- L. Poller, J. M. Thomson, W. Thomas
- med. J., 4, 648-650. Poller, L., Thomson, J. M…
Pathology of Caisson Disease of Bone MARY E. CATTO (Department of Pathology, Western Infirmary, Glasgow) While histological examination is of little help in elucidating the pathogenesis of aseptic bone necrosis in compressed air workers, it throws some light on the sequence of events and radiological changes following bone death. Revascularization of both medullary and juxtaarticular lesions may begin but halt short of completion, the revascularization front becoming collagenous. Bone trabeculae adjacent to this fibrous tissue are often greatly thickened and may give rise to a sclerotic line on clinical radiographs. When such a radio-dense line is seen traversing a bone end it is highly probable that the tissue between it and the joint surface is still dead. The necrotic bone trabeculae may later fracture, with collapse of the articular surface associated with pain. Incongruity of the joint surface is often followed by formation of osteophytes at the living joint margins. At first the joint space remains normal and the articular cartilage covering dead bone is relatively well preserved but later it and the underlying dead bone may be ground away, the end result sometimes being difficult to distinguish from primary osteoarthritis. A similar pattern of events and morphological changes may be seen following juxtaarticular bone necrosis due to other causes.