Biomedical Engineering Reference
In-Depth Information
A short-term study (60 month follow-up) reported by Nikolaou
et al
(2012) [39] assessed and
compared the performance of 36 metal-on-UHMWPE, 32 metal-on-highly XLPE and 34
third-generation ceramic-on-ceramic hip joints. The apparent wear of the bearing surfaces
was assessed radiologically. The ceramic-on-ceramic joints showed the lowest wear (mean
linear wear 0.035 mm) and the metal-on-highly XLPE gave nearly 3 times lower wear than
the metal-on-UHMWPE joints (0.329 mm cf. 0.869 mm). At 60 months, no difference in clini‐
cal outcome was found for these three different material combinations. “Squeaking” was ob‐
served in 3 (8.8%) of the ceramic-on-ceramic joints; no revision procedures were necessary
as a results of this squeaking though.
Early to mid-term results were also reported by Stafford
et al
(2012) [40]. At a mean follow-
up of 59 months six of these 250 ceramic-on-ceramic hips were revised. Two were revised
for recurrent dislocation secondary to impingement, two for deep infection, one for recur‐
rent dislocation and one due to fracture of the femoral head. Although no patients experi‐
enced “squeaking”, six described a grinding or crunching noise that was experienced
mainly during deep flexion. One of these “squeaking joints” was a BIOLOX
®
delta ceramic
prosthesis. Again, no revision surgery was performed on these noisy joints.
Mesko
et al
(2011) [41] assessed the outcome of 930 ceramic-on-ceramic hips over 10 years
that were implanted by nine different surgeons. The survivorship at 10 years (96.8%) was
referred to as 'excellent' with 0.9% fracture, 2.3% dislocation and 2.5% reported incidents of
noise such as clicking, squeaking, popping, or creaking.
Another 10 year follow-up was reported by Yeung
et al
(2012) [42]. The clinical information
was available for 244 hips (227 patients) and the radiographic information was available for
184 hips (172 patients). The success of these joints led to an overall survival rate of 98%
(again, with revision for any reason as the end point).
In a multicentre study performed by Capello
et al
(2008) [43], 452 patients (475 hips) were
assessed. The majority of the hips implanted were ceramic-on-ceramic (380) whilst the re‐
mainder (95) were conventional metal-on-UHMWPE and used as a comparison. The aver‐
age patient age was 53 years and there was an average 8 year follow-up period. The authors
found the clinical results to be excellent. The ten-year Kaplan-Meier survivorship (with revi‐
sion of either component for any reason given as the end-point) was stated as 95.9% for the
ceramic-on-ceramic hip joints and 91.3% for metal-on-UHMWPE. The ceramic joints, there‐
fore, performed better than the conventional joints and because one of the major causes of
failure for conventional metal-on-UHMWPE joints is late aseptic loosening due to osteolysis,
a longer term study is likely to give a greater difference in survivorship ratings. Of the ce‐
ramic-on-ceramic failures requiring revision, only 2/380 (0.5%) were due to ceramic frac‐
tures. Therefore, overall it was concluded that the third-generation ceramic-on-ceramic hip
joints performed well clinically and radiographically in this young patient group. Although
these joints performed relatively well “squeaking” was reported in 3/380 (0.8%) cases for the
ceramic-on-ceramic joints.
In the study reported by Lee
et al
(2010) [44], the ten year survival rate of 88 ceramic-on-ce‐
ramic hip joints, with revision of either the head or the cup for any reason being as the end
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