Abstract
This study attempts to establish the factors on which the prognosis of an intracapsular fracture of the femoral neck depends, and to draw attention to certain causes of non-union and ischaemic necrosis. These factors are of two kinds: those inherent in the fracture, and those produced by the surgeon.
The prognosis depends largely on the nature of the fracture. Original displacement and comminution are the factors which have most influence. Fractures of Type IV with severe comminution have mainly contributed to the bad reputation of intracapsular fractures. Accurate reduction and firm fixation are necessary if the best results for the type of fracture are to be expected. Accurate reduction does not mean merely accurate apposition of the fragments. Fixation of the fracture in certain rotational malpositions such as valgus of over 20 degrees and rotation round the long axis of the neck may occlude the only remaining source of blood supply, the vessels of the ligamentum teres. If these vessels remain open they may produce revascularisation in a femoral head deprived of its blood supply. The degree of valgus can easily be measured but it is impossible to detect rotation round the long axis of the neck.
In this analysis only two methods of fixation were studied. It is clear that rigid fixation is of great significance, and a nail-plate, though it may not be the ideal method of fixation, is greatly superior to a Smith-Petersen nail introduced in the usual way. From the results of this survey there is no justification for continuing the use of this method except perhaps in Type II fractures.
The greater the risk of non-union the more important is the fixation, and this is true of all fractures.
This study also has a bearing on the indications for primary prosthetic replacement. If the nature of the fracture and the result of the reduction make it likely that replacement by a prosthesis is going to be the ultimate solution, and if the patient is over seventy years old, it is wiser to do it as a primary measure.
Finally it was shown that condensation and collapse of the femoral head are not the only radiological signs of ischaemic necrosis. An earlier sign is flattening of the weight-bearing area, which appears on an average six and a half months after injury, as compared to condensation, which may not be apparent until eighteen months after injury.
