Among the other consequences of panarthritis may be the formation of sequestra in or near the epiphyses, and such destruction as shall lead to pathological dislocation, the latter being well illustrated in [Figs. 204] and [207]. This dislocation is always the result of the pull of muscles thrown into that condition of reflex spasm which is a characteristic feature of this disease. It appears conspicuously at the knee, usually as a backward subluxation ([Fig. 207]), and at the hip as an upward dislocation, sometimes with more or less apparent migration of the acetabulum. Another consequence of tuberculous hydrarthrosis, which frequently persists even long after the subsidence of the acute stage of the disease, is the occurrence within the joint cavity of rice-grain or melon-seed bodies, for whose presence it is not easy to account. The generally received explanation is that they are the result of fibrinous outpour, whose fluid portions have been absorbed, while the remaining nearly pure fibrin is broken up into particles and rounded off by attrition during the movements of the joint. They may accumulate in astonishing amount, thus stamping the disease as having a chronic rather than an acute character. After a time they provoke a fresh outpour of fluid, as a result of the irritation which they produce. This fluid is at first usually clear serum, but becomes turbid or seropyoid, and, if infected, becomes pure pus, in which the rice-grain bodies are dissolved or disintegrated.
Fig. 204
Bony ankylosis of knee. (Ransohoff.)
Fig. 205
Fig. 206
Section of bony ankylosis of hip. (Original.)
Tuberculous panarthritis, illustrating various types of degeneration and destruction. (Lexer.)