Reduction of a dislocation by rotation. The thigh is flexed, slightly adducted and rotated inward, as in the first stage of reduction of a dorsal dislocation. (Erichsen.)
The after-treatment of hip dislocations consists mainly in rest and quiet. These should be enforced, at least by a binder around the pelvis, and, if necessary, a starch or plaster-of-Paris protection. The anterior suspension splint affords a comfortable and efficient method of treating these cases after the first few days. (See [Fig. 322].) Very little liberty should be allowed the patient until the expiration of the first month.
Ancient and Unreduced Dislocations.
—The longer a hip dislocation is allowed to go unreduced the more difficult is its replacement. The expiration of six weeks will usually make a hip reduction very difficult, while after a lapse of three or four months it becomes wellnigh impossible. The longer a limb is disused the more do its osseous structures atrophy. Therefore a fracture of the neck of the femur or upper end of the shaft may occur in attempting to reduce an old luxation. The most marked obstacles are offered by formation of adhesions about the femoral head in its new position, and the shrivelling or change in shape of the capsule, whose opening may be distorted or obliterated, so as to make reëntrance impossible within it of the head of the bone.
Other things being equal, then, more force and wider range of motion are necessary in reducing the older dislocations, while success may be attained only by the expenditure of wellnigh all the muscular energy of a powerfully built man. Attempts prolonged too far produce serious laceration, with hemorrhages, which tend to encourage new adhesions in case of failure. If a dislocated hip cannot be reduced by any apparently safe procedure the operator should decide whether to leave it, in the hope of securing a false joint, or to cut down the parts and make such further division of tissues as may be necessary. Should this be contemplated it implies, of course, that each case should be adjudged upon its merits.
DISLOCATIONS OF THE PATELLA.
By various contractions of the quadriceps muscles the patella may be displaced outward, it being practically slipped over the external condyle. The same result may be produced by a blow from the inward direction and in the extended position of the limb. These displacements may be complete or incomplete; in the former case the flat plane and inner edge of the bone are directed forward instead of sidewise. Inward displacements are unusual and usually produced by direct violence. Such previous disease as shall have weakened the capsule, or caused its distention, permits these dislocations to occur with a minimum of violence. In fresh cases the capsule is usually torn.
Reduction is easily effected by lifting the limb, thus relaxing the quadriceps muscle and making pressure and manipulation in the indicated direction. An anesthetic may be given if thought admissible.
When the limb is partially flexed, and a blow is received on the edge of the patella directly from the front, it is occasionally rotated on its tendinous axis, so that without being displaced from its position in front of the condyles its articular surface looks inward and it rides the knee upon its edge. This is referred to as vertical rotation. It is relieved and replaced by suitable manipulation, a feature of which may be sudden and forcible flexion with external pressure.