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AbstractPrevious studies have shown that the nucleus could offer structural support to the lens capsule. This study investigated the biomechanical performance of porcine lens with and without nucleus for 4 mm, 4.5 mm, 5 mm, 5.5 mm and 6 mm capsulotomy and its potential impact on the stretch ratio of capsular bag when the anterior capsulotomy edge was stretched. Our simulation results showed higher strain for the capsular bag with nucleus, which is crucial for the porcine lens to tolerate more stretch without failure. This simulation could support future study on the optimization of capsulotomy based on patient specific condition, that is, the geometry of lens. [ABSTRACT FROM AUTHOR]

Tendinopathy of the long head of the biceps (LHB) tendon causes degeneration and changes its stiffness. However, a reliable means of diagnosis has not been established. Shear wave elastography (SWE) provides quantitative tissue elasticity measurements. In this study, the relationship of preoperative SWE values with biomechanically measured stiffness and degeneration of the LHB tendon tissue was investigated. LHB tendons were obtained from 18 patients who underwent arthroscopic tenodesis. SWE values were measured preoperatively at 2 sites, proximal to and within the bicipital groove of the LHB tendon. The LHB tendons were detached immediately proximal to the fixed sites and at their superior labrum insertion. Tissue degeneration was histologically quantified using the modified Bonar score. Tendon stiffness was determined using a tensile testing machine. The SWE values of the LHB tendon were 502.1 ± 113.6 kPa proximal to the groove and 439.4 ± 123.3 kPa within the groove. The stiffness was 39.3 ± 19.2 N/mm. The SWE values displayed a moderate positive correlation with the stiffness proximal to the groove (r = 0.80) and within it (r = 0.72). The SWE value of the LHB tendon within the groove showed a moderate negative correlation with the modified Bonar score (r = −0.74). These findings suggest that preoperative SWE values of the LHB tendon correlate moderately positively with stiffness and moderately negatively with tissue degeneration. Therefore, SWE may predict LHB tendon tissue degeneration and changes in stiffness caused by tendinopathy. [ABSTRACT FROM AUTHOR]

Introduction Bone graft is the best option to repair postsurgical bone defects. The biomaterial is highly adaptive, structurally dynamic, metabolically active and characterized by high strength. Standard preparation of grafts for implantation includes cleaning followed by deep freezing and sterilization. However, methods used for processing bone material and reagents can change the biomechanical properties of the bone. The purpose was to explore the effect of chemical purification and subsequent lyophilization on the mechanical strength of bone grafts in comparison with native fresh frozen bone. Material and methods Metaepiphyseal sections of a single level of one tibia of a single cattle were used to rule out the influence of the variable density of native bone obtained from different donors. The bone was cut into blocks with a hand saw. Three groups of samples formed depending on the processing method included freshly frozen native bone, bone purified by combined chemical and physical methods and bone purified by the same technique followed by lyophilization. Mechanical properties were measured by axial compression mode using a 1958U-10-1 strength machine. Statistical data analysis was performed using the Kolmogorov-Smirnov (K-S) test and the Lilliefors correction with statistical significance of differences assessed with one-way analysis of variance (One-Way ANOVA). Results The cross-sectional area of hand-made blocks was comparable. No decrease in bone strength below the baseline was recorded regardless of the method of bone processing. Purified bone blocks demonstrated maximum strength characteristics prior to lyophilization. The sample strength decreased after lyophilization and was higher as compared to freshly frozen native bone. No statistically significant differences in the maximum force applied and the cross-sectional area were recorded between groups of samples. Modulus of elasticity and relative deformation had statistically significant differences in the groups (p < 0.05). Conclusion Modern methods of bone processing were shown to maintain biomechanical properties of the bone and can be used in the form of bone blocks or chips and as a structural graft.

Most orchids have high ornamental value with long-lived flowers. However, the mechanisms by which orchids maintain floral longevity are poorly understood. Here, we hypothesized that floral longevity in Dendrobium is maintained by high resource investment and complementary water and nutrient utilization in different structural units of the perianth. To test this hypothesis, we determined which water- and nutrient-related traits are correlated with flower longevity in 23 Dendrobium species or cultivars, and examined variations of the related traits during flower development of one long-lived cultivar. We found that floral longevity was correlated with dry mass per unit area of perianths and total flower biomass, which indicates that maintaining floral longevity requires increased resource investment. During development of long-lived flowers, labella showed a high capacity for water storage and nutrient reutilization, which could partly remedy high water demand and biomass investment. Sepals and petals, in contrast, had stronger desiccation avoidance and higher metabolic activity with lower biomass investment. These findings indicate that Dendrobium flowers maintain longevity by complementary water and nutrient utilization strategies in the sepals, petals and labella, with labella consuming more water and nutrients to extend flower display, and sepals and petals using a more conservative strategy. [ABSTRACT FROM AUTHOR]

Background: The effect of obliquity of tendon laceration on repair strength is not well studied. The overwhelming majority of biomechanical studies assess repair strength following a laceration that is perpendicular to the long axis of the tendon. The aim of this study was to investigate whether the angle of tendon laceration affects the core suture strength. Methods: In all, 110 fresh human cadaveric flexor tendons were cut at varying angles of 15°, 30°, 45°, and 60° and the control group at 90°. All tendons were repaired with 6-strand modified Tang technique. The repair strength was tested using a custom-made tensioning machine, and the initial static gap force and the ultimate breaking force were measured. Results: The mean gap force and 95% confidence interval (CI) for the 15°, 30°, 45°, 60°, and 90° groups were 15.2 N (11.4-19.0 N), 15.8 N (13.6-18.1 N), 15.6 N (13.1-18.4 N), 16.6 N (13.7-19.5 N), and 22.3 N (16.6-27.9 N), respectively. In the same respective order, the break force and 95% CI were 25.9 N (21.9-29.8 N), 26.5 N (23.2-29.7 N), 31.1 N (26.1-36.1 N), 35.6 N (28.2-43.1 N), and 51.8 N (62.5-41.0), respectively. The Fisher least significant difference demonstrated significant differences between the control group and all experimental groups for both gap force and break force. Conclusions: Obliquity of tendon laceration affects the core suture strength when compared with a transverse cut. Flexor tendons cut at 90° demonstrated a higher overall gap force and breaking strength that were statistically significant when compared with all obliquely cut groups. These findings should be considered when repairing and starting postoperative therapy for obliquely cut tendons. [ABSTRACT FROM AUTHOR]

Biological scaffolds are plagued by poor biomechanical properties and untimely degradation. These limitations have yet to be addressed without compromising their biocompatibility. It is desirable to avoid inflammation and have degradation with concomitant host collagen deposition or even site-appropriate in situ regeneration for the successful outcome of an implanted biological scaffold. This work aims to achieve this by utilizing a biocompatible method to modify acellular scaffolds by impregnating alkaline-catalyzed citric acid (CA) cross-linking between the extracellular matrix proteins and silk fibroin (SF)/SF-gelatin (SFG) blends. Combinatorial detergent decellularization was employed to prepare a decellularized porcine liver scaffold (DPL). After proving the decellularization efficiency, the scaffold underwent modification by vacuum impregnation with CA containing SF (SF100DPL) and SFG blends (SFG5050DPL and SFG3070DPL) following pre-cross-linking, drying, and post-cross-linking. The subsequent strength augmentation was demonstrated by significant improvement in tensile strength from 2.4 ± 0.4 MPa (DPL) to, 3.8 ± 0.7 MPa (SF100DPL), 3.4 ± 0.7 MPa (SFG5050DPL), and 3.5 ± 0.2 MPa (SFG3070DPL); Young's modulus from 8.7 ± 1.8 MPa (DPL) to 20 ± 1.9 MPa (SF100DPL), 13.3 ± 2.6 MPa (SFG5050DPL), and 16 ± 1.2 MPa (SFG3070DPL); and suture retention strength from 0.9 ± 0.08 MPa (DPL) to 2.3 ± 0.2 MPa (SF100DPL), 2.8 ± 1.2 MPa (SFG5050DPL), and 2.6 ± 0.9 MPa (SFG3070DPL). The degradation resistance of the modified scaffolds was also markedly improved. Being cytocompatible, its ability to incite tolerable inflammatory and immune responses was confirmed by rat subcutaneous implantation for 14, 30, and 90 days, in terms of inflammatory cell infiltration, neoangiogenesis, and in vitro cytokine release to assess B-cell and T-cell activation. Such ECM composite scaffolds with appropriate strength and biocompatibility offer great promise in soft tissue repair applications such as skin grafting.

Purpose: The aims of the present study were to compare the biomechanical properties of tibial fixation in hamstring-graft ACL reconstruction using interference screw and a novel combination interference screw and dowel construct. Material and Methods: We compared the fixation of 30 (2- and 4-stranded gracilis and semitendinosis tendons) in 15 fresh-frozen porcine tibiae with a biocomposite resorbable interference screw (Group 1) and a screw and dowel construct (Group 2). Each graft was subjected to load-to-failure testing (50 mm/min) to determine maximum load, displacement at failure and pullout strength. Results: There were no significant differences between the biomechanical properties of the constructs. Multivariate analysis demonstrated that combination constructs (β = 140.20, p = 0.043), screw diameter (β = 185, p = 0.006) and 4-strand grafts (β = 51, p = 0.050) were associated with a significant increase in load at failure. Larger screw diameter was associated with increased construct stiffness (β = 20.15, p = 0.020). Conclusion: The screw and dowel construct led to significantly increased fixation properties compared to interference screws alone in a porcine model. Increased screw diameter and utilization of 4-strand ACL grafts also led to improvement in load-to-failure of the construct. However, this is an in vitro study and additional investigations are needed to determine whether the results are reproducible in vivo. Level of evidence: Level V; Biomechanical study. [ABSTRACT FROM AUTHOR]

AIM: To evaluate the effect of posterior sclera collagen cross-linking induced by riboflavin-ultraviolet A (UVA) on form-deprived myopia in guinea pigs. RESULTS: After 4wk, the interocular difference of refractive error were -0.11±0.67, -2.93±0.56, 1.10±0.58, and -1.63±0.41 D in the NOR, FDM, NOR+CL, and FDM+CL groups respectively. Mixed-effect linear model revealed significant effect of FDM (P

Background: The Latarjet procedure reduces recurrent glenohumeral instability but has potential hardware and graft complications. The procedure has been modified to use various screw types as well as suture buttons. Biomechanical studies have evaluated the effect of these implants on construct strength. With varying results it is unclear whether there is an optimal implant to use. Methods: We conducted a systematic review of human cadaveric biomechanical studies evaluating Latarjet ultimate failure load. Two independent reviewers screened articles and included them after full text review. Additional factors including implants used, graft orientation, cortices engaged, drill diameter, and screw characteristics were recorded. Meta-regression was performed on the 145 specimens from eight studies that met inclusion criteria. Results: Screw fixation resulted in a 396.8 N (95% CI, 149.8–643.7) N higher ultimate failure load against shear stresses than suture buttons (p = 0.002). There were no differences between implants for ultimate failure load against tensile forces. Tensile strength was significantly affected by drill diameter with each millimeter of increase reducing the mean ultimate failure load by 127.4 N (95% CI, 41.2–213.6) N (p = 0.004). Conclusions: These results suggest that using screw fixation and minimizing drill diameter can obtain the maximum ultimate failure load against both shear and tensile forces in a Latarjet construct. [ABSTRACT FROM AUTHOR]

Bisphenol-A (BPA) and bisphenol-S (BPS) are estrogen disrupting chemicals (EDCs) found in the environment and common household items. Estrogen is a primary hormonal regulator of bone growth and development; however, the impact of gestational BPA or BPS exposure on skeletal health of offspring remains relatively unknown. In this longitudinal study, adult female mice were randomized into three groups: 200 μg BPA/kg BW (BPA), 200 μg BPS/kg BW (BPS) or control (CON). Animals in each group were further randomized to exercise treatment (EX) or sedentary (SED) control, resulting in six overall groups. BPA/BPS/CON and EX/SED treatment were initiated prior to mating and continued through mating, gestation, and lactation. One female offspring from each dam (n = 6/group) was assessed at 17 weeks of age to evaluate effects of EDC exposure on the adult skeleton. Cortical geometry of the mid-diaphysis and trabecular microarchitecture of the distal femur were assessed via micro-computed tomography. Biomechanical strength and mineral apposition rate of the femoral diaphysis were assessed via three-point bending and dynamic histomorphometry, respectively. Sclerostin expression was measured using immunohistochemistry. Two-factor ANOVA or ANCOVA were used to determine the effects of maternal exercise and BPA or BPS exposure on trabecular and cortical bone outcomes, respectively. Consistent with prior studies, there were no significant differences in body weight, femoral length, cortical geometry, trabecular microarchitecture, or biomechanical strength between groups in female offspring. In conclusion, gestational BPA exposure and maternal exercise have minimal impact on skeletal outcomes in female adult offspring.

Bisphenol-A (BPA) and bisphenol-S (BPS) are endocrine disrupting chemicals (EDCs) found primarily in plastics. Estrogen is a primary hormonal regulator of skeletal growth and development; however, the impact of gestational BPA or BPS exposure on skeletal health of offspring remains relatively unknown. Here, adult female mice were randomized into three treatment groups: 200 μg BPA/kg BW (BPA), 200 μg BPS/kg BW (BPS) or control (CON). Animals were then further randomized to exercising (EX) or sedentary (SED) groups. Treatment continued through mating, gestation, and lactation. One male offspring from each dam (n = 6–8/group) was assessed at 16 weeks of age to evaluate effects of EDC exposure on the adult skeleton. Cortical geometry of the mid-diaphysis and trabecular microarchitecture of the distal femur were assessed via micro-CT. Biomechanical strength and mineral apposition rate of the femoral diaphysis were assessed via three-point bending and dynamic histomorphometry, respectively. Two-factor ANOVA or ANCOVA were used to determine the effects of maternal EX and BPA or BPS on trabecular and cortical bone outcomes. Maternal EX led to a significant decrease in body fat percentage and bone stiffness, independent of EDC exposure. Offspring exposed to BPA had significantly lower trabecular bone volume, trabecular number, connectivity density, cortical thickness, and greater trabecular spacing compared to BPS or CON animals. In conclusion, gestational BPA, but not BPS, exposure negatively impacted trabecular microarchitecture and cortical geometry in adult male offspring. If these findings translate to humans, this could have significant public health impacts on expecting women or those seeking to become pregnant.

The most common cause of secondary osteoporosis is glucocorticoid administration. Liraglutide is a glucagonlike peptide-1, which is a new class antidiabetic drug. Glucagon-like peptide 1 agonist has shown a role in bone physiology and remodeling. Previous studies suggested promising results of using liraglutide on bone health. Evaluate the skeletal protective effects of a low dose of liraglutide in a glucocorticoid-induced osteoporotic rat model. Twenty-one three-month-old male Wistar rats (; 300-325g) were randomly divided into three groups (n=7/group). The normal control group received intramuscular normal saline twice weekly as a vehicle of dexamethasone and subcutaneous normal saline daily as a vehicle of liraglutide; the negative control group received intramuscular dexamethasone 2.5 mg twice weekly and subcutaneous normal saline as a vehicle of liraglutide; liraglutide treatment group received intramuscular normal saline twice weekly as a vehicle of dexamethasone and subcutaneous liraglutide 75 mg/ml daily. Dual X-Ray absorptiometry was performed before sacrifice. Upon euthanasia, femurs of the rats were harvested. Bone calcium content and biomechanical strength were evaluated. Dexamethasone treatment significantly lowered the final bodyweight femur and vertebral BMDs and bone biomechanical strength compared to the normal control group. The low dose of liraglutide showed a significant increase in the femur and vertebral bone mineral densities and bone calcium content compared to the negative control group. However, there are no significant differences in biomechanical load and elastic modulus between the liraglutide treated group and the negative control group. In conclusion, daily administration of 75 mg/ml liraglutide augments bone mass and bone calcium level in rats with a glucocorticoid-induced osteoporosis mode. [ABSTRACT FROM AUTHOR]

Osteogenesis imperfecta (OI), which is most often due to a collagen type 1 gene mutation, is characterized by low bone density and bone fragility. In OI patients, gender-related differences were reported, but data in the literature are not convergent. We previously observed that sclerostin antibody (Scl-Ab), which stimulates osteoblast Wnt pathway via sclerostin inactivation, improved spine and long-bone parameters and biomechanical strength in female oim/oim mice, a validated model of human type 3 OI. Here, we wanted to highlight the effect of Scl-Ab on male oim/oim bones in order to identify a possible distinct therapeutic effect from that observed in females. According to the same protocol as our previous study with female mice, male wild-type (Wt) and oim/oim mice received vehicle or Scl-Ab from 5 to 14 weeks of age. Clinimetric and quantitative bone parameters were studied using X-rays, peripheral quantitative computed tomography, microradiography, and dynamic histomorphometry and compared to those of females. Contrary to Wt mice, male oim/oim had significantly lower weight, snout–sacrum length, and bone mineral content than females at 5 weeks. No significant difference in these clinimetric parameters was observed at 14 weeks, whereas male oim showed significantly more long-bone fractures than females. Scl-Ab improved bone mineral density and bone volume/total volume ratio (BV/TV) of vertebral body in Wt and oim/oim, without significant difference between male and female at 14 weeks. Male vehicle oim/oim had a significantly lower cortical thickness (Ct.Th) and BV/TV of tibial diaphysis than female and showed a higher number of fractures at 14 weeks. Scl-Ab increased midshaft periosteal apposition rate in such a way that tibial Ct.Th of male oim/oim was not significantly different from the female one at 14 weeks. The number of fractures was lower in male than female oim/oim after 14 weeks of Scl-Ab treatment, but this difference was not significant. Nevertheless, Scl-Ab–treated oim/oim male and female mice remained smaller than the Wt ones. In conclusion, our results highlighted differences between male and female oim/oim at 4 and 14 weeks of age, as well as some male-specific response of cortical bone to Scl-Ab. These gender-related particularities of oim/oim should be considered when testing experimental treatments. [ABSTRACT FROM AUTHOR]

Osteogenesis imperfecta (OI), which is most often due to a collagen type 1 gene mutation, is characterized by low bone density and bone fragility. In OI patients, gender-related differences were reported, but data in the literature are not convergent. We previously observed that sclerostin antibody (Scl-Ab), which stimulates osteoblast Wnt pathway via sclerostin inactivation, improved spine and long-bone parameters and biomechanical strength in female oim/oim mice, a validated model of human type 3 OI. Here, we wanted to highlight the effect of Scl-Ab on male oim/oim bones in order to identify a possible distinct therapeutic effect from that observed in females. According to the same protocol as our previous study with female mice, male wild-type (Wt) and oim/oim mice received vehicle or Scl-Ab from 5 to 14 weeks of age. Clinimetric and quantitative bone parameters were studied using X-rays, peripheral quantitative computed tomography, microradiography, and dynamic histomorphometry and compared to those of females. Contrary to Wt mice, male oim/oim had significantly lower weight, snout–sacrum length, and bone mineral content than females at 5 weeks. No significant difference in these clinimetric parameters was observed at 14 weeks, whereas male oim showed significantly more long-bone fractures than females. Scl-Ab improved bone mineral density and bone volume/total volume ratio (BV/TV) of vertebral body in Wt and oim/oim, without significant difference between male and female at 14 weeks. Male vehicle oim/oim had a significantly lower cortical thickness (Ct.Th) and BV/TV of tibial diaphysis than female and showed a higher number of fractures at 14 weeks. Scl-Ab increased midshaft periosteal apposition rate in such a way that tibial Ct.Th of male oim/oim was not significantly different from the female one at 14 weeks. The number of fractures was lower in male than female oim/oim after 14 weeks of Scl-Ab treatment, but this difference was not significant. Nevertheless, Scl-Ab–treated oim/oim male and female mice remained smaller than the Wt ones. In conclusion, our results highlighted differences between male and female oim/oim at 4 and 14 weeks of age, as well as some male-specific response of cortical bone to Scl-Ab. These gender-related particularities of oim/oim should be considered when testing experimental treatments.

Vascular grafts with a diameter of less than 6 mm are made from a variety of materials and techniques to provide alternatives to autologous vascular grafts. Decellularized materials have been proposed as a possible approach to create extracellular matrix (ECM) vascular prostheses as they are naturally derived and inherently support various cell functions. However, these desirable graft characteristics may be limited by alterations of the ECM during the decellularization process leading to decreased biomechanical properties and hemocompatibility. In this study, arteries from the human placenta chorion were decellularized using two distinct detergents (Triton X-100 or SDS), which differently affect ECM ultrastructure. To overcome biomechanical strength loss and collagen fiber exposure after decellularization, riboflavin-mediated UV (RUV) crosslinking was used to uniformly crosslink the collagenous ECM of the grafts. Graft characteristics and biocompatibility with and without RUV crosslinking were studied in vitro and in vivo. RUV-crosslinked ECM grafts showed significantly improved mechanical strength and smoothening of the luminal graft surfaces. Cell seeding using human endothelial cells revealed no cytotoxic effects of the RUV treatment. Short-term aortic implants in rats showed cell migration and differentiation of host cells. Functional graft remodeling was evident in all grafts. Thus, RUV crosslinking is a preferable tool to improve graft characteristics of decellularized matrix conduits. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Background: Despite the increasing use of biceps tenodesis, there is a lack of consensus regarding optimal implant choice (suture anchor vs interference screw) and implant placement (suprapectoral vs subpectoral). Purpose/Hypothesis: The purpose was to determine the associations of procedural parameters with the biomechanical performance of biceps tenodesis constructs. The authors hypothesized that ultimate failure load (UFL) would not differ between sub- and suprapectoral repairs or between interference screw and suture anchor constructs and that the number of implants and number of sutures would be positively associated with construct strength. Study Design: Meta-analysis. Methods: The authors conducted a systematic literature search for studies that measured the biomechanical performance of biceps tenodesis repairs in human cadaveric specimens. Two independent reviewers extracted data from studies that met the inclusion criteria. Meta-regression was then performed on the pooled data set. Outcome variables were UFL and mode of failure. Procedural parameters (fixation type, fixation site, implant diameter, and numbers of implants and sutures used) were included as covariates. Twenty-five biomechanical studies, representing 494 cadaveric specimens, met the inclusion criteria. Results: The use of interference screws (vs suture anchors) was associated with a mean 86 N–greater UFL (95% CI, 34-138 N; P =.002). Each additional suture used to attach the tendon to the implant was associated with a mean 53 N–greater UFL (95% CI, 24-81 N; P =.001). Multivariate analysis found no significant association between fixation site and UFL. Finally, the use of suture anchors and fewer number of sutures were both independently associated with lower odds of native tissue failure as opposed to implant pullout. Conclusion: These findings suggest that fixation with interference screws, rather than suture anchors, and the use of more sutures are associated with greater biceps tenodesis strength, as well as higher odds of native tissue failure versus implant pullout. Although constructs with suture anchors show inferior UFL compared with those with interference screws, incorporation of additional sutures may increase the strength of suture anchor constructs. Supra- and subpectoral repairs provide equivalent biomechanical strength when controlling for potential confounders. [ABSTRACT FROM AUTHOR]

Polymer based implants provide excellent biocompatibility due to porous structure and minimum chances of stress shielding. However, 3D Printed PLA structures possess insufficient mechanical strength, restricting their utility in biomedical domain. This challenge can be addressed by enhancing their mechanical properties through surface modification. The one-step oxidative polymerization process transforms dopamine hydrochloride into biocompatible polydopamine coating, that facilitates adhesion to both hydrophilic and hydrophobic surfaces. The mechanical performance of these structures is influenced significantly by the printing and coating parameters. Thus, this study undertakes the fabrication of bone plates at varying printing parameters followed by investigating the effects of polydopamine coating on their tensile and flexural behavior across varying coating conditions. In the study, SEM/EDS analysis has been performed for examining the morphological characteristics, interaction of coating with PLA and assessing the elemental distribution on the coated surface. The study further explores the impact of coating on substrate roughness and hydrophilicity through AFM and water contact angle measurement techniques. The deposition of polydopamine coating on PLA bone plates was confirmed using XRD and Raman spectroscopy. Upon application of coating, the findings suggested enhancement in tensile strength and flexural strength in the ranges of 47.18%–94.47% and 8.5%–33.78% respectively, across varying printing parameters. Similarly, varying coating parameters resulted in improvement ranging from 38.68% to 93.03% for tensile strength and 2.8%–30.57% for flexural strength. Furthermore, the deposition of coating substantially enhanced the hydrophilicity of the bone plates, making them suitable for tissue engineering applications. Thus, the successful deposition of polydopamine coating not only enhanced the mechanical behavior but also improved the hydrophilicity of bone plates, thereby advancing their suitability for biomedical applications. [Display omitted] • Printing and coating parameters play an important role in affecting the mechanical properties of 3D printed structures. • Polydopamine improves the mechanical behavior of 3D printed PLA based bone plates by covalent interactions. • Polydopamine improved the maximum tensile and flexural strengths of the bone plates. • The coating led to reduction in water contact angle with increase in surface roughness. [ABSTRACT FROM AUTHOR]

Osteogenesis imperfecta type III (OI) is a serious genetic condition with poor bone quality and a high fracture rate in children. In a previous study, it was shown that a monoclonal antibody neutralizing sclerostin (Scl-Ab) increases strength and vertebral bone mass while reducing the number of axial fractures in oim/oim, a mouse model of OI type III. Here, we analyze the impact of Scl-Ab on long bones in OI mice. After 9 weeks of treatment, Scl-Ab significantly reduced long bone fractures (3.6 ± 0.3 versus 2.1 ± 0.8 per mouse, p < 0.001). In addition, the cortical thickness of the tibial midshaft was increased (+42%, p < 0.001), as well as BMD (+28%, p < 0.001), ultimate load (+86%, p < 0.05), plastic energy (+184%; p < 0.05) and stiffness (+172%; p < 0.01) in OI Scl-Ab mice compared to OI vehicle controls. Similar effects of Scl-Ab were observed in Wild type (Wt) mice. The plastic energy, which reflects the fragility of the tissue, was lower in the OI than in the Wt and significantly improved with the Scl-Ab treatment. At the tissue level by nanoindentation, Scl-Ab slightly increased the elastic modulus in bones of both OI and Wt, while moderately increasing tissue hardness (+13% compared to the vehicle; p < 0.05) in Wt bones, but not in OI bones. Although it did not change the properties of the OI bone matrix material, Scl-Ab reduced the fracture rate of the long bones by improving its bone mass, density, geometry, and biomechanical strength. These results suggest that Scl-Ab can reduce long-bone fractures in patients with OI. • A randomized placebo-controlled trial demonstrating the strong anti-fracture effect of Scl-Ab in long bones of oim/oim mice • Scl-Ab markedly improved the biomechanical properties of both WT and OI tibias • Scl-Ab increased volume, midshaft diameter, cortical BMD and thickness in long bones but did not change their total length • The tissue intrinsic properties of OI long bone did not improve with Scl-Ab treatment • The treatment did not change the survival rate of OI mice [ABSTRACT FROM AUTHOR]

Objective: We evaluated the loop and knot security of a novel arthroscopic knot, the Wiese knot, using different types of sutures. Methods: The Wiese knot was tied using four different brands of braided sutures (Ethibond, Orthocord, FiberWire, and UltraBraid) with and without a series of three reversing half-hitches (RHAPs) and tested for loop and knot security. Results: Orthocord provided the greatest amount of loop security. FiberWire delivered the highest knot security. UltraBraid had the greatest ultimate force. Three half-hitches increased the maximal load to clinical failure. Conclusion: The biomechanical characteristics of the Wiese knot are affected by suture material qualities. [ABSTRACT FROM AUTHOR]

Aims: While most antiepileptic drugs (AEDs) have been associated with various adverse effects on bone health, for the recently introduced lacosamide (LCM) no corresponding data have been published. The present study evaluates the effect of LCM on bone mineral density, bone turnover markers, and bone mechanical strength in a rat model. Methods: 16 orchidectomized Wistar rats were divided into control and experimental groups, 8 rats each. Dual energy X-ray absorptiometry was used to measure bone mineral density (BMD). As bone metabolism markers, the concentrations of bone markers were assayed in bone homogenate. In addition, both femurs were measured and used for biomechanical testing. Results: Compared to the control group, we found lower BMD in the experimental group in the area of the left (8%) as well as the right femur (12%), all differences being statistically significant. In both femur diaphyses, but not in lumbar vertebrae, BMD was lower in the LCM group, suggesting a preferential effect on cortical bone. However, neither the thickness of the diaphyseal cortical bone nor the fragility in biomechanical testing was different between the groups. Of the bone metabolism markers, the significant decline was in procollagen type I N-terminal peptide (PINP) levels (37.4%), suggesting a decrease in osteoid synthesis. Conclusion: We assume then that long-lasting exposure to LCM can represent a certain risk to the health of bone in the setting of gonadal insufficiency. Further studies will be needed to confirm these findings and to determine how high the risk will be in comparison to the other AEDs.

Aim: Biologically derived surgical graft materials come from a variety of sources with varying mechanical properties. This study aimed to evaluate the host response and mechanical performance of two extracellular matrix devices in a large animal preclinical model. Materials & methods: Bilateral defects were created in the fascia lata of sheep and repaired with either an acellular dermal matrix (ADM) or urinary bladder matrix (UBM). After 1 or 3 months, the repair site was explanted for histological and mechanical analysis. Results & conclusion: Despite pre-implantation mechanical differences, both UBM and ADM demonstrated similar mechanical performance at 3 months. However, UBM was completely remodeled into site-appropriate tissue by 3 months, while ADM showed limited tissue incorporation. [ABSTRACT FROM AUTHOR]

The contralateral limb is often used as a control in various clinical, forensic and anthropological studies. However, no studies have been performed to determine if the contra-lateral limb is a suitable control during the bone development period. The aim of this study was to determine the bilateral symmetry of growing rat tibiae in terms of geometric shape, mechanical strength and bone morphological parameters with developmental stages. Left and right tibias of 18 male Sprague–Dawley rats at 4, 8 and 12 weeks of age were scanned with micro-CT for bone-morphometric evaluation and for 3D deviation analysis to quantify the geometric shape variations between left and right tibiae. Overall tibial lengths and curvatures were also measured, and bone mechanical strength was investigated using three-point bending tests. Deviation distributions between bilateral tibiae remained below 0.5 mm for more than 80% of the geometry for all groups. Tibial lengths, longitudinal tibial curvatures, bone-morphometric parameters and mechanical strengths changed significantly during the growing period but kept a strong degree of symmetry between bilateral tibiae. These results suggest that bilateral tibiae can be considered symmetrical in nature and that contralateral limb can be used as a control during the growing period in different experimental scenarios. [ABSTRACT FROM AUTHOR]

The goal of fixation surgery for atlantoaxial instability is to achieve solid bony fusion. Achieving bony fusion as early as possible is beneficial for patients. Although placement of a transverse cross-link connector (XL) provides greater biomechanical strength, XLs have not been able to be placed when performing the Goel/Harms procedure. Recently, placing a XL on the screw head (on-the-head XL [OH-XL]) has become a viable option during the Goel/Harms procedure. However, there is little evidence demonstrating whether applying an OH-XL achieves early solid bony union. A matched-control study was conducted to investigate whether placing an OH-XLs in C1/2 fixation surgery provides earlier bone union or not. Eighteen patients who underwent atlantoaxial fusion with OH-XLs (X-group), and 17 age and sex-matched patients without OH-XLs (NX-group) were compared. Bony union was assessed using reconstructed sagittal and coronal computed tomography images. Six months after surgery, six patients in the X-group and one patient in the NX-group achieved bony union ( p  = .0338). One year after surgery, 14 patients in the X-group and 4 patients in the NX-group achieved bone union ( p  = .0010). Two years after surgery, 17 patients in the X-group and 9 patients in the NX-group achieved bony union ( p  = .0011). This is the first report of the clinical application of OH-XLs for the Goel/Harms procedure. OH-XLs yield earlier bony fusion; thus, placing OH-XLs is beneficial for atlantoaxial fixation surgery using lateral mass screws of the atlas. [ABSTRACT FROM AUTHOR]

Study Design: Randomized Biomechanical Cadaveric Study-Level II.Objective: We aimed to elucidate that placing lateral lumbar interbody cages that span the stronger ring apophysis will require increasing loads for failure, decreasing rates of subsidence, regardless of bone density or endplate integrity.Summary Of Background Data: There are several reports regarding the rates and grades of cage subsidence when utilizing the lateral lumbar interbody fusion technique. However, there is limited data on how spanning the lateral cage across the ring apophysis can prevent it.Methods: Eight fresh-frozen human spines (L1-L5) were utilized. Each vertebra was placed with their endplates horizontal in an MTS actuator. A total of 40 specimens were randomized into Groups:Load displacement data was collected at 5 Hz until failure.Results: Longer cages spanning the ring apophysis provided more strength in compression with less subsidence relative to shorter cages, regardless of endplate integrity.Longer cages, spanning the ring apophysis, resting on intact endplates (G2) had a significant (P < 0.05) increase in strength and less subsidence when compared with the smaller cage group resting on intact endplates (G1) (P = 0.003).Longer cages spanning the ring apophysis of intact endplates (G2) showed a significant (P < 0.05) increase in strength and resistance to subsidence when compared with similar length cages resting on decorticated endplates (G4) (P = 0.028).Conclusion: Spanning the ring apophysis increased the load to failure by 40% with intact endplates and by 30% with decorticated endplates in this osteoporotic cadaveric model. Larger cages that span the endplate ring apophysis could improve the compressive strength and decrease subsidence at the operative level despite endplate violation or osteoporosis.Level Of Evidence: 2. [ABSTRACT FROM AUTHOR]

Purpose: Cranioplasty for recovering skull defects carries the risk for a number of complications. Various materials are used, including autologous bone graft, metallic materials, and non-metallic materials, each of which has advantages and disadvantages. If the use of autologous bone is not feasible, those artificial materials also have constraints in the case of complex anatomy and/or irregular defects. Material and methods: This study used metal 3D-printing technology to overcome these existing drawbacks and analyze the clinical and mechanical performance requirements. To find an optimal structure that satisfied the structural and mechanical stability requirements, we evaluated biomechanical stability using finite element analysis (FEA) and mechanical testing. To ensure clinical applicability, the model was subjected to histological evaluation. Each specimen was implanted in the femur of a rabbit and was evaluated using histological measurements and push-out test. Results and Conclusion: We believe that our data will provide the basis for future applications of a variety of unit structures and further clinical trials and research, as well as the direction for the study of other patient-specific implants. [ABSTRACT FROM AUTHOR]

Objective To investigate bone microstructural and biomechanical changes following ketogenic diets in mice，and to study osteoporosis induced by the ketogenic diets． Methods Ten C57 mice ( 8-week-in-age) were randomly divided into the ketogenic diet ( KD) group and the standard diet ( SD) group． The KD is a formula food with 4∶ 1 ratio of fat to carbohydrate and protein． Body weight，blood glucose and blood ketone levels were tested every 2 weeks for 3 months． Bone micro-structures at the distal metaphysis and the middle shaft of femur，including bone mineral density，bone volume /tissue volume，trabecular thickness， trabecular number，trabecular separation， cortical bone thickness and cortical bone cross sectional area，were measured using a micro CT． The histologic observation of the distal femur was performed on HE staining images． Biomechanical evaluation of tibia was conducted using a three-point-bending test． Ｒesults Blood ketone in the KD group was significantly higher than that of the SD group ( 0. 8 mmol /L vs． 0. 2 mmol /L，P ＜ 0. 05) ． Bone density，bone volume fraction and trabeculae connection density at the distal femur in the KD group were 49. 5 ± 3. 6 mgHA /ccm，4. 1 ± 0. 5% and 12. 4 ± 1. 9 mm － 3 ，respectively，which were significantly lower than those in the SD group ( 69. 1 ± 4. 0 mgHA /ccm，6. 4 ± 1. 0% and 27. 4 ± 9. 7 mm － 3 ，respectively，all P ＜ 0. 05) ． Crosssectional bone area at the femoral shaft was 0. 69 ± 0. 08 mm2 in the KD group，and significantly smaller than the area in the SD group ( 0. 80 ± 0. 06 mm2 ，P ＜ 0. 05) ． The maximum force，stiffness and maximum absorption energy of tibia in the KD group was 7. 3 ± 0. 7 N、25. 1 ± 2. 4 N /mm and 1. 4 ± 0. 4 mJ，which were significantly lower than those in the SD group ( 10. 1 ± 0. 6 N，33. 4 ± 2. 9 N /mm and 2. 3 ± 0. 5 mJ，P ＜ 0. 05) ． Conclusion The ketogenic diet led to osteoporosis in mice by attenuating microstructure of trabecular bones，decreasing the cross-sectional area of cortical bones，and weakening the mechanical strength of bones． [ABSTRACT FROM AUTHOR]

Abstract Injuries to the parotid ducts are difficult to locate, assess, and repair, and traditionally, solid metal dilators and soft plastic tubes have had only limited success. We describe the Seldinger technique with a central venous catheter, which makes repair easier. [ABSTRACT FROM AUTHOR]

Most orchids have high ornamental value with long-lived flowers. However, the mechanisms by which orchids maintain floral longevity are poorly understood. Here, we hypothesized that floral longevity in Dendrobium is maintained by high resource investment and complementary water and nutrient utilization in different structural units of the perianth. To test this hypothesis, we determined which water- and nutrient-related traits are correlated with flower longevity in 23 Dendrobium species or cultivars, and examined variations of the related traits during flower development of one long-lived cultivar. We found that floral longevity was correlated with dry mass per unit area of perianths and total flower biomass, which indicates that maintaining floral longevity requires increased resource investment. During development of long-lived flowers, labella showed a high capacity for water storage and nutrient reutilization, which could partly remedy high water demand and biomass investment. Sepals and petals, in contrast, had stronger desiccation avoidance and higher metabolic activity with lower biomass investment. These findings indicate that Dendrobium flowers maintain longevity by complementary water and nutrient utilization strategies in the sepals, petals and labella, with labella consuming more water and nutrients to extend flower display, and sepals and petals using a more conservative strategy., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Society for Experimental Biology.)

The drug, theophylline is frequently used as an additive to medications for people suffering from chronic obstructive pulmonary diseases (COPD). We studied the effect of theophylline in bone cells, skeleton and parameters related to systemic calcium homeostasis. Theophylline induced osteoblast apoptosis by increasing reactive oxygen species production that was caused by increased cAMP production. Bone marrow levels of theophylline were higher than its serum levels, indicating skeletal accumulation of this drug. When adult Sprague-Dawley rats were treated with theophylline, bone regeneration at fracture site was diminished compared with control. Theophylline treatment resulted in a time-dependent (at 4- and 8 weeks) bone loss. At 8 weeks, a significant loss of bone mass and deterioration of microarchitecture occurred and the severity was comparable to methylprednisone. Theophylline caused formation of hypomineralized osteoid and increased osteoclast number and surface. Serum bone resorption and formation marker were respectively higher and lower in the theophylline group compared with control. Bone strength was reduced by theophylline treatment. After 8 weeks, serum 25-D3 and liver 25-hydroxylases were decreased in theophylline group than control. Further, theophylline treatment reduced serum 1, 25-(OH) 2 vitamin D 3 (1,25-D3), and increased parathyroid hormone and fibroblast growth factor-23. Theophylline treated rats had normal serum calcium and phosphate but displayed calciuria and phosphaturia. Co-administration of 25-D3 with theophylline completely abrogated theophylline-induced osteopenia and alterations in calcium homeostasis. In addition, 1,25-D3 protected osteoblasts from theophylline-induced apoptosis and the attendant oxidative stress. We conclude that theophylline has detrimental effects in bone and prophylactic vitamin D supplementation to subjects taking theophylline could be osteoprotective. [ABSTRACT FROM AUTHOR]