Fifteen cases

27 hips

of idiopathic necrosis of the femoral head （INFH） were included i our series.The role of radiography

isotopic bone scanning

intraosseous pressure measure- ment and intraosseous venography in the diagnosis of INFH were evaluated.Radiological examination could not reveal early cases

while isotopic bone scanning was more sensitive. There was an increase of intraosseous pressure in most of the diseased hips.and intraos- seous venography showed abnormalities in all examined hips.The latter two tests could therefore detect early INFH.Core decompression was performed in 23 hips

21 of which were followed for 7 to 27 months.Functional evaluation was good or excellent in 18 hips. Radiological re-examination remained unchanged in 19 hips.Postoperative intraosseous pressure measurement and intraosseous venography revealed a decrease of intraosseous pres- sure and improvement of venous drainage.Core decompression is therefore an ideal method of treatment for early INFH.