Evaluation Of Biomechanical Properties Research Articles

Ex vivo biomechanical evaluation and comparison of lateral femoro-fabella ligament suture and lateral suture with bone anchor for cranial cruciate ligament repair in cats.

To compare the biomechanical properties of lateral femoro-fabella ligament suture (FFLS) and lateral suture with a bone anchor suture (BAS) for management of feline cranial cruciate ligament disease. 12 femurs from 6 mature cat cadavers. The samples were collected from April to June 2023. The specimens had an FFLS and, subsequently, BAS placed and were positioned into a biomechanical testing machine, preloaded from 5 N to 15 N for 100 cycles, and subsequently, a load to suture failure was applied. The displacement at 5 N and 15 N, the total precycle displacement (millimeters), the force at 3 mm displacement and at failure (newtons), the displacement at failure (millimeters), and the stiffness to failure (Newton:millimiter) were recorded. Nonparametric Wilcoxon signed-rank tests were used to compare data between the 2 groups. The displacement at 5 N and 15 N and the total precycle displacement were significantly higher in the FFLS group compared to the BAS group. Additionally, the FFLS group results showed less consistent displacement and marked variability. The force (newtons) at 3 mm displacement was higher in the BAS group. There was no significant difference in force and no significant difference in displacement at failure between the 2 groups. However, the stiffness to failure (N/mm) was significantly higher in the BAS group. BAS represented a more stable and reliable femur attachment for extracapsular suture in cats. To demonstrate the stability and reliability between BAS and FFLS and influence implant selection in the treatment of cranial cruciate ligament rupture in cats with evaluation of biomechanical properties.

Evaluation of biomechanical properties and biocompatibility: are partially absorbable cords eligible for anterior cruciate ligament reconstruction?

Introduction: Independent augmentation technology based on reinforcing devices has been reported to signifi-cantly reduce the elongation behavior of graft and improve knee stability after anterior cruciate ligament reconstruction (ACLR). Using biodegradable devices could reduce the risk of severe inflammatory reactions due to particle accumulation from foreign bodies. Given the limitations of the mechanical properties of biodegradable materials, partially biodegradable composite devices may offer a compromise strategy. Methods: Three types of partially absorbable core-sheath sutures, including low-absorbable cord (LA-C), medium-absorbable cord (MA-C) and high-absorbable cord (HA-C), were braided using unabsorbable ultra-high molecular weight polyethylene (UHMWPE) yarn and absorbable polydioxanone (PDO) monofil-ament bundle based on the desired configuration. The feasibility of these partially absorbable cords were verified by biomechanical testing, material degradation testing, and cell experiments, all performed in vitro. Results: Reinforcement of an 8mm graft with the cords decreased dynamic elongation by 24%-76%, was positively related to dynamic stiffness, and increased the failure load by 44%-105%, during which LA-C showed maximum enhancement. Human ligament-derived fibroblasts showed good proliferation and vitality on each cord over 2weeks and aligned themselves in the direction of the fibers, especially the UHMWPE portion. Discussion: This study supports the potential of partially degradable UHMWPE/PDO cords, particularly LA-C, for graft protection. Nervertheless, a higher proportion of biodegradable material results in lower stiffness, which may impair the protective and lead to mechanical instability during degradation.

Evaluation of Biomechanical Properties and Morphometric Structures of the Trachea in Pigs and Rabbits.

Animals differ in the biochemical composition, attachments, and mechanical properties of tracheal cartilage. This study examined the biomechanical properties and morphological structure of the trachea of pigs, and rabbits as preclinical models. The trachea in pigs and rabbits can be divided into four regions, cranial cervical, middle cervical, thoracic inlet, and intra-thoracic parts. The total number of tracheal rings in pigs and rabbits was 32-35 and 34-38 rings, respectively. The pig bronchus first branches from the trachea, reaching the cranial lobe of the lungs before branching to the main bronchus, while the rabbit bronchus branched after the main bronchus. A comparison of the posterior region of the crosssectional trachea shows that the rabbit has a C-shape with cartilage connected to the tracheal muscle, and the pig has the tracheal muscle covered with cartilage. The trachea of pigs and rabbits decreased in tracheal thickness and size from the thoracic inlet toward the lungs. The stress-strain in the longitudinal and transverse tensile test was higher in rabbits than in pigs. The tensile stress of the four regions was significantly different in the transverse tensile test (p<0.001). In the bending test, more force was required to bend pig than rabbit tracheas. Microscopic and scanning electron microscopy showed no structural differences in tracheal cartilage between the two species. These results suggest that there is great variation in morphology and physical properties of the trachea in pigs and rabbits. We found porcine tracheas have similar biomechanical properties to those of humans.

Evaluation of biomechanical properties on partial and complete epitendinous suture in human cadaver flexor tendon repair

ObjectiveThis study was designed to compare the ultimate tensile strength and force to 2 mm gap formation among 50% partial, 75% partial, and complete circumferential epitendinous suture with a combination of 4-strand core suture in human cadaver flexor tendon.Materials and methodsForty-five flexor tendons from four soft human cadavers were used to evaluate the biomechanical property among 50% partial, 75% partial, and complete circumferential epitendinous suture with a combination of 4-strand core suture.ResultsThe force to 2 mm gap of complete epitendinous was significantly greater than partial epitendinous suture (P < 0.05); however, there was no difference between 50% partial and 75% partial epitendinous suture (P > 0.05). For the ultimate strength, there was no significant difference between partial and complete epitendinous suture (P > 0.05). The partial epitendinous was approximately 60% of the complete epitendinous suture in force to 2 mm gap and also 70% of complete epitendinous suture in ultimate tensile strength with a combination of core sutures.ConclusionsThe complete epitendinous suture showed better ultimate tensile strength and force to 2 mm gap compared with a partial 50% and 75% epitendinous suture. However, in some clinical scenario which the complete epitendinous suture is not possible to perform, the authors suggested only partial epitendinous suture with 50% circumference is recommended as the additional epitendinous repair up 75% circumference cannot provide any mechanical benefit to the repaired site.

Evaluation of biomechanical properties: are porcine flexor tendons and bovine extensor tendons eligible surrogates for human tendons in in vitro studies?

Porcine flexor tendons, bovine extensor tendons, and human (semitendinosus) tendons are frequently used as substitutes for human ACL grafts in biomechanical in vitro studies. This study compares the biomechanical properties and structural differences of these tendons. In this biomechanical study, fresh-frozen porcine flexor tendons, bovine extensor tendons, and human semitendinosus tendons were used (n=36). The tendons were mounted in a uniaxial testing machine (Zwick/Roell) with cryo-clamps, leaving a 60mm tendon part free between the two clamps. Specimens have been loaded to failure to evaluate the biomechanical parameters stiffness, yield load, and maximum load. A Total Collagen Assay Kit was used to detect differences in the total collagen type I concentration (n=30). A one-way ANOVA was performed to detect differences in the means. The significance level was set at p<0.05. There were no significant differences in the stiffness between the groups (bovine 194±43N/mm, porcine 211±63N/mm, and human cadaveric 208±58N/mm). The yield and maximum loads were high (>1000N) in all groups, but they were significantly increased in both animal specimens (means of 1681-1795N) compared with human cadaveric specimen (means of 1289-1406N; p<0.01). No difference in the collagen type I concentration was detected (N.S.). Porcine flexor and bovine extensor tendons are eligible substitutes with similar stiffness and high failure loads compared with human cadaveric semitendinosus tendons in in vitro studies.

Evaluation of biomechanical properties of the cornea in patients with primary hyperparathyroidism.

The purpose of this study is to compare the corneal biomechanical properties in primary hyperparathyroid patients and healthy control subjects. The study consisted of 31 patients with primary hyperparathyroidism (study group) and 31 healthy subjects (control group). Corneal biomechanical properties, including corneal hysteresis (CH), corneal resistance factor (CRF), and intraocular pressure (IOP) were measured with an ocular response analyzer (ORA). IOP was also measured using Goldmann applanation tonometry (GAT), and central corneal thickness (CCT) was measured with an ultrasonic pachymeter. The differences in ORA parameters and CCT between study and control group participants were analyzed. The mean CH in study and control groups was 8.7±1.9mmHg (5.3-13.7mmHg) and 9.8±1.5mmHg (7.7-14.3mmHg), respectively (p=0.018). The mean CRF was 9.5±1.8 (5.5-13.7) in the study group compared with 9.8±1.5 (6.2-12.8) in the control group. The difference for CRF was not statistically significant (p=0.41). In study and control group, corneal-compensated IOP (IOPcc) values were 18.2±4.2and 16.9±2.7mmHg, respectively (p=0.12). Mean IOP measurement values with GAT were 16.3±3.4mmHg for study group and 16.5±2.7mmHg for control group (p=0.71). The mean differences of IOPcc and IOPGAT in the study group eyes were higher than that of control group eyes (1.9 vs. 0.4mmHg). CCT was 536.5±25.4µm (490-593µm) in study group eyes compared with 534.2±31.4µm (472-602µm) in control eyes (p=0.75). Hyperparathyroidism could be associated with a decrease of CH. The differences between IOPcc and IOPGAT in these patients were higher than normal subjects. Underestimation of IOP readings with GAT may be a consequence of the lower CH in patients with hyperparathyroididsm.

Dose Dependent Effect of Iso-Octane on HaCaT: A Model Study.

Improved understanding of cytotoxicity under chemical assaults may be achieved by multimodal analysis of cellular morphology, viability, molecular expressions, and biophysical properties. In this study dose-dependent effects of an organic solvent (OS), iso-octane (IO), known to cause skin irritation, has been explored multimodally for understanding its effect on structural and functional profile of normal epithelial cell population in vitro. Under IO exposures, after 5 h there was a sharp decrease in viability of HaCaT with increasing doses which may be due to disruption in cellular association noted via immunocytochemical study and was further supported by the decreased expression of E-cadherin at transcriptomic level. Dislocation of E-cadherin from membrane to the cytoplasm occurred with increasing doses. The dose-dependent changes in varied aspects of bioelectrical properties, having plausible correlation with cellular viability, association, and adherence were noteworthy at 5 h of IO exposure. Evaluation of biomechanical properties by micropipette aspiration showed a distinct change in cellular stiffness in terms of increase in suction force and post-suction alteration in cellular shape. The cells became stiffer and fragile with increasing IO doses. Present study explicated dose-dependent cytotoxicity of IO on HaCaT and explored the usefulness of this approach to develop in vitro model system to evaluate epithelial toxicity with level-free markers.

Dose dependent effect of Iso-Octane on HaCaT: A model study

Objective:Improved understanding of cytotoxicity under chemical assaults may be achieved by multimodal analysis of cellular morphology, viability, molecular expressions, and biophysical properties.Materials and Methods:In this study dose-dependent effects of an organic solvent (OS), iso-octane (IO), known to cause skin irritation, has been explored multimodally for understanding its effect on structural and functional profile of normal epithelial cell population in vitro.Results:Under IO exposures, after 5 h there was a sharp decrease in viability of HaCaT with increasing doses which may be due to disruption in cellular association noted via immunocytochemical study and was further supported by the decreased expression of E-cadherin at transcriptomic level. Dislocation of E-cadherin from membrane to the cytoplasm occurred with increasing doses. The dose-dependent changes in varied aspects of bioelectrical properties, having plausible correlation with cellular viability, association, and adherence were noteworthy at 5 h of IO exposure. Evaluation of biomechanical properties by micropipette aspiration showed a distinct change in cellular stiffness in terms of increase in suction force and post-suction alteration in cellular shape. The cells became stiffer and fragile with increasing IO doses.Conclusion:Present study explicated dose–dependent cytotoxicity of IO on HaCaT and explored the usefulness of this approach to develop in vitro model system to evaluate epithelial toxicity with level-free markers.

In vivo evaluation of biomechanical properties in the patellofemoral joint after matrix-associated autologous chondrocyte transplantation by means of quantitative T2 MRI

To determine in vivo biomechanical properties of articular cartilage and cartilage repair tissue of the patella, using biochemical MRI by means of quantitative T2 mapping. Twenty MR scans were achieved at 3T MRI, using a new 8-channel multi-function coil allowing controlled bending of the knee. Multi-echo spin-echo T2 mapping was prepared in healthy volunteers and in age- and sex-matched patients after matrix-associated autologous chondrocyte transplantation (MACT) of the patella. MRI was performed at 0° and 45° of flexion of the knee after 0 min and after 1 h. A semi-automatic region-of-interest analysis was performed for the whole patella cartilage. To allow stratification with regard to the anatomical (collagen) structure, further subregional analysis was carried out (deep-middle-superficial cartilage layer). Statistical analysis of variance was performed. During 0° flexion (decompression), full-thickness T2 values showed no significant difference between volunteers (43 ms) and patients (41 ms). Stratification was more pronounced for healthy cartilage compared to cartilage repair tissue. During 45° flexion (compression), full-thickness T2 values within volunteers were significantly increased (54 ms) compared to patients (44 ms) (p < 0.001). Again, stratification was more pronounced in volunteers compared to patients. The volunteer group showed no significant increase in T2 values measured in straight position and in bended position. There was no significant difference between the 0- and the 60-min MRI examination. T2 values in the patient group increased between the 0- and the 60-min examination. However, the increase was only significant in the superior cartilage layer of the straight position (p = 0.021). During compression (at 45° flexion), healthy patellar cartilage showed a significant increase in T2-values, indicating adaptations of water content and collagen fibril orientation to mechanical load. This could not be observed within the patella cartilage after cartilage repair (MACT) of the patella, most obvious due to a lack of biomechanical adjustment. III.

Evaluation of biomechanical properties of Expanded-Polytetrafluoroethylene? Soft Tissue Patch after dorsal implantation in the rat to mimic TMJ lateral reconstruction

Evaluation of biomechanical properties of Expanded-Polytetrafluoroethylene? Soft Tissue Patch after dorsal implantation in the rat to mimic TMJ lateral reconstruction