Journal of Musculoskeletal Research

A simple yet efficient paradigm for geometric mesh generation using the Visible Human Project Male dataset for further finite element analysis was presented. The minimum distance classifier was used for the discriminant function between the class centers classified by the fuzzy c-means clustering method in the RGB space. Furthermore, based on two major geometric assumptions on the boundary curves, star-shaped polygon and geometric conformity, a points-on-line search technique was devised for efficient computation of the boundary points of the contours for each anatomical component of the human forearm complex. The computed boundary points in each slice were fitted to a closed spline curve and resampled and then refitted for correct alignment with the consecutive boundary curves in order to improve geometric fidelity. By using the refitted contours, a 3-D geometric model of the human radius, ulna, and surrounding soft tissue was generated in a commercial computer–aided design system and exported to a commercial finite element analysis package for meshing with its built-in automatic mesh generator. The proposed method can be applied to geometric mesh generation of other long bones, which allows easy handling, storage, and exchange of the model.

This study involves a comparative biomechanics of facet joints (FJ) versus lateral mass (LM) screw insertion technique in the human cadaveric lower cervical spine (C3, C4, C5 and C6). The objective of this study is to understand the promising usage of the facet joint insertion technique and to determine the pullout strength of FJ insertion technique for posterior cervical fixation system. A total of 52 disarticulated human vertebrae (C3–C6) were used in this study. DEXA scan was carried out on all specimens before testing. Cortical screws of 3.5 mm and 4.0 mm were used for both FJ and LM techniques, which were subjected to uniaxial load. From the study made so far, the facet joint technique performed well based on the pullout strength values obtained. Having addressed the main concern on screw perforation of lateral mass technique, this facet joint technique not only demonstrated a significantly higher pullout resistance but it is also a relatively low risk surgical procedure.

Degeneration of articular cartilage begins from deterioration of the collagen fibres in the superficial zone. Standard histology using 2D imaging technique is often used to determine the microstructure of collagen fibres and the physiological functions of articular cartilage. However, information of the 3D collageneous structure in the cartilage could be lost and misinterpreted in 2D observations. In contrast, confocal microscopy permits studying the 3D internal structure of bulk articular cartilage with minimal physical disturbing. Using fibre optic laser scanning confocal microscopy, a 3D histology has been previously developed to visualize the collagen matrix in the superficial zone by means of identifying the early arthritic changes in articular cartilage. In this study, we characterized the collagen orientation in the superficial zone of normal cartilage, the cartilage with surface disruption and fibrillated cartilage using Fast Fourier transforms and power spectral analysis techniques. Thus, we have established an objective method for assessing the early pathology changes in the articular cartilage.

The objective of this study was to build and validate the FE models of thoracolumbar junctional T11-T12 and T12-L1 functional spinal units (FSUs) and compare the biomechanical responses of the two FSUs under physiological loading modes: flexion, extension, lateral bending and axial rotation.

Anatomically accurate FE models of thoracolumbar T11-T12 and T12-L1 FSUs were developed and validated against published experimental results in terms of load displacement responses and range of motion (ROM) under flexion and extension pure moments of 7.5 Nm, left and right lateral bending pure moments of 7.5 Nm and left and right axial torque of 7.5 Nm. The overall responses predicted by the T11-T12 and T12-L1 FE models showed differences in stiffness under different load configurations. Amongst all loading configurations, the motions at T11-T12 and T12-L1 were the stiffest under axial torque. The lateral bending motions of T11-T12 and T12-L1 were relatively flexible. Under sagittal moments, the motion in extension was greater than in flexion at level T11-T12, while the rotation in flexion was greater than in extension at level T12-L1.

We tested the efficacy of 4 local agents for protection against tumor growth after tumor contamination and tumor bloc inoculation. Tumors were prepared by injecting human HT-1080 fibrosarcoma cells into the subcutaneous tissue of 6–9 week old male athymic nude mice (BALB/c nu/nu). When the tumors reached the desired size, the nude mice were sacrificed, and the tumors were harvested en bloc. Then the tumors were used in either contamination group or tumor inoculation group. In the contamination group, 34 tumors were cut by Gigli saw (Group G) and 35 tumors were cut by No. 11 scalpel (Group S). The cut surface of the tumor was rubbed into the subcutaneous tissues of non-tumor bearing nude mice for 10 seconds. Then, the nude mice from the S and G groups were randomized into either one of five subgroups: groups S–N and G–N: no local agent was used, groups S–S and G–S: lavage by saline, groups S–P and G–P: lavage by povidone iodine 10%, groups S–H and G–H: lavage by hydrogen peroxide 3%, groups S–C and G–C: lavage by cisplatin and distilled water. In the tumor inoculation group, a tumor weight of 100 mg was inoculated into 32 non-tumor bearing nude mice. Then, the nude mice were randomized into either of 5 subgroups: group B–N: no local agent was used, group B–S: lavage by saline, group B–P: lavage by povidone iodine 10%, group B–H: lavage by hydrogen peroxide, group B–C: lavage by cisplatin and distilled water. For lavage, the fluid was kept in the wound for 5 minutes apart from the cisplatin which was kept in the wound for 2.5 minutes and then the wound was filled with distilled water for the next 2.5 minutes. Tumor growth occurred in S–N, S–S, S–H, S–P and S–C groups in 33.3%, 67.7%, 16.7%, 16.7%, and 0% respectively. Tumor growth occurred in G–N, G–S, G–H, G–P, and G–C groups in 50%, 67.7%, 33.3%, 33.3%, and 0%, respectively. The total growth incidence after tumor contamination in the no-agent, saline, hydrogen peroxide, povidone iodine and cisplatin groups were 41.7%, 58.3%, 25%, 25% and 0%, respectively. Growth occurred in 100% of B–N and B–S groups, 83% of B–H and B–P groups and 33.3% of the B–C group. Cisplatin used for 2.5 minutes followed by distilled water for 2.5 minutes is effective for protection against local tumor recurrence due to tumor contamination. It also has a reasonable effect against tumor blocks.

The purposes of this study were to investigate the mechanical properties of the carpal tunnel and to examine carpal tunnel compliance as it related to gender difference. Twelve male and twelve female subjects without any neuromusculoskeletal disorders in the upper extremities participated in the study. Indentation testing was manually performed on the wrist volar to the transverse carpal ligament. Effective compliance was defined as the slope of the regression analyses of indentation force and displacement data. In the tested indentation force range (2.45–19.60 N), the displacement of females was 1.38 ± 0.25 mm, significantly smaller than that of the males, 1.82 ± 0.30 mm (p < 0.001). Regression analyses in the force range showed that the effective compliance for females, 0.075 ± 0.012 mm/N, was 26.3% lower than that for males, 0.101 ± 0.018 mm/N (p < 0.005). It was concluded that females have less compliant carpal tunnel than males. The gender difference in carpal tunnel mechanics may predispose females to detrimental compression of the median nerve and carpal tunnel syndrome.