The clinical features are usually so characteristic that there is little difficulty in diagnosis. Restriction of the movements of abduction and adduction, the presence of cracking and of grating of the articular surfaces, and the aggravation of the pain and stiffness after resting the limb, are characteristic of arthritis deformans. The prominence of sciatic pain may lead to the disease being regarded as sciatica.
The greatest difficulty is met with in cases in which the disease occurs as mon-articular affection in adolescents, for the resemblance to tuberculous disease of the hip and to coxa vara may be close. Skiagrams do not always enable one to differentiate between them.
Treatment is conducted on the same lines as in other joints. The normal movements are maintained by suitable exercises, and an effort is made to diminish the pressure on the articular surfaces in walking by the use of sticks or crutches.
Shortening of the limb may be compensated by raising the sole of the boot. When the X-rays show that the disability is mainly due to new bone locking the head of the femur, such new bone may be removed by operation, cheilotomy (Sampson Handley). Excision of the joint has in some cases yielded satisfactory results; it is indicated in young patients who are otherwise healthy, and who are unable to walk on account of pain and deformity.
Osteo-chondritis Deformans Juvenilis.—Under this term Perthes describes an affection of the hip in children which differs in many respects from the juvenile form of arthritis deformans. Islands of cartilage appear in the epiphysis of the head of the femur, and the epiphysis itself becomes flattened without involvement of the articular surface or of the acetabulum.
The disease is met with in children between five and ten; there is a limp in walking without pain or sensitiveness, so that the child continues to take part in games. Abduction is markedly restricted and the trochanter is elevated and prominent. There is no crepitation on movement or other signs of involvement of the articular surfaces. The X-rays show the deformity of the head and clear areas in the interior of the upper epiphysis corresponding to the islands of cartilage; these clear areas resemble those due to caseous foci in tuberculous coxitis.
The disease runs a chronic course, and in the course of a year or two the limp and the restriction of abduction disappear, so that no active treatment is called for.
Neuro-Arthropathies.—Charcot's disease is usually met with in men over thirty who suffer from tabes dorsalis. One or both hip-joints may be affected. Sometimes the first manifestation is a hydrops and a fluctuating swelling in the upper part of Scarpa's triangle. In many of the recorded cases, however, attention has first been directed to the disease by the deformity and limp associated with disappearance of the head of the femur, or by the occurrence of pathological dislocation. The absence of pain and tenderness is characteristic. When dislocation has occurred, the limb is short, and the upper end of the femur is freely movable on the dorsum ilii. When both hips are dislocated, the attitude and gait are similar to those observed in bilateral congenital dislocation. The rotation arc of the great trochanter may be much reduced as a result of the disappearance of the head of the femur. There may be considerable formation of new bone, giving rise to large tumour-like masses in relation to the capsular ligament and the muscles surrounding the joint.
The treatment consists in protecting and supporting the joint. When the affection is unilateral, advantage may be derived from a Thomas' or other form of splint, along with a patten and crutches; in bilateral cases, from the use of crutches alone.
Loose bodies in the hip are mostly the result of hypertrophy of synovial fringes in arthritis deformans and in Charcot's disease, and do not figure in the clinical features of these affections; Caird has observed a case in which the cavity of the joint and the bursa beneath the psoas were filled with loose bodies, many of which had undergone ossification and gave a characteristic picture with the X-rays.