The calcar femorale is a vertical plate of bone lying deep to the lesser trochanter and is formed as a result of traction of the iliopsoas which separates the femoral cortex into two distinct layers, the calcar femorale and the medial femoral cortex. They fuse together proximally to form the medial femoral neck. A stem placed centrally will abut against the calcar femorale with little or no spa...

The Norwegian Arthroplasty Register recorded 24,408 primary total hip replacements from 1987 to 1993; 2907 of them (13%) were performed with uncemented femoral components. We have compared the results of eight different designs, each used in more than 100 patients. Survivorship of the components was estimated by the Kaplan-Meier method using revision for aseptic loosening of the femoral compone...

Early subsidence >1.5 mm is considered to be a predictive factor for later aseptic loosening of the femoral component following total hip arthroplasty (THA). The aim of this study was to assess five-year subsidence rates of the cementless hydroxyapatite-coated twinSys stem (Mathys Ltd., Bettlach, Switzerland).This prospective single-surgeon series examined consecutive patients receiving a twinS...

The expandable nail concept uses high-pressure saline to inflate the diameter of a cylindrical implant to achieve fixation within the medullary canal of bone. Expandable nails are used clinically in a number of fracture management applications and have been more recently developed as a femoral component for total hip replacement. In this study, the expandable total hip replacement stem design w...

Although cementless revision arthroplasty of the hip has become the gold standard, revision arthroplasty of the distal femur is controversial. This study evaluated the anchoring principles of different femoral revision stem designs in extended bone defect situations, taking into account the anatomical conditions of the proximal and distal femur, and the resulting primary stability. Cementless p...

BACKGROUND The Zweymüller stem is well-known in Europe and widely used for total hip replacement since 1980. Few authors have noted the presence of increased bone density below the tip of the stem; however, the underlying mechanism is still unknown. The aim of this study was to reveal factors influencing bone remodeling around the tip of the Zweymüller stem. MATERIAL AND METHODS 102 consecuti...

BACKGROUND There are still many questions related to aseptic femoral stem loosening. Systemic and local immune responses to the implanted "foreign body" is one of the reasons for loosening. The purpose of the study was to measure metal ion concentration (Ti, Co, Cr, Mo, Ni, Al) around loosened femoral stems and compare their levels around uncemented and cemented implants. METHODS This paper r...

Six pairs of human cadaver femora were divided equally into two groups one of which received a non-cemented reference implant and the other a very short non-dependent experimental implant. Thirteen strain-gauge rosettes were attached to the external surface of each specimen and, during application of combined axial and torsional loads to the femoral head, the strains in both groups were measure...

This paper, the first of a series on the regulation of the hematopoIetic stem cell, examines the effects of stem cell kinetics during an acute exposure to hypoxichypoxia. This physiologic perturbation was chosen because of the well-established role It plays In Influencing erythropoiesis. BDF, male mice were exposed to a simulated altitude of 22,000 ft for periods of time ranging from 3 to 48 hr...