Affiliations: [a] Design and Communication Systems – Bioengineering Division, Anglia Polytechnic University, Victoria Road South, Chelmsford, Essex, CM1 1LL, UK | [b] Broomfield Hospital, Orthopaedics Department, Court Road, Broomfield, Essex, CM1 7EP, UK | [c] IRC in Biomedical Materials, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
Correspondence:
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Design and Communication Systems – Bioengineering Division, Anglia Polytechnic University, Victoria Road South, Chelmsford, Essex, CM1 1LL, UK. Tel.: +1 44 1245 493131, ext. 3316; Fax: +1 44 1245 252646; E-mail: r.mootanah@anglia.ac.uk.
Abstract: Long-term studies have shown that failure of the acetabular component in total hip replacement increases exponentially ten years following surgery and occurs mostly at the bone-cement interface. During the cemented fixation of the acetabular cup, straight anchorage holes, 3–15 mm diameter and 3–20 mm deep, are drilled in the acetabulum in order to increase torsional resistance at the bone-cement interface. The aim of this paper is to provide guidelines for improving the profile of anchorage holes. Results from our finite element models show that the efficiency of anchorage holes may be improved if they are drilled perpendicularly to the acetabulum floor and if they have chamfered necks. A 10° inclination of the anchorage hole increases Von Mises stress in the cement mantle by 6% anchorage holes, instead of straight holes, decreases it by 14%. Increasing depth of anchorage holes does not improve efficiency.
