Effects of experimental excision arthroplasty of the hip joint.

The experimental results are reported on a series of sheep in which unilateral hip excision arthroplasty was performed. These sheep were slaughtered at regular postoperative intervals. Radiography and histology were performed on the normal and excised hip joints of the experimental sheep to provide information of the formation of the pseudarthrosis that develops following excision arthroplasty. The efficiency of the false joint that develops is good, judged on a clinical basis. Continuous remodelling of the acetabulum and resected face was noted throughout the experimental period. A sequence of degenerative changes in the acetabular cartilage was observed followed by filling in of the acetabular favity with new bone. New bone also developed on the cemoral component of the pseudarthrosis in the form of osteophytes situated around the perimeter of the resected surface. Growth deformities of the contralateral, nonoperated limb were induced.