The effect of steroids on regional perfusion, intraosseous pressure and partial pressures of oxygen and carbon dioxide in the femoral bone of minipigs

Regional blood peifusion. intraosseous pressure (IOP) and partial pressures of the intraosseous P02 and PCO2. were studied in the femoral bones of full grown minipigs. Half of the animals were treated with high, pulsed doses ot‘prednisone for 8months, in order to examine the influence of corticosteroids on the bone blood flow, the IOP and the respiratory gases, and in an attempt to develop an animal model of steroid induced osteoneerosis. The regional perfusion of the femoral bones varied from 19.7 ml/100 g/min in the femoral neck to 1.1 ml/100 g/min in the diaphysis. The mean intraosseous pressure in the femoral head was 18.9 +/- 2.5 mmHg (mean : SEM) in the treated group and 16.2 +/- 1.4 mmllg in the controls (n.s.). The mean P02 in the femoral head was 52.1 +/- 2.7 mmHg and 54.2 : 3.2., respectively (11.5.) and PCO: was 39.2 +/- 1.9 mmllg and 44.5 +/- 1.2 (n.s.) Femoral head blood flow in the steroid treated animals was 13.4 +/- 2.1 ml/100 g/min and 14.3 +/- 1.0 ml/100g/min in controls. There was no difference in corresponding areas at the right and the left femoral bone, and no difference in any of the examined parameters in animals that had received steroids and those that had not. It is concluded, that a pronounced heterogeneity exists in the blood flow and in the intraosseous respiratory gases in the femoral bone, and that it is not possible to induce necrosis in the femoral head of minipigs by treating them with prednisone alone