Search Results (52)

Background/Objectives: The most common limb-salvage procedure for end-stage ankle arthropathy with severe bone defect is arthrodesis. Successful fusion requires rigid metal fixation, effective filling of the bone defect space, and maximal securing of the contact area between the tibia and talus. In cases with severe bone defect, sufficient grafting using autogenous bone alone is limited, and there is still controversy regarding the effectiveness of allogeneic or xenogeneic bone grafting. This study aimed to evaluate the intermediate-term clinical outcomes after shortening arthrodesis using fibular osteotomy for ankle arthropathy with severe bone defect. Methods: Twenty-two patients with shortening ankle arthrodesis were followed up ≥ 3 years. All operations were performed by one senior surgeon and consisted of internal fixation with anterior fusion plate, fibular osteotomy, and autogenous bone grafting. The causes of ankle joint destruction were failed total ankle arthroplasty (7 cases), neglected ankle fracture (6 cases), delayed diagnosis of degenerative arthritis (5 cases), avascular necrosis of talus (2 cases), and diabetic neuroarthropathy (2 cases). Clinical outcomes including daily living and sport activities were evaluated with the Foot and Ankle Outcome Score (FAOS) and the Foot and Ankle Ability Measure (FAAM). Radiological evaluation included fusion rate, time to fusion, leg length discrepancy, and degenerative change in adjacent joints. Results: The FAOS and FAAM scores significantly improved from a mean of 21.8 and 23.5 points preoperatively to 82.2 and 83.4 points at final follow-up, respectively (p < 0.001). Visual analogue scale for pain during walking significantly improved from a mean of 7.7 points preoperatively to 1.4 points at final follow-up (p < 0.001). The average time to complete fusion was 16.2 weeks, and was achieved in all patients. The average difference in leg length compared to the contralateral side was 11.5 mm based on physical examination, and 13.8 mm based on radiological examination. During the average follow-up of 56.2 months, no additional surgery was required due to progression of degenerative arthritis in the adjacent joints, and no cases required the use of height-increasing insoles in daily life. Conclusions: Shortening ankle arthrodesis using fibular osteotomy and anterior fusion plate demonstrated satisfactory intermediate-term clinical outcomes and excellent fusion rate. Advantages of this procedure included rigid fixation, preservation of the subtalar joint, effective filling of the bone defect space, and maximal securing of the contact area for fusion. The leg length discrepancy, which was concerned to be a main shortage, resulted in no significant clinical symptoms or discomfort in most patients. Full article

Metallic biomaterials are prevalent in medical applications. In the treatment of mandibular fractures, the use of metallic biomaterials makes it possible to recover the ability to bite and partially recover speech through preventing ankylosis of the temporomandibular joints, the formation of pseudoarthritic joints, and the consolidation of reduced bones. This article presents the concept of a triaxial plate for osteosynthesis of basal fractures of the mandibular condyle, which are very common fractures in humans. Approximately half of patients with such fractures have wide (squat) condylar processes, which allows for the use of as many as three straight plates. However, installing three plates is quite troublesome, and the use of a single and transversely reinforced plate would facilitate treatment. This study proposes a plate with three reinforcements running along three divergent axes. The plate is fixed to the bone fragments with 11 screws. This concept for the treatment of basal fractures allows patients to quickly recover their primary system functions due to rigid fixation through the use of short (4 mm) screws, as there is no trauma to the medial pterygoid muscle and the mandible canal contents and no intermaxillary immobilization. Full article

Background: Curettage represents a reliable therapeutic option for large-sized benign and locally aggressive bone tumors. In cases of impending fractures, internal fixation with plates and screws can be necessary to stabilize the treated bone after curettage. Metal plates have been the only fixation devices available on the market for decades, but Carbon-fiber-reinforced polyetheretherketone (CFR-PEEK) now represents an alternative in orthopedic oncology. Methods: We reviewed our patients with benign or locally aggressive bone tumors treated with curettage and fixation with CFR-PEEK plates. Plate length and curettage technique were chosen considering the characteristics of each lesion. We recorded the size and location of the lesions, adjuvant treatments and fillers used after curettage, complications, and local recurrences. Postoperative functionality was assessed using the MSTS score. Results: Forty cases were included in our study. The tumors were located in the distal femur (19 cases), femur shaft (1), humerus (17), or proximal tibia (3). Local adjuvants were used in 20 cases. Cavities were filled with bone allografts in 30 cases and cement in 10 cases. Only four cases suffered postoperative complications, and two developed local recurrences. The mean postoperative follow-up was 29.2 months. The mean postoperative upper and lower limb MSTS was 28.0 and 26.7, respectively. Conclusions: After an accurate curettage and an adequate filling of the resulting bone gap, CFR-PEEK plates can provide good mechanical resistance, and their radio-transparency can ease the early diagnosis of local recurrences. CFR-PEEK plates should be considered in selected cases, in a personalized surgical approach. Full article

This study introduces a novel titanium hollow structure for mandibular reconstruction designed to optimize mechanical stability and stress distribution. A comparative evaluation with a similar polyetheretherketone (PEEK) structure is performed to assess material-specific biomechanical behavior. Methods: Finite element analysis (FEA) simulations were conducted to evaluate stress distribution, displacement, and structural stability of the symmetrical titanium and PEEK hollow structures under physiological conditions. The reconstructions were designed based on Scherk minimal surfaces, integrating fixing plates to achieve optimal mechanical performance while maintaining symmetry. Results: The FEA simulations demonstrated that the titanium hollow structure exhibited higher mechanical stability, lower displacement, and more uniform stress distribution, ensuring structural integrity under applied forces. In contrast, the PEEK structure displayed greater flexibility, which reduced stress shielding but resulted in higher deformation and lower load-bearing capacity. While titanium inherently supports osseointegration, PEEK requires surface modifications to enhance bone integration and long-term stability. Conclusions: The titanium hollow structure presents a promising advancement in metal-based mandibular reconstruction, effectively balancing strength, durability, and biological integration. Future research should focus on using more structures, enhancing surface modifications and optimizing lattice structures to further improve the biological and biomechanical performance of PEEK-based and titanium-based implants in load-bearing conditions. Full article

Background and Objectives: Distal tibia fractures are high-energy injuries characterized by a mismatch between standard plate designs and the patient’s specific anatomical bone structure, which can lead to severe soft tissue damage. Recent advancements have focused on the development of customized metal plates using three-dimensional (3D) printing technology. However, 3D-printed metal plates using titanium alloys have not incorporated a locking system due to the brittleness of these alloys. Therefore, this study aimed to determine whether a locking mechanism can be effectively implemented using 3D-printed pure titanium and further evaluate the clinical outcomes of such implants in patients with distal tibia fractures. Materials and Methods: Between March 2021 and June 2022, nine patients who underwent open reduction and internal fixation for distal tibia fractures using 3D-printed pure titanium plates were enrolled. Pure titanium powder (Ti Gr.2, Type A, 3D Systems, USA) was spread to a thickness of 30 μm and partially sintered using a 500 W laser to produce the 3D-printed metal plates. The locking screws were fabricated using a milling process. Open reduction and internal fixation were performed on the nine patients using 10 customized plates. The clinical efficacy was analyzed using the union rate, and complications, such as infection and skin irritation, were evaluated to ensure a comprehensive outcome assessment. Results: Surgical treatment was successfully performed on nine patients, with nine of ten plates remaining stable and undamaged. However, one patient with neurofibromatosis experienced a fractured metal plate, which necessitated revision surgery using a metal rod. No screw loosening or surgical wound complications occurred. Conclusions: This study showed that 3D-printed pure titanium plates with integrated locking screw systems provide a viable and effective solution for managing distal tibia fractures. Three-dimensional printing and pure titanium show promise for orthopedic advancements. Full article

The bone plates used in surgery to assist in fracture healing are often manufactured by metal injection molding (MIM) using a feedstock material consisting of metal powder and polymer binder. However, if the local powder concentration is too low or uneven, black lines may be formed, which impair the product appearance. Furthermore, if the melding temperature is too low, it can lead to meld lines and reduced mechanical properties. Accordingly, this study combines mold flow analysis simulations with the single-objective Taguchi robust design method to determine the MIM processing conditions that optimize the powder concentration and melding temperature. Grey relational analysis (GRA) is then used to establish the processing conditions that simultaneously optimize both MIM objectives. It is found that the processing conditions determined through GRA provide a significant improvement over the original design; however, the experimental outcomes are poorer than those achieved through the single-objective Taguchi experiments since the melt temperature effect suppresses that of all the other processing conditions. Consequently, a robust multi-criteria optimization (RMCO) technique is employed to improve the optimization outcome by identifying the dominant factors in the MIM process and fixing them at optimal levels to redesign the Taguchi experiments to optimize the non-primary factors. It is shown that the RMCO method eliminates interference between the multiple factors and hence provides an improved multi-objective optimization outcome. Overall, the integrated framework proposed in this study advances the optimization of the MIM process for bone plates and leads to improved product quality and performance. Full article

This article reviews the research and development focus of metallic glasses in the field of biomedical applications. Metallic glasses exhibit a short-range ordered and long-range disordered glassy structure at the microscopic level, devoid of structural defects such as dislocations and grain boundaries. Therefore, they possess advantages such as high strength, toughness, and corrosion resistance, combining characteristics of both metals and glasses. This novel alloy system has found applications in the field of biomedical materials due to its excellent comprehensive performance. This review discusses the applications of Ti-based bulk metallic glasses in load-bearing implants such as bone plates and screws for long-term implantation. On the other hand, Mg-based metallic glasses, owing to their degradability, are primarily used in degradable bone nails, plates, and vascular stents. However, metallic glasses as biomaterials still face certain challenges. The Young’s modulus value of Ti-based metallic glasses is higher than that of human bones, leading to stress-shielding effects. Meanwhile, Mg-based metallic glasses degrade too quickly, resulting in the premature loss of mechanical properties and the formation of numerous bubbles, which hinder tissue healing. To address these issues, we propose the following development directions: (1) Introducing porous structures into titanium-based metallic glasses is an important research direction for reducing Young’s modulus; (2) To enhance the bioactivity of implant material surfaces, the surface modification of titanium-based metallic glasses is essential. (3) Developing antibacterial coatings and incorporating antibacterial metal elements into the alloys is essential to maintain the long-term effective antibacterial properties of metallic biomaterials. (4) Corrosion resistance must be further improved through the preparation of composite materials, while ensuring biocompatibility and safety, to achieve controllable degradation rates and degradation modes. Full article

Clinical indications for the Ti-Zr alloy (Roxolid^®) mini-implants (MDIs) in subjects with narrow ridges are still under review. The aim was to analyze peri-implant and posterior edentulous area strains dependent on the MDI number, splinting status, loading force, and loading position. Six models were digitally designed and printed. Two, three, or four Ti-Zr MDIs, splinted with a bar or unsplinted (single units), supported mandibular overdentures (ODs), loaded with 50–300 N forces unilaterally, bilaterally, and anteriorly. The artificial mucosa thickness was 2 mm. Strain gauges were bonded on the vestibular and oral peri-implant sides of each MDI, and on the posterior edentulous area under the ODs. Loadings were performed through the metal plate placed on ODs’ artificial teeth (15 times repeated). Arithmetic means with standard deviations and the significance of the differences (MANOVA, Sheffe post hoc) were calculated. Different MDI numbers, loading positions, forces, and splinting elicited different peri-implant microstrains. In the two-MDI models, 300 N force during unilateral loading elicited the highest microstrains (almost 3000 εμ on the loaded side), which can jeopardize bone reparation. On the opposite side, >2500 εμ was registered, which represents high strains. During bilateral loadings, microstrains hardly exceeded 2000 εμ, indicating that bilateral chewers or subjects having lower forces can benefit from the two Ti-Zr MDIs, irrespective of splinting. However, in subjects chewing unilaterally, and inducing higher forces (natural teeth antagonists), or bruxers, only two MDIs may not be sufficient to support the OD. By increasing implant numbers, peri-implant strains decrease in both splinted and single-unit MDI models, far beyond values that can interfere with bone reparation, indicating that splinting is not necessary. When the positions of the loading forces are closer to the implant, higher peri-implant strains are induced. Regarding the distal edentulous area, microstrains reached 2000 εμ only during unilateral loadings in the two-MDI models, and all other strains were lower, below 1500 εμ, confirming that implant-supported overdentures do not lead to edentulous ridge atrophy. Full article

Stress shielding is a problem for traditional metal bone fixation plates made of magnesium and titanium alloys. This problem can be solved by using composite materials with a low elastic modulus. This study analyzed the effect of carbon fiber reinforced PEEK (CFRP) composites on stress shielding under static loading using finite element simulations. Callus formation times relative to the healing period were gradually imposed according to the elapsed time, considering 1% and 75% as healing stages. The Inventor© 3D CAD 2024 software was used for modeling, and the ANSYS© FEA R2023 software was used for analysis. The results showed that metal fixation plates made of titanium and magnesium alloys transferred less stress to the bone than the CFRP fixation plate. In particular, the use of the CFRP fixation plate resulted in a higher peak stress and a more uniform stress field in the bone, especially in the bone-plate contact area, where the risk of stress shielding is higher in the 1% and 75% healing phases. Full article

Addressing non-unions involves stabilizing the affected area through osteosynthesis and improving bone biology using bone grafts. However, there is no consensus on the optimal treatment method. This study aims to compare outcomes of non-union surgery using conventional treatment methods (metal hardware ± graft) versus osteosynthesis with the human allogeneic cortical bone screw (Shark Screw^®) alone or in combination with a metallic plate. Thirty-four patients underwent conventional treatment, while twenty-eight cases received one or more Shark Screws^®. Patient demographics, bone healing, time to bone healing, and complications were assessed. Results revealed a healing rate of 96.4% for the Shark Screw^® group, compared to 82.3% for the conventionally treated group. The Shark Screw^® group exhibited a tendency for faster bone healing (9.4 ± 3.2 vs. 12.9 ± 8.5 weeks, p = 0.05061). Hardware irritations led to six metal removals in the conventional group versus two in the Shark Screw^® group. The Shark Screw^® emerges as a promising option for personalized non-union treatment in the foot, ankle, and select lower leg cases, facilitating effective osteosynthesis and grafting within a single construct and promoting high union rates, low complications, and a rapid healing process. Full article

Clinical indications for the newly released Ti-Zr (Roxolid^®) alloy mini-implants (MDIs) aimed for overdenture (OD) retention in subjects with narrow alveolar ridges are not fully defined. The aim of this study was to analyze peri-implant and posterior edentulous area microstrains utilizing models of the mandible mimicking a “real” mouth situation with two (splinted with a bar or as single units) or four unsplinted Ti-Zr MDIs. The models were virtually designed from a cone beam computed tomography (CBCT) scan of a convenient patient and printed. The artificial mucosa was two millimeters thick. After MDI insertion, the strain gauges were bonded on the oral and vestibular peri-implant sites, and on distal edentulous areas under a denture. After attaching the ODs to MDIs, the ODs were loaded using a metal plate positioned on the first artificial molars (posterior loadings) bilaterally and unilaterally with 50, 100, and 150 N forces, respectively. During anterior loadings, the plate was positioned on the denture’s incisors and loaded with 50 and 100 N forces. Each loading was repeated 15 times. The means with standard deviations, and the significance of the differences (two- and three-factor MANOVA) were calculated. Variations in the MDI number, location, and splinting status elicited different microstrains. Higher loading forces elicited higher microstrains. Unilateral loadings elicited higher microstrains than bilateral and anterior loadings, especially on the loading side. Peri-implant microstrains were lower in the four-MDI single-unit model than in both two-MDI models (unsplinted and splinted). Posterior implants showed higher peri-implant microstrains than anterior in the four-MDI model. The splinting of the two-MDI did not have a significant effect on peri-implant microstrains but elicited lower microstrains in the posterior edentulous area. The strains did not exceed the bone reparatory mechanisms, although precaution and additional study should be addressed when two Ti-Zr MDIs support mandibular ODs. Full article

The bone healing process is influenced by various physiological factors. Fracture fixation traditionally relied on rigid metallic implants. However, excessively rigid constructs can lead to complications, necessitating revision surgery. This review focuses on approaches to improve bone healing by introducing adequate interfragmentary movement (IFM) at the fracture site. IFM promotes secondary fracture healing and callus formation. Studies suggest that rigid fixation may impair fracture healing by inhibiting callus formation and causing stress shielding. Titanium alloy locking plates have been shown to be biomechanically superior to stainless steel. Flexible fixation and techniques to regulate implant stiffness are crucial for managing fractures with bridge plating. Materials with a lower Young’s modulus balance biomechanical properties. A novel TiNbSn alloy with a low Young’s modulus has been developed to address stress shielding issues. It is effective in promoting osteosynthesis, bone healing, and superior mechanical properties compared with materials with higher Young’s moduli. The enhanced formation of bone and callus associated with TiNbSn alloy suggests its promise for use in fracture treatment plates. Understanding the biomechanics of fracture healing, optimizing fixation stiffness, and exploring innovative materials like TiNbSn alloys, are crucial for advancing approaches to accelerate and enhance bone healing. Full article

(1) Background: Anatomically pre-contoured plates usually require only minimal or even no intraoperative contouring. For complex cases, such plates also assist the surgeon as an anatomical template during fracture reduction. In this study, we present our experience of using a 3D printing technology for the treatment of bicondylar humeral fractures in feline cadavers. (2) Methods: Surgeries were performed on 15 pairs of front limbs amputated at the scapula. The limbs were obtained from 15 adult cats without obvious pathology of the skeleton. After flexion of the elbow and subperiosteal elevation of the anconeus muscle, the humeral Y-T fractures were created using a bone chisel and mallet. A custom-made anatomically pre-contoured interlocking plate was used to reduce and stabilise the medial aspect of the humeral condyle to the humeral diaphysis. After reduction of the humeral condyle, a positional locking screw was then inserted from the medial to the lateral side and a straight 2.4/2.7 interlocking bone plate was used to stabilise the lateral part of the condyle to the humeral diaphysis. (3) Results: The length of the humerus ranged from 98.2 to 107.0 mm and did not differ significantly between the left and right bone. The diameter of the isthmus of the humeral condyle ranged from 5.2 to 5.5 mm and did not differ significantly between the left and right bone. In all 30 limbs, bicondylar fracture was accompanied by epicondylar comminution. In 7/30 limbs (4 left, 3 right) the fracture of the humeral shaft was also present. In the left limbs, the postoperative articular surface defect of the humeral condyle was small (<1 mm) in 11/15 cases, moderate (1–2 mm) in 2/15 cases and large (>2 mm) in 2/15 cases in which the condylar screw was incorrectly inserted. In the right limbs, the postoperative articular surface defect of the humeral condyle was small (<1 mm) in 14/15 cases and moderate (1–2 mm) in 1 case. (4) Conclusions: 3D printing and the technology of metal powder sintering offers a wide range of possibilities for the development of new surgical implants. The anatomically pre-contoured bone plate appears to be a valuable tool in the reduction and stabilisation of Y-T humeral fractures in adult domestic cats weighing 3.0 to 4.5 kg. Full article

Background: To compare the potential of various bone evaluations by considering photon-counting CT (PCCT) and multiple energy-integrating-detector CT (EIDCT), including three dual-energy CT (DECT) scanners with standardized various parameters in both standard resolution (STD) and ultra-high-resolution (UHR) modes. Methods: Four cadaveric forearms were scanned using PCCT and five EIDCTs, by applying STD and UHR modes. Visibility of bone architecture, image quality, and a non-displaced fracture were subjectively scored against a reference EIDCT image by using a five-point scale. Image noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were also compared. To assess metal artifacts, a forearm with radial plate fixation was scanned by with and without Tin filter (Sn+ and Sn−), and virtual monoenergetic image (VMI) at 120 keV was created. Regarding Sn+ and VMI, images were only obtained from the technically available scanners. Subjective scores and the areas of streak artifacts were compared. Results: PCCT demonstrated significantly lower noise (p < 0.001) and higher bone SNR and CNR (p < 0.001) than all EIDCTs in both resolution modes. However, there was no significant difference between PCCT and EIDCTs in almost all subjective scores, regardless of scan modes, except for image quality where a significant difference was observed, compared to several EIDCTs. Metal artifact analysis revealed PCCT had larger artifact in Sn− and Sn+ (p < 0.001), but fewer in VMIs than three DECTs (p < 0.001 or 0.001). Conclusions: Under standardized conditions, while PCCT had almost no subjective superiority in visualizing bone structures and fracture line when compared to EIDCTs, it outperformed in quantitative analysis related to image quality, especially in lower noise and higher tissue contrast. When using PCCT to assess cases with metal implants, it may be recommended to use VMIs to minimize the possible tendency for artifact to be pronounced. Full article

This study aims to address the challenges associated with conventional metallic bone fixation plates in biomechanical applications, such as stainless steel and titanium alloys, including stress shielding, allergic reactions, corrosion resistance, and interference with medical imaging. The use of materials with a low elastic modulus is regarded as an effective approach to overcome these problems. In this study, the impact of different types of chopped carbon fiber-reinforced polyether ether ketone (CCF/PEEK) functionally graded material (FGM) bone plates on stress shielding under static and instantaneous dynamic loading was explored using finite element analysis (FEA). The FGM bone plate models were established using ABAQUS and the user’s subroutine USDFLD and VUSDFLD, and each model was established with an equivalent overall elastic modulus and distinctive distributions. The results revealed that all FGM bone plates exhibited lower stress shielding effects compared to metal bone plates. Particularly, the FGM plate with an elastic modulus gradually increased from the centre to both sides and provided maximum stress stimulation and the most uniform stress distribution within the fractured area. These findings offer crucial insights for designing implantable medical devices that possess enhanced mechanical adaptability. Full article