The long-term functional result of exposed total knee arthroplasty, treated by flap cover, is presented and the results compared with those of a randomly selected control group. The wound was successfully covered and the prosthesis was preserved in 76% of cases, but the final functional score was not as good as in those with primary wound healing.

The development of the iron-cored electromagnet as a stimulator of bony union is described. In a clinical trial extending over eight years, 80 patients were treated for various forms of failed union. Their results are presented, as well as tentative conclusions regarding the indications and efficiency of the method. The latest, fully-portable apparatus is described.

A non-invasive method of electrical stimulation of healing in ununited fractures of the tibia by pulsed magnetic fileds has been evaluated. In a series of 17 patients all but two of the fractures united within 4 to 10 months, with an average time of just under six months. The method is sufficiently promising to merit further clinical investigation.

1. The various surgical procedures in common use for the treatment of the osteoarthritic hip are briefly reviewed and compared with the operation of replacement of both the acetabulum and head of the femur by a metal prosthesis, that is, a complete artificial hip joint.

2. The development, description and technique of insertion of this artificial hip joint are given in detail.

3. The results of the first fifty cases of this operation show a success rate of over 90 per cent. The few failures are analysed in detail. The revision procedure has been the insertion of another artificial hip joint.

4. The essential details necessary for success are stressed and the indications and aims of the operation given.