The importance of choosing the right prosthesis: The Bristol experience of the PCA uniprosthesis

Sixty unicompartmental arthroplasties were carried out at the Winford orthopaedic hospital, Bristol using the Porous Coated Anatomical (PCA) prosthesis. All cases were prospectively scored before operation and at subsequent follow-up according to the Bristol knee score. At latest follow-up, after an average of 8 years and 5 months, with a minimum of 5 years and 11 months, seven knees had been lost due to death, four lost to follow-up and a further 13 revised. The currently surviving knees have an average follow-up of 8 years and 2 months. The interval between primary and revision surgery averaged 56 months. The causes of failure were varied with loosening of components and polyethylene wear being most common. The longevity of this series is greater than previously reported but falls far short of the results achieved with other uni-compartment replacements. The reason for failure, we believe, was heat treated polyethylene and instrumentation which fully corrected the deformity.