172. 20
years performance of Boneloc cemented primary Exeter hip
arthroplasty.
Per B. Thomsen, Jesper Dalsgaard, Dovydas Vainorius, Torben B. Hansen
Orthopaedic Research Unit Hospital Vest, Holstebro; Department of
Orthopaedics, Hospital Vest, Holstebro; Department of Orthopaedics, Hospital
Vest, Holstebro; Department of Orthopaedics, Hospital Vest, Holstebro
Background:
Primary hip arthroplasty with Boneloc cement has in most
studies resulted in high or even catastrophic short and midterm revision
incidences. However, one femoral stem design concept (highly polished and
tapered) has shown acceptable results.
Purpose / Aim of Study:
The aim of our study is to evaluate 20 years survival
of Boneloc cemented primary Exeter hip arthroplasty and the clinical and
radiographical long term results.
Materials and Methods:
In the period March 1992 - June 1994 200
consecutive Boneloc cemented primary Exeter hip arthroplasties were
performed in 183 patients aged 26-90 (mean 70.7) years. 141 hips died without
revision, 32 hips were revised. 18 hips plus 6 hips with only cup revision had
clinical (Harris Hip Score) and radiographical follow-up and 12 hips had
telephonic follow-up after 18-20 years. Long term prosthetic survivcal was
assessed by Kaplan-Meier analysis.
Findings / Results:
After mean 18.4 (17.6-19.6) years HHS was mean 78 (46-
99)
and Pain Score mean 40 (20-44). According to patients own evaluation of
their hip all were very satisfied or satisfied. Twenty years cumulative
prosthetic survival without revision was 73 (49-89) %. Twenty years
cumulative stem and cup survival without revision for mechanical failure was
84 (68-96) %
and 76 (61-92) % respectively. Deep infection accounted for 2
revisions. According to the Chi- Square test neither cementing technique nor
cup size or metalbacking had any bearing on revision incidences. Radiographic
evaluation showed definate loosening of 2 cups and one pelvic osteolysis.
Stem subsidence greater than 2 mm was seen in 15 hips. Shift in stem
orientation in 3 hips, one femoral osteolysis in Gruen zone 7 but no stem
loosening.
Conclusions:
This study provides the first long term results on Boneloc
cemented primary hip arthroplasty. The Exeter prosthesis, especially the stem,
maintains earlier published acceptable results in spite of the documented
inferior quality of the cement.
