BACKGROUND Knee or tibiotalocalcaneal arthrodesis is a salvage procedure, often with unacceptable rates of nonunion. Basic science of fracture healing suggests that compression across a fusion site may decrease nonunion. A novel ratcheting arthrodesis nail designed to improve dynamic compression is mechanically tested in comparison to existing nails. METHODS A novel ratcheting nail was design...

Fatigue crack growth can be strongly influenced by crack closure, i. e., the contacting of the opposing faces of a fatigue crack above the minimum load in a loading cycle. This crack closure shields the crack tip from the full stress field, but different views are held regarding the extent of this shielding. The type of closure, whether it be plasticity-induced, or roughness-induced may also pl...

Effects of dislocation emission from a mode I crack and of pinning distances on the behavior of the crack and on fracture toughness in aluminum were studied by using the Molecular Statics Technique with atomic interactions described in terms of the Embedded Atom Method. It was found that aluminum is a ductile material in which the cracks generate dislocations, blunting the cracks. The blunting ...

BACKGROUND AND PURPOSE Stress shielding from rigid internal fixation may lead to refracture after removal of the osteosynthesis material. We investigated the effect of a low-rigidity (Ti-24Nb-4Zr-7.9Sn) intramedullary nail regarding stress shielding and bone healing of osteoporotic fractures in the rat. METHODS 40 female Sprague-Dawley rats, aged 3 months, were divided into the following grou...

INTRODUCTION Revision total knee arthoplasty often requires modular implants to treat bone defects of varying severity. In some cases, it may not be clear which module size and implant combination (e.g. sleeve and stem) should be chosen for a specific defect. When balancing implant stability and osseointegration against stress-shielding, it is important to choose an appropriate implant combinat...

BACKGROUND Asymptomatic local bone resorption of the tibia under the baseplate can occasionally be observed after total knee arthroplasty (TKA). Its occurrence is not well documented, and so far no explanation is available. We report the incidence of this finding in our practice, and investigate whether it can be attributed to specific mechanical factors. METHODS The postoperative radiographs...

Purpose The aim of this study was to assess the mid-term results of primary cementless total hip arthroplasty (THA) using Summit® stems. Materials and Methods One hundred twenty-eight arthroplasties in 121 patients who were performed THA from December 2004 to March 2013, were reviewed retrospectively a minimum of 4 years follow-up (mean age, 60.3 years; mean postoperative follow up period, 86...

We describe the development and early clinical application of a ported, proximally-cemented titanium stem for cemented total hip arthroplasty. PMMA bone cement is delivered to the proximal femur under pressure after the stem has been positioned within the femoral canal. A mid-stem cement occluder contains the cement to the proximal stem only. A tapered body is incorporated in the design of the ...

background: gonad shielding has been recommended during pelvic x-rays since the 1950s. the popular method of gonad shielding is placement a lead shield in the midline of the pelvis. the aim of this study was to evaluate the prevalence and utility of gonad shielding in pediatrics undergoing pelvic x-rays.materials and methodsfollowing study approval, we retrospectively retrieved data from the di...