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Aim: Many different fixation methods have been proposed in the literature for the treatment of open bite. Beginning with the use of plates and screws, rigid fixation methods have become commonplace, however, open bite is a disorder prone to relapse despite rigid fixation. In our study, we aimed to eliminate the need for guided split usage during surgery and to increase postoperative stabilization in open bite patients with a new personalized plate design. Material and Method: For this purpose, a three-dimensional (3D) head model was created in the virtual environment. After the Le Fort I osteotomy on the model, the inferior segment of the maxilla was placed 1 cm forward and positioned to leave a space between the inferior and superior part of the maxilla. Different fixation methods were applied to fix the bone segments. In the first group, four plates with a thickness of 0.8 mm were fixed. In the other groups, we used three different thicknesses (0.4 mm, 0.6 mm, 0.8 mm) of the continuous plate we designed. The amount of movement and tension that occurred on the bone segments, plates, and screws were evaluated. Results: The maximum movement in the study was observed with the standard 4-plate fixation method, and the minimum movement was observed with the custom plate system with 11-screw type with a thickness of 0.8 mm. As a result, it has been found that the custom-made continuous plates provide a more rigid fixation than the standard plates. Conclusion: It may be possible to reduce the likelihood of a relapse problem by designing a plate with the appropriate thickness and form to spread the stress on the bone over a wider area. [ABSTRACT FROM AUTHOR]

Background: The most problematic complication of external fixation is infection at the pin insertion site. Technology that improves the adhesion of the external fixation pin to the skin, subcutaneous tissue, and bone may prevent infection at the pin site. The purpose of this study is to formulate a calcium phosphate–fibroblast growth factor (Cp-FGF) coating on a stainless-steel external fixation pin and to verify its effectiveness in reducing infection at the pin site and its possible influence on bone fixation in animal experiments. Methods: We compared stainless-steel screws without coating (SS group; n = 32), those with a calcium phosphate coating (Cp group; n = 30), those with a Cp-FGF coating (FGF group; n = 32), and those with a Cp-FGF coating having enhanced biological activity (FGF+ group; n = 32) in male Japanese white domesticated rabbits. Screws were inserted percutaneously into the bilateral proximal tibial diaphysis of the rabbits and implanted for 4 weeks. Screws and periscrew tissue were observed postoperatively for qualitatively assessing infection. Results: Infection assessment by gross findings after 4 weeks (at screw removal) showed no significant differences between the groups. Histopathological evaluation of soft tissue infection and bone tissue infection showed no significant differences between the groups for either soft tissue or bone tissue. Since neither the FGF+ group nor the FGF group showed anti-infective effects, the biological activity of FGF is not the only determining factor. We compared SEM, XRD, coating detaching test, sustained release test, and bioassay to examine physicochemical properties among the coatings but found no sufficient differences. Conclusions: It is suggested that improving the tissue adhesion to and/or biocompatibility of pins is also important to improve the in vivo performance of Cp-FGF-coated external fixation pins. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to evaluate, through qualitative and semi‐quantitative histological analysis, onlay autologous bone grafts fixed with ethyl‐cyanoacrylate adhesive and titanium screw, in order to verify whether the method of applying the adhesive would interfere with the graft incorporation. Materials and Methods: Fourteen rats underwent bone graft surgery: seven grafts were fixed with ethyl‐cyanoacrylate (SB group, n = 7) and seven grafts were fixed with titanium screws (TS group, n = 7). After 30 days, the grafts were histologically analysed for vitality, adhesive presence, tissue reaction with formation of osteoid matrix, bone resorption presence, capillaries formation, inflammatory infiltrate, fibroblastic proliferation, presence of osteoblasts, osteocytes and osteoclasts. The data were submitted to non‐parametric tests, Mann–Whitney, Fisher's Test, Wilcoxon and McNemar and to statistical analysis (p < 0.05). Results: No significant differences were found in the qualitative evaluations. While findings of more osteocytes (p = 0.035) in the TS group in greater inflammation (p = 0.030) and more osteoclasts (p = 0.048) in the SB. Despite the fact that the titanium screw has presented bone neoformation with welding points, there was no complete incorporation and the adhesive affected the bone repair in a way that not even neoformation points could be seen in 30 days. Conclusion: The method of applying the adhesive did not show an advantage according to the histological aspects studied, as there was the formation of a dead space at the interface of the SB group and the adhesive acted as a barrier. [ABSTRACT FROM AUTHOR]

Background: The most problematic complication of external fixation is infection at the pin insertion site. Technology that improves the adhesion of the external fixation pin to the skin, subcutaneous tissue, and bone may prevent infection at the pin site. The purpose of this study is to formulate a calcium phosphate–fibroblast growth factor (Cp-FGF) coating on a stainless-steel external fixation pin and to verify its effectiveness in reducing infection at the pin site and its possible influence on bone fixation in animal experiments. Methods: We compared stainless-steel screws without coating (SS group; n = 32), those with a calcium phosphate coating (Cp group; n = 30), those with a Cp-FGF coating (FGF group; n = 32), and those with a Cp-FGF coating having enhanced biological activity (FGF+ group; n = 32) in male Japanese white domesticated rabbits. Screws were inserted percutaneously into the bilateral proximal tibial diaphysis of the rabbits and implanted for 4 weeks. Screws and periscrew tissue were observed postoperatively for qualitatively assessing infection. Results: Infection assessment by gross findings after 4 weeks (at screw removal) showed no significant differences between the groups. Histopathological evaluation of soft tissue infection and bone tissue infection showed no significant differences between the groups for either soft tissue or bone tissue. Since neither the FGF+ group nor the FGF group showed anti-infective effects, the biological activity of FGF is not the only determining factor. We compared SEM, XRD, coating detaching test, sustained release test, and bioassay to examine physicochemical properties among the coatings but found no sufficient differences. Conclusions: It is suggested that improving the tissue adhesion to and/or biocompatibility of pins is also important to improve the in vivo performance of Cp-FGF-coated external fixation pins.

Background: Meniscal allograft transplantation (MAT) is an accepted and effective treatment option in the context of unsalvageable menisci, particularly in young and active patients. It has been shown to reduce pain and improve knee function in previously symptomatic patients. However, there is still limited knowledge about the long-term survival rates of allografts, the durability of clinical results, and the influence of patient-specific parameters, such as leg alignment, tibial slope, and preoperative International Cartilage Regeneration & Joint Preservation Society (ICRS) grade. Purpose: To determine (1) the long-term clinical success rate after MAT with bony fixation in a large, single-center cohort of consecutive patients, and (2) if patient-specific and procedural variables influence the clinical, anatomic, and subjective outcomes and risk of failure. Study Design: Case-control study; Level of evidence, 3. Methods: Data on 185 consecutive knees undergoing MAT in a single institution were prospectively collected and screened for inclusion in this study. The minimum follow-up time was 2 years. Radiographic variables (ICRS grade and Kellgren-Lawrence grade) were assessed preoperatively and at follow-up. Subjective patient-reported outcome measures (PROMs) (Lysholm score, Knee injury and Osteoarthritis Outcome Score [KOOS] including subscores, International Knee Documentation Committee [IKDC] score, and visual analog scale [VAS] score) were collected preoperatively and at follow-up. Clinical failure was defined as revision surgery due to graft failure or conversion to total knee arthroplasty. Anatomic failure was considered a tear covering >20% of the allograft, any peripheral tear, and unstable peripheral fixation leading to dislocation of the graft. Subjective failure was defined as Lysholm score ≤65. Preoperative tibial slope and leg alignment were assessed. Survival analyses were performed using the Kaplan-Meier estimate. Univariate and multivariate analyses were performed to determine risk factors for clinical and anatomic failure. Results: A total of 157 knees met inclusion criteria. After a mean follow-up time of 7 ± 3.5 years, 127 (80.9%) knees were free of clinical, anatomic, and subjective failure. Fourteen (8.9%) knees experienced clinical failure, 26 (16.6%) knees were identified as having experienced anatomic failure, and 13 (8.3%) patients experienced subjective failure with a reported Lysholm score of ≤65 at a mean follow-up of 7 years. Concurrent osteochondral allograft transplantation was identified as a predictor of both clinical (hazard ratio [HR], 4.55; 95% CI, 1.46-14.17; P =.009) and anatomic (HR, 3.05; 95% CI, 1.34-6.92; P =.008) failure. Cartilage damage of ICRS grade 3 or 4 of the index compartment conveyed an increased risk for clinical (HR, 3.41; 95% CI, 1.05-11.01; P =.04) and anatomic (HR, 3.04; 95% CI, 1.31-7.11; P =.01) failure. High-grade cartilage damage preoperatively (HR, 10.67; 95% CI, 1.037-109.768; P =.046), patient age >25 years (HR, 5.44; 95% CI, 0.120-246.070; P =.384), and a body mass index >30 (HR, 2.24; 95% CI, 0.748-6.705; P =.149) were associated with subjective failure. PROMs including KOOS and IKDC were significantly improved at final follow-up compared with preoperative scores across all measurements (P <.005). Conclusion: MAT showed good to excellent clinical results at a mean follow-up of 7 years. Low ICRS lesion grade was associated with a higher clinical and anatomic survival rate. Patients with concurrent OCA transplantation are at a higher risk of clinical and anatomic failure, but still report significantly improved PROMs. These results suggest that MAT has a lasting beneficial effect both in isolation and in complex cases with ≥1 concurrent procedures. [ABSTRACT FROM AUTHOR]

This study aimed to define basicervical and transcervical shear fractures using area classification and to determine the optimal osteosynthesis implants for them. The clinical outcomes of 1042 proximal femur fractures were investigated. A model of the proximal femur of a healthy adult was created from computed tomography images, and basicervical and transcervical shear fractures were established in the model. Osteosynthesis models were created using a short femoral nail with a single lag screw or two lag screws and a long femoral nail with a single lag screw or two lag screws. The minimum principal strains of the fracture surfaces were compared when the maximum loads during walking were applied to these models using finite element analysis software. Basicervical fractures accounted for 0.96% of all proximal femur fractures, 67% of which were treated with osteosynthesis; the failure rate was 0%. Transcervical shear fractures accounted for 9.6% of all proximal femur fractures, 24% of which were treated with osteosynthesis; the failure rate was 13%. Finite element analysis showed that transcervical shear fracture has high instability. To perform osteosynthesis, multiple screw insertions into the femoral head and careful postoperative management are required; joint replacement should be considered to achieve early mobility. [ABSTRACT FROM AUTHOR]

Abstract Purpose Ischemic time is a key factor in satisfactory functional results after forearm replantation. In this study, we provide a detailed description of our surgical technique, the temporary screw plate fixation technique, which aims to reduce ischemic time. Methods From June 2007 to June 2017, we performed a retrospective study of 20 patients who underwent forearm replantation. Eighteen cases involved male patients, and their mean age was 46 years. The mechanism of injury was roller injuries in 5 cases, power saw injuries in 3 cases, traffic accident in 7 cases, rope injuries in 2 cases, machinery injuries in 2 cases, and crushing injuries by rebar beam in 1 case. Results A total of 20 replantation patients survived. According to injury level, there were 3 cases of the proximal type, 11 cases of the middle type, and 6 cases of the distal type. The average time to revascularization was 331 min. The total operation time was, on average, 5.73 h. In the rest of the 18 cases, the temporary screw plate fixation technique was performed, and the average time required for bone shortening and plate fixation was 38.3 min. Conclusions To reduce ischemic time, we need a plan that progressively reduces time at each stage. Among our tips, temporary screw plate fixation can reduce the initial bone surgical operation to

Purpose: Ischemic time is a key factor in satisfactory functional results after forearm replantation. In this study, we provide a detailed description of our surgical technique, the temporary screw plate fixation technique, which aims to reduce ischemic time. Methods: From June 2007 to June 2017, we performed a retrospective study of 20 patients who underwent forearm replantation. Eighteen cases involved male patients, and their mean age was 46 years. The mechanism of injury was roller injuries in 5 cases, power saw injuries in 3 cases, traffic accident in 7 cases, rope injuries in 2 cases, machinery injuries in 2 cases, and crushing injuries by rebar beam in 1 case. Results: A total of 20 replantation patients survived. According to injury level, there were 3 cases of the proximal type, 11 cases of the middle type, and 6 cases of the distal type. The average time to revascularization was 331 min. The total operation time was, on average, 5.73 h. In the rest of the 18 cases, the temporary screw plate fixation technique was performed, and the average time required for bone shortening and plate fixation was 38.3 min. Conclusions: To reduce ischemic time, we need a plan that progressively reduces time at each stage. Among our tips, temporary screw plate fixation can reduce the initial bone surgical operation to < 40 min, does not have many complications, and can be used as definitive surgery. This method for bone fixation should be considered as a strategy to actively reduce operation time during forearm replantation. Level of evidence: Retrospective study, Level III. [ABSTRACT FROM AUTHOR]

Spinal disorders cover a broad spectrum of pathologies and are among the most prevalent medical conditions. The management of these health issues was noted to be increasingly based on surgical interventions. Spinal fixation devices are often employed to improve surgery outcomes, increasing spinal stability, restoring structural integrity, and ensuring functionality. However, most of the currently used fixation tools are fabricated from materials with very different mechanical properties to native bone that are prone to pull-out effects or fail over time, requiring revision procedures. Solutions to these problems presently exploited in practice include the optimal selection of screw shape and size, modification of insertion trajectory, and utilization of bone cement to reinforce fixation constructs. Nevertheless, none of these methods are without risks and limitations. An alternative option to increasing biomechanical resistance to the pull-out effect is to tackle bone regenerative capacity and focus on screw osteointegration properties. Osteointegration was reportedly enhanced through various optimization strategies, including use of novel materials, surface modification techniques (e.g., application of coatings and topological optimization), and utilization of composites that allow synergistic effects between constituents. In this context, this paper takes a comprehensive path, starting with a brief presentation of spinal fixation devices, moving further to observations on how the pull-out strength can be enhanced with existing methods, and further focusing on techniques for implant osteointegration improvement. [ABSTRACT FROM AUTHOR]

A known complication for mechanically loaded bone implants is the instability due to screw loosening, resulting in infection and the non-union of fractures. To investigate and eventually prevent such bone degradation, it is useful to know the stress state in the bone around the screw. Considering only in-plane loadings and simplifying the mandibular bone into an orthotropic laminated plate, the analysis was reduced to a two-dimensional pin-loaded plate problem. An analytic model, based on the complex stress analysis, was introduced to the bone biomechanics field to obtain the stress distributions around the screw hole in the bone. The dimensionless normalized stresses were found to be relatively insensitive to the locations of the screw hole over the mandible. Parametric analyses were carried out regarding the friction coefficient and load direction. It was found that the load direction had a negligible influence. On the contrary, the friction coefficient had a significant effect on the stress distributions. Whether the screw was well bonded or not thus played an important role. The proposed analytic model could potentially be used to study bone failure together with stress-based failure criteria. [ABSTRACT FROM AUTHOR]

Compared to metallic hardware, an effective bone adhesive can revolutionize the treatment of clinically challenging situations such as comminuted, articular, and pediatric fractures. The present study aims to develop such a bio-inspired bone adhesive, based upon a modified mineral-organic adhesive with tetracalcium phosphate (TTCP) and phosphoserine (OPS) by incorporating nanoparticles of polydopamine (nPDA). The optimal formulation, which was screened using in vitro instrumental tensile adhesion tests, was found to be 50%molTTCP/50%molOPS-2%wtnPDA with a liquid-to-powder ratio of 0.21 mL/g. This adhesive has a substantially stronger adhesive strength (1.0–1.6 MPa) to bovine cortical bone than the adhesive without nPDA (0.5–0.6 MPa). To simulate a clinical scenario of autograft fixation under low mechanical load, we presented the first in vivo model: a rat fibula glued to the tibia, on which the TTCP/OPS-nPDA adhesive (n = 7) was shown to be effective in stabilizing the graft without displacement (a clinical success rate of 86% and 71% at 5 and 12 weeks, respectively) compared to a sham control (0%). Significant coverage of newly formed bone was particularly observed on the surface of the adhesive, thanks to the osteoinductive property of nPDA. To conclude, the TTCP/OPS-nPDA adhesive fulfilled many clinical requirements for the bone fixation, and potentially could be functionalized via nPDA to offer more biological activities, e.g., anti-infection after antibiotic loading. [ABSTRACT FROM AUTHOR]

Spinal disorders cover a broad spectrum of pathologies and are among the most prevalent medical conditions. The management of these health issues was noted to be increasingly based on surgical interventions. Spinal fixation devices are often employed to improve surgery outcomes, increasing spinal stability, restoring structural integrity, and ensuring functionality. However, most of the currently used fixation tools are fabricated from materials with very different mechanical properties to native bone that are prone to pull-out effects or fail over time, requiring revision procedures. Solutions to these problems presently exploited in practice include the optimal selection of screw shape and size, modification of insertion trajectory, and utilization of bone cement to reinforce fixation constructs. Nevertheless, none of these methods are without risks and limitations. An alternative option to increasing biomechanical resistance to the pull-out effect is to tackle bone regenerative capacity and focus on screw osteointegration properties. Osteointegration was reportedly enhanced through various optimization strategies, including use of novel materials, surface modification techniques (e.g., application of coatings and topological optimization), and utilization of composites that allow synergistic effects between constituents. In this context, this paper takes a comprehensive path, starting with a brief presentation of spinal fixation devices, moving further to observations on how the pull-out strength can be enhanced with existing methods, and further focusing on techniques for implant osteointegration improvement.

The main purpose of spinal fixation is to provide conditions for vertebral fusion at the level of injury. Bone fusion is associated with many factors including stability of injured segment, restoration of the anterior support column, condition of the bone tissue and other aspects. The timing of bone formation can be affected by soft tissue inflammation at the site of the rods of the external fixation system. Peri-implant infection is reported to occur in 0.7-20 % of cases with external transpedicular fixation. The timing of the complication and the dependence of the frequency of the occurrence on the patient's treatment strategy are debatable. Another topical issue is the study of the consequences of peri-implant infection with the need to establish the validity of the assumption about the effect of peri-implant infection on the rate of bone formation using a clinical model. This would allow the findings to be used for new methods of treatment considering the risk of possible complications, giving preference to low-traumatic semi-closed methods of spine fixation. Nevertheless, external transpedicular fixation is practical for open spinal injury or significant vertebral displacement with the need of significant reduction efforts to be applied. The purpose was to explore the effect of soft tissue inflammation on the timing of bone formation with spinal fusion surgery using different surgical methods of treatment of uncomplicated spinal fractures. Material and methods The review included 111 patients with uncomplicated fractures of the lower thoracic and lumbar spine. Based on a retrospective analysis the participants were assigned to three groups depending on the presence/absence of peri-implant infection and the timing of the occurrence: 81 patients experienced no complications, 16 had serous-purulent inflammation of soft tissues at the site of the rods of the external fixation device that developed on average after 20 days with 14 patients seen with pin tract infection after 2 months of anterior fusion surgery and failed bone formation. Results Peri-implant infection rate was found to be higher with external fixation (14.4 %) than that with anterior fusion surgery (12.6 %). The complication rate was 1.85 times less with one-stage surgical treatment as compared to two-stage treatment. Peri-implant infection developed later (after 21‑63 days) with one-stage treatment as compared with two-stage procedure (after 12-24 days). Infection associated with the external fixation led to increase in timing of bone formation by 6-7 %, by 2-4 weeks on average. Bone formation failed in 35 % of cases (p < 0.0002) due to peri-implant inflammation caused by Staphylococcus aureus, as the common pathogen and the bacteria detected resulted in ineffective antibacterial therapy. Immunological parameters (IgM and haptoglobin) were quantified to assess the risk of peri-implant infection. Discussion Peri-implant infection rate associated with external transpedicular fixation was shown to be comparable with the previously obtained data. Sharply defined notions were reported earlier to differentiate between infectious peri-implant osteolysis and mechanical loosening. We compared the data on the duration of bone formation and the timing of peri-implant infection and developed a model that with high sensitivity (73 %) and specificity (100 %) allowed description of cases with impaired osteogenesis. Changes in some immunological parameters (immunoglobulins, acute-phase proteins) were shown to affect both bone formation and stability of bone fixation.

The oral and maxillofacial regions have complex anatomical structures and different tissue types, which have vital health and aesthetic functions. Biodegradable metals (BMs) is a promising bioactive materials to treat oral and maxillofacial diseases. This review summarizes the research status and future research directions of BMs for oral and maxillofacial applications. Mg-based BMs and Zn-based BMs for bone fracture fixation systems, and guided bone regeneration (GBR) membranes, are discussed in detail. Zn-based BMs with a moderate degradation rate and superior mechanical properties for GBR membranes show great potential for clinical translation. Fe-based BMs have a relatively low degradation rate and insoluble degradation products, which greatly limit their application and clinical translation. Furthermore, we proposed potential future research directions for BMs in the oral and maxillofacial regions, including 3D printed BM bone scaffolds, surface modification for BMs GBR membranes, and BMs containing hydrogels for cartilage regeneration, soft tissue regeneration, and nerve regeneration. Taken together, the progress made in the development of BMs in oral and maxillofacial regions has laid a foundation for further clinical translation.

A known complication for mechanically loaded bone implants is the instability due to screw loosening, resulting in infection and the non-union of fractures. To investigate and eventually prevent such bone degradation, it is useful to know the stress state in the bone around the screw. Considering only in-plane loadings and simplifying the mandibular bone into an orthotropic laminated plate, the analysis was reduced to a two-dimensional pin-loaded plate problem. An analytic model, based on the complex stress analysis, was introduced to the bone biomechanics field to obtain the stress distributions around the screw hole in the bone. The dimensionless normalized stresses were found to be relatively insensitive to the locations of the screw hole over the mandible. Parametric analyses were carried out regarding the friction coefficient and load direction. It was found that the load direction had a negligible influence. On the contrary, the friction coefficient had a significant effect on the stress distributions. Whether the screw was well bonded or not thus played an important role. The proposed analytic model could potentially be used to study bone failure together with stress-based failure criteria.

This work intended to elucidate, in an in vitro approach, the cellular and molecular mechanisms occurring during the bone healing process, upon implantation of a tailored degradable multifunctional Mg-based alloy. This was prepared by a conjoining anodization of the bare alloy (AZ31) followed by the deposition of a polymeric coating functionalized with hydroxyapatite. Human endothelial cells and osteoblastic and osteoclastic differentiating cells were exposed to the extracts from the multifunctional platform (having a low degradation rate), as well as the underlying anodized and original AZ31 alloy (with higher degradation rates). Extracts from the multifunctional coated alloy did not affect cellular behavior, although a small inductive effect was observed in the proliferation and gene expression of endothelial and osteoblastic cells. Extracts from the higher degradable anodized and original alloys induced the expression of some endothelial genes and, also, ALP and TRAP activities, further increasing the expression of some early differentiation osteoblastic and osteoclastic genes. The integration of these results in a translational approach suggests that, following the implantation of a tailored degradable Mg-based material, the absence of initial deleterious effects would favor the early stages of bone repair and, subsequently, the on-going degradation of the coating and the subjacent alloy would increase bone metabolism dynamics favoring a faster bone formation and remodeling process and enhancing bone healing. [ABSTRACT FROM AUTHOR]

Compared to metallic hardware, an effective bone adhesive can revolutionize the treatment of clinically challenging situations such as comminuted, articular, and pediatric fractures. The present study aims to develop such a bio-inspired bone adhesive, based upon a modified mineral-organic adhesive with tetracalcium phosphate (TTCP) and phosphoserine (OPS) by incorporating nanoparticles of polydopamine (nPDA). The optimal formulation, which was screened using in vitro instrumental tensile adhesion tests, was found to be 50%molTTCP/50%molOPS-2%wtnPDA with a liquid-to-powder ratio of 0.21 mL/g. This adhesive has a substantially stronger adhesive strength (1.0–1.6 MPa) to bovine cortical bone than the adhesive without nPDA (0.5–0.6 MPa). To simulate a clinical scenario of autograft fixation under low mechanical load, we presented the first in vivo model: a rat fibula glued to the tibia, on which the TTCP/OPS-nPDA adhesive (n = 7) was shown to be effective in stabilizing the graft without displacement (a clinical success rate of 86% and 71% at 5 and 12 weeks, respectively) compared to a sham control (0%). Significant coverage of newly formed bone was particularly observed on the surface of the adhesive, thanks to the osteoinductive property of nPDA. To conclude, the TTCP/OPS-nPDA adhesive fulfilled many clinical requirements for the bone fixation, and potentially could be functionalized via nPDA to offer more biological activities, e.g., anti-infection after antibiotic loading.

Background: The ability to utilize magnetic resonance imaging (MRI) to assess bony fixation in 3 dimensions may allow a better understanding of the implant design and bony integration. We hypothesized that a new 3-dimensionally printed cementless highly porous acetabular component (Stryker Trident II TritaniumTM) would show better fixation than an earlier cup from the same manufacturer as assessed by the noninvasive technique of multispectral MRI. Methods: Multiacquisition variable-resonance image combination selective metal suppression MRI was performed in 19 patients implanted with a new 3-dimensionally printed cup and 20 patients who had received a previous-generation cup from the same manufacturer at 1-year follow-up. Each cup was graded globally as well as by 9 specific zones. Integration grades were performed for each zone: 0, full bone integration; 1, fibrous membrane present; 2, osteolysis; and 3, fluid present. A mixed-effects logistic regression model was used to compare fixation between the 2 groups. Results: All cups in both cohorts showed greater than 90% estimated global bony integration (3-dimensionally printed cups, 99.4%; regular cups 91.6%) with no osteolysis or fluid observed in any cup. The 3-dimensionally printed cup had 1 of 171 zones (0.6%) graded as fibrous membrane present, while the 2-dimensional group had 15 of 180 zones (8.3%) graded as fibrous. Of note, screw hole regions were omitted but may be read as fibrous membrane areas. Conclusion: Using multiacquisition variable-resonance image combination selective MRI, our analysis showed greater osteointegration and less fibrous membrane formation in the 3-dimensionally printed cups than the control group at 1-year follow-up.

The aim of this study was to support surgeons to decide where to place the screws in order to achieve an optimal fracture healing and to prevent implant failure after a femoral shaft fracture So this paper focus on the analysis of bone-plate construct by using Finite element Analysis (FEA), comminuted femur fractured bone fixed with Dynamic Compression Plate (DCP) 16 holes by 4.5 Cortex screws, to investigate the effects of screws configuration on the mechanical behavior of different seven model as Interfragmentary strain which is the most important factor for femur fracture healing. The results state the relationships between the Von-Mises stress, Total deformation and Interfragmentary strain with respect to the screws configuration. The study shows the regions of maximum stress from stress distribution and also founded that we can decrease the Interfragmentary strain by increasing the number of screws.

Open reduction internal fixation metal plates and screws remain the established standard-of-care for complex fracture fixation. They, however, have drawbacks such as limited customization, soft-tissue adhesions, and a lack of degradation. Bone cements and composites are being developed as alternative fixation techniques in order to overcome these issues. One such composite is a strong, stiff, and shapeable hydroxyapatite-containing material consisting of 1,3,5-triazine-2,4,6-trione (TATO) monomers, which cures through high energy visible light-induced thiol-ene coupling (TEC) chemistry. Previous human cadaver and in vivo studies have shown that patches of this composite provide sufficient fixation for healing bone fractures; however, the composite lacks degradability. To promote degradation through hydrolysis, new allyl-functionalized isosorbide-based polycarbonates have been added into the composite formulation, and their impact has been evaluated. Three polycarbonates with allyl functionalities, located at the termini (aPC1 and aPC2) or in the backbone (aPC3), were synthesized. Composites containing 1, 3, and 5 wt % of aPCs 1-3 were formulated and evaluated with regard to mechanical properties, water absorption, hydrolytic degradation, and cytotoxicity. Allyl-functionalized polycaprolactone (aPCL) was synthesized and used as a comparison. When integrated into the composite, aPC3 significantly impacted the material's properties, with the 5 wt % aPC3 formulation showing a significant increase in degradation of 469%, relative to the formulation not containing any aPCs after 8 weeks' immersion in PBS, along with a modest decrease in modulus of 28% to 4.01 (0.3) GPa. Osteosyntheses combining the aPC3 3 and 5 wt % formulations with screws on synthetic bones with ostectomies matched or outperformed the ones made with the previously studied neat composite with regard to bending stiffness and strength in four-point monotonic bending before and after immersion in PBS. The favorable mechanical properties, increased degradation, and nontoxic characteristics of the materials present aPC3 as a promising additive for the TATO composite formulations. This combination resulted in stiff composites with long-term degradation that are suitable for bone fracture repair.

Open reduction internal fixation (ORIF) metal plates provide exceptional support for unstable bone fractures; however, they often result in debilitating soft‐tissue adhesions and their rigid shape cannot be easily customized by surgeons. In this work, a surgically feasible ORIF methodology, called AdhFix, is developed by combining screws with polymer/hydroxyapatite composites, which are applied and shaped in situ before being rapidly cured on demand via high‐energy visible‐light‐induced thiol–ene coupling chemistry. The method is developed on porcine metacarpals with transverse and multifragmented fractures, resulting in strong and stable fixations with a bending rigidity of 0.28 (0.03) N m2 and a maximum load before break of 220 (15) N. Evaluations on human cadaver hands with proximal phalanx fractures show that AdhFix withstands the forces from finger flexing exercises, while short‐ and long‐term in vivo rat femur fracture models show that AdhFix successfully supports bone healing without degradation, adverse effects, or soft‐tissue adhesions. This procedure represents a radical new approach to fracture fixation, which grants surgeons unparalleled customizability and does not result in soft‐tissue adhesions. [ABSTRACT FROM AUTHOR]

This work intended to elucidate, in an in vitro approach, the cellular and molecular mechanisms occurring during the bone healing process, upon implantation of a tailored degradable multifunctional Mg-based alloy. This was prepared by a conjoining anodization of the bare alloy (AZ31) followed by the deposition of a polymeric coating functionalized with hydroxyapatite. Human endothelial cells and osteoblastic and osteoclastic differentiating cells were exposed to the extracts from the multifunctional platform (having a low degradation rate), as well as the underlying anodized and original AZ31 alloy (with higher degradation rates). Extracts from the multifunctional coated alloy did not affect cellular behavior, although a small inductive effect was observed in the proliferation and gene expression of endothelial and osteoblastic cells. Extracts from the higher degradable anodized and original alloys induced the expression of some endothelial genes and, also, ALP and TRAP activities, further increasing the expression of some early differentiation osteoblastic and osteoclastic genes. The integration of these results in a translational approach suggests that, following the implantation of a tailored degradable Mg-based material, the absence of initial deleterious effects would favor the early stages of bone repair and, subsequently, the on-going degradation of the coating and the subjacent alloy would increase bone metabolism dynamics favoring a faster bone formation and remodeling process and enhancing bone healing.

Background: Fixation of bone flaps after craniotomy is a routine part of every neurosurgical procedure. The ideal fixation device should be safe, reliable, biologically inert, easy to use, and inexpensive and should not produce artifacts on neuroimaging. The authors describe a new device that meets these criteria. Methods: This is an observational, multicentric, and case series study of 56 patients who underwent a craniotomy and were subject to cranial bone flap fixation with the NT cranial small fixation system. A case--control group in whom titanium miniplates and screws were implanted was collected. All patients underwent CT scans of the head with 3D reconstruction at day 1 and day 90 postoperatively to evaluate bone flap position and fusion. Results: A total of 140 NT cranial small were implanted in 56 patients (mean age 44.2, range 22--63 years). The new device has shown stronger fixation qualities with optimal bone flap fusion and good cosmetic features. No surgical or relevant postsurgical follow-up complications have been associated with the device. Conclusion: Although this is a preliminary report in a relatively small number of patients, NT cranial small provides a safe, reliable, and easily applied postoperative cranial bone flap fixation system. [ABSTRACT FROM AUTHOR]

Biodegradable materials are used in two key sectors of orthopaedics – to fabricate bone fixators and scaffolds for bone tissue regeneration. In case of osteosynthesis, fixators made from biodegradable materials disappear from the body after a certain time. So, a necessity of a one more operation for their removal is excluded. In the present study, the acromioclavicular joint osteosynthesis plates made of magnesium alloy (WE43), titanium alloy (Ti-6Al-7Nb) and stainless steel (316L) are compared utilizing the finite element analysis. The research showed that stresses in the magnesium alloy plate were lower, compared to the titanium alloy plate or the stainless steel plate. However, the tensile strength of magnesium is over 2 times lower, as compared to stainless steel and 5 times lower, than titanium alloys. Magnesium alloy is not suitable for manufacturing plates with low thickness (2 and 2.5 mm), because the stresses generated in them exceed the yield strength of the material. Santrauka Biodegraduojančios medžiagos ortopedijoje naudojamos dviejose pagrindinėse srityse: kaulų fiksatorių ir kaulų regeneravimo karkasų gamyboje. Osteosintezės fiksatoriai iš biodegraduojančių medžiagų po tam tikro laiko organizme ištirpsta. Nereikia daryti pakartotinos operacijos ir juos išimti. Straipsnyje baigtinių elementų metodu lyginamos raktikaulio ir mentės sąnario osteosintezės plokštelės iš magnio lydinio (WE43), titano lydinio (Ti-6Al-7Nb) ir nerūdijančiojo plieno (316L). Tyrimas parodė, kad įtempiai magnio lydinio plokštelėje susidarė mažesni nei titano lydinio ar nerūdijančiojo plieno plokštelėje. Tačiau magnio stiprumo riba yra daugiau kaip perpus mažesnė nei nerūdijančiojo plieno ir net penkis kartus mažesnė nei titano lydinių. Magnio lydinys netinka gaminant mažesnio storio plokšteles (2 ir 2,5 mm), nes juose susidarė įtempiai, didesni už tamprumo ribą. Reikšminiai žodžiai: biodegraduojančios medžiagos, baigtinių elementų analizė, magnio lydinys.

Biodegradable materials are used in two key sectors of orthopaedics - to fabricate bone fixators and scaffolds for bone tissue regeneration. In case of osteosynthesis, fixators made from biodegradable materials disappear from the body after a certain time. So, a necessity of a one more operation for their removal is excluded. In the present study, the acromioclavicular joint osteosynthesis plates made of magnesium alloy (WE43), titanium alloy (Ti-6Al-7Nb) and stainless steel (316L) are compared utilizing the finite element analysis. The research showed that stresses in the magnesium alloy plate were lower, compared to the titanium alloy plate or the stainless steel plate. However, the tensile strength of magnesium is over 2 times lower, as compared to stainless steel and 5 times lower, than titanium alloys. Magnesium alloy is not suitable for manufacturing plates with low thickness (2 and 2.5 mm), because the stresses generated in them exceed the yield strength of the material. [ABSTRACT FROM AUTHOR]

Screw-shaped implants were prepared with three different surface topographies: One was left as machined, ie, a turned surface, and two were blasted surfaces with differing degrees of surface roughness. The surface topography was measured with a confocal laser scanning profilometer and the surface roughness was characterized using height and spatial descriptive parameters. The turned surface had an average surface roughness of 0.96 µm and an average peak spacing of 8.6 µm. The two blasted surfaces had surface roughness values of 1.16 µm and 1.94 µm, respectively; the corresponding values for the peak spacing parameter were 10.00 µm and 13.22 µm, respectively. After 1 year in rabbit bone, the bone response to the turned implants was compared with the response to the two blasted implant surfaces. Firmer bone fixation was found for the two blasted surfaces, with statistically significant increases in removal torque and percentage of bone-to-metal contact. Furthermore, about 2 mm from the implant surface, the titanium release was similar for the turned and the 25-µm aluminum oxide--blasted implants. [ABSTRACT FROM AUTHOR]

Purpose: The role of the proximal tibiofibular joint (PTFJ) in tibial plateau fractures is unknown. The purpose of this study was to assess, with finite-element (FE) calculations, differences in interfragmentary movement (IFM) in a split fracture of lateral tibial plateau, with and without intact fibula. It was hypothesized that an intact fibula could positively contribute to the mechanical stabilization of surgically reduced lateral tibial plateau fractures.Methods: A split fracture of the lateral tibial plateau was recreated in an FE model of a human tibia. A three-dimensional FE model geometry of a human femur-tibia system was obtained from the VAKHUM project database, and was built from CT images from a subject with normal bone morphologies and normal alignment. The mesh of the tibia was reconverted into a geometry of NURBS surfaces. The fracture was reproduced using geometrical data from patient radiographs, and two models were created: one with intact fibula and other without fibula. A locking screw plate and cannulated screw systems were modelled to virtually reduce the fracture, and 80 kg static body weight was simulated.Results: Under mechanical loads, the maximum interfragmentary movement achieved with the fibula was about 30% lower than without fibula, with both the cannulated screws and the locking plate. When the locking plate model was loaded, intact fibula contributed to lateromedial forces on the fractured fragments, which would be clinically translated into increased normal compression forces in the fractured plane. The intact fibula also reduced the mediolateral forces with the cannulated screws, contributing to stability of the construct.Conclusion: This FE model showed that an intact fibula contributes to the mechanical stability of the lateral tibial plateau. In combination with a locking plate fixation, early weight bearing may be allowed without significant IFM, contributing to an early clinical and functional recovery of the patient. [ABSTRACT FROM AUTHOR]

Mg-based biodegradable materials are considered promising candidates in the paediatric field due to their favourable mechanical and biological properties and their biodegrading potential that makes a second surgery for implant removal unnecessary. In many cases the surgical fixation technique requires a crossing of the growth plate by the implant in order to achieve an adequate fragment replacement or fracture stabilisation. This study investigates the kinetics of slowly and rapidly degrading Mg alloys in a transphyseal rat model, and also reports on their dynamics in the context of the physis and consecutive bone growth. Twenty-six male Sprague–Dawley rats received either a rapidly degrading (ZX50; n  = 13) or a slowly degrading (WZ21; n  = 13) Mg alloy, implanted transphyseal into the distal femur. The contralateral leg was drilled in the same manner and served as a direct sham specimen. Degradation behaviour, gas formation, and leg length were measured by continuous in vivo micro CT for up to 52 weeks, and additional high-resolution µCT (HRS) scans and histomorphological analyses of the growth plate were performed. The growth plate was locally destroyed and bone growth was significantly diminished by the fast degradation of ZX50 implants and the accompanying release of large amounts of hydrogen gas. In contrast, WZ21 implants showed homogenous and moderate degradation performance, and the effect on bone growth did not differ significantly from a single drill-hole defect. Statement of Significance This study is the first that reports on the effects of degrading magnesium implants on the growth plate in a living animal model. The results show that high evolution of hydrogen gas due to rapid Mg degradation can damage the growth plate substantially. Slow degradation, however, such as seen for WZ21 alloys, does not affect the growth plate more than drilling alone, thus meeting one important prerequisite for deployment in paediatric osteosynthesis. [ABSTRACT FROM AUTHOR]

In this study, we investigated the in vitro cytotoxicity and in vivo biosafety of reinforced polylactide (PLA) composites with hyaluronic acid-chitosan (HACS) complex and β-tricalcium phosphate ( β-TCP) powder. The cytotoxicity of HACS/PLA (with β-TCP) composites was almost the same as that of neat PLA indicating that HACS/PLA (with β-TCP) composites did not have toxic effects. In in vivo biosafety tests using X-ray and micro-CT imaging, HACS/PLA (with β-TCP) composites did not show any fracture during 20 weeks of implantation in the tibia and femur of rabbits. The HACS/PLA (with β-TCP) composites did not induce severe inflammatory responses such as recruitment of macrophages around the implantation site, as assessed by H&E and immune staining of biopsy samples, for 6 weeks after insertion into SD rats. Addition of β-TCP powder to HACS/PLA composite enhanced bone induction and regeneration. The HACS/PLA composites prepared in the present study have potential maxillofacial and orthopedic applications. [ABSTRACT FROM AUTHOR]

This review covers several aspects of the rapid development of magnesium (Mg) alloys from the owned properties and corrosion mechanism to the effect of optimization of mechanical properties, alloying and surface coating preparation. Firstly, the category of biomedical materials and commonly used metal-based implant materials are briefly presented. Then, advantages and disadvantages of Mg-based biomedical materials are listed. To solve the poor mechanical properties and high corrosion rate of Mg-based materials, effective methods are adopted. Heat-treated can adjust and transform internal structure, shape and distribution of the second phase, and plastic deformation can enhance mechanical properties by refining grains of dynamic recrystallization and decreasing structure segregation. Alloying will enhance corrosion resistance by improving the structure distribution, grain refinement, and solid solution ability; surface modification can protect the substrate from corrosion by preventing a direct contact with body fluids. Finally, applications as the bone fixation and vascular stent are discussed in detail. This review hopes that it can provide experienced researchers in the field of Mg-based biomedical materials an opportunity and approach to obtain the latest research direction and progress information, and give useful guidance for newcomers to understand the market. [ABSTRACT FROM AUTHOR]

Curing and treatment of accidental injuries in birds that have the nature of complex, old and contaminated wounds demand maximum caution from the surgeon. Birds, in particular wild fowl, are sensitive to manipulation during examinations and the diagnosis of the injuries. The estimate of the complexity of an injury and the general condition of the patient are of key importance for the correct choice of diagnostic procedures, anesthesia, and the operative procedure. The implementation of ketamine and diazepam for general injection anesthesia provides possibilities for the unhindered executing of the surgical procedure. The implementation of Kischner needles and pins is a good choice for the fixation of long bones in birds. The postoperative course in the patient requires constant medical and professional supervision which must be followed to the letter.