Aggressive granulomatosis post hip replacement

Aggressive granulomatosis post hip replacement (also known as particle disease) is a potential complication of a hip joint replacement.

Pathology

Aggressive granulomas consist of well organized connective tissue containing histiocytic-monocytic and fibroblastic reactive zones. They can be highly vascularized, and villous structures can be observed. On immunohistological evaluation, most of the cells in the aggressive granulomatous tissue tends to be multinucleated giant cells and C3bi-receptor and nonspecific esterase-positive monocyte-macrophages. ¹

Radiographic features

Plain radiograph

There may be evidence of progressive lytic focal regions around the replacement. There is usually smooth endosteal scalloping ⁷ and no sclerotic reaction.

MRI

The presence of a joint effusion due to reactive synovitis may be an early MR finding. This may occur before symptoms arise. There may also be capsular thickening and the presence of low signal intensity debris within the joint, though the normal fluid signal intensity of the effusion may also be seen.

Differential diagnosis

On certain occasions, it may be mistaken for primary or secondary neoplasia.

Treatment and prognosis

Aggressive granulomatosis post-hip replacement causes morphological changes and limping in the patient, repeat surgery is usually preferable.

History and etymology

The process is thought to have been first recognized by Sir John Charnley, British orthopedic surgeon, in the 1960s ⁸.