Studying the strength of the tibia during the replacement of a post-resection defect with a segmental allograft using locked intramedullary nailing (experimental clinical study)

Abstract

Background. To achieve success in the incorporation of allografts and bone of the recipient, many factors are taken into account, which can be divided into two main groups: those related to sterilization and processing of the bone allograft and factors affecting the reliability of implant fixation in the bone of the recipient. The second important factor is the method for fixing the allografts and the bone of the recipient. The purpose was to determine the mechanical properties of bone after segmental bone alloplasty. Materials and methods. Female patient Sh., 30 years old, diagnosed with osteosarcoma of the left distal tibia T2N0M0 GIII, degree II, clinical group II, underwent polychemotherapy courses, surgical intervention according to the developed method. The tumor was removed en block, a post-resection defect was replaced with an articulating segmental bone allograft, fixed to the recipient’s bone through a stepped osteotomy and an intramedullary locked nail. Bone autografts were additionally placed into the area of the allograft contact with the recipient’s bone. After 2 years, the patient underwent surgery: amputation at the left third of the thigh. Radiographically, fusion of the allograft and the recipient’s bone was noted. An experimental study of the tensile strength of the tibia after segmental alloplasty of a post-resection defect was carried out using the developed surgical technique and a segmental allograft. Results. To compare the results of an experimental study of the tibia preparation after segmental bone alloplasty, data about the values of the ultimate strength of the bone tissue under compression and bending loads were selected. As shown by the experiment, the ultimate strength of the tibia preparation after its bone alloplasty was 51.82 MPa. This value corresponds to the minimum ultimate strength of a compact bone in bending — 51 MPa. Although this is twice as low as the maximum value of the ultimate strength of a compact bone in bending (133 MPa), it should be borne in mind that all the given reference values were obtained when testing intact preparations of a compact bone. Conclusions. The use of a segmental bone allograft to replace a post-resection defect in a long bone with its fixation to the recipient’s bone through a stepped osteotomy and locked intramedullary nailing with additional bone autoplasty in the area of the allograft contact with the recipient’s bone makes it possible to obtain in the osteotomy zone the bone, the ultimate strength of which corresponds to that of the intact tissue.