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Bicontact Plasmacup THA in patients with staged bilateral hip replacement.

AIM
In a retrospective study, all patients with bilateral cementless Bicontact-Plasmacup total hip arthroplasty in the period May 1993 to June 2000 were followed up clinically and radiologically.


METHOD
Out of 537 hip replacements performed in this period with this combination of implants, 46 patients had bilateral surgery. At follow-up, the Harris Hip Score, the radiological changes between primary implantation and most recent follow-up and the radiologically visible wear of the polyethylene cup component were studied.


RESULTS
Thirty-seven patients were followed up. One patient had died and 8 patients could not be contacted. The average age at the first hip replacement was 57.8 years and it was 59.1 years at the second operation. The follow-up period was 6.5 years (min 4.8 and max 9.8 years). The average Harris Hip Score at the time of follow-up was 91 points. Up to the time of follow-up, no stem or cup implant had to be revised. There were no radiological signs of stem loosening. In the case of the cup components, increased linear wear values of more than 0.15 mm/year were found in 4 THAs that used a 28-mm ceramic-polyethylene bearing. In two of these cases, the cup was in a markedly steep position. One of these cup components was assessed as loosened.


CONCLUSION
The results of this study have confirmed the biomechanical concept of the implant system employed. In contrast to the stem design, the cup design and slide bearing options have been supplemented in the meantime. The ceramic bearing was only available from 1997 and was used less often in this group of patients than would be indicated today for patients of the same age and degree of activity.