Extract
Wear-related complications have been a major cause of revisions and
reoperations following total hip arthroplasty. In the past, several materials
have shown promise for reducing polyethylene wear, but they have draw-backs.
Elimination of polyethylene from prosthetic designs has not gained wide
acceptance because it limits design flexibility and introduces other risks:
fractures with ceramic-on-ceramic bearings and metal-ion release with
metal-on-metal
bearings1,2.
In an attempt to address the problem on the femoral side, opposite the
polyethylene, ceramic modular heads were introduced because their surfaces are
more abrasion-resistant and produce less friction than do metal surfaces,
thereby reducing abrasive and adhesive wear of the
polyethylene3. The
use of oxide ceramics for the articulating femoral head can reduce wear by 25%
to
50%4-6.
However, ceramics such as monolithic zirconia and alumina are susceptible to
brittle fracture, with the need for immediate
revision1. On the
acetabular side, highly crosslinked ultra-high molecular weight polyethylene
was used for liners more than thirty years
ago7-9.
This practice was ended after a brief time because of commercial
considerations, but subsequent clinical results have indicated that these
liners undergo substantially less wear than do conventional ultra-high
molecular weight polyethylene liners.