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...

Background We investigated whether the calcar femorale, a cortical septum in the region of the lesser trochanter of the femur, correlates with results of femoral stem implantation in patients with osteoarthritis of the hip secondary to developmental dysplasia using computed tomography. Methods This retrospective study included 277 hips (41 males and 236 females; age, 37 to 92 years) of patien...

Bone loss around femoral hip stems is one of the problems threatening the long-term fixation of uncemented stems. Many believe that this phenomenon is caused by reduced stresses in the bone (stress shielding). In the present study the mechanical consequences of different femoral stem materials were investigated using adaptive bone remodeling theory in combination with the finite element method....

BACKGROUND AND PURPOSE The clinical results of THR may be improved by correct femoral torsion. We evaluated the stem position by postoperative CT examination in 60 patients. METHODS 60 patients requiring total hip arthroplasty were prospectively enrolled in this study. Minimally invasive THR was performed (anterior approach) in a lateral decubitus position and each patient underwent a postope...

Hip resurfacing is being performed more frequently in the United Kingdom. The possible benefits include more accurate restoration of leg length, femoral offset and femoral anteversion than occurs after total hip arthroplasty (THA). We compared anteroposterior radiographs from 26 patients who had undergone hybrid THA (uncemented cup/cemented stem), with 28 who had undergone Birmingham Hip Resurf...

BACKGROUND AND PURPOSE According to the manual of the cementless Link MP reconstruction prosthesis, a distal femoral stem-bone anchorage of at least 80 mm is necessary to gain implant stability. There have been no in vivo studies showing that this distance is either achieved in clinical practice or needed for clinically satisfying results. Thus, we assessed the femoral stem-bone anchorage of th...

In 1995, the NIH (National Institutes of Health) Consensus Development Panel on Total Hip Replacement supported the use of hybrid fixation with a cemented stem and a noncemented cup because of excellent long-term results. However, today, 60% to 90% of the approximately 200,000 total hip arthroplasties performed yearly in the United States involve both a cementless cup and a cementless stem. The...

conclusions large amounts of preclinical studies have been made of stem cells and there is an increasing interest to perform these studies within the human population but preclinical studies are insufficient; therefore, much more and efficient studies should be conducted to evaluate the efficacy and safety of stem cells. context musculoskeletal injuries may be painful, troublesome, life limitin...

The purpose of this study was to determine the biological effects of the elastic modulus of the femoral stem in canine hip arthroplasty. Cementless total hip arthroplasty was performed in 12 dogs, six had a low elastic modulus polyacetal resin stem and six had a high modulus stainless steel stem. The components were otherwise similar. At six and 12 months after operation, radiographic and histo...