Femur Research Articles

Red cell distribution width: a potential marker of reduced femoral neck bone mineral density in men and postmenopausal women

Red cell distribution width: a potential marker of reduced femoral neck bone mineral density in men and postmenopausal women

An MRI-Derived Formula for Estimating the Native Joint Line Position in the Presence of Distal Femoral Bone Loss

An MRI-Derived Formula for Estimating the Native Joint Line Position in the Presence of Distal Femoral Bone Loss

Sex hormone deficiency in male and female mice expressing the Alzheimer’s disease-associated risk-factor TREM2 R47H variant impacts the musculoskeletal system in a sex- and genotype-dependent manner

Abstract The R47H variant of the Triggering Receptor Expressed on Myeloid Cells 2 (TREM2) is a risk factor for Alzheimer’s disease in humans and leads to lower bone mass accrual in female but not male 12-month-old mice. To determine whether, as with aging, gonadectomy results in sex-specific musculoskeletal effects, gonad removal or SHAM surgery were performed in 4-month-old TREM2R47H/+ mice and wild type (WT) male and female littermates (n = 10-12/group), with sexes analyzed separately. Body weight was lower in males, but higher in females after gonadectomy, independently of their genotype. Gonadectomy also lead to decreased BMD in males at all sites and in whole body (total) and spine in female mice for both genotypes. Total and femur BMD was lower in gonadectomized male mice 6-weeks post-surgery, independently of the genotype. On the other hand, BMD was only lower in ovariectomized WT but not TREM2R47H/+ mice in all sites measured at this time point. Bone formation and resorption markers levels were not affected by orchiectomy, whereas CTX was higher 3 weeks after surgery and P1NP showed a tendency towards lower values at the 6 weeks timepoint only in ovariectomized WT mice. μCT analyses showed no differences resulting from gonadectomy in structural parameters in femoral cortical bone for either sex, but lower tissue mineral density in males of either genotype 6 weeks post-surgery. Nevertheless, biomechanical properties were overall lower in gonadectomized males of either genotype, and only for WT ovariectomized mice. Distal femur cancellous bone structure was also affected by gonadectomy in a genotype- and sex-dependent manner, with genotype-independent changes in males, and only in WT female mice. Thus, expression of the TREM2 R47H variant minimally alters the impact of gonadectomy in the musculoskeletal system in males, whereas it partially ameliorates the consequences of ovariectomy in female mice.

Experimental investigation on the mechanical properties of Ti6Al4V cellular structures produced with selective laser melting: Effects of rib thickness, unit cell type and orientation

The objective of this study is to investigate the mechanical performance of Ti6Al4V cellular structures, including different unit cell forms such as honeycomb, re-entrant, hybrid (honeycomb + re-entrant), and chiral structures manufactured with selective laser melting. The study examines the influence of rib thickness and unit cell orientation on compressive strength, elasticity modulus, Poisson's ratio, energy absorption, and specific energy absorption. Increasing the rib thickness of the unit cells improved not only the compressive strength and elasticity modulus of the samples but also their energy absorption capacities. The mechanical properties of the cellular structures varied with changes in unit cell orientation, and no direct relationship was found. The highest values for compressive strength, energy absorption, and specific energy absorption were observed in re-entrant structures, while hybrid structures had the highest elasticity modulus values. It was also found that chiral structures had the lowest compressive strength, modulus of elasticity and energy absorption capacity of all the parameters investigated. In addition, re-entrant structures with negative Poisson's ratio tend to perform positive Poisson’s ratio when they are subjected to deformation under compression. The elasticity modulus of the biocompatible Ti6Al4V cellular structures is similar to that of femoral bone values. These structures meet the requirements for use in the core of implants. The results obtained from this experimental study may guide researchers in the field of biomechanics.

Relationship between the microstructural energy release rate of cortical bone and age under compression condition

Most studies evaluated the energy release rate of cortical bone macrostructure under Mode I, Mode II, and mixed Mode I-II loading conditions. However, testing the macrostructural energy release rate requires an initial crack and recording the applied load and the corresponding crack length in real-time, which may introduce measurement errors and differences with the actual fracture scenarios. To further understand how the energy release rate contributed to the cortical bone fracture characteristics, this study predicted the microstructural energy release rate of cortical bone and then investigated its age-related varitions. The microstructural energy release rate of femoral cortical bone in rats from different ages was back-calculated by fitting the experimental and simulated load–displacement curves under compression load. The trends in the microstructural energy release rate were revealed, and the underlying reasons for the age-related changes were investigated by integrating the discussion on the cortical bone mechanical parameters at various levels obtained from the previous experiment. The predicted microstructural energy release rate of femoral cortical bone in the rats from 1, 3, 5, 7, 9, 11, and 15 months of age were in the range of 0.08–0.12, 0.12–0.14, 0.15–0.19, 0.25–0.28, 0.23–0.25, 0.19–0.22, and 0.13–0.16 N/mm, respectively. The statistical analyses showed the significant differences in the microstructural energy release rate at different ages. The results indicated an increasing trend followed by a decrease from 1 to 15 months of age, and the correlations between microstructural energy release rate and age were significant. The age-related variations in the microstructural energy release rate may be linked to the changes in the microarchitecture, and the fracture load is influenced by the micro-level mechanical parameters. Notably, the age-related trends in microarchitecture and energy release rate were similar. These findings were valuable for understanding the mechanism underlying the weakening mechanical properties of cortical bone microstructure with age from an energy perspective.

Hypoxia-Preconditioned Human Umbilical Cord Mesenchymal Stem Cells Transplantation Ameliorates Inflammation and Bone Regeneration in Peri-Implantitis Rat Model.

The failure of dental implant treatments is predominantly attributed to peri-implantitis, which entails chronic inflammation within the peri-implant tissue, ultimately leading to tissue degradation. Addressing this condition, human umbilical cord mesenchymal stem cell (hUCMSC) transplantation serves as a regenerative therapy; however, concerns regarding the viability and efficacy of transplanted cells in inflamed regions persist. Hypoxic preconditioning of hUCMSCs has emerged as a potential strategy for augmenting their regenerative and immunomodulatory capacities. This study aimed to evaluate the expression of inflammatory (tumor necrosis factor [TNF]-α) and bone regenerative biomarkers (nuclear factor of activated T-cell [NFATc1], osteocalcin, collagen type I alpha 1 [COL1α1]) within peri-implantitis models subsequent to the transplantation of hypoxia-preconditioned hUCMSCs. Peri-implantitis models were established through the insertion of implants into the femur bone of 42 Wistar strain Rattus norvegicus, followed by intrasocket injection of lipopolysaccharide. The experimental animals were categorized into three groups (control, normoxia, and hypoxia) and underwent observation on days 14 and 28. The expression levels of TNF-α, NFATc1, COL1α1, and osteocalcin were evaluated using immunohistochemical staining, and the resulting data were subjected to one-way analysis of variance analysis (p < 0.05). Transplantation of hypoxia-preconditioned hUCMSCs significantly ameliorated inflammation and osteoclastogenesis, as evidenced by significant reductions in TNF-α and NFATc1 expression compared with the control group. Furthermore, hypoxic preconditioning of hUCMSCs demonstrated a significant elevation in the expression of osteocalcin and COL1α1 relative to the control group. The transplantation of hypoxia-preconditioned hUCMSCs exhibited a capacity to ameliorate inflammation and enhance bone regenerative processes in peri-implantitis rat models.

Preparation and Characterization of Mechanical Properties of HAP/45S5 Bioglass Laminated Ceramic Composites via Spark Plasma Sintering

Hydroxyapatite (HAP) displays a high degree of similarity to the inorganic components that make up roughly 70% of human hard tissue, and it possesses exceptional biological activity and biocompatibility. It is currently internationally recognized as the most biologically active hard tissue implant material. However, its substandard mechanical properties have significantly limited the application of HAP in areas requiring load bearing or in the repair of large bone defects. In this study, HAP/45S5 bioglass laminated ceramic composites were consolidated using the spark plasma sintering (SPS) technique. The grain growth and phase transformation of HAP and 45S5 bioglass were examined at various sintering temperatures. The mechanical properties of the laminated composites were investigated. At 950 °C, the flexural strength and fracture work of the sintered body were (153.22 ± 7.7) MPa and (2049 ± 34) J·m−2, respectively. These results corresponded to the load–displacement curves and showed that the composites met the mechanical performance requirements of the support material.

Effect of Acetylsalicylic Acid Application on Gait Score and Femur Osteometry in Broiler Chickens

The current research examined the effects of adding 0.03%, 0.06%, 0.1%, 0.3%, and 0.6% acetylsalicylic acid (ASA) to drinking water between 24-45 days on gait score and femur osteometry. The gait score average of the birds slaughtered on the 49th day was above 3, and no difference was found between the groups. It was determined that ASA treatment did not affect the osteometric and index values of the femur bones taken and examined after slaughter. In conclusion, it was concluded that ASA was not effective in preventing skeletal deformations caused by rapid growth in broilers.

Incorporating Hydrogel (with Low Polymeric Content) into 3D-Printed PLGA Scaffolds for Local and Sustained Release of BMP2 in Repairing Large Segmental Bone Defects.

Treating large bone defects remains a considerable challenge for clinicians: bone repair requires scaffolds with mechanical properties and bioactivities. Herein, based on crosslinking o-phthalaldehyde (OPA) with amine groups, 4-arm polyethylene glycol (4armPEG)-OPA/Gelatin hydrogel loaded with bone morphogenetic protein 2 (BMP2) is prepared and a three dimensional (3D)-printed poly (lactic-co-glycolic acid) (PLGA) porous scaffold is filled with the hydrogel solution. The composite scaffold, with a compression modulus of 0.68 ±0.097GPa similar to the cancellous bone, has a porosity of 56.67 ± 4.72% and a pore size of about 380µm, promoting bone growth. The hydrogel forms a porous network at low concentrations, aiding protein release and cell migration. The hydrogel degrades in approximately three weeks, and the scaffold takes five months, matching bone repair timelines. BMP2 release experiment shows a sustained BMP2 release with a 72.4 ± 0.53% release ratio. The ALP activity test and alizarin red staining shows effective osteogenic promotion, while RT-PCR confirms BMP2@Gel enhanced COL-1 and OPN expression. Animal experiments further validate the composite scaffold's bone repair efficacy. This study demonstrates the effectiveness of the hydrogel in releasing BMP2 and the mechanical support of the 3D-printed PLGA porous scaffold, providing a new treatment for bone defects.

Plating after tumor curettage in human femora does not efficiently improve torsional stability ex vivo

BackgroundSurgical treatments of benign primary bone tumors of the femur face the challenge of limiting tissue damage and contamination while providing sufficient stabilization to avoid fracture. While no clear treatment guidelines exist, surgical treatment commonly consists of femoral fenestration and curettage with optional filling and plating of the defect. Mono- or bicortical plating of distal femoral defects aim to reduce fracture risk and have been shown to increase axial stability. However, it remains unclear whether plating increases torsional stability of the affected femur. Questions/purposesThis biomechanical study aimed to determine how much additional stability can be achieved by mono- or bicortical plating of femoral defects after fenestration. The following hypotheses were investigated: 1. Preventive plating of distal femur bone defects enhances torsional stability when compared to femoral fenestration alone. 2. A condition close to the intact (nonpathological) bone can be achieved by bone plating. 3. Defect shape influences torsional stability. Patients and methodsThiel embalmed human femora (n = 24) were left intact or subjected to the following surgical treatments (A) defect creation via fenestration, (B) defect with short monocortical plating, (C) defect with long bicortical plating. All femora were torsion tested in midstance position using pre-cycling and testing until failure. Quantitative computed tomography pre and post testing allowed bone mineral density calculation and crack path analysis. Finite element analysis provided insight into defect shape variations. ResultsTorsion experiments showed no relevant enhancement of torsional stability due to mono- or bicortical plating. There were no significant differences in maximum torque between unplated and plated femora with defect (defect: 35.38 ± 7.53 Nm, monocortical plating: 37.77 ± 9.82 Nm, bicortical plating: 50.27 ± 9.72 Nm, p > 0.05). Maximum torque for all treatment groups was significantly lower compared to intact femora (155–200 Nm, p < 0.001). Cracks originated predominantly from the proximal posterior corner of the defect and intersected with screw holes in plated femora. The influence of variations of the defect corner shapes had no significant influence on maximum torque and angle. ConclusionThis biomechanical study shows that mono- or bicortical plating is not an effective preventive treatment against torsional failure of femora with distal defects as the resulting maximum torque was drastically reduced compared to intact femora. Thus, the initial hypotheses have to be rejected. As habitual loading of the femur includes a combination of axial and torsional loading, the observed lack of prevention against torsional failure might help to explain the occurrence of fractures despite plating. Future research towards ameliorating clinical outcome should address the role of defect filling with bone cement or bone grafts regarding the improvement of torsional stability after primary bone tumor treatment in the femur.

Shape modelling reveals age-related knee bony shape changes in asymptomatic knees.

Osteoarthritis (OA) causes bony shape changes within the knee. Furthermore, the risk of developing OA increases with age. However, age alone does not cause OA. It is therefore important to understand the healthy age-related trajectories of knee shape before attributing these changes to OA. The aim of this study was to determine the association between bony knee shape and age using statistical-shape modelling (SSM). 96 participants received a CT scan of their knee. Three-dimensional models were created using manual segmentation. Separate SSM's for the distal femur and proximal tibia were created. Linear regression models were used to assess the association between age and femoral and tibial shape. Fourteen modes of the femoral and tibial SSM's captured 68% and 73% shape variation, respectively. Only femoral mode 3 and tibial mode 7 were associated with age. Increasing age was related to larger femoral bone volume and deepening of the femoral trochlear groove. Furthermore, increased age was associated with medial tibial plateau expansion. Aspects of bony femoral and tibial shape were significantly associated with aging, including femoral and tibial bone size, femoral trochlear groove, and medial tibial plateau area. Changes in knee morphology occur as a normal process of aging without osteoarthritis development. This may be a response to mechanical loading over time. Further research investigating the effect of these changes on loading in the knee may provide valuable information for knee health in older age.

Optimized Methyl methacrylate embedding of small and large undecalcified bones.

Methyl methacrylate (MMA) plastic embedding has been long established as a technique for the processing and histological assessment of bones. It provides the added benefit over paraffin in that it does not require decalcification of the tissue in order visualize the cellular detail, thus preserving vital information about the amount of unmineralized osteoid present in addition to the degree of mineralization in the bone. It also allows for the incorporation of dynamic histomorphometric analysis through the retention of fluorescent labels incorporated into the bone. Efficient infiltration of hard tissue is essential to the processing of bones and producing quality slides suitable for achieving usable quantifiable histology out the other end. This technique:• Updates previously published MMA embedding protocols to reflect utilization of stabilized acrylamides (over the unstabilized reagents of the past)• Outlines the techniques that are important for embedding both small (mus), medium (rattus), and large (porcine, lagomorph, human) histological samples.• Updates the clearing and infiltration processes utilized and validates quality of the sample preparation though histological staining to confirm preservation of cellular detail, mineralization information, and enzymatic activity

Electrophoretic deposition of curcumin-loaded mesoporous bioactive glass nanoparticle-chitosan composite coatings on titanium for treating tumor-induced bone defect

Clinical treatment of osteosarcoma (OS) presents significant challenges in postoperative tumor recurrence and large segmental bone defects, often necessitating joint replacement or artificial bone implantation to repair failed or defective bone tissue. At the same time, fibroblastic encapsulation can impede direct contact between implants and bones, leading to implant failure. To tackle these issues, mesoporous bioactive glass nanoparticles (MBN) were synthesized and then loaded with curcumin (CUR). Subsequently, chitosan (CTS) was chosen as the charger and coating matrix, and electrophoretic deposition (EPD) was utilized to fabricate a CTS-MBN-CUR composite coating with triple functionality on Ti implants aiming for OS-induced bone repair. MBN-CUR nanoparticles are encapsulated in CTS and uniformly distributed within the coating, achieving robust adhesion and long-term release of CUR. Concurrently, the developed CTS-MBN-CUR coating exhibits moderate hydrophilicity, and good bioactivity. Moreover, three different types of cells, MC3T3-E1, L929, and MG63 cells, were individually cultured with the composite coating and subjected to comprehensive cellular studies. The coating presented favorable bioactivities, and osteogenic performance, and the ability to resist the activity of fibroblast and OS cells. These findings suggest that CTS-MBN-CUR holds promising potential for bone regeneration following OS resection surgery.

Stress transfer, stress shielding, and micro-movement analysis in the implanted femoral bone region with various hip implant stem materials: a finite element approach

Stress transfer, stress shielding, and micro-movement analysis in the implanted femoral bone region with various hip implant stem materials: a finite element approach

Gu Sui Bu (Drynaria fortunei J. Smith) prevents osteoporosis in ovariectomized rats by inhibiting pyroptosis through NLRP3/GSDMD/CASPASE-1

Traditional Chinese medicine Gu Sui Bu (Drynaria fortunei J. Smith) has the effect of tonifying the kidneys and strengthening bone. There are many modern studies on the anti-osteoporosis pharmacological mechanism of Drynariae, but no reports on the pharmacological mechanism of Drynariae improving cell pyroptosis and anti-osteoporosis have been found. AimThis study aims to verify the changes in cellular standard indicators in postmenopausal osteoporosis, thereby revealing the participating mechanism of pyroptosis and the intervention effect of Gu Sui Bu (Drynaria fortunei J. Smith) . MethodsDrynariae was subjected to UHPLC-Q-Orbitrap-MS/MS analysis, and the OVX rat model was constructed in vivo as the research object. It was divided into sham operation group (SHAM), ovariectomized osteoporosis model group (OVX) and bone fragmentation. Supplementary drug group (TFRD-L, TFRD-H). After 3 months of modeling, the medication group was treated with Drynariae and the samples were collected after 12 weeks of intervention. ELISA was used to detect the levels of Caspase-1, NLRP3, GSDMD, IL-1β, and IL-18 in rat serum; the right femur was taken for Micro-CT large bone microstructure scanning and femoral BMD detection; the femur was subjected to rat histopathology HE, TRAP staining; immunohistochemistry and immunofluorescence staining of rat histopathology were performed. WB and PCR were used to observe the expression of cell pyroptosis-related indicators Caspase-1, NLRP3, GSDMD and RUNX2, IL-1β, and IL-18. ResultsUHPLC-Q-Orbitrap-MS/MS analysis the main compounds in Gu Sui Bu (Drynaria fortunei J. Smith) samples were identified. These 9 chemical components are Palmitic acid, Fisetin, Caffeic acid, Naringin, Rutin, Uridine, Cafestol, Astilbin . Rat Micro-CT, The results of HE staining and TRAP showed that compared with the rats in the OVX group, the number of bone trabeculae in the rats in the Gu Sui Bu (Drynaria fortunei J. Smith) medication group (TFRD-L, TFRD-H) increased, became wider and thicker, and the bone density increased. Continuity increases and bone lacunae decrease. Rat serum ELISA, femoral tissue immunohistochemistry, immunofluorescence staining and WB, PCR showed that compared with the OVX group, Caspase-1, NLRP3, The expression levels of GSDMD and inflammation were reduced (p<0.05), and the expression of osteogenic marker RUNX2 was reduced and increased (p<0.05). ConclusionThe traditional Chinese medicine Gu Sui Bu (Drynaria fortunei J. Smith) can improve the bone density of ovariectomized osteoporosis model rats and significantly enhance the bone microstructure. At the same time, it reduced the expression of rat cell pyroptosis markers Caspase-1, NLRP3, and GSDMD in vivo, confirming that Gu Sui Bu (Drynaria fortunei J. Smith) may play an anti-osteoporosis effect through the NLRP3/GSDMD/Caspase-1 pathway.

Progressive pseudorheumatoid dysplasia involving a novel CCN6 mutation: a case report

ObjectiveThis study aims to report a case of progressive pseudorheumatoid dysplasia (PPRD) with two kinds of cellular communication network factor 6 (CCN6) gene mutation. In this paper, the clinical profile and the process of diagnosis were analyzed, and the related literature was reviewed. A 15-year-old boy, who developed progressive ankle and hip joint pain and enlargement with spine involvement, was diagnosed with PPRD. The erythrocyte sedimentation rate and C-reactive protein (CRP) were in the normal range; rheumatoid factor and anti-cyclic citrullinated peptide antibody (ACPA) were all negative. Human leukocyte antigen 27 (HLA-B27) was also negative. Cene study discovered two kinds of mutations in CCN6 gene: c. 802T&amp;gt;C and c.624dup. Radiographic studies revealed spine platyspondyly and shaped beaked, osteoporosis, and bilateral symmetric bony enlargements of the interphalangeal joints. Hip shows bilateral acetabulum and femoral head bone marrow edema, which revealed hip arthritis. Gene detection, laboratory examination, and typical radiographic features are helpful for the diagnosis of PPRD. This is the first report of c. 802T&amp;gt;C and c.624dup mutations in patients with PPRD in our country.

3D Bioprinting Strategies for Melatonin‐Loaded Polymers in Bone Tissue Engineering

AbstractBone pathologies are still among the most challenging issues for orthopedics. Over the past decade, different methods are developed for bone repair. In addition to advanced surgical and graft techniques, polymer‐based biomaterials, bioactive glass, chitosan, hydrogels, nanoparticles, and cell‐derived exosomes are used for bone healing strategies. Owing to their variation and promising advantages, most of these methods are not translated into clinical practice. Three dimensonal (3D) bioprinting is an additive manufacturing technique that has become a next‐generation biomaterial technique adapted for anatomic modeling, artificial tissue or organs, grafting, and bridging tissues. Polymer‐based biomaterials are mostly used for the controlled release of various drugs, therapeutic agents, mesenchymal stem cells, ions, and growth factors. Polymers are now among the most preferable materials for 3D bioprinting. Melatonin is a well‐known antioxidant with many osteoinductive properties and is one of the key hormones in the brain–bone axis. 3D bioprinted melatonin‐loaded polymers with unique lipophilic, anti‐inflammatory, antioxidant, and osteoinductive properties for filling large bone gaps following fractures or congenital bone deformities may be developed in the future. This study summarized the benefits of 3D bioprinted and polymeric materials integrated with melatonin for sustained release in bone regeneration approaches.

Compositional Variations in Calcium Phosphate Cement and Poly(Lactic-Co-Glycolic-Acid) Porogens Do Not Affect the Orthotopic Performance of Calcium Phosphate Cement/Poly(Lactic-Co-Glycolic-Acid) Cements.

Calcium phosphate cement (CPC) has evolved as an appealing bone substitute material, especially since CPCs were combined with poly(lactic-co-glycolic acid) (PLGA) porogens to render the resulting CPC/PLGA composite degradable. In view of the multiple variables of CPC and PLGA used previously, the effect of CPC composition and PLGA porogen morphology (i.e., microspheres versus microparticles) on the biological performance of CPC/PLGA has not yet been investigated. Consequently, we here aimed to evaluate comparatively various CPC/PLGA formulations varying in CPC composition and PLGA porogen morphology on their performance in a rabbit femoral condyle bone defect model. CPCs with a composition of 85 wt% α-TCP, 15 wt% dicalcium phosphate anhydrate (DCPA) and 5 wt% precipitated hydroxyapatite (pHA), or 100 wt% α-TCP were combined with spherical or irregularly shaped PLGA porogens (CPC/PLGA ratio of 60:40 wt% for all formulations). All CPC/PLGA formulations were applied via injection in bone defects, as created in the femoral condyle of rabbits, and retrieved for histological evaluation after 6 and 12 weeks of implantation. Descriptive histology and quantitative histomorphometry (i.e., material degradation and new bone formation) were used for analyses. Descriptively, all CPC/PLGA formulations showed material degradation at the periphery of the cement within 6 weeks of implantation. After 12 weeks, bone formation was observed extending into the defect core, replacing the degraded CPC/PLGA material. Quantitatively, similar material degradation (up to 87%) and new bone formation (up to 28%) values were observed, irrespective of compositional variations of CPC/PLGA formulations. These data prove that neither the CPC compositions nor the PLGA porogen morphologies as used in this work affect the biological performance of CPC/PLGA formulations in a rabbit femoral condyle bone defect model.

Prediction of Femoral Bone Strength in the Presence of Tumors and Tumor-like Lesions Using Finite Element Analysis.

Patients with bone tumors in their femurs are at risk of developing pathological fractures. Tumors with high fracture risk, especially fragile malignant lesions, are treated surgically. However, it is difficult to estimate bone strength based on clinical and radiographic findings. This study aimed to determine whether finite element analysis (FEA) provides useful information on the bone strength of femurs with tumors and tumor-like lesions. Total femoral computed tomography (CT) data (slice thickness, 0.5 mm) were retrospectively obtained from 18 patients with femoral bone tumors. Three-dimensional FEA of femurs were developed using CT data. The virtual femoral head compression test and direct three-point bending test were performed on the femurs using FEA to predict bone strength and fracture location. The compression direction was parallel to the mechanical axis, whereas that of the three-point bending test was applied to the tumor itself. In the femoral head compression test using FEA, 13 out of 18 femurs with bone tumors fractured at the femoral head, while 14 out of 18 femurs fractured at the tumor site during the virtual direct three-point bending test. The median loads predicted using the femoral head compression test were significantly higher than those predicted by the direct three-point bending test. The FEA results indicated that pathological fractures are unlikely to occur during normal walking. Direct external forces applied to the tumor body may lead to fractures.

Influence of genotype on carcass composition, metric traits of the digestive system and leg bones of laying hens after the egg-production season

Context The genotype of laying hens is one of the most important factors influencing their carcass composition and anatomical features. Aims The aim of the present study was to compare two genotypes of laying hens, Lohmann Brown and Lohmann White, after the laying period. Methods The experimental material consisted of 26 carcasses obtained after slaughtering spent laying hens at the age of 83 weeks. Key results The genotype of the birds had a significant (P &lt; 0.05) effect on carcass weight, and the proportion (%) of the breast muscle, leg muscle and gizzard weight. Significant correlations were also found between bodyweight and the weight of the stomach, proventriculus, liver and spleen. The origin of the laying hens also had a significant impact on the length of the sections on intestinal segments, namely, jejunum, ileum and colon. Significant differences in the correlations between bodyweight and length of duodenum, jejunum and rectum were also found. The compared hybrids of laying hens differed significantly in the dimensions of the femur and tibia. Lohmann Brown (LB) hens were characterized by higher greatest length, medial length, smallest breadth of the corpus, and greatest breadth of the distal end of the femur compared with Lohmann White (LW) hens. Dimensions of the tibia greatest length, axial length, smallest breadth of the corpus, greatest breadth of the distal end and greatest depth of the distal end in LB hens were also significantly (P &lt; 0.05) higher than those in LW hens. Conclusions The results showed that the genotype of laying hens tested after the laying period influenced carcass weight and muscle percentage, as well as differentiated the birds in terms of dimensions of individual segments of the digestive tract, femur, and tibia bones. Implications The results of this research may be useful for consumers of laying hen carcasses and people interested in poultry anatomy.