DOS Kongressen 2014 ·
59
Higher UHMWPE wear rate in cementless compared with
cemented cups with the Saturne® Dual-Mobility system.
Steffan Tabori Jensen, Morten Homilius, Christina Frølich, Torben Bæk Hansen,
Maiken Stilling
Ortopædkirurgisk, Hospitalsenheden Vest
Background:
Displaced medial femoral neck fracture (FNF) may be treated
with primary arthroplasty. Dual-mobility articulations have advantages on sta-
bility and range of motion, however polyethylene (PE) wear on two articulating
sides might lead to excessive wear.
Purpose / Aim of Study:
To investigate PE wear rate of primary DM cups in
patients with acute FNF
Materials and Methods:
From 2005-2011, 414 consecutive patients were
operated with Saturne DM cups, 28mm femoral metal heads, UHMWPE.
Cementless cups were coated with hydroxyapatite (HA). 239 cups were ce-
mented and 175 were press-fit by choice of the surgeon. In 2012, at minimum
1-year follow-up, 155 patients were dead and the remaining 259 were invited
for clinical follow-up. 80 patients were evaluated with standard radiographs for
analysis of cup placement, 2D wear and wear rate (PolyWare software 3D Pro).
Mean age at time of surgery was 80 (range 30-98) years.
Findings / Results:
At a mean follow-up of 3.5 (1.4 – 7.7) years the mean
2D wear was 0.82 (sd 0.38, 0.3-2.2) mm and 2D wear rate was 0.29 (sd
0.21, 0.1-1.2). Wear rate of 0.35 (sd 0.22) in cementless cups were higher
(p=0.045) than 0.16 (sd 0.07) in cemented cups. Patients with cementless
cups were younger (78 vs. 81 years, p=0.005). Mean cup inclination was 44
(26-65) degrees and mean cup anteversion 17 (-12-47). There was no cor-
relation between cup inclination and wear (p>0.34) and no difference in wear
between gender (p>0.33). There was no correlation between age at time of
surgery and wear (p>0.06). Cup inclination was similar (p=0.13) for cemented
and cementless cups.
Conclusions:
At short term follow-up, we found a higher wear rate in cement-
less HA coated cups compared with cemented cups. In general mean 2D wear
and wear rate in these old and low demand patients was high and above the
osteolysis threshold (0.1mm).
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