Perosseous venography in the diagnosis of viability in subcapital fractures of the femur.

Although perosseous venography of the hip is simple, variations in the circulation of the femoral head and difficulties in prediction of viability account for its limited acceptance. The venogram accurately demonstrates viability in 77% of 50 routinely fixed subcapital fractures. Factors causing variations in the circulation of the fractured head are: method of surgical fixation; efficiency of the fixation, and the clinical course of healing. These and other less obvious factors make it impossible to correctly interpret a venogram. Because of a 3 week delay before cell death becomes apparent, a histological examination of a further 20 femoral heads excised after venography is equally unsatisfactory. In 50 fractures labelled with tetracycline preoperatively, subjected to venography, and then treated by hemiarthroplasty, the level of tetracycline fluorescence by the osteocytes can be correlated with the venogram predictions. There is a 92% correlation of venography with tetracycline evaluations of head viability. Venography can distinguish the dead femoral heads from those with potential or adequate vascularity and thereby provide essential clinical information for the operating surgeon.