In _impacted_ cases the signs of fracture are often obscure, and the patient may even be able to walk after the accident. The skin over the trochanter is generally discoloured from bruising. Eversion is usually present, but there may be little shortening. Crepitus is absent. In old people it is never advisable to undo impaction, as the interlocking of the bones favours the occurrence of osseous union.
_Prognosis._--A fracture of the neck of the femur in an old person is always attended with danger to life, a considerable proportion of the patients dying within a few weeks or months of the accident from causes associated with it. In some cases the mental and physical shock so far diminishes the vitality of the patient that death ensues within a few days. It is possible that fat embolism may account for death in some of the more rapidly fatal cases. In others, the continued dorsal position induces hypostatic congestion of the lungs, or, owing to the difficulties of nursing, bed-sores may form and death result from absorption of toxins. Frequently the prolonged confinement to bed, the continuous pain, and the natural impairment of appetite wear out the strength. In many cases the patient becomes peevish, irritable, or mentally weak.
Osseous union is the exception in intra-capsular fracture, especially when the periosteum and the retinacular ligaments have been completely torn, but in sub-periosteal and in impacted fractures it sometimes occurs. As a rule, however, the neck of the femur becomes absorbed and disappears, the head of the bone comes to lie in contact with the base of the trochanter, and a false joint forms (Fig. 64). Chronic changes of the nature of arthritis deformans may occur in and around such false joints.
[Illustration: FIG. 64.--Fracture of Narrow Part of Neck of Femur. The neck has become absorbed, the head has not united, and a false joint has formed.]
When osseous union fails to take place, although the patient may eventually be able to get about, he can do so only with the aid of a stick or crutch, and as there is marked shortening, he walks with a decided limp. There is considerable antero-posterior thickening of the neck of the femur, and the femoral vessels may be pushed forward in Scarpa's triangle.