T. Schneider et al., THE ABILITY OF REPERFUSION OFF THE EPIPHY SIS OF THE FEMORAL-HEAD AFTER ISCHEMIA - AN EXPERIMENTAL-STUDY, Zeitschrift fur Orthopadie und Ihre Grenzgebiete, 136(2), 1998, pp. 132-137
Purpose of the study: The aim of this study was to evaluate bone blood
flow of the proximal femur during experimentally induced ischemia and
to document the ability of epiphyseal and metaphyseal reperfusion. Me
thods: 11 pigs (danish landrace) were used to investigate the effect o
f tamponade by increased joint pressure (Dextran 70) on the perfusion
of the femoral head. Additional 8 pigs were used as control. The blood
flow in the hip joint was studied by means of the microsphere techniq
ue. The flow was determined before, during and after intraarticular pr
essure Increase. With the ''radioactive tracer microsphere'' - method
the blood now of the epiphysis, metaphysis and proximal femoral cortic
alis could be measured. Results: In the epiphyseal femoral head the in
itial blood flow rate, 11.7 ml/min/100 g, was not significant differen
t from that of the control side (11.1 ml/min/100 g). The blood flow de
creased in the ischemic phase to 1.8 ml/min/100 g followed by reperfus
ion to 13.5 ml/min/100 g (p < 0.01). The bone blood flow of reperfusio
n was not significant different from that of the initial blood flow ra
te but in 2 cases a ''blow out'' of the epiphyseal bone blood flow was
seen. The proximal femoral metaphysis showed the highest of the measu
red intraosseous flow rates (17.9 resp. 23.3 ml/min/100 g). During isc
hemia and reperfusion of the epiphysis bone blood flow of the metaphys
is remained the same. The proximal femoral corticalis showed the lowes
t of the measured intraosseous flow rates. The operated (10.1 ml/min/1
00 g) and contralateral hip side (11.7 ml/min/100 g) showed no signifi
cant differences in the initial blood flow rate. During ischemia and r
eperfusion the blood flow of the proximal corticalis showed no signifi
cant difference to the initial blood flow corresponding to the metaphy
sis. Conclusions. Our study demonstrates disturbances of the circulati
on of different regions of the femoral head during intraarticular pres
sure increase and following pressure decrease of the growing pig. 2 ''
blow outs'' document a vulnerable proximal epiphysis already after a 6
-hour ischemia. Additional minor ''bone quality'' in cases of certain
diseases (kidney transplantation, leukemia) and special administration
of drugs (corticosteroids) seem to create an additional vulnerability
of the proximal femoral head. The experiment proves to be a reliable
model for decreasing the blood now of the growing epiphysis temporaril
y and to document the beginning of normal reperfusion. With this model
it is possible to examine the vulnerability of the epiphyseal perfusi
on after different deseases and under the influence of different medic
ation.