Revision total hip replacement using a cementless interlocking distal femoral stem with allograft-cemented composite and the application of intramedullary and onlay cortical strut allografts: two case reports

It is often difficult to perform repeated revision total hip replacement (re-THR) after prosthesis loosening stemming from infection, mechanical loosening, and osteolysis. Reasons for this include the size of the bone defect and poor quality of the remaining bone. We have previously performed revision surgery using a cementless interlocking distal femoral stem with segmental cortical allograft-cemented composite for reconstruction in the presence of circumferential bone loss of the proximal femur according to Gustilo classification type IV [1]. However, in the case where the distal femur had a stovepipe canal due to osteoporosis, osteolysis, and infection, it was difficult to achieve stable fixation to the distal femoral cortical bone using a cementless interlocking distal femoral stem. Therefore, a cortical strut allograft is inserted into the femoral bone canal on the medial side, followed by the insertion of an interlocking stem. A further cortical strut allograft is inserted on the lateral side of the distal femur. In addition, the distal onlay allograft should pass over the allograft-host bone junction. The two allografts are finally secured with interlocking screws. The bone allografting to augment femoral bone deficiency was performed using mainly cadaveric bone allografts obtained from our bone bank [2, 3]. In this report, we describe two cases of re-THR involving the use of intramedullary and onlay cortical strut allografts with a cementless interlocking distal femoral long stem to achieve favorable fixation stability. The two patients were asked if the data from the case could be submitted for publication, and both gave their consent