The structural properties of ligament insertions change dramatically during growth and maturation, but little is known about their developmental anatomy. This study describes and quantifies changes in the gross and microscopic anatomy of the tibial insertion of the rabbit medial collateral ligament (MCL) during development and at skeletal maturity. Eighty animals were used for growth and descriptive studies. From this group, 27 animals, ranging in age from 1 to 24 months, were injected with fluorescent bone markers and their tibial insertions were processed undecalcified for histology. Sections were examined by polarized light and fluorescence microscopy to identify matrix and cells and to quantify mineral formation. Results showed that animals achieved histological skeletal maturity between 9 and 12 months of age. Body weights were a poor index of skeletal maturity. The tibial insertion was composed of five tissue layers, which changed proportions during growth and maturation. In immature animals, MCL fibers entered the periosteum; in older animals, MCL fibers were cemented to the tibia by advancing mineral. The tibial attachment of the MCL was thus transferred from the periosteum to the cortex during growth, suggesting that the term "periosteal insertion" is imprecise in adults. The hypothesis is put forward that these structural changes account for the reported increase in tensile failure of this insertion near skeletal maturity.

No abstract

No abstract

This numerical study predicted wear of lubricated total knee replacements with the existing of textured surface and the possibility of surface designs to reduce wear. In the first part, a wear model of metal-on-polyethylene total knee replacement was developed. The medial and lateral knee compartments was accounted for separately, with the contact force and motion during walking cycles applied. An adapted Archard wear formula was employed where the wear factor was an exponential function of the 'Lambda ratio' (film thickness to the average roughness). Wear of the soft bearing surface (polyethylene insert) was simulated with regularly geometry update until a steady-state wear observed. In the second part, the effect of surface topography of the knee replacements was investigated. The surface texturing techniques have shown promising benefit to machine components in many areas of engineering practice. The texture parameters were designed using the Taguchi method for the geometry, size, and distribution of the micro dimples. It was observed that the lateral compartment may benefit from surface texturing if dimples were properly designed, while the texturing showed hardly advantageous effect on the medial surface in terms of lubrication enhancement and wear reduction. Some results were presented in the 6th World Tribology Conference.

No abstract