Objective To investigate the incidence and extent of biopsy tract contamination in malignant bone tumors by either core needle biopsy or open biopsy and detect the safe extent in resection of biopsy tract. Methods Forty-eight cases were performed core needle biopsy, including 37 osteosarcomas, 5 malignant fibrous histiocytomas, 1 juxtacortical osteosarcoma, 1 low grade central osteosarcoma, 1 periosteal osteosarcoma, 1 primary malignant melanoma of bone and 2 chondrosarcomas. There were 37 males and 11 females with a mean age of 23.3 years (range, 10-64 years). The mean time between core needle biopsy and definitive surgery was 1.3 months (range, 0-2 months). All the patients were performed limb salvage surgery.Twenty-six cases were performed open biopsy, including 20 osteosareomas, 1 Ewing's sarcoma, 2 chondrosarcomas, 1 mesenchymal chondrosarcoma, 1 malignant fibrous histiocytoma, 1 lymphoma. There were 21males and 5 females with a mean age of 21.9 years (range, 8-59 years). The mean time between open biopsy and definitive surgery was 2.3 months (range, 1-4 months). The tumor and tissue around the biopsy tract at least 2 cm were resected. The pathological examination was performed in specimens via the biopsy tract, including the normal soft tissue outside the tumor, deep fascia, subcutaneous tissue and skin. The incidence and extent of biopsy tract contamination were evaluated with pathological examination. Results Forty-four cases were followed up. The mean follow-up time was 17.6 months (range, 4-39 months). In core needle biopsy group, four of forty-eight cases were found malignant tumor cells seeding in biopsy tract, the positive rate was 8.3%. In open biopsy group, all the cases were followed up with the mean time of 12.9 months (range, 2-29 months), and two of twenty-six cases were found malignant tumor cells seeding in biopsy tract,the positive rate was 7.7%. Conclusion Biopsy of malignant bone tumors has the risk of biopsy tract contamination. The tumor cell seeding exists in both core needle biopsy and open biopsy. The biopsy tract should be performed en bloc resection with the tumor.

Objective To describe the epidemiological and clinical characteristics of fibrous dysplasia of bone admitted to a single center in the past 30 years. Methods We analyzed the clinical features of 744 patients with bone fibrous dysplasia diagnosed by pathology, including age, gender, disease location, monostotic or polyostotic lesions, pathological fracture and malignant transformation. Results There were 1183 lesions in 744 patients. The mean age at admission was 31.1±13.5 years old. The ratio of male to female was close to 1:1. The most common site was the lower extremities (916(77.4%)), followed by the upper extremities (106(9.0%)). The most common sites of lower extremities were the femur (645(54.5%)) and the tibia (224(18.9%)). Polyostotic cases accounted for 25.4%, and monostotic cases accounted for 74.6%. Pathological fracture occurred in 163 (13.8%) patients. There were 6 (0.8%) patients with malignant transformation. The mean age was 40.5 years old. The mean time of malignant transformation was 7.7 years. Conclusion Fibrous dysplasia of bone is a rare group of benign bone tumors, with typical epidemiological and clinical features.

Objective To determine the prosthesis survival and limb function after revision of global modular replacement system (GMRS) tumor prosthesis. Methods We retrospectively analyzed the clinical data of 16 patients who developed aseptic loosening of lower extremity tumor prosthesis and subsequently received revision with GMRS from 2009 to 2012. Kaplan-Meier method was used to calculate the 5- and 8-year survival rates of the prosthesis. The MSTS function scale was used to evaluate the functional outcomes. Results The average follow-up time was 90 months (52-118 months). The 5- and 8-year survival rates of GMRS prosthesis were both 94%. After revision, two patients failed, including one case of infection and one case of repeated aseptic loosening. The average interval between the first joint replacement and revision surgery was 81 months (27-187 months). Until the last follow-up, 93.3%(14/15) of the patients did not develop repeated aseptic loosening, 85.7%(12/14) of the patients who underwent GMRS revision had a longer loosening-free survival than those with the primary joint replacement (90.6±19.3 vs. 43.4±29.7 months, P=0.001). The average MSTS functional score was 27.7(24-30). Conclusion The incidence of repeated aseptic loosening for GMRS prosthesis is low and the limb function is good. The reported technique is satisfactory in the middle and long term.

Objective:To explore the mid-term efficacy of liquid nitrogen-inactivated autologous tumor segment bone replantation for repairing bone defects after resection of malignant tumors in the long bone shaft.Methods:A retrospective analysis was performed on the clinical data of 16 patients treated with liquid nitrogen-inactivated autologous bone graft at Beijing Jishuitan Hospital from July 2015 to June 2017 to repair defects caused by malignant tumour resection of the diaphysis. There were 10 males and 6 females with a mean age of 23.4±11.6 years (range, 8-44 years), including 8 classic osteosarcoma, 2 high-grade surface osteosarcoma, 4 Ewing's sarcoma, 1 periosteal osteosarcoma, and 1 undifferentiated pleomorphic sarcoma. Tumors were located in the humerus in 2 cases, in the femur in 8 cases and in the tibia in 6 cases. The mean length of tumor was 12.4±4.8 cm (range, 5.5-26 cm). Postoperative imaging examination was performed every 6 months, and the healing status of the transplanted bone-host bone was evaluated based on the imaging assessment method of the International Society of Limb Salvage (ISOLS) imaging assessment after allogeneic bone transplantation, and the complications were assessed using the Henderson classification. The five-year survival rate for patients and grafted bone was calculated using the Kaplan-Meier survival curve.Results:The median follow-up was 64 (60.3, 69.8) months. At the end of follow-up, 13 patients were tumour free and 3 patients died of multiple metastases at 19, 20 and 33 months after surgery. There were 32 osteotomy ends in 16 patients, of which 30 healed, including 11 metaphyseal osteotomy ends, and the healing time was 9 (6, 12) months after replantation of the tumour segment with liquid nitrogen-inactivated autologous bone; 19 osteotomy ends in the diaphysis took 13 (9, 21) months to heal, with a statistically significant difference in healing time between different sites ( Z=-2.25, P=0.025). Sixteen patients had six complications, including two cases of non-union at the diaphyseal site, one case of failure of internal fixation due to non-union, three cases of recurrence, and no soft tissue complications or infections. One patient with failed internal fixation was treated with a vascularized tip iliac bone graft that healed 6 months after surgery. Another patient died of multiple metastases with 1 unhealed diaphysis left. Three cases of recurrence were all located in the extracranial soft tissue of the autologous tumor segment inactivated by liquid nitrogen. Among them, one case underwent reoperation and local radiotherapy, and there was still no tumor survival after 65 months of surgery, and two cases died due to multiple metastases. The five-year survival rate of patients was 81% as calculated using the Kaplan-Meier survival curve, and the graft survival rate was 100%. There was no amputation and the limb salvage rate was 100%. Conclusion:The use of liquid nitrogen-inactivated autologous tumor segment bone replantation for reconstruction of bone defects after resection of malignant tumors in the shaft has advantages of higher healing rate, shorter healing time at the metaphyseal end compared to the osteotomy end, fewer complications, and higher survival rate of the replanted bone.

Objective:To investigate the effects of parallel reconstruction with titanium cable fixation and concentric reconstruction with plate fixation in the reconstruction of femoral shaft continuity after resection of malignant tumor.Methods:From September 2013 to December 2017, the data of 11 consecutive patients with thigh malignancies and related complications were retrospectively analyzed, including 10 males and 1 female. The mean age of the 11 patients was 27.1±15.6 years (range, 7-49 years). These case series included 6 cases of primary bone defect reconstruction after resection of femoral shaft malignant tumor, 4 cases of nonunion or allogeneic bone fracture after massive bone allograft for femoral malignant tumor, and 1 case of femoral fracture caused by radiotherapy after resection of thigh soft tissue sarcoma. Vascularized fibular autograft combined with massive bone allograft or devitalized bone graft was used for reconstruction. The patients were divided into two groups according to reconstruction method, namely parallel reconstruction group and concentric reconstruction group. In the parallel reconstruction group, the vascularized fibula was placed on the medial side of the femur and the allograft and fixed with titanium cable. In the concentric reconstruction group, the vascularized fibula was placed in the medullary cavity of the allogeneic bone or devitalized bone and further fixed with the plate and screws.Results:There were 5 patients with 7 allograft-host junctions or fracture were treated with parallel reconstruction. The grafted length of fibula was 15.0±4.3 cm (range, 10-20 cm). The follow-up duration was 33.2±15.6 months (range, 20-53 months). Six patients with 10 allograft-host junctions were treated by concentric reconstruction. The grafted length of fibula was 15.5±2.3 cm (range, 12-18 cm). The follow-up duration was 45.8±15.3 months (range, 22-62 months). There was no significant difference during follow-up between the two groups ( t=1.36, P=0.208). The union rate in parallel reconstruction group was 100% (7/7), and the union duration was 15.9±6.8 months (range, 3-22 months). The union rate in the concentric reconstruction group was 70% (7/10), and the union duration was 18.9±6.4 months (range, 11-30 months). There was no significant difference in the union rate ( P=0.228) or the union duration ( t=0.846, P=0.414) between the two groups. Conclusion:Both parallel reconstruction and concentric reconstruction of vascularized fibular autograft are important methods for reconstruction of femoral shaft continuity after resection of malignant tumor. There might be no significant difference in union rate or union duration between the two methods.