[Phlebography of the femoral head following femoral neck fracture].

The incidence of avascular necrosis (AVN) of the head of the femur after transcervical fracture is 30-60%, depending on the diagnostic methods used. A poor outcome in AVN is not inevitable, since early diagnosis and treatment with prolonged non-weightbearing can produce satisfactory revascularisation without deformity. Nineteen patients with fractures of the femoral neck treated with internal fixation were assessed after operation by per-osseous phlebography. Weightbearing was allowed, irrespective of the state of union of the fracture, only if this test was positive. Of 13 patients who were allowed to bear weight after consolidation of the fracture, only one developed avascular necrosis. A further six patients were treated by non-weightbearing for up to eight months. Only one, in whom the fracture did not unite, developed avascular necrosis. The average time to union was 3.2 months, and the time to weightbearing was 4.1 months. This small difference, taking into account the low incidence of AVN (2 out of 19 or 10.5%, has led us to suggest a fresh approach to fractures of the femur neck in which the indications for immediate arthroplasty are restricted if the patient can tolerate prolonged non-weightbearing. Revascularisation may be assessed with phlebography and weightbearing allowed when this becomes positive. This approach should diminish the incidence of advanced AVN of the femoral head, and widen the indications for internal fixation.