Degenerative disease of the sacroiliac joint.

Analysis of 46 sacroiliac joints removed in toto at random during routine autopsies was undertaken to define the pathologic and radiographic alterations of this joint in middle-aged and elderly patients. Each joint was sectioned, photographed and radiographed and large microscopic slides were prepared. Sacroiliac osteoarthrosis resulted in progressive cartilage degeneration, particularly on the ilial side of the joint, with eventual cartilaginous fusion. Para-articular bony ankylosis was produced by bridging osteophytes on the anterior and inferior surfaces. Sacroiliac intra-articular bony ankylosis was confined to cadavers with ankylosing spondylitis. In some patients radiographic differentiation of osteoarthrosis and ankylosing spondylitis may require tomography.