Reconstructive Hip Prosthesis Surrounded by Allografts

Abstract

Autologous grafts, unlike allogenic grafts, have an important osteogenic potential. But, as the procurement volume is limited, they do not permit bone or joint reconstruction where there has been partial or total resection as a result of either a bone tumor or post-traumatic lack of substance. For this reason, we have elected since 1976 to use fresh allogenic bone grafts and since 1981 deep-frozen allogenic grafts to rebuild the skeleton (421 cases, 1976-1990). Deep-freezing alone allows the preservation of even large bone pieces in satisfactory conditions of sterilization. This type of preservation keeps the bone architecture in an optimal biological and biomechanical state. With the bone cells destroyed and the bone being recolonized by the host's own cells, there is no immunological risk of inadequate blood and leukocyte compatibility between donor and recipient. If the bone is to be totally or partially integrated by the skeleton within a few years, the functional value of the cartilaginous surfaces can be altered after a massive osteocartilaginous graft. At the hip therefore we prefer to use a massive prosthesis surrounded by allografts.

Reconstructive hip prosthesis surrounded by deep-frozen preserved bone has several advantages: easy fixation of the muscles on the graft; close tightening of the muscles; increasing of the bone mass; rapid loading.

Since 1983, 103 hips have been rebuilt with cortico-spongious allografts (femoral heads, total hemipelvis or acetabulum) associated with total hip prosthesis. To reconstruct the upper part of the femur we used a mega hip prosthesis surrounded by allograft. The reconstructive mega hip prosthesis has to have the inner shape of the femur with its two sagittal curves to permit cement less fixation at the upper part of the prosthesis which is placed into the allograft and cemented fixation of the lower part of the stem which is fixed into the receiver bone.

When great precautions are taken during surgical procurement and grafting (sterility, stability, and appropriate muscular surrounding) the long-term results are excellent in 80% of cases.