We used MRI to examine the hips of 32 asymptomatic patients at 9 to 21 months after renal transplantation covered by high-dose corticosteroids. Five hips in three patients showed changes which indicate avascular necrosis, although radiographs, CT scans and isotope scans were normal. These patients had repeat MRI scans after another two years and three years. One patient with bilateral MRI changes developed symptoms and abnormal radiographs and CT and isotope scans in one hip nine months after the abnormal MRI. Intraosseous pressure was found to be raised in both hips, and core biopsies revealed necrotic bone on both sides. The other three hips have remained asymptomatic with unchanged MRI appearances three years after the initial MRI. It seems that idiopathic avascular necrosis does not always progress to bone collapse in the medium term.

In a prospective, randomised controlled trial, the efficacy of the A-V Impulse System in the prevention of deep-vein thrombosis was investigated in 84 patients who had undergone total hip replacement. The incidence of venographically proven, and clinically significant postoperative deep-vein thrombosis was 40% in the control group and 5% in the treatment group (p less than 0.001). No adverse reactions were recorded.

We have reviewed 107 patients of 80 years or over who underwent primary total hip replacement. They had many more complications than younger patients. Thus, acute dislocation occurred in 15%, and became chronic in 9%; there were femoral shaft fractures in 4.6% and these, with shaft perforation gave universally poor results. Nevertheless, 75% of patients had a satisfactory outcome, with worthwhile relief of pain. It would seem sensible to warn elderly patients and their relatives of the increased risks in this age group.