Introduction: Patients’ demands from hip arthroplasty are changing. Bigger bearings with alternative bearing surfaces are marketed to meet these demands. The aim of this study is to investigate the level of function achieved by patients with the larger hard-on-hard hip replacements in the short term.

Methods: Three groups of patients were identified from the arthroplasty register. The two study groups were those who received a 36mm ceramic-on-ceramic hip replacement (28 patients) and those who received larger metal-on-metal hip replacements (56 patients). The control group (25 patients) was age matched patients receiving 28mm hip replacements with a polyethylene acetabular component.

All patients received postal questionnaires comprising the Oxford Hip Score, the HOOS score and a satisfaction score. Routine yearly radiological examination was also undertaken. Demographic data are shown in Table 1.

Results: All three groups showed significant improvement in the oxford hip score after hip arthroplasty. Those with the larger head sizes had significantly lower scores than those with 28mm.

Activity scores in the HOOS hip survey were not significantly different in the three groups.

There was no difference in satisfaction scores and whether patients would have the same operation again.

Discussion: Our findings suggest that in the short term, functional levels achieved following hip replacement are not influenced by the size of bearing. Should these results be reproduced in larger and longer term studies use of these costly implants may have to be questioned.