Signs. — (1) Deformity, (2) Sudden loss of function—motion, (3) Change of length of the limb, (4) Change in the relationship of processes, (5) Pain, swelling, and discoloration.
(1) The Deformity is to be ascertained by com parison with the sound side of the body, and care must be taken that distortion, supposed to be the result of dislocation, is not swelling or due to previous injury or disease. The latter is to be learned from the patient himself. The distortion is the effect of the unnatural posi tion of the limb, and generally consists of a prominence at one place and a hollow at another.
(2) Loss of Function.—The person cannot move the limb at the joint involved. Inability to move a joint is often present because great pain is produced by the effort, and therefore the patient keeps his muscles tense, so that move ment cannot be effected. In dislocation, how ever, there is actual inability to move the part because the bones have lost their relations to one another, and the muscles cannot act upon the bones in the proper direction. Further, there is unnatural fixture of the bones even to a person, other than the patient, attempting to move them, and even after the patient has been chloroformed and the muscles relaxed.
(3) Change of Length. — In all dislocations with one exception the limb is shortened. The exception is the case of dislocation of the thigh bone forward on the front of the hip—strictly speaking on the obturator foramen (see p. 63). In this case the limb is lengthened.
(4) Change in the Relationship of Bony Pro cesses is one of the most reliable signs. For in stance, in dislocation at the shoulder-joint, the head of the arm-bone loses its relation to the acromion process of the shoulder-blade, a hollow existing beneath the point of the shoulder where the head of the bone ought to be; in dislocation at the elbow-joint the olecranon process—point of the elbow—and the condyles or projecting pro cesses on each side of the lower end of the arm bone, are severed from their connection. Some times, owing to swelling, considerable difficulty is experienced in detecting this sign.
Signs that Distinguish between Fracture and Dislocation. — Distinctions have already been noted between dislocation and fracture at special places. The following general differences are to be noted : (1) Movement—in fracture the movement is increased, in dislocation diminished.
(2) Presence in fracture of crepitation or grating, when the ends of the broken bone are rubbed against one another. In dislocation there is no true crepitation. A slight crackling or rubbing may exist in dislocation, though it is not developed for a day or two after the acci dent.
(3) The bony processes have in dislocation lost their relationship ; in fracture it is not so, the bony processes of the lower fragment being still in the grasp of the connected bone.
(4) In fracture the deformity is easily re moved, but returns on extension being removed; in dislocation reduction is difficult but perma nent, the bone returning to its own place usually with a snap.
It is frequently difficult even for experienced surgeons to determine whether the accident is of the nature of a fracture or a dislocation. When it is imrossible to decide, the rule is to treat it as a fracture.
Treatment. —The object of treatment is to restore the bone to its natural position. The action of the muscles opposes this object, the tendons also, and sometimes the torn ligaments by being caught round the bead of the bone.
Not only does the natural tension of the muscles oppose the reduction, but the patient unavoid ably increases the force. This difficulty can be overcome by chloroform. It call, however, be administered only by a medical man. There are other means at the disposal of those unquali fied to give chloroform. A hot bath, for in stance, relaxes the muscles. A simple method is to attempt reduction before the person has recovered the shock of the accident, while the muscles are still relaxed ; or, if that period has passed, the same result may be partially ob tained by suddenly, by a shout or quick exclama tion, diverting the patient's attention. In order to draw the bone down from its new position to the place of its socket, extension is necessary. To effect this the upper bone containing the socket is fixed by an assistant, who, by this means, provides counter-extension. The dis placed bone is then pulled continuously and steadily downwards, till it is brought into such a position that the muscles may set it. At the same time the hands, knee, or foot of the ope rator may act upon the bone so as to aid in its proper adjustment. This is called coaptation. The extension should be performed in the line of the opposing muscles. Extension may be performed by hand, or by various mechanical contrivances, especially pulleys, while the coun ter-extension may also be by hand, or by means of bandages passed round the body of the person and fixed to a staple in a wall. A more recent method of reduction is by manipulation. It is specially serviceable in dislocation at the hip joint, in which great force is required to over come the resistance of the muscles. In the method by manipulation no force is employed, but the limb is caused to execute certain move ments by the hand alone by which the head of the bone is induced to slip back into the joint, the resistance of the muscles not being called forth by the movements. This will be de scribed in discussing the treatment of special dislocations. After reduction the joint ought to be kept at rest for some time to permit of the healing of time torn ligaments, and to avoid the risk of inflammation. Should inflammation be feared, with perfect rest the use of warm fomen tations may be conjoined. The application of cold cloths or cloths wrung out of iced water will often give even greater relief. After all danger of this kind has passed away the joint will remain weak for some time. This is to be gradually remedied by gentle movement, made at first by hand then by the muscles of the part, by the use of the hot and cold douche alter nately, and by friction with some liniment— soap and opium liniment. Restoration of func tion by this means is attempted soon enough a fortnight after the accident. For a considerable time, even months, afterwards, the joint must never be placed in a position that would strain its ligaments, since a second dislocation would very readily follow a first.
Fracture is a ;very serious and dangerous complication of dislocation.
When a wound communicates with the joint from which the bone has been dislocated, in flammation of the joint is apt to ensue and to run a rapid course ending in complete dis organization, demanding amputation of the limb or cutting out of the joint—excision—to save the life of the patient.