion of Mg forming corrosion byproducts, to optimize the Mg particle content, PLA/TCP-1 Mg was selected for further evaluation. As determined by in vitro biological and antibacterial testing, PLA/TCP-1 Mg showed enhanced bioactivity with pre-osteoblast cells and exhibited antibacterial properties by suppressing bacterial colonization. Overall, the multifunctional PLA/TCP-Mg composite showed improved mechanobiological performance, making it a promising material for biodegradable orthopedic implants.