Finite Element Method for the Evaluation of the Human Spine: A Literature Overview

The finite element method (FEM) represents a computer simulation method, originally used in civil engineering, which dates back to the early 1940s. Applications of FEM have also been used in numerous medical areas and in orthopedic surgery. Computing technology has improved over the years and as a result, more complex problems, such as those involving the spine, can be analyzed. The spine is a complex anatomical structure that maintains the erect posture and supports considerable loads. Applications of FEM in the spine have contributed to the understanding of bone biomechanics, both in healthy and abnormal conditions, such as scoliosis, fractures (trauma), degenerative disc disease and osteoporosis. However, since FEM is only a digital simulation of the real condition, it will never exactly simulate in vivo results. In particular, when it concerns biomechanics, there are many features that are difficult to represent in a FEM. More FEM studies and spine research are required in order to examine interpersonal spine stiffness, young spine biomechanics and model accuracy. In the future, patient-specific models will be used for better patient evaluations as well as for better pre- and inter-operative planning.

The structural role of osteocalcin in bone biomechanics and its alteration in Type-2 Diabetes

This study presents an investigation into the role of Osteocalcin (OC) on bone biomechanics, with the results demonstrating that the protein’s α-helix structures play a critical role in energy dissipation behavior in healthy conditions. In the first instance, α-helix structures have high affinity with the Hydroxyapatite (HAp) mineral surface and provide favorable conditions for adsorption of OC proteins onto the mineral surface. Using steered molecular dynamics simulation, several key energy dissipation mechanisms associated with α-helix structures were observed, which included stick–slip behavior, a sacrificial bond mechanism and a favorable binding feature provided by the Ca2+ motif on the OC protein. In the case of Type-2 Diabetes, this study demonstrated that possible glycation of the OC protein can occur through covalent crosslinking between Arginine and N-terminus regions, causing disruption of α-helices leading to a lower protein affinity to the HAp surface. Furthermore, the loss of α-helix structures allowed protein deformation to occur more easily during pulling and key energy dissipation mechanisms observed in the healthy configuration were no longer present. This study has significant implications for our understanding of bone biomechanics, revealing several novel mechanisms in OC’s involvement in energy dissipation. Furthermore, these mechanisms can be disrupted following the onset of Type-2 Diabetes, implying that glycation of OC could have a substantial contribution to the increased bone fragility observed during this disease state.

PROTECTIVE EFFECTS OF VIRGIN COCONUT OIL AND TOCOTRIENOL-RICH FRACTION ON BONE BIOMECHANICS

Osteoporosis is a metabolic disease characterized by low bone mineral density. Both virgin coconut oil (VCO) and tocotrienol-rich fraction (TRF) are known to have higher antioxidant activity. The study aimed to determine the effect of combined therapy of VCO and TRF on biomechanical bone strength parameters of the ovariectomised rat model fed with high fat diet and heated palm oil. Thirty-six female Sprague-Dawley rats were divided into; Sham-operated (SHAM), ovariectomised control (OVX), ovariectomised and given Premarin 64.5 µg/kg (OVX+P), ovariectomised and given VCO 1.43 ml/kg (OVX+V), ovariectomised and given TRF 30 mg/kg (OVX+T) and ovariectomised and given combined therapy of VCO and TRF (OVX+VT). Following 24 weeks, the rats were sacrificed and the right femora were analyzed for three-point bending test using Shimadzu machine (AG-X 500 N). The parameters were divided into two classes: extrinsic (load, displacement and stiffness) and intrinsic (stress, strain and Young modulus). The statistical tests used were analysis of variance (ANOVA), followed by Tukey’s HSD test. The Young modulus value of OVX+VT group was significantly higher than OVX+V and OVX+T groups (p<0.05). Combined therapy of VCO and TRF have offered better bone protective effects than single dose of VCO or TRF in preventing bone loss of osteoporotic rat model.

Effect of quercetin on bone metabolism and serum osteocalcin in osteoporotic rats

Purpose: To determine the effect of quercetin on bone metabolism and serum osteocalcin in osteoporotic rats. Methods: Sixty specific pathogen-free rats were randomly divided into control group, model group; high, medium and low dose quercetin groups, and diethylstilbestrol group, with 10 rats in each group. The high, middle and low dose quercetin groups were given quercetin suspension at doses of 200, 100, 50 mg/kg/day, respectively; the ethylene estradiol group was given ethylene estradiol (1.0 mg/kg/week), while control rats received ethylene estradiol at doses of 200, 100, 50 mg/kg/day. Rats in the model group were given saline. Samples were taken after 6 weeks of administration. The levels of serum bone-derived alkaline phosphatase (BALP), estradiol (E2) and serum osteocalcin (BGP) in femur tissue were measured using ELISA kits. Bone mineral density (BMD) was determined using BMD tester. Results: Relative to normal rats, BALP and BGP levels in the model rats were markedly increased, while E2 was significantly lower (p < 0.5). Quercetin treatment led to significant increases in BALP and E2 levels in the middle and high dose groups, relative to the model group, while BGP levels in all quercetin treatment groups decreased significantly, when compared to model rats (p < 0.05). There were higher BMD values in quercetin and diethylstilbestrol groups than in model (p < 0.05). Conclusion: Quercetin enhances bone formation and BMD, but decreases osteocalcin levels and maintains bone biomechanics in ovariectomized rats. Thus, it may find therapeutic application in maintaining bone health. Keywords: Quercetin, Osteoporosis, Bone metabolism, Osteocalcin