(P 384) Tibial Defect Reconstruction using Hydroxyapatite Scaffold Seeded with Expanded Stem Cells

Introduction: Critical long bone defects can not heal spontaneously and a replacement technique is needed. Material and Method: A 6 cm. tibial defect of a 24 years old male, result of a complicated open fracture, had to be reconstructed. Because of the comminution of the homolateral fibula and the refuse of the patient to harvest the contra lateral fibula for a pediculated bone graft, another reconstruction method was needed. Classic reconstruction methods (calcium sulfate pellets, autologus bone marrow and iliac crest bone graft) failed. A tissue engineering approach was then used by obtaining a three dimensional construct made of a porous hydroxyapatite ceramic scaffold, seeded with culture expanded stem cells isolated from the patients own bone marrow. The resulting living structure was implanted in the diaphyseal defect. By plating the fibula using long fibulo-tibial screws, internal bone stabilization was secured. Results: The surgical wound healed without complications. The patient was monitored by x-rays and periodical clinical examination. Callus formation was observed at the bone-scaffold interface at 80 days after the operation when the patient was allowed to a partial limb bearing. Now, at 120 postoperative days, using a cane, he is walking without having pain and on x-ray examination peri implant bone formation is detectable. Discussion: Although the described defect can not be considered healed yet, the clinical and radiological evolution of the lesion is promising. The use of expanded autologus stem cells seeded on porous ceramic scaffolds could represent a progress in critical long bone defects reconstruction.