Combined application of artificial bone powders and concentrated growth factor membranes on the autotransplantation of mature third molars: A 5-year retrospective case series.

AIM: This study aimed to observe the efficacy and outcomes of the combined application of artificial bone powder and concentrated growth factor (CGF) membranes for tooth transplantation in cases with wide recipient sockets and small donor teeth. MATERIAL AND METHODS: A total of 36 teeth from 36 patients with wide recipient sockets and small donor teeth were enrolled. Autogenous tooth transplantation was performed using bone powders and CGF membranes. After transplantation, the visual analog scale (VAS) score, Landry Wound Healing Index, probing depth (PD), mobility, and gray value of the alveolar bone around the transplanted teeth were measured, and a patient satisfaction questionnaire was administered. All patients underwent clinical and radiographic examinations during follow-up. RESULTS: The VAS score of 16 (44.4%) cases after 1 week was 0, and 26 (72.2%) patients showed excellent gingival healing after 2-4 weeks. The PD of a few cases was deeper than 3 mm during the first month; however, returned to normal after 3 months. Although the majority of the transplanted teeth possessed mobility greater than grade I during the first month, the mobility gradually improved within 3 months. The gray value of the alveolar bone around the transplanted teeth, 1 year postoperatively showed no difference with pre-operation (p > .05). During the mean follow-up period of 42.7 months (range 20-72 months), 33 of the 36 transplanted teeth remained in situ without clinical or radiographic complications, with an overall success rate of 91.7%. CONCLUSIONS: Although the PD and mobility of the transplanted teeth were not ideal during the early stages of healing, most of the transplanted teeth had good clinical outcomes. In cases with large recipient sites accompanied by small donor teeth, autotransplantation of teeth using artificial bone powder combined with CGF membranes is a viable option and can lead to optimistic results with favorable success rates.

Preparation of Cu2+/TA/HAP composite coating with anti-bacterial and osteogenic potential on 3D-printed porous Ti alloy scaffolds for orthopedic applications.

Because of stress shielding effects, traditional titanium (Ti) alloy scaffolds have a high elastic modulus, which might promote looseness and bone disintegration surrounding the implant, increasing the likelihood of a second surgery. In contrast, 3D-printed porous Ti alloy scaffolds can reduce the scaffold weight while enhancing biocompatibility. Further, these scaffolds' porous nature allows bone tissue ingrowth as well as strong pore connectivity, which can improve nutrient absorption. Nevertheless, bare Ti alloy implants may fail because of inadequate bone integration; hence, adding a coating on the implant surface is an effective technique for improving implant stability. In this study, a composite coating comprising hydroxyapatite (HAP), chitosan (CS), tannic acid (TA) and copper ions (Cu2+) (Cu2+/TA/HAP composite coating) was prepared on the surface of 3D printed porous Ti alloy scaffolds using electrophoretic deposition. Using the standard plate count method, Live/Dead bacteria staining assay, FITC Phalloidin and 4',6-diamidino-2-phenylindole staining assay, and live/dead staining of cells we determined that the composite coating has better antibacterial properties and cytocompatibility as well as lower cytotoxicity. The Alkaline Phosphatase assay revealed that the coating results showed good osteogenesis potential. Overall, the composite coatings produced in this investigation give new potential for the application of Ti alloys in clinics.

Platelets: A Potential Factor that Offers Strategies for Promoting Bone Regeneration.

Bone defects represent a prevalent category of clinical injuries, causing significant pain and escalating health care burdens. Effectively addressing bone defects is thus of paramount importance. Platelets, formed from megakaryocyte lysis, have emerged as pivotal players in bone tissue repair, inflammatory responses, and angiogenesis. Their intracellular storage of various growth factors, cytokines, and membrane protein receptors contributes to these crucial functions. This article provides a comprehensive overview of platelets' roles in hematoma structure, inflammatory responses, and angiogenesis throughout the process of fracture healing. Beyond their application in conjunction with artificial bone substitute materials for treating bone defects, we propose the potential future use of anticoagulants such as heparin in combination with these materials to regulate platelet number and function, thereby promoting bone healing. Ultimately, we contemplate whether manipulating platelet function to modulate bone healing could offer innovative ideas and directions for the clinical treatment of bone defects.

Three-Dimensional Modeling with Osteoblast-like Cells under External Magnetic Field Conditions Using Magnetic Nano-Ferrite Particles for the Development of Cell-Derived Artificial Bone.

The progress in artificial bone research is crucial for addressing fractures and bone defects in the aging population. However, challenges persist in terms of biocompatibility and structural complexity. Nanotechnology provides a promising avenue by which to overcome these challenges, with nano-ferrite particles (NFPs) exhibiting superparamagnetic properties. The ability to control cell positioning using a magnetic field opens up new possibilities for customizing artificial bones with specific shapes. This study explores the biological effects of NFPs on osteoblast-like cell lines (MC3T3-E1), including key analyses, such as cell viability, cellular uptake of NFPs, calcification processes, cell migration under external magnetic field conditions, and three-dimensional modeling. The results indicate that the impact of NFPs on cell proliferation is negligible. Fluorescence and transmission electron microscopy validated the cellular uptake of NFPs, demonstrating the potential for precise cell positioning through an external magnetic field. Under calcification-inducing conditions, the cells exhibited sustained calcification ability even in the presence of NFPs. The cell movement analysis observed the controlled movement of NFP-absorbing cells under an external magnetic field. Applying a magnetic field along the z-axis induced the three-dimensional shaping of cells incorporating NFPs, resulting in well-arranged z-axis directional patterns. In this study, NFPs demonstrated excellent biocompatibility and controllability under an external magnetic field, laying the foundation for innovative treatment strategies for customizing artificial bones.

Synthesis of Tubular Hydroxyapatite and Its Application in Polycaprolactone Scaffold Materials.

Nano-hydroxyapatite (HAp) is an ideal material in the field of biomedicine due to its good biocompatibility and bioactivity. However, a significant drawback of pure HAp materials is their inferior mechanical properties. Therefore, in this rigorous investigation, the optimal calcium-to-phosphorus ratio for the synthesis of HAp was meticulously delineated, followed by its nuanced modification using KH550 (γ-aminopropyltriethoxysilane). This was further amalgamated with polycaprolactone (PCL) with the aim of providing a superior material alternative within the domain of bone scaffold materials. The post-modified HAp demonstrated enhanced interfacial compatibility with PCL, bestowing the composite with superior mechanical characteristics, notably a peak bending strength of 6.38 ± 0.037 MPa and a tensile strength of 3.71 ± 0.040 MPa. Scanning electron microscope (SEM) imagery revealed an intriguing characteristic of the composite: an initial ascension in porosity upon HAp integration, subsequently followed by a decline. Beyond this, the composite not only exhibited stellar auto-degradation prowess but also realized a sustained release cycle of 24 h, markedly optimizing drug utility efficiency. A kinetic model for drug dispensation was developed, positing an adherence to a pseudo-second-order kinetic principle. In tandem, through the formulation of an intra-particle diffusion model, the diffusion mechanisms pre- and post-modification were deeply probed. Cytotoxicity assays underscored the composite's exemplary biocompatibility. Such findings accentuate the vast potential of the modified HAp-PCL composite in bone tissue engineering, heralding a novel and efficacious avenue for impending bone defect amelioration.

An analytical model to measure dental implant stability with the Advanced System for Implant Stability Testing (ASIST).

A non-invasive method of quantitatively assessing dental implant stability is important to monitor its long-term health. The Advanced System for Implant Stability Testing (ASIST) is a noninvasive technique that couples the impact technique with a linear vibration model of the implant system, such that the measured signal can be used to determine a matching analytical response. The purpose of this study was to evaluate the ASIST technique by comparing stability estimates obtained from artificial implant installations with various abutments. Two Straumann dental implants were installed in four densities of uniform polyurethane foam, and the stability of each installation was measured using different healing abutments and artificial dental crowns. With the ASIST, values for the estimated interfacial stiffness increased with foam density and did not significantly change with abutment type for a specific sample. This provides evidence that the analytical model is representative of the physical system. Current methods, such as resonance frequency analysis, interpret the interface stiffness based on a single frequency measurement. With the ASIST, the measured signal provides information about the first and second modes of vibration of the implant system, both of which are influenced by the properties of the corresponding abutment. The consideration of both modes allows the technique to reliably measure the interfacial stiffness independently of the system components. As a result, the ASIST technique may provide an improved non-invasive method of measuring the stability of dental implants.

3D-printed PCL/ß-TCP/CS composite artificial bone and histocompatibility study.

BACKGROUND: Tissue-engineered bone materials are an effective tool to repair bone defects. In this study, a novel biodegradable polycaprolactone (PCL)/ß-tricalcium phosphate (ß-TCP)/calcium sulfate (CS) composite scaffold was prepared by using three-dimensional (3D) printing technology. METHODS: Scanning electron microscopy, gas expansion displacement, and contact goniometry were used to examine the 3D-printed PCL/ß-TCP/CS composite scaffolds. The results showed that the PCL/ß-TCP/CS scaffolds possessed controllable porosity, hydrophobicity, biodegradability, and suitable apatite mineralization ability. To confirm the bone regenerative properties of the fabricated composite scaffolds, scaffold extracts were prepared and evaluated for their cytotoxicity to bone marrow mesenchymal stem cells (BMSCs) and their ability to induce and osteogenic differentiation in BMSCs. RESULTS: The PCL/ß-TCP/CS composite scaffolds induced a higher level of differentiation of BMSCs than the PCL scaffolds, which occurred through the expression of bone metastasis-related genes. The New Zealand white rabbit radial defect experiment further demonstrated that PCL/ß-TCP/CS scaffolds could promote bone regeneration. CONCLUSIONS: In summary, the 3D-printed PCL/ß-TCP/CS composite porous artificial bone has good cytocompatibility, osteoinductivity, and histocompatibility, which make it an ideal bone material for tissue engineering.

The influence of truncated-conical implant length on primary stability in maxillary and mandibular regions: an in vitro study using polyurethane blocks.

OBJECTIVES: This in vitro study is aimed at assessing whether implant primary stability is influenced by implant length in artificial bone with varying densities. MATERIALS AND METHODS: A total of 120 truncated-conical implants (60 long-length: 3p L, 3.8 × 14 mm; 60 short-length: 3p S, 3.8 × 8 mm) were inserted into 20, 30, and 40 pounds per cubic foot (PCF) density polyurethane blocks. The insertion torque (IT), removal torque (RT), and resonance frequency analysis (RFA) values were recorded for each experimental condition. RESULTS: In 30 and 40 PCF blocks, 3p S implants exhibited significantly higher IT values (90 and 80 Ncm, respectively) than 3p L (85 and 50 Ncm, respectively). Similarly, RT was significantly higher for 3p S implants in 30 and 40 PCF blocks (57 and 90 Ncm, respectively). However, there were no significant differences in RFA values, except for the 20 PCF block, where 3pS implants showed significantly lower values (63 ISQ) than 3p L implants (67 ISQ) in both the distal and mesial directions. CONCLUSIONS: These results demonstrated that the implant's length mainly influences the IT and RT values in the polyurethane blocks that mimic the mandibular region of the bone, resulting in higher values for the 3p S implants, while the RFA values remained unaffected. However, in the lowest density block simulating the maxillary bone, 3p L implants exhibited significantly higher ISQ values. CLINICAL RELEVANCE: Therefore, our data offer valuable insights into the biomechanical behavior of these implants, which could be clinically beneficial for enhancing surgical planning.

Comparing Bone Fusion Rates Between Novel Unidirectional Porous Tricalcium Beta-Phosphate and Autologous Bone in Lumbar Lateral Interbody Fusion: A Two-Year Radiographic Outcome Study.

This retrospective cohort study aims to examine the potential differences in bone fusion between autologous bone and artificial bone in the lumbar lateral interbody fusion at 2two years post-surgery. The bone fusions performed in 15 cases and at 34 intervertebral levels were compared to assess the differences between the artificial bone, Affinos® (Kuraray Co., Tokyo, Japan), and autogenous bone. Two years post-surgery, we evaluated computed tomography (CT) multi-planar reconstruction images in the coronal and sagittal planes. One year after surgery, out of the 24 windows, 17 (70.8%) windows transplanted with autologous bones showed bone fusion. Additionally, out of the 38 windows, 18 (47.4%) windows transplanted with Affinos® showed bone fusion. Two years post-surgery, out of the 24 windows, 19 (79.2%) windows transplanted with autologous bones showed bone fusion. Additionally, out of the 38 windows, 30 (79.0%) windows transplanted with Affinos® showed bone fusion, and no difference was observed in the fusion rate at two years post-surgery (P = 0.238). In cases using Affinos® for transplanted bone, the bone fusion rate increased between one and two years. The rate of bony fusion using Affinos® in lateral lumbar interbody fusion (LLIF) cages is at par with that of autologous bone grafts at two years post-surgery. Affinos® is a promising candidate for graft material in LLIF surgery.

Osteocyte-Like Cells Differentiated From Primary Osteoblasts in an Artificial Human Bone Tissue Model.

In vitro models of primary human osteocytes embedded in natural mineralized matrix without artificial scaffolds are lacking. We have established cell culture conditions that favored the natural 3D orientation of the bone cells and stimulated the cascade of signaling needed for primary human osteoblasts to differentiate into osteocytes with the characteristically phenotypical dendritic network between cells. Primary human osteoblasts cultured in a 3D rotating bioreactor and incubated with a combination of vitamins A, C, and D for up to 21 days produced osteospheres resembling native bone. Osteocyte-like cells were identified as entrapped, stellate-shaped cells interconnected through canaliculi embedded in a structured, mineralized, collagen matrix. These cells expressed late osteoblast and osteocyte markers such as osteocalcin (OCN), podoplanin (E11), dentin matrix acidic phosphoprotein 1 (DMP1), and sclerostin (SOST). Organized collagen fibrils, observed associated with the cell hydroxyapatite (HAp) crystals, were found throughout the spheroid and in between the collagen fibrils. In addition to osteocyte-like cells, the spheroids consisted of osteoblasts at various differentiation stages surrounded by a rim of cells resembling lining cells. This resemblance to native bone indicates a model system with potential for studying osteocyte-like cell differentiation, cross-talk between bone cells, and the mineralization process in a bonelike structure in vitro without artificial scaffolds. In addition, natural extracellular matrix may allow for the study of tissue-specific biochemical, biophysical, and mechanical properties. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Aerogel-Based Materials in Bone and Cartilage Tissue Engineering-A Review with Future Implications.

Aerogels are fascinating solid materials known for their highly porous nanostructure and exceptional physical, chemical, and mechanical properties. They show great promise in various technological and biomedical applications, including tissue engineering, and bone and cartilage substitution. To evaluate the bioactivity of bone substitutes, researchers typically conduct in vitro tests using simulated body fluids and specific cell lines, while in vivo testing involves the study of materials in different animal species. In this context, our primary focus is to investigate the applications of different types of aerogels, considering their specific materials, microstructure, and porosity in the field of bone and cartilage tissue engineering. From clinically approved materials to experimental aerogels, we present a comprehensive list and summary of various aerogel building blocks and their biological activities. Additionally, we explore how the complexity of aerogel scaffolds influences their in vivo performance, ranging from simple single-component or hybrid aerogels to more intricate and organized structures. We also discuss commonly used formulation and drying methods in aerogel chemistry, including molding, freeze casting, supercritical foaming, freeze drying, subcritical, and supercritical drying techniques. These techniques play a crucial role in shaping aerogels for specific applications. Alongside the progress made, we acknowledge the challenges ahead and assess the near and far future of aerogel-based hard tissue engineering materials, as well as their potential connection with emerging healing techniques.

Artificial Bone Graft Substitutes for Curettage of Benign and Low-Grade Malignant Bone Tumors: Clinical and Radiological Experience with Cerasorb.

Background: Artificial bone graft substitutes (ABGS) for curettage of bone tumors are becoming increasingly popular. The aim of this retrospective analysis was to determine the efficacy of the ABGS Cerasorb (Curasan-AG, Kleinostheim, Germany), a beta-tricalcium phosphate (beta-TCP), concerning resorption profile, bone healing, and remodeling after surgery and to evaluate potential complications. Methods: Forty-three patients suffering from benign and low-grade malignant bone tumors were treated with curettage and refilling of the bony cavity using the ABGS Cerasorb between 2018 and 2021 and included in the final analysis. Clinical follow-up exams with X-rays in two planes were performed 6 weeks, 3 months, 6 months, and 1 year after surgery. Results: After a mean follow-up period of 14.6 months, radiological consolidation following curettage was observed in all patients. Total resorption was observed in 16.3% of patients; in the other 83.7%, resorption was partial. In four patients, of whom two had a tumor in the distal femur and two in the humeral diaphysis, fractures occurred within 6 weeks after primary surgery. Conclusion: In conclusion, the beta-TCP Cerasorb seems to be a reliable bone graft substitute with low complication rates and is a suitable alternative to autologous bone grafts or allografts. Nonetheless, it shows a tendency of delayed resorption. Level of Evidence: III; retrospective cohort study.

Biomechanical properties of artificial bones made by Sawbones: A review.

Biomedical engineers and physicists frequently use human or animal bone for orthopaedic biomechanics research because they are excellent approximations of living bone. But, there are drawbacks to biological bone, like degradation over time, ethical concerns, high financial costs, inter-specimen variability, storage requirements, supplier sourcing, transportation rules, etc. Consequently, since the late 1980s, the Sawbones® company has been one of the world's largest suppliers of artificial bones for biomechanical testing that counteract many disadvantages of biological bone. There have been many published reports using these bone analogs for research on joint replacement, bone fracture fixation, spine surgery, etc. But, there exists no prior review paper on these artificial bones that gives a comprehensive and in-depth look at the numerical data of interest to biomedical engineers and physicists. Thus, this paper critically reviews 25 years of English-language studies on the biomechanical properties of these artificial bones that (a) characterized unknown or unreported values, (b) validated them against biological bone, and/or (c) optimized different design parameters. This survey of data, advantages, disadvantages, and knowledge gaps will hopefully be useful to biomedical engineers and physicists in developing mechanical testing protocols and computational finite element models.

Mechanical Properties of Synthetic Bones Made by Synbone: A Review.

Biomechanical engineers and physicists commonly employ biological bone for biomechanics studies, since they are good representations of living bone. Yet, there are challenges to using biological bone, such as cost, degradation, disease, ethics, shipping, sourcing, storage, variability, etc. Therefore, the Synbone® company has developed a series of synthetic bones that have been used by biomechanical investigators to offset some drawbacks of biological bone. There have been a number of published biomechanical reports using these bone surrogates for dental, injury, orthopedic, and other applications. But, there is no prior review paper that has summarized the mechanical properties of these synthetic bones in order to understand their general performance or how well they represent biological bone. Thus, the goal of this article was to survey the English-language literature on the mechanical properties of these synthetic bones. Studies were included if they quantitatively (a) characterized previously unknown values for synthetic bone, (b) validated synthetic versus biological bone, and/or (c) optimized synthetic bone performance by varying geometric or material parameters. This review of data, pros, cons, and future work will hopefully assist biomechanical engineers and physicists that use these synthetic bones as they develop experimental testing regimes and computational models.

Synthesis of ß-tricalcium phosphate by modifying the heating process of a dental casting mold.

This study investigated a novel method for artificial synthesis of ß-tricalcium phosphate (ß-TCP). The binder of the phosphate-bonded investment was replaced with calcium oxide instead of magnesium oxide and sintered in an electric furnace. The water/powder mixing ratio for hardening was determined using preliminary experiments. Thermal analysis was performed to check the thermal behavior of the sample tested. In addition, the fired sample was analyzed using an X-ray diffraction apparatus to identify the compounds after sintering. The hardened sample exhibited multiple compounds, including unreacted components, post which, new compounds were generated by heating. Peaks of calcium pyrophosphate and ß-TCP were confirmed at 800ºC and 1,300ºC, respectively. ß-TCP could be easily synthesized within the limited study by sintering at 1,300ºC both monoammonium phosphate and calcium oxide. Experimental results suggest that ß-TCP can be easily synthesized by simulating the conventional dental casting process.

A Comparison of Conical and Cylindrical Implants Inserted in an In Vitro Post-Extraction Model Using Low-Density Polyurethane Foam Blocks.

Combining tooth extraction and implant placement reduces the number of surgical procedures that a patient must undergo. Thus, the present study aimed to compare the stability of two types of conical implants (TAC and INTRALOCK) and another cylindrical one (CYROTH), inserted with a range of angulation of 15-20 degrees in low-density polyurethane blocks (10 and 20 pounds per cubic foot, PCF) with or without a cortical lamina (30 PCF), which potentially mimicked the post-extraction in vivo condition. For this purpose, a total of 120 polyurethane sites were prepared (10 for each implant and condition) and the Insertion Torque (IT), Removal Torque (RT), and Resonance Frequency Analysis (RFA) were measured, following a Three-Way analysis of variance followed by Tukey's post hoc test for the statistical analysis of data. The IT and RT values registered for all implant types were directly proportional to the polyurethane density. The highest IT was registered by INTRALOCK implants in the highest-density block (32.44 ± 3.28 Ncm). In contrast, the highest RFA, a well-known index of Implant Stability Quotient (ISQ), was shown by TAC implants in all clinical situations (up to 63 ISQ in the 20 PCF block without the cortical sheet), especially in lower-density blocks. Although more pre-clinical and clinical studies are required, these results show a better primary stability of TAC conical implants in all tested densities of this post-extraction model, with a higher ISQ, despite their IT.

Analysis of risk factors for non-fusion of bone graft in anterior cervical discectomy and fusion: A clinical retrospective study.

BACKGROUND: Bone graft fusion is a major concern among surgeons after Anterior Cervical Discectomy and Fusion (ACDF) surgery as non-fusion may lead to further physical and drug therapies. METHODS: The related risk elements of non-fusion of bone graft in ACDF surgery were retrospectively assessed. Patients receiving ACDF operation in our hospital from January 2015 to December 2019 were retrospectively analyzed. According to the criteria, 107 study subjects were recruited with a total of 164 surgical segments. The general information of patients, bone graft materials, imaging parameters, and clinical efficacy was recorded. T-test, chi-square test and binary logistic regression evaluation were employed to explore the risk factors of bone graft nonunion. RESULTS: Low housefield unit (HU) value, diabetes, allogeneic bone, and hydroxyapatite (HA) artificial bone could be risk factors for bone graft fusion in ACDF surgery. Further multivariate analysis was performed and confirmed those related factors of bone graft non-fusion including low HU value (non-fusion rate: 32.53% [27/83], OR = 5.024, p = 0.025), diabetes (non-fusion rate: 53.33% [8/15], OR = 4.776, p = 0.031), allogeneic bone (18.57% [13/70], OR = 3.964, p = 0.046), and artificial bone (68.29% [28/41], OR = 50.550, p < 0.01). CONCLUSION: By looking at bone graft fusion, selecting autologous iliac bone is an ideal selection to avoid non-fusion of bone graft in ACDF. Diabetes was more important predictor of bone graft nonunion than low HU value. Larger sample size and longer follow-up are required to further confirm these findings in the future.

Open reduction and Kirschner wire fixation method using a cylindrical block of unidirectional porous ß-tricalcium phosphate for tongue-shaped calcaneal fracture: Report of three cases.

Background: The artificial bone grafts are performed on the defect after reduction of the calcaneal fracture. Generally, it is an artificial bone graft with an implant, and there are a few reports of an artificial bone graft without an implant. Cases: We report three cases (42-year-old male, 67-year-old male, 21-year-old female) of a tongue-shaped calcaneal fracture treated using a cylindrical unidirectional porous ß-tricalcium phosphate artificial bone (Affinos®, Kurare co Ltd., Hyougo, Japan) to surgically repair bone defects after reduction. The bone defect is often observed when fracture is reduced in calcaneal fracture. There were significant bone defects, which were then fixed using Affinos® (forming a cylindrical shape block; diameter 10 mm x height 20 mm) to support the bone fragment, an artificial ß-tricalcium phosphate bone with a porosity of 57 % (pore size 25-300 µm), characterized by a novel unidirectional porous structure. Postoperative early rehabilitation started with partial load from 5 weeks after surgery and was full weight bearing at 9 weeks after surgery. There was no correction loss and good bone fusion was obtained. By 12 months postoperatively, patients were able to be walking without pain and absorption and bone fusion around the artificial bone were observed maintaining the morphology immediately after reduction. The result was a good clinical result of one excellent (92 points) and two good (81 and 84 points) 1 year after surgery in the postoperative AOFAS Ankle-Hindfoot Scale. Conclusion: Affinos® has a frost-like structure, which endows it with good tissue invasive properties because of the capillary effect. Moreover, it has excellent osteoconduction capability. In these 3 cases, Affinos® showed good strength, affinity, absorption, and bone substitution in a tongue-shaped calcaneal fracture. Further prospective studies are required to confirm our findings.

Simulated full weight bearing following posterior column acetabular fracture fixation: a biomechanical comparability study.

PURPOSE: The incidence of acetabular fractures (AFs) is increasing in all industrial nations, with posterior column fractures (PCFs) accounting for 18.5-22% of these cases. Treating displaced AFs in elderly patients is a known challenge. The optimal surgical strategy implementing open reduction and internal fixation (ORIF), total hip arthroplasty (THA), or percutaneous screw fixation (SF), remains debated. Additionally, with either of these treatment methods, the post-surgical weight bearing protocols are also ambiguous. The aim of this biomechanical study was to evaluate construct stiffness and failure load following a PCF fixation with either standard plate osteosynthesis, SF, or using a screwable cup for THA under full weight bearing conditions. METHODS: Twelve composite osteoporotic pelvises were used. A PCF according to the Letournel Classification was created in 24 hemi-pelvis constructs stratified into three groups (n = 8) as follows: (i) posterior column fracture with plate fixation (PCPF); (ii) posterior column fracture with SF (PCSF); (iii) posterior column fracture with screwable cup fixation (PCSC). All specimens were biomechanically tested under progressively increasing cyclic loading until failure, with monitoring of the interfragmentary movements via motion tracking. RESULTS: Initial construct stiffness (N/mm) was 154.8 ± 68.3 for PCPF, 107.3 ± 41.0 for PCSF, and 133.3 ± 27.5 for PCSC, with no significant differences among the groups, p = 0.173. Cycles to failure and failure load were 7822 ± 2281 and 982.2 ± 428.1 N for PCPF, 3662 ± 1664 and 566.2 ± 366.4 N for PCSF, and 5989 ± 3440 and 798.9 ± 544.0 N for PCSC, being significantly higher for PCPF versus PCSF, p = 0.012. CONCLUSION: Standard ORIF of PCF with either plate osteosynthesis or using a screwable cup for THA demonstrated encouraging results for application of a post-surgical treatment concept with a full weight bearing approach. Further biomechanical cadaveric studies with larger sample size should be initiated for a better understanding of AF treatment with full weight bearing and its potential as a concept for PCF fixation.