Syphilitic osteo-arthritis results from a gumma in the periosteum or marrow of one of the adjacent bones. There is gradual enlargement of one of the bones, the patient complains of pains, which are worst at night. The disease may extend to the synovial membrane and be attended with effusion into the joint, or it may erupt on the periosteal surface and invade the skin, forming one or more sinuses. The further progress is complicated by the occurrence of pyogenic infection leading to necrosis of bone, in the knee-joint, for example, the patella or one of the condyles of the femur or tibia, may furnish a sequestrum. In such cases, anti-syphilitic treatment must be supplemented by operation for the removal of the diseased tissues. In the knee, excision is rarely necessary; but in the elbow it may be called for to obtain a movable joint.

In inherited syphilis the earliest joint affections are those in which there is an effusion into the joint, especially the knee or elbow; and in exceptional cases pyogenic infection may be superadded, and pus form in the joint.

In older children, a gummatous synovitis is met with of which the most striking features are: its insidious development, its chronic course, symmetrical distribution, freedom from pain, the free mobility of the joint, its tendency to relapse, and its association with other syphilitic stigmata, especially in the eyes. The knees are the joints most frequently affected, and the condition usually yields readily to anti-syphilitic treatment without impairment of function.

Joint Diseases accompanying certain Constitutional Conditions

Gout.Arthritis Urica.—One of the manifestations of gout is that certain joints are liable to attacks of inflammation associated with the deposit of a chalk-like material composed of sodium biurate, chiefly in the matrix of the articular cartilage, it may be in streaks or patches towards the central area of the joint, or throughout the entire extent of the cartilage, which appears as if it had been painted over with plaster of Paris. As a result of this uratic infiltration, the cartilage loses its vitality and crumbles away, leading to the formation of what are known as gouty ulcers, and these may extend through the cartilage and invade the bone. The deposit of urates in the synovial membrane is attended with effusion into the joint and the formation of adhesions, while in the ligaments and peri-articular structures it leads to the formation of scar tissue. The metatarso-phalangeal joint of the great toe, on one or on both sides, is that most frequently affected. The disease is met with in men after middle life, and while common enough in England and Ireland, is almost unknown in hospital practice in Scotland.

The clinical features are characteristic. There is a sudden onset of excruciating pain, usually during the early hours of the morning, the joint becomes swollen, red, and glistening, with engorgement of the veins and some fever and disturbance of health and temper. In the course of a week or ten days there is a gradual return to the normal. Such attacks may recur only once a year or they may be more frequent; the successive attacks tend to become less acute but last longer, and the local phenomena persist, the joint remaining permanently swollen and stiff. Masses of chalk form in and around the joint, and those in the subcutaneous tissue may break through the skin, forming indolent ulcers with exposure of the chalky masses (tophi). The hands may become seriously crippled, especially when the tendon sheaths and bursæ also are affected; the crippling resembles that resulting from arthritis deformans but it differs in not being symmetrical.

The local treatment consists in employing soothing applications and a Bier's bandage for two or three hours twice daily while the symptoms are acute; later, hot-air baths, massage, and exercises are indicated. It is remarkable how completely even the most deformed joints may recover their function. Dietetic and medicinal treatment must also be employed.

Chronic Rheumatism.—This term is applied to a condition which sometimes follows upon acute articular rheumatism in persons presenting a family tendency to acute rheumatism or to inflammations of serous membranes, and manifesting other evidence of the rheumatic taint, such as chorea or rheumatic nodules.

The changes in the joints involve almost exclusively the synovial membrane and the ligaments; they consist in cellular infiltration and exudation, resulting in the formation of new connective tissue which encroaches on the cavity of the joint and gives rise to adhesions, and by contracting causes stiffness and deformity. The articular cartilages may subsequently be transformed into connective tissue, with consequent fibrous ankylosis and obliteration of the joint. The bones are affected only in so far as they undergo fatty atrophy from disuse of the limb, or alteration in their configuration as a result of partial dislocation. Osseous ankylosis may occur, especially in the small joints of the hand and foot.

The disease is generally poly-articular and may be met with in childhood and youth as well as in adult life. In some cases pain is so severe that the patient resists the least attempt at movement. In others, the joints, although stiff, can be moved but exhibit pronounced crackings. When there is much connective tissue formed in relation to the synovial membrane, the joint is swollen, and as the muscles waste above and below, the swelling is spindle-shaped. Subacute exacerbations occur from time to time, with fever and aggravation of the local symptoms and implication of other joints. After repeated recurrences, there is ankylosis with deformity, the patient becoming a helpless cripple. On account of the tendency to visceral complications, the tenure of life is uncertain.