Cementless socket fixation based on the “press-fit” concept in total hip arthroplasty
February 2002 Acta chirurgiae orthopaedicae et traumatologiae Cechoslovaca 69(1):8-15 Cementless socket fixation based on the “press-fit” concept in total hip arthroplasty E W Morscher, K-H Widmer, H Bereiter Abstract The key problem of implant fixation in THR is stress distribution, i.e. load transmission between bone and implant. The closer the load transfer is to the […]
Temperature threshold levels for heat-induced bone tissue injury: A vital-microscopic study in the rabbit
Healing following bone surgery may be delayed or even prevented if the bone cells are severely injured by the frictional heat generated during the surgical preparation.lT4 However, little is known about the critical temperature that causes a reversible or irreversible bone injury. This critical temperature is popularly believed to be around 56” C because alkaline […]
The Accuracy of Acetabular Reaming in Total Hip Replacement
The stability of cementless cups depends upon the fit of the shell in the reamed acetabulum. Consequently, over-reaming can lead to increased micromotion or traumatic disruption with loss of cementless fixation. Therefore, it is critical that the surgeon knows the true size of the reamed acetabulum before implanting a cementless acetabular cup. In this study, […]
Assessment of Bone Viability After Heat Trauma
Abstract In the present investigation a comparison was made between conventional histology, histochemistry, and vital microscopy for assessment of heat induced bone tissue injury. The extent of the bone damage around a burr hole or after heating fibular bone samples in saline solutions of various temperatures was evaluated by means of histology and histochemistry, using […]
Determinants of the primary stability of cementless acetabular cup implants: A 3D finite element study
Determinants of the primary stability of cementless acetabular cup implants: A 3D finite element study Abstract Primary stability of cementless implants is crucial for the surgical success and long–term stability. However, primary stability is difficult to quantify in vivo and the biomechanical phenomena occurring during the press–fit insertion of an acetabular cup (AC) implant are still poorly understood. The […]
Deeper Central Reaming May Enhance Initial Acetabular Shell Fixation
Deeper Central Reaming May Enhance Initial Acetabular Shell Fixation Background: The initial stability of press-fit acetabular components is partially determined by the reaming technique. Nonhemispherical (NHS) acetabular shells, which have a larger radius at the rim than the dome, often require larger reaming preparations than the same-sized hemispherical (HS) shells. Furthermore, deeper central reaming may […]
Comparative in vitro assessment of the primary stability of cementless press-fit acetabular cups
Abstract Long-term stable osseointegration of porous-coated acetabular cups depends on bony ingrowth within their porous surface. For ingrowth to take place, one must ensure rigid initial fixation of the implant, by means of screws or by impaction or using a threaded ring. Primary stability is a prerequisite for long term stability through bony ingrowth. We […]
Variability of Cutting and Thermal Dynamics Between New and Used Acetabular Reamers During Total Hip Arthroplasty
Variability of Cutting and Thermal Dynamics Between New and Used Acetabular Reamers During Total Hip Arthroplasty Background: Aseptic loosening of the acetabular component remains one of the leading causes of early failure of total hip arthroplasty. Poor apposition of bone onto the implant surface can be due to inaccurate reaming and osteonecrosis of the acetabular […]
Initial stability of cementless acetabular cups: press-fit and screw fixation interaction – an invitro biomechanical study
Abstract Background Press-fit and screw fixation are important technical factors to achieve initial stability of a cementless acetabular cup for good clinical results of total hip arthroplasty. However, how these factors affect one another in initial cup fixation remains unclear. Therefore, this study aimed to evaluate the mutual influence between press-fit and screw fixation on […]
Hemispherical and minimally invasive total hip reamers: a biomechanical analysis of use and design
Hemispherical and minimally invasive total hip reamers: a biomechanical analysis of use and design Background: The purpose of this study was to determine the accuracy of used and new reamer systems for both hemispherical and minimally invasive (MIS) acetabular reamers. Methods: New and used hemispherical and MIS acetabular reamers were tested on a computer numerical […]