There are a lot factors in the genesis of the ischemic femoral head necrosis. In the early stage the intraosseous pressure increases without any clinical or radiological sign. The disease is often bilateral. The early diagnosis (NMR) is essential in the treatment. In the case of a severe femoral head necrosis the radiological investigation of the other side is obligatory, in order to diagnose the early stage of the disease and to prevent the progression of the collapse with core decompression. The object of the adequate treatment of the collapsed femoral head is to release the pain and to avoid the total destruction of the femoral head. The untreated femoral head necrosis results in a painful, arthritic hip, where spontaneous regeneration is limited, and takes 8-10 years. With osteotomy and revascularisation the results are good, and the regeneration takes about 2-3 years. As a result of this treatment, the patients have a moderately limited function, and minimal limping. Rehabilitation is possible into the original profession, or into a somewhat easier job. Remodellation of the femoral head in younger patients following the revascularisation procedure has been observed in our experience in the last few years.