Abstract
Various assumptions must be made during total hip replacement when placing the acetabular component within the reamed acetabulum with regards to its orientation. Various methods have been described for different acetabular components, some relying on knowledge of the existing anatomy and some relying on the use of jigs to align the component. Many of these assumptions are based on opinion rather than science and the current study was designed to define the position of the acetabulum in relation to a fixed position of the pelvis.
A neutral position of the pelvis must be defined and this is represented by having a line from the anterior superior iliac spine to the pubis fixed in the coronal plane and taking measurements of the perpendicular axis of the pelvis taken from this.
A variety of measurements were made using measurement techniques and the conclusion was reached that the average angle for operative inclination is 43 degrees ± 5 degrees and the average angle for operative anteversion is 29 degrees ± 8 degrees. These figures should give a preliminary guide to the correct placement of the acetabular socket in total hip replacement although other factors may need to be taken into account.
The abstracts were prepared by Professor A. J. Thurston. Correspondence should be addressed to him at the Department of Surgery, Wellington School of Medicine, PO Box 7343, Wellington South, New Zealand
