Bone and Joint Pyogenic Infections

Clinical, radiological, and bacteriologic findings are generally sufficient to establish the diagnosis of bone and joint pyogenic infection. Histopathological examination is helpful in diagnosing infection in specific locations such as the spine or in subacute or chronic forms, which can mimic bone tumors. The pathological diagnosis of bone and joint pyogenic infection can be made by the examination of surgical or percutaneous biopsies or by the cytologic analysis of joint fluids or abscess samples. Tissular changes depend on the stage (acute, subacute, chronic), the severity of the infection, and host immunity. Regardless of the infection site, microscopic features include fibrinous exudate, edema, and granulation tissue formation associated with mixed inflammatory infiltrate with predominant neutrophils. Osseous changes consist of sequestrum and involucrum. In all cases, the histopathological examination results should be correlated with clinical, radiological, and microbiological data to establish an adequate diagnosis.