Hybrid fixed resurfacing components:

A limited range of three acetabular components with hydroxyapatite coating on a largely smooth surface and three femoral components designed for fixation with cement were manufactured and inserted from March 1994. The early results with this implant were most satisfactory, but because of the limited range we could not treat very small or very large patients, nor could we deal effectively with significant acetabular dysplasia, and dysplasia is a common problem in these young patients.

Towards the end of 1996 a small number of patients with recently inserted Hybrid resurfacings reported a grating noise. This new complication could not be explained either by the Surgeons or the manufacturer, and there was no alternative but to withdraw this implant from the marketplace pending further investigation. Subsequent investigation showed that the introducer holes for the cup introducer instrument had inadvertently been malpositioned.(Fig. 38 & 39) This meant that with introduction of the component at surgery, burrs could be raised on the articular surface giving rise to noise. Happily, the noise from these patient’s hips settled quickly and all patients have continued to function well. It was clear however that redesign of the implant system would be necessary so that a new cup introducer instrument could be employed, ensuring that there was no risk of damaging the articular surface with cup insertion.