Abstract
In the 1980s, uncemented prostheses were considered advantageous in younger patients. One of the prostheses used in Denmark was the Porous Coated Anatomic (PCA) prosthesis. Follow-up results from Aarhus University Hospital (AaUH) showed progressive osteolysis along the stem at five to seven years, and use of the prosthesis was no longer recommended.
We used the PCA prosthesis with a modular 28mm head, and so far our results with patients operated on between 1989 and 1993 do not confirm the negative results published. Thirty-nine consecutive cases were followed prospectively with clinical and radiographic assessment.
At the 8–12 year follow-up four patients had undergone revision. Three revisions were for aseptic loosening of the cup at 5, 10 and 12 years, and one was because of thigh pain without radiological signs of loosening at revision. The cumulative survival rate was 95% at five years, 92% at ten years and 85% at twelve years. If we include radiologically loose components, five cups were re-operated or radiographically loose (12.8%) and 4 stems were re-operated or radiographically loose (10.2%). Thus the survival rate at 12 years was 85% and 90% for cup and stem respectively. So far we have not experienced progressive radiographic changes.
The difference in results may stem from the fact that we used 28mm heads (versus 32mm heads in the Aarhus series), which allows a more adequate polyethylene thickness and thereby lesser creep of the polyethylene and less polyethylene debris production.
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