Abstract
1. A method is described for measuring blood flow to the head of the femur after fracture of the femoral neck, by estimation of the rate of uptake of radioactive phosphorus.
2. Of one hundred cases investigated the readings in fifteen were incomplete, and in seventeen were unreliable. Reasons are given for discarding the latter seventeen cases. After two years seven patients had died, leaving sixty-one available for analysis.
3. The results in sixty-one surviving patients with a follow-up of not less than two years are analysed. In twenty of these radioactivity was measured by bone sampling and in forty-one by direct readings with a needle counter.
4. The twenty-one intertrochanteric fractures studied were used as controls. In these the P32 ratio varied from 0·4 to 3·0. Union occurred in all patients and none developed avascular necrosis.
5. Of the forty patients with displaced fractures of the femoral neck twenty-eight showed a low P32 ratio. In twenty-three of these (82 per cent) the fracture united.
6. Twelve patients with fractures of the femoral neck showed a borderline or abnormal P32 ratio. In ten of these there was subsequent avascular necrosis or non-union.
7. The possible reasons for the discrepancy between expected and actual results are discussed.
8. Almost 40 per cent of the cases investigated had to be abandoned because of technical faults and in one-fifth of the remaining cases the expected results failed to agree with the clinical results. The method of investigation is therefore not of much practical value at the present time. Improvements in apparatus and technique might make the method more reliable and more useful.
