1. Of fifty consecutive double hemiarthroplasties of the knee for rheumatoid arthritis using Maclntosh prostheses, forty-six were available for detailed assessment in thirty-six patients after one to six years.

2. Two early deaths were related to the operation but two late deaths were not. Three knees required revision, one of them twice.

3. The late results were 87 per cent good and 13 per cent fair. No patients followed up were the same as previously or worse. Every patient stated that he would have the operation performed again.

4. In our experience this operation in carefully selected patients produces satisfactory results. It is essential that great care is given to the operative technique.