Institute of Bone and Joint Surgery

Related Articles

Acute Liner Disassociation of a Pinnacle Acetabular Component.

J Arthroplasty. 2008 Jun 12;

Authors: Mesko JW

A primary total hip arthroplasty using a cementless Pinnacle cup and neutral Marathon polyethylene liner mated via a 32-mm cobalt chrome head to a Summit pore coated stem (Depuy, Warsaw, IN). At 23 months postoperative an acute disassociation occurred. This was resolved with a liner exchange to a 36-mm metal liner with a 36-mm metal head. The retrieved polyethylene liner was noted to have 3 of the 6 peripheral locking tabs sheared off.

PMID: 18555645 [PubMed - as supplied by publisher]

Related Articles

Acetabular component deformation with press-fit fixation.

J Arthroplasty. 2006 Sep;21(6 Suppl 2):72-7

Authors: Squire M, Griffin WL, Mason JB, Peindl RD, Odum S

Acetabular component deformation secondary to forces encountered during insertion is a potential consequence of the press-fit technique. This study characterized the stiffness of Pinnacle 100 cups (DePuy, Warsaw, Ind) via mechanical testing and used this information with intraoperative measurements of cup deformation to calculate the in vivo forces acting on cups inserted during hip arthroplasty in 21 patients. We found that 90.5% of cups had measurable compression deformity, averaging 0.16 +/- 0.16 mm. The corresponding forces acting on these cups averaged 414 +/- 421 N. For hard-on-hard bearing surfaces, such in vivo deformation of acetabular shells may result in negative clinical consequences such as equatorial loading with increased wear and potential seizing of components, chipping of ceramic inserts, or locking mechanism damage.

PMID: 16950065 [PubMed - indexed for MEDLINE]

Related Articles

Long-term porous-coated cup survivorship using spikes, screws, and press-fitting for initial fixation.

J Arthroplasty. 2004 Oct;19(7 Suppl 2):54-60

Authors: Engh CA, Hopper RH, Engh CA

This study examined the long-term outcome of a single institution's experience with 4,289 primary total hip arthroplasties using hemispheric porous-coated cups. Initial fixation was achieved with spikes (255 AML TriSpike cups), by press-fitting with rim screws (427 Arthropor cups) or by press-fitting the component (83 Harris-Galante, 391 ACS Triloc+, 2,537 Duraloc, and 596 Pinnacle cups). Among 203 revised hips, only 18 cups were found to be loose at the time of revision. Using revision for any reason as an end point, 15-year survivorship was 82.9% +/- 5.6% (95% confidence interval) for spiked components, 71.6% +/- 8.5% for press-fit cups with adjunctive rim screws, and 72.0% +/- 12.6% for press-fit components (P<.001, log rank). Using revision for aseptic loosening as an end point, 15-year survivorship was 94.7% +/- 3.4% for spiked cups, 98.4% +/- 1.9% for press-fit cups with screws and 100% +/- 0.1% for press-fit cups. Despite an increasing incidence of polyethylene wear-related revisions, porous-coated acetabular components have demonstrated excellent long-term fixation.

PMID: 15457419 [PubMed - indexed for MEDLINE]