Knee joint preservation surgery in osteosarcoma using tumour-bearing bone treated with liquid nitrogen.

Purpose: To preserve the joint structure in order to maintain good limb function in patients with osteosarcoma, we perform epiphyseal or metaphyseal osteotomy and reconstruction using frozen autografts that contain a tumour treated with liquid nitrogen. There are two methods of using liquid nitrogen-treated autografts: the free-freezing method and the pedicle-freezing method. The purpose of this study was to evaluate the results of intentional joint-preserving reconstruction using the free-freezing method and the pedicle-freezing method in patients with osteosarcoma. Methods: Between 2006 and 2014, we performed joint-preserving surgery (12 with the free-freezing method and six with the pedicle freezing method) to treat 18 cases of osteosarcoma (12 distal femurs and six proximal tibias) in patients who had achieved a good response to neoadjuvant chemotherapy. Results: Among the 18 patients (nine boys and nine girls) who had a mean age of 11.6 years, 13 remained continuously disease-free, three showed no evidence of disease, one was alive with the disease, and one died from the disease. Functional outcomes were assessed as excellent in 15 patients and poor in three, with a mean follow-up period of 46.1 months. The mean Musculoskeletal Tumour Society (MSTS) score was 90.2%. Except for one patient who underwent amputation, all patients could bend their knee through >90° flexion, and nine achieved full ROM. All but two patients could walk without aid, and 11 were able to run normally throughout the follow-up period. No intraoperative complications were observed, such as surrounding soft-tissue damage, neurovascular injury, or recurrence from frozen bone. Conclusions: Joint-preserving reconstruction using frozen autografts yielded excellent function in patients with osteosarcoma. [ABSTRACT FROM AUTHOR]