BACKGROUND Monsegmental pedicle instrumentation (MSPI) has been used to treat thoracolumbar fractures. However, there are few reports about the biomechanical characteristics of MSPI compared with traditional short-segment pedicle instrumentation (SSPI) in management of unstable thoracolumbar fractures, and the influence of vertebral fracture on screw stability is still unclear. METHODS This s...

Inertial e4ects in the mechanism of 'bre pullout (or push-in) are examined, with emphasis on how the rate of propagation of stress waves along the 'bre, and thence the pullout dynamics, are governed by friction and the propagation of companion waves excited in the matrix. With a simple shear lag model (assuming zero debond energy at the 'bre/matrix interface), the e4ect of uniform frictional co...

Surface treatment interferes with the primary stability of dental implants because it promotes a chemical and micromorphological change on the surface and thus stimulates osseointegration. This study aimed to evaluate the effects of different surface treatments on primary stability by analyzing insertion torque (IT) and pullout force (PF). Eight samples of implants with different surface treatm...

BACKGROUND The biomechanical performance of the hooks and screws in spinal posterior instrumentation is not well-characterized. Screw-bone interface failure at the uppermost and lowermost vertebrae is not uncommon. Some have advocated for the use of supplement hooks to prevent screw loosening. However, studies describing methods for combined hook and screw systems that fully address the benefit...

INTRODUCTION: Rotator cuff injuries account for more than 4.5 million physician visits annually in the U.S. Injuries to the rotator cuff are typically treated arthroscopically by using implanted suture anchors for the repair. Common suture anchor designs include variations in thread design and the material used. The primary objective of this study was to understand and model the effects of fron...

Many successful attempts to increase pullout strength of pedicle screws in osteoporotic bone have been accompanied with an increased risk of catastrophic damage to the patient. To avoid this, a single-armed expansive pedicle screw was designed to increase fixation strength while controlling postfailure damage away from the nerves surrounding the pedicle. The screw was then subsequently tested i...

The adhesion between a polymer melt and substrate is studied in the presence of chemically attached chains on the substrate surface. Extensive molecular dynamics simulations have been carried out to study the effect of temperature, tethered chain areal density (Σ), tethered chain length (Nt), chain bending energy (kθ) and tensile pull velocity (v) on the adhesive failure mechanisms of pullout a...

Abstract Rock anchors are used to stabilise large scale infrastructures. Failure of rock could threaten the stability and lead severe economic social consequences. The design is based on four principal failure modes, which breakage steel tendon, tendon-grout interface failure, grout-rock mass around anchor. current dimensioning methods uncertain due limited knowledge bond strength failure. meth...

BACKGROUND The purpose of the present study was to compare the results of various types of anchor applications with or without augmentation in both osteopenic and severely osteoporotic bone models. METHODS Two different types of suture anchors were tested in severely osteoporotic (SOP) and osteopenic polyurethane (PU) foam blocks using an established protocol. An Instron machine applied stati...