We report the 12 to 74 month results of our mark I saddle prosthesis after its use as a salvage device for gross loss of pelvic bone stock in 76 patients with failed hip arthroplasties. The implant transmits load between iliac bone and bare polish chrome-cobalt. Our clinical and radiological results indicate that a useful and stable articulation can be achieved in most cases, provided that continued deep infection can be avoided. The appearance of radiological sclerosis at the bearing site in successful cases seems to indicate that significant late migration will not occur. Based on our experience with the mark I prosthesis we have designed and developed a mark II model which has freedom of axial rotation of the saddle. Our early results in 40 cases show a significant improvement over the results which could have been predicted for the mark I device.

The use of a total femoral prosthesis can offer a realistic alternative to amputation or disarticulation. The limited indications for such a prosthesis in the surgical management of primary bone tumours and pathological fractures still exist. In this specialised clinic there is an increased need to replace the entire femur where repeated procedures have failed, from loss of bone stock with infection or because of non-union in the presence of a prosthesis. Over the past eight years, four basic models have been developed. The most recent designs allow for the preservation of non-involved bone or for stable support where there is complete acetabular destruction.