Today, different implant designs exist in the market; however, there is not a clear understanding of which are the best implant design parameters to achieve mechanical optimal conditions. Therefore, the aim of this project was to investigate if the geometry of a commercial short stem hip prosthesis can be further optimized to reduce stress shielding effects and achieve better short-stemmed impl...

Because controversy surrounds the management of end-stage hip disease in juvenile rheumatoid arthritis (JRA), this study evaluated the long-term outcome of bipolar hemiarthroplasty as an alternative to conventional joint arthroplasty. A total of 24 JRA patients underwent 39 hemiarthroplasties; follow-up averaged 12 years (range, 3 to 15 years). There were 14 hips (36%) revised, and 25 hips (64%...

The most important factors for long-term survival of cementless prostheses are the initial fixation, the osteoconducting properties of the metal shell and the bony response. Porous tantalum, a new biomaterial with a geometric structure similar to trabecular bone, was reported in animal studies to allow for bone ingrowth even when 3-mm gaps exist between the implant and the bone. This new materi...

The Birmingham hip resurfacing metal-on-metal arthroplasty was introduced in 1997 and has shown promising short- to mid-term results. We used radiostereophotogrammetric analysis (RSA) to study the stability of 20 resurfacing arthroplasties over a follow-up period of 24 months. Radiological examinations for RSA were performed immediately after surgery and at two, six, 12 and 24 months after oper...

Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the source is credited. DOI 10.3109/17453674.2011.623575 Clinical practice guidelines are being used in many countries throughout the world to improve the quality of patient care. The Dutch O...

A model of tissue differentiation at the bone-implant interface is proposed. The basic hypothesis of the model is that the mechanical environment determines the tissue differentiation. The stimulus chosen is related to the bone-implant micromotions. Equations governing the evolution of the interfacial tissue are proposed and combined with a finite element code to determine the evolution of the ...

BACKGROUND Among other causes the long-term result of hip prostheses in dogs is determined by aseptic loosening. A prevention of prosthesis complications can be achieved by an optimization of the tribological system which finally results in improved implant duration. In this context a computerized model for the calculation of hip joint loadings during different motions would be of benefit. In a...

Prospective, randomized studies must be performed when new surgical techniques or implants are evaluated. In this study, a new implant system was compared with the Charnley prosthesis, which over the years has been the most used hip implant in Sweden. Between 1985 and 1989, 410 hips were randomized to treatment with a Charnley or a Spectron total hip arthroplasty: 206 Charnley and 204 Spectron ...

BACKGROUND AND PURPOSE Over the past 20 years, several changes in treatment policy and treatment options have taken place regarding hip replacement. For this reason, we wanted to investigate the results after hip replacement in terms of revision rate, during a 21-year period among hip replacements reported to the Norwegian Arthroplasty Register. METHODS 110,882 primary total hip replacements ...

Dual energy X-ray absorptiometry (DXA) is the reference standard method used to study bone mineral density (BMD) after total hip arthroplasty (THA). However, the subtle, spatially complex changes in bone mass due to strain-adaptive bone remodeling relevant to different prosthesis designs are not readily resolved using conventional DXA analysis. DXA region free analysis (DXA RFA) is a novel comp...