Arthrography after total hip arthroplasty: a modified technique used in the diagnosis of pain

The results of plain film radiography and arthrography in diagnosing loosening of a prosthetic component after total hip arthroplasty were correlated with surgical findings in 31 patients who required surgery because of hip pain. The accuracy of arthrography in diagnosing component loosening using 5 ml of contrast material was 51%, and the accuracy of plain radiography was 69%. An accuracy of 92% was achieved using a modified arthrographic technique in which the pressure in the joint was recorded after injection of contrast material and while the patient walked to ensure that it was comparable with the pressure that caused the patient's pain prior to the study. Three per cent of the arthrographic studies using this technique were false negative and 5% were false positive.