1. The early results of thirty Austin Moore arthroplasty operations with acetabular reaming in twenty-five patients with advanced osteoarthritis of the hip have been investigated.

2. The radiological changes after insertion of a prosthesis have been studied.

3. There was a variable degree of improvement in all patients. There was a worth-while improvement in function and relief of pain. Stability, however, was disappointing in more than half (and in all the bilateral cases). An average of three-quarters of an inch of shortening was found in the unilateral cases.

4. In such advanced cases the results of Austin Moore arthroplasty are probably of the same order as for cup arthroplasty, and in many cases they show no more than marginal improvement over pseudarthrosis.

5. It is concluded that at the present stage of progress in the development of arthroplasty the use of the Austin Moore prosthesis with acetabular reaming has very limited indications.