Abstract
Inadequate cementation remains a prime cause of aseptic loosening in Hip Arthroplasties. While good progress has been made in preparation of femoral canal and cement, with newer techniques there are problems with ensuring adequate cement mantle. A distal centraliser available with some prosthesis does aid in better alignment and distal centralisation, but proximal centralisation remains a problem especially with some approaches.
We have recently used a new prosthesis CPS (Endoplus) which has a smooth polished double tapered design and also comes with a proximal and distal centraliser. We undertook a study to evaluate the effect of these on cement mantle, stem alignment, centralisation and supero-medial cement thickness. We defined adequate mantle as a thickness of at least 2mm. 75 consecutive cases were included in the study. All cases were done either by or under direct supervision of the senior author using the antero-lateral approach.
We found 88% of stem’s aligned within 2 deg. of anatomical axis of the femur. Distal tip of the prosthesis was within 2mm of centre of the medullary canal in 92% in the lateral view and in 95% in AP view. Deficiencies in cement mantle were noted in very few cases, zones 6 & 13 had the highest incidence but even here only 9% of cases had inadequate cementation.
We find the centralisers a useful adjunct in cemented hip arthroplasty.
Editoral Secretary Mr Peter Howard. Correspondence should be addressed to BHS at the Royal College of Surgeons, 35 - 43 Lincoln’s Inn Fields, London WC2A 3PN.
