Abstract
Cemented acetabular components continue to be used in more than half of the total hip replacements performed in the United Kingdom. The implants are relatively inexpensive but the results rely heavily on precise surgical technique, with restoration of the centre of rotation of the hip and the creation of an equal cement mantle with good pressurisation and penetration of the cement into the bone.
The Opera all polyethylene acetabular component was designed with a malleable flange, which could be independently pressurised, a long posterior wall to promote stability and instrumentation which ensured that pressurisation could be maintained throughout the curing process.
We present for the first time, the medium-term results of 409 consecutive cemented flanged Opera acetabular components performed in 374 patients.
247 operations were performed via a trochanteric osteotomy and 162 via a posterior approach, using multiple key holes, cement pressurisation and Palacos-R cement. Autograft was used in 32 cases.
Cemented femoral components were used in all cases. There were 241 Charnley stems with 22mm heads and 168 polished triple tapered C-stems (146 with 22mm heads and 22 with 26mm heads).
The average age at the time of surgery was 68.2 years (32–87) and the average duration of follow-up was 89 months (60–130). 54 patients (56 hips) died during the follow-up period.
The acetabulum was assessed using the zones of DeLee and Charnley, and the Hodgkinson classification.
There was one temporary femoral nerve palsy, two dislocations and 3 non-fatal pulmonary emboli.
Both components were revised in two hips for deep sepsis, and in two hips only the femoral implant was revised, one for a fractured stem and one for aseptic loosening, with the original acetabular components remaining in situ.
Of the remaining original acetabular components 6% have shown progressive radiological demarcation, none have migrated, but in two hips there is evidence of rapid wear and the development of osteolysis.
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