Initial stability is an essential prerequisite to achieve osseointegration of press-fit acetabular cups in total hip replacements. Most in vitro methods that assess cup stability do not reproduce physiological loading conditions and use simplified acetabular models with a spherical cavity. The aim of this study was to investigate the effect of bone density and acetabular geometry on cup stabili...

BACKGROUND In total hip replacement (THR), it is essential to achieve a primary stability to guarantee good long-term results. A novel locking screw hip (LSH)-stem, anchored to the medial cortex of the proximal femur by 5 monocortical locking screws, was developed to overcome the shortcomings of uncemented press-fit and cemented straight stems while simultaneously achieving primary stability. T...

Introduction Lack of primary stability has been regarded as a major cause for implant loosening in total hip arthroplasty. For a cementless press-fit acetabular cup, primary stability is achieved by inserting an oversized component into an under-reamed acetabulum. Two features that result from the press-fitting process are – 1) pre-stress due to the difference in the radii of the cup and the re...

A consecutive group of 60 patients who had intraoperative custom press-fit total hip arthroplasties (67 hips; Identifit, Thackray, London, United Kingdom) was compared with a similar group of 60 patients who had standard press-fit arthroplasties (66 hips; McCutchen, Wright Medical Technologies, Arlington, Tennessee) to determine if there were differences in operative time and charges, as well a...

We assessed differences in the incidence and appearance of the radiological signs of loosening of the cup for various types of design. This was an observational study based on hip registry data of 15,340 patients with 17,951 total hip arthroplasties collected over a period of 33 years in 49 hospitals in Central Europe. The threaded and the press-fit titanium cups showed significantly less asept...

It seems that new WMAP data require a fit with a primordial spectrum containing small negative tilt index in addition to the featureless Harrison-Zeljdovič-Peebles spectrum thus implying a broken scale invariance. We show that the data could be otherwise interpreted by a scale invariant primordial spectrum with the scale noninvariant evolution of density contrast using the Press-Schechter forma...