We adduce the following conclusions from our experience of using this spring-loaded compression screw on completely displaced medial fractures of the femoral neck: 1. That this method probably eliminates non-union when the head is fully viable. 2. That primary "first-intention" osseous union occurs in approximately 33·3 per cent of cases. 3. That a vascular complication, of varying severity, undetectable by orthodox radiological tests, is revealed by extrusion of the screw in 66·6 per cent of cases. 4. That these observations disprove the idea that the main obstacle to revascularisation of an ischaemic head is the existence of forces so inclined to the axis of the femoral neck as to cause "shear." 5. That, compared with the Smith-Petersen nail used for completely displaced fractures, continuous spring compression can materially reduce the incidence of utter mechanical failure within the first year after operation. This is the result of "mushroom" impaction which itself can resist shearing strain and so can permit function as a fibrous union. 6. That early and rapid extrusion is a sensitive indication of a vascular complication in the head. Forewarned by this, activity can be restricted, or possibly other measures adopted, to anticipate or permanently postpone serious trouble.
1. Fifty-one cases of fracture of the odontoid have been analysed. Forty were reported by other surgeons; eleven were new cases first reported by us. 2. Fracture of the odontoid in young children is an epiphysial separation. It occurs up to the age of seven years. As in epiphysial separations elsewhere, it unites readily, and remodelling occurs when reduction has been incomplete, so that normal anatomy is restored. 3. In adults forward displacement is twice as common as backward displacement. 4. Immediate paralysis is commoner if backward displacement occurs, but late neurological disorders are seen only after fractures with forward displacement. 5. Failure of bony healing is not dangerous if treatment has resulted in firm fibrous union, for there is neither excessive abnormal mobility nor progressive subluxation, either of which could injure the spinal cord or medulla. Neurological disorders developing after the fracture are the result of mobility from inadequate early treatment. It is the results of inadequate early treatment which have given this fracture a sinister reputation. 6. The fracture should be reduced by skeletal traction through a skull caliper. The reduction should be maintained for six weeks by continuous traction, and this should be followed by a period of six weeks in a plaster. 7. The increasing definition of the fracture-line seen in the radiographs of some patients indicates non-union.
