Cemented Polyethylene Cup Research Articles

Acetabular reconstruction with impacted morsellised cancellous bone graft and cement: A 10- to 15-year follow-up of 60 revision arthroplasties

We report a long-term review of 60 acetabular components revised using impacted, morsellised bone allografts and a cemented polyethylene cup. The acetabular defects were cavitary (37) or combined (23). Follow-up was for a mean 11.8 years (10 to 15). Further revision was needed in five hips, two for septic and three for aseptic loosening. The overall survival rate at 11.8 years was 90%; excluding the septic cases it was 94%. Acetabular reconstruction with impacted morsellised cancellous grafts and cement gives satisfactory long-term results.

Compressed allograft chips for acetabular reconstruction in revision hip arthroplasty

We report the results of 24 acetabular reconstructions in which cemented polyethylene cups and tamped corticocancellous allografts were used for severe acetabular bone deficiency. Eleven hips had type-II (cavitary) bone deficiency and 13 had type-III (combined) defects. At a mean follow-up of 5.8 years, two components had migrated more than 5 mm and had accompanying radiolucent zones of more than 2 mm width. A radiolucency 5 mm wide was also seen in zone III of an acetabular implant which had not migrated. None of the patients had required revision because of loosening or infection.

Principles of Bone Grafting in Revision Total Hip Arthroplasty

Multiple revisions of the acetabulum ultimately lead to severe loss of bone stock. Each bone loss type requires a specific method of allograft reconstruction to achieve acetabular component stability. A series of 316 acetabular revisions in which 69 required support allograft were followed for a mean of 5.1 years (range, two to ten years). Support allograft was required when radiographs showed superior component migration greater than 2 cm. Severe ischial lysis was indicative of posterior column insufficiency. Distal femurs were used instead of femoral heads as support for porous-coated cups. If in addition to the radiographic findings, Kohler's line also was violated (which was indicative of anterior column deficiency as well), then whole acetabular allografts were used with cemented polyethylene cups. Biologic fixation of a porous-coated cup and support allograft were not possible in these cases. All of the distal femoral allografts united to host bone, and there was no migration of porous-coated components at a mean of 5.1 years when Kohler's line was intact. When Kohler's line was not intact, 70% of the porous cups had migrated more than 4 mm and were considered failures. Conversely, when whole acetabular allografts with cemented polyethylene cups were used in these cases, all 14 showed graft union and no change in the cement-graft interface at a minimum follow-up period of 24 months. The postoperative clinical results using the D'Aubigne and Postel rating scales were 10.1 of 12, with 76% good to excellent results. This study indicates that better results with support allografts can be achieved at similar periods than has previously been reported.

Parametric Analysis of Cemented Ultrahigh Molecular Weight Polyethylene (UHMWPE) Total Hip Acetabular Cups in a Quasi-Static Loading Model

ABSTRACTOwing to the interest in ever increasing lifetimes for total hip prostheses, possible failure due to aseptic loosening of the acetabular component is an issue that may require increased attention. Mechanical factors, especially the deformation behavior of the material and the stress distribution at the implant-cement and the bone-cement interfaces, presumably play an essential role in total hip failure. Therefore the experimental model of the present work makes use of rosette strain gauge techniques to evaluate the deformation behavior of cemented polyethylene cups under quasi-static loading. Standard tests in UHMWPE beam specimens confirmed that the present method is a reliable tool for strain measurements in the polymer that was tested. On the other hand, the apparent elastic modulus of UHMWPE can be shown to be markedly dependent on the testing method, the geometry, and, owing to the visco-elastic properties, dependent on the strain rate. Thus in the present work a correlation between the measured strain and the ultimate strength was not attempted. Instead a parametric analysis quantifying the influence of the cup thickness and the cement distribution on the strain pattern was performed.