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Lessons learned from early clinical experience and results
of 300 ASR® hip resurfacing implantations
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Journal |
Proceedings of the
Institution of Mechanical Engineers, Part H: Journal
of Engineering in Medicine </content/0954-4119/ |
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Publisher |
Professional Engineering Publishing |
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ISSN |
0954-4119 |
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Issue |
Volume 220, Number 2 /
2006 </content/t8263g0007xn/ |
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DOI |
10.1243/095441105X69079 |
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Pages |
345-353 |
AuthorsT Siebel, S Maubach, M M Morlock
Abstract
Between August 2003 and April 2005, 300 ASR® metal-on-metal
resurfacing hip endoprostheses were implanted by the first
author and a fellow surgeon. The mean age at surgery was
56.8 years (18-75.9 years) and mean body mass index was 27.6
kg/m2 (range, 19-41 kg/m2). The mean
follow-up time was 202 days. The mean Harris hip score
improved from 44 pre-operatively to 89 at 3 months
post-operatively. In total, eight (2.7 per cent) cases [five
neck fractures (1.66 per cent) and three cup revisions (1
per cent)] were revised. Two neck fractures occurred within
a group of seven cases of femoral neck notching detected
postoperatively; one neck fracture occurred out of two cases
of incomplete seating of the femoral implant. A
significantly higher (p< 0.001) failure rate was observed
for patients who had undergone a previous osteosynthesis of
the proximal femur (three revisions in a group of 15
patients). Revision cases had a significantly greater body
mass index (p = 0.031). A learning curve was evident from
the reduction in revisions from 5 in the first 100 surgical
procedures to 2 in the next 100 and 1 in the last 100.
These
results show the importance of accurate surgical technique
and careful patient selection for fourth-generation hip
resurfacing implants.
Keywords in English
resurfacing, fourth generation, hip, revision, ASR
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