Abstract
1. Evidence is presented which suggests that after total joint replacement bone necrosis and consequent loosening of the prosthesis may be due to the development of sensitivity to the metals used.
2. Nine patients, from a total of fourteen with loose prostheses, were found to be metal sensitive by skin-patch testing. In twenty-four patients with intact prostheses no sensitivity was demonstrated.
3. In material from the joints of sensitive patients the metal content was raised.
4. Examination of this material showed necrosis of bone and soft tissue following obliterative changes in the vascular supply.
5. Similar reactions were found following the injection of cobalt into a sensitive patient.
6. The release of metal around a prosthesis is greatest where metal rubs against itself.
7. We conclude that prostheses in which metal articulates with polyethylene should be preferred; that any patient in whom loosening or fragmentation occurs should be patch tested; and that if sensitivity is found the implant should be removed.
