Biomedical Engineering Reference
In-Depth Information
KAPLAN-MEIER SURVIVAL ESTIMATE
(Endpoint: Revision for any reason)
100
90
BP 95. 5% @ 11yr
Muller Stem 94% @ 10yr
AML 90. 8% @ 10yr
C
harnley 90% @ 9yr
HG Acet Rev 79.7% @ 13yr
HG Fem Rev 76.3% @ 13yr
PCA 44% @ 9yr
80
Mallory-Head 94% @ 8yr
70
0123456789 0 1 2 3 4 5
TIME (Years)
Fig. 5.26
Comparison of survival of Typical Third, Fourth and Fifth Generation Total Hip
Arthroplasties
The current prosthesis also improves upon the survivorship of the Mallory
Head [134] (94% at 8 years), the Harris-Galante [130] (acetabular survivorship of
79.7% at 13 years and femoral stem survivorship of 76.3% at 13 years), and the
PCA stem [133] (44% at 9yr).
Early clinical and survivorship results which document equivalence or superiority
to standard devices while providing an improved feature, such as calcar retention, has
been proposed as a method for improving joint replacement technology without
sacrificing safety and efficacy [138]. The current study follows these guidelines for
improving the state-of-the-art. Based on the current radiographic, clinical and
survivorship data this proximally-porous-coated hip replacement offers design
improvements over other standard devices and its continued use is recommended.
The refinements discussed in the next section produced outstanding results [61]
with one exception, excessive wear. Time will tell if the use of ceramic-ceramic
articulation or highly cross-linked UHMWPe will solve this remaining problem.
d)
Resurfacing
The B-P resurfacing, notwithstanding the excellent simulator performance [77], did not
fare as well clinically. Several wear-throughs of the standard polyethylene bearing were
observed although some lasted for more than 20 years. Most were easily
revised by replacing the bearing liner or by converting to a standard stem-type
component. Highly cross-linked polyethylene bearing liners, completely reinforced by
