Today's News

Friday, March 12, 2004

Researchers test instrument to remove well-fixed acetabular component

By Mary Ann Porucznik

Poster exhibt P005 demonstrates the results of removing well-fixed cementless acetabular components during revision hip arthroplasty with a new instrument specifically designed for this purpose.

Removing well-fixed cementless acetabular components during revision hip arthroplasty may result in significant damage to the host bone, which, in turn, can compromise reconstructive options. Using an instrument specifically designed to remove these components, Canadian and British researchers tested whether the use of this new technique would minimize bone damage and permit a more straightforward reconstruction.

The Explant Acetabular Removal System (Zimmer, Warsaw, Ind.) was used, and the first 31 consecutive patients who had revision of well-fixed cementless acetabular components using system were included in the study. All preoperative radiographs were assessed for implant stability and acetabular bone loss, according to AAOS criteria. Preoperative templating was performed by a surgeon who was blinded to the operative procedure. Researchers recorded the size of acetabular component removed, the size of the final reamer used during reconstruction and the time needed to remove the component. The indications for revision were malposition, polyethylene wear, infection and locking mechanism failure.

In all cases, the acetabular component was removed in less than 5 minutes. The mode difference between size of implant removed and diameter of final reamer used was 4 mm (range: 0 mm to 10 mm). Additionally, the preoperative templating matched the size of component actually implanted in every case. The classification of acetabular deficiency did not change after component removal, and no bone was removed at the time of component removal. In three patients, additional reaming was performed to facilitate implantation of a constrained component.

Researchers concluded that the Explant Acetabular Removal Sysytem enables a safe and reliable technique for removal of well-fixed cementless acetabular components during revision hip arthroplasty. Researchers included Philip Mitchell, FRCS, Surrey England, United Kingdom, and Donald S Garbuz, MD; Bassam A. Masri, MD, and Clive P Duncan, MD, all of Vancouver, BC, Canada.

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Last modified 20/February/2004