Cemented long stem prostheses for hip revision
The main long-term threat to hip replacements appears to be polyethylene and metallic wear debris from the interacting surfaces of the components. This debris can cause inflammation in adjacent tissues that results in bone loss which, in turn, leads to prosthesis loosening. Up to 35% of retrieved modular prostheses exhibit corrosion or other evidence of damage. Fracture, dislocation, malpositioning of components, infection around the implant, poor cementing technique, and certain stem designs can also contribute to loosening of the stem component.
Long Prosthesis Stems from Link. Manufacturer of …
N2 - Stress shielding phenomenon is an important issues in considering the primary stability of the cementless hip arthroplasty. Stress shielding occurs when there is a mismatch in the elastic modulus of two materials perfectly bonded to each other, such as the prosthesis stem and the bone. In this study, influences of different prosthesis stem lengths on stress distribution in cementless THA are examined using finite element method. The calculated stress distribution is discussed with respect to stress shielding and primary stability issues in THA femur cases. Results show that similar pattern in stress distribution for intact and THA femur but differs in magnitudes. The stress level increases from the neck to the middle region and peaks at locations coinciding with the tip of the prosthesis. The maximum stress for intact femur is 55.5 MPa, THA with short stem is defined up to 112 MPa, while with medium and long stem are 204 MPa and 278 MPa, respectively.
Long stem cemented hemiarthroplasty appears to provide an adequate means for treating impending and actual pathologic fractures as a result of metastatic disease of the proximal femur in selected patients. Overall patient survival is comparable to that seen with other surgical approaches to metastatic bone disease. Patients with longer postoperative lifespans can be sufficiently palliated with substantial pain relief, return of mobility, and a higher degree of function provided there are no compounding variables related to their underlying disease negatively impacting recuperation. Even in patients with poorer prognosis, long stem cemented hemiarthroplasty may still be a useful means of pain control. Major complications were uncommon in this series, although a longer followup period is desirable to detect less common complications or potential hardware failure. Rigorous trials applying consistent indications and inclusion criteria are needed to directly compare long stem cemented hemiarthroplasty with other forms of endoprosthetic reconstruction as well as intramedullary nailing supplemented with polymethylmethacrylate and osteosynthesis with a plate-screw construct and polymethylmethacrylate.
Reverse Shoulder Prosthesis (RSP) | DJO Global
Long stem cemented hemiarthroplasty results in fair levels of function in a complex population of patients whose prognosis is sometimes measured only in months and who otherwise might be disabled by their metastatic lesions. Comparative trials applying consistent indications and inclusion criteria should be performed between this approach and fixation with intramedullary nailing supplemented with polymethylmethacrylate as well as osteosynthesis with a plate-screw construct and polymethylmethacrylate.
Prosthetic Heart Valves | Circulation
The above models of the femora, prostheses and cement were synthetized in Hypermesh to assemble the following four replacement types: (a) long-stem cemented prosthesis (Fig. ), (b) long-stem porous prosthesis (Fig. ), (c) short-stem cemented prosthesis (Fig. ), and (d) short-stem porous prosthesis (Fig. ).
Basics of Failed Shoulder Surgery | UW Orthopaedics …
The total hip prostheses were amplified by 2 pixels during the Mimics execution and then extracted by *.stl format. Simulative osteotomy occurred on Geomagic-studio along the break-angle of prosthesis by same direction. The remaining prosthetic stem, which was amplified by 2 voxels, was imported onto UG to fit 3D-solid model. The models were then exported to Hypermesh to remove the original prosthetic stem from the amplified prosthetic stem by Boolean calculation. The virtual model of the bony cement layer with 3 mm-thickness  and a cavity are shown in Fig. & .
Literary Terms and Definitions N - Carson-Newman …
A “Short-stem femoral prosthesis” of 100 mm (Fig. ) was developed after simulatively osteotomized by 35 mm from the (1) “Long-stem femoral prosthesis”.