UNCEMENTED FEMORAL REVISION

Abstract

Goals of femoral revision arthroplasty are to achieve stability of the femoral component, to restore biomechanical function of the hip joint and to restore the femoral bone stock. In order to accomplish such an ideal revision arthroplasty, several points should be reminded before and during the revision arthroplasty such as exposure, removal of the failed component, restoration of bone loss, placement of the new component and hip stability. Appropriate options of femoral components for revision depend on the degree of femoral bone loss. When the bone loss is minimum, a standard length component can be used like in primary total hip arthroplasty (THA). When it is moderate or severe, special components and techniques would be necessary.

Loss of bone stock is the most difficult problem in femoral revision surgery. It increases a risk of complications during operation such as fracture or perforation, and also results in difficulty to achieve stability of the component. Even when the bone defect is moderate or severe, immediate fixation of the femoral component should be mainly supported by native bone. Additionally, in the remaining bone loss, bone tissue is grafted as much as possible.

Survival rate of revision arthroplasty is low comparing with that of primary THA. In addition to the present revision, a possible next operation in the future should be considered when we plan revision surgery.

Cemented femoral revision has a disadvantage of removal of the prosthesis when it is failed. Removal of cemented component has a high possibility of complications including perforation and fracture. During revision arthroplasty of a cemented femoral component using a modern cement technique, removal of the cement mantle is difficult, time-consuming and hazardous. The cement mass distal to the tip of the femoral component is the most difficult to be removed since it is often well fixed. The removal procedure has a high risk of causing femoral perforation or fracture. Furthermore, in re-revision, the cement fixation will be often beyond the isthmus and into distal bone defect. And revised cemented femoral components would be more difficult to be removed. On the contrary, loosened uncemented components will be removed relatively easily.

Uncemented stem has the advantage of bone stock restoration. Simultaneous bone graft induces restoration of bone stock. Restored bone tissue will support the component, and this improvement of the bone stock would be beneficial when it is failed again in the future.

According to these principles, we prefer uncemented femoral revisions rather than cemented revisions. This paper will show the clinical results of femoral revisions in our department mainly using an uncemented femoral component.