Core
decompression of the necrotic area for treatment of idiopathic
osteonecrosis of the femoral head was developed and published by Ficat and Arlet in 1962 within the scope of their "Functional exploration of bone". The mode of action is attributed to a reduction of the intramedullary pressure in the bony compartment of the femoral head. The possibilities of repair and bone regeneration following core
decompression are still discussed controversially. Core
decompression is a common but not generally accepted procedure in the treatment of idiopathic
osteonecrosis of the femoral head. After first publications of positive mid- and long-term effects, some subsequent studies judged it as an ineffective and high-risk method. Analysis of the literature shows that the effectiveness of core
decompression depends on the stage of
osteonecrosis at the time of surgical intervention. Prognosis is influenced by the extent and location of the necrotic area, the presence and amount of head depression, and continued risk factors--mainly
corticoid medication. The best prognosis can be given for patients with a small, medial-centrally located
necrosis without head depression. The classification according to Ficat appears to be insufficient, as the extent and localization of the necrotic area are not assessed. Magnetic resonance imaging has become a diagnostic gold standard, as radiographic diagnosis showed poor sensitivity and specificity, especially in the early stages of the disease. As an essential part, MRI was integrated into the new classification of the "Association Internationale de Recherche sur la Circulation Osseuse" (
ARCO). On account of the literature and our own experience, treatment by core
decompression can be recommended in cases of reversible early stages of
osteonecrosis (
ARCO 1), as well as in those cases of irreversible early stages (
ARCO 2) that show a medial or central location of the
necrosis with an extent of less than 30% of the femoral head. Once the disease reaches the irreversible early stage, complete recovery cannot be expected. In these cases only reduction of
pain and retardation of the natural course of the
osteonecrosis are possible to gain time until
total hip replacement is unavoidable.