Purpose: We assess the advantages of helical computerised tomography as compared to conventional radiological methods in the diagnosis of this problem in the acetabulum.

Materials and methods: We studied 51 patients with 63 porous hemispheric acetabular implants coated with hydroxyapatite who were part of a planned radiological follow-up. After 10 years they were examined with helical computerised tomography according to a protocol designed to minimise metal artefacts. We compared the diagnosis of acetabular osteolysis by the two imaging techniques, taking the presence of delimited areas of absent trabeculation as a criterion.

Results: With computerised tomography we detected 23 osteolytic lesions in 19 hips, of which 5 had been diagnosed by conventional radiology. Only 3 patients presented symptoms in the form of mild-moderate pain. The mean volume of the lesions was 1.61 cc (SD: 1.41) with a minimum of 0.3 and maximum of 5.5 cc.

Conclusions: Computerised tomography can be a useful tool in the diagnosis and follow-up of acetabular osteolysis in total hip replacement. More studies are needed to complete its diagnostic possibilities and specify its indications.