When the condition is bilateral it is usually the result of disease in the bone, rickets most frequently in this country. The attitude and gait are highly characteristic, as the adducted and everted legs tend to cross each other at the knee, the deformity being of the scissors-like type ([Fig. 134]), and in extreme cases the patient is only able to walk with the aid of crutches.
Diagnosis.—Pain in the hip and a limp in walking suggest hip-joint disease, but while in coxa vara the movements are chiefly restricted in the direction of abduction, in hip disease they are restricted or absent in all directions. From congenital dislocation of the hip the diagnosis can usually be made by the history, the examination of the joint and of its movements; and by the Trendelenburg test ([p. 252]). In sacro-iliac disease, the pain and tenderness are over the sacro-iliac joint and the movements at the hip are free in all directions. Valuable evidence is obtained from skiagrams.
Treatment.—In the early stages, especially if there is pain and tenderness, the patient must lie up and extension is applied in the abducted position of the limb; after a fortnight or so recourse is had to massage and exercises and the patient is allowed up for a little each day, attention being paid to flat-foot, which is a common accompaniment. When deformity is the prominent feature and interferes with locomotion it must be corrected. The bloodless method is to be preferred; under general anæsthesia, the shortened adductors are stretched or divided, and forcible movements are carried out in all directions, until the limb can be brought into an attitude of marked abduction and internal rotation. A plaster-case is then applied, from the pelvis to the middle of the calf, the knee being slightly flexed for greater comfort; in a week or so the patient is able to go about, and in a couple of months a second plaster-case is applied, this time leaving the knee free. After another six weeks or so a moulded splint is used, which can be removed at bedtime. The traumatic forms can nearly always be corrected by this bloodless method. In advanced cases the deformity can only be corrected by open operation, which consists in dividing the femur obliquely downwards and medially through the great trochanter, and, the adductor muscles having been ruptured or divided, the limb is put up in the abducted position along with, if required, powerful weight extension.
| Fig. 133.—Coxa Vara, showing adduction curvature of neck of femur associated with arthritis of the hip and knee. | Fig. 134.—Bilateral Coxa Vara, showing scissors-leg deformity. |
In cases of traumatic origin—epiphysial separation—Sprengel has obtained good results by forcibly abducting and internally rotating the limb under an anæsthetic, and then applying a plaster-case which extends down to the knee.
Other Forms of Coxa Vara.—In rickety children, coxa vara is most often associated with pronounced eversion of both lower extremities, without the capacity for abduction being necessarily restricted, and with but little impairment of function. The child should be treated for rickets, and put up in a double long splint with the limbs abducted and inverted.
In arthritis deformans of the hip, it is not uncommon to have considerable depression of the head of the bone and diminution in the angle of its neck, with consequent restriction of abduction. Sometimes the upper end of the shaft is also curved.
In osteomyelitis fibrosa, involving the upper end of the femur, a gross form of coxa vara may be observed, of which a marked example is shown in figures on pp. 476, 478, Volume I.
The congenital variety of coxa vara is due to various intra-uterine conditions, of which the chief is defective development of the upper end of the femur; as it does not manifest itself until the child begins to walk, the resemblance to congenital dislocation of the hip is very close.
Coxa Valga.—Coxa valga is the reverse of coxa vara, the angle at the neck of the femur being over 140°. It is not nearly so important in practice as coxa vara. It may result from incomplete fractures or epiphysial separations, rickets, or various forms of osteomyelitis, but it is also a frequent accompaniment of other deformities, such as congenital dislocation of the hip and paralysis following anterior poliomyelitis. It is commoner in boys than in girls, and is more often single than bilateral. The limb is lengthened, abducted, and rotated outwards; there is flattening of the buttock, and the trochanter is depressed so that it lies below Nélaton's line. The patient is unable to adduct the limb, and shows a peculiar gait, which has frequently caused the condition to be mistaken for unilateral congenital dislocation at the hip.