Background: Reconstruction with an endoprosthesis following pelvic tumor resection has increased over the years. However, the long-term results reflect a disappointing frequency of mechanical complications and failures. In an attempt to enhance implant fixation, an electron beam melting (EBM)-based modular hemipelvic endoprosthesis was introduced. Our aim was to explore the preliminary clinical outcomes for patients who have been managed with this prosthesis. Methods: We reviewed the records of 80 consecutive patients who had been managed at a single center between June 2015 and September 2017. Chondrosarcoma was the predominant diagnosis (31.3%). Osseous metastases were diagnosed in 16 patients (20.0%). The position of the reconstructed metallic acetabulum was measured on an anteroposterior pelvic radiograph. Bone ingrowth was evaluated in 2 samples harvested from patients with tumor recurrence. Results: After a median duration of follow-up of 32.5 months (range, 9 to 52 months), no acetabular component instability was detected on radiographs. Histological sectioning of specimens harvested from 2 patients with tumor recurrence showed bone trabeculae extending toward the implant and bone ingrowth within the porous network. At the time of the latest follow-up, 59 patients (73.8%) were alive with no evidence of disease, 5 patients (6.3%) were alive with disease, and 16 patients (20.0%) had died of disease. Local recurrence occurred in 9 patients (11.3%). The mean Musculoskeletal Tumor Society score at the time of the latest follow-up was 83.9% (range, 43% to 100%). Complications occurred in 16 patients (20%), with wound dehiscence being the most common complication (8 patients; 10%). No aseptic loosening was found. Five patients (6.3%) had deep infection, and 2 patients (2.5%) had dislocation. Conclusions: The use of a 3-dimensional (3D)-printed modular hemipelvic endoprosthesis with a highly porous metal interface represents a potential choice as a pelvic endoprosthesis after internal hemipelvectomy for the treatment of a primary or metastatic tumor. These preliminary results demonstrate stable fixation with acceptable early functional and radiographic outcomes. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Background: Few investigations of venous tumor thrombus (VTT) in primary pelvic bone sarcomas are available. We aimed to identify the prevalence, associated factors, and prognosis of VTT across different types of pelvic sarcomas and to propose an algorithm for management. Methods: We included 451 consecutive cases of primary, bone-derived, treatment-naive, pelvic sarcomas in this study. Demographic data and the results of initial laboratory tests, imaging examinations, and oncological evaluations were extracted and analyzed. Forty-four cases of VTT were diagnosed with radiographic examinations, and 18 of them were verified histologically. Results: The cohort consisted of chondrosarcomas (41.2%), osteosarcomas (30.4%), Ewing sarcomas (15.5%), bone-derived undifferentiated pleomorphic sarcomas (5.8%), and other bone sarcomas (7.1%). The prevalence of VTT was 9.8% in the whole group, and associated factors included a lactate dehydrogenase (LDH) level of ≥230.5 U/L and invasion of the L5-S1 intervertebral foramen. Patients with pelvic osteosarcoma had a high prevalence of VTT (22.6%), and the associated factors in this group included a chondroblastic subtype, an LDH level of ≥187 U/L, and invasion of the obturator foramen and the L5-S1 intervertebral foramen. Patients with VTT had a poor prognosis with a median overall survival time of 14 months. Subgroup analyses of localized pelvic osteosarcoma indicated that the presence of VTT decreased the median overall survival time (21.5 versus 54.0 months for those without VTT, p = 0.003), median recurrence-free survival time (18.6 versus 32.4 months, p = 0.020), and median metastasis-free survival time (11.2 versus 41.0 months, p < 0.001). Conclusions: VTT is most common in patients with pelvic osteosarcoma as compared with patients with other primary bone sarcomas, and it is associated with several factors. It is a negative prognostic factor. An algorithm for management of pelvic sarcomas with VTT stratified by the classification of the VTT might be beneficial, but further validation is necessary. Level of Evidence: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Malignant giant cell tumor of bone (GCTB) is a rare malignant bone tumor. This analysis was conducted on patients with malignant GCTB at our center. The clinical, demographic, and prognostic characteristics were evaluated and compared. During 1 January 2015 to 31 December 2022, fifty patients were included in the study, which made up 3.3% of the contemporary GCTB patients. The clinical characteristics were comparable between the 24 patients with primary malignant GCTB (PMGCTB) and 26 patients with secondary malignant GCTB (SMGTCB). The tumor location was mainly at the axial and pelvic region (70%) and differed between the two types (p = 0.040). H3F3A pathogenic variant presented frequently in SMGCTB (p = 0.020). Cox regression analysis showed the prognostic outcomes were poor in those with a tumor located in the axial bone and sacrum with invasion of other places. H3F3A mutation status is also a risk factor, while chemotherapy and denosumab failed to demonstrate prognostic benefits. Malignant GCTB is a rare condition with a poor prognosis, especially in SMGTCB. The location and H3F3A mutation status had an influence on prognosis, and systemic therapy should be taken into consideration for patients with unfavorable prognostic features.

Objective: To investigate the causes,prevention and treatment of femoral artery puncture related complications caused by the application of resuscitative endovascular balloon occlusion of the aorta (REBOA) in the resection of pelvic and sacral tumors. Methods: Clinical data of 23 patients with femoral artery puncture related complications who received REBOA in the resection of pelvic and sacral tumors from August 2010 to August 2018 at the Musculoskeletal Tumor Center,Peking University People's Hospital were retrospectively analyzed.There were 8 males and 15 females,with the an age of (37.0±16.2) years (range:15 to 65 years).Arterial access via the Seldinger technique for REBOA was obtained in the right common femoral artery of 18 cases,and in the left of 6 cases.An arterial sheath with a diameter of 11 to 12 F(1 F≈0.33 mm) was used for the patient.The occurrence and treatment of postoperative complications were analyzed. Results: Acute femoral arterial thrombosis occurred in 18 patients,which was managed by open repair 48 hours postoperatively.Among the 349 patients admitted before 2015 who received hemostasis by compression after femoral artery sheath removal,12 patients (3.4%) developed acute femoral artery thrombosis.While the 476 patients admitted after 2015 who used a vascular stapler to close the femoral artery wound,6 patients (1.3%) developed acute femoral artery thrombosis.One case of retroperitoneal hematoma and 1 case of femoral pseudoaneurysm were found and surgically fixed.Postoperative follow-up was (40±18) months (range:13 to 108 months).Three cases with chronic lower extremity ischemia were confirmed by Doppler ultrasonography during 1 to 5 years follow-up.Two of them had minimal symptoms and denied further treatment,while the other one received femoral-femoral artery bypass surgery to restore distal flow for pain and numbness relief. Conclusions: Acute femoral arterial thrombosis was the most common femoral artery puncture.Technique refinement of REBOA,the use of percutaneous suture device and close follow-up can reduce the approach-specific complications,and help to detect and treat the complications timely,which may popularize the clinical application of REBOA.

Reconstruction of a large segment defect resulting from an en bloc resection of an aggressive or malignant tumor in the long bones has always been difficul

Background/Objectives: Osteosarcoma exhibits bimodal age distribution with distinct clinical behaviors between pediatric and adult patients. Despite genomic evidence supporting age-related molecular heterogeneity, systematic transcriptomic characterization remains lacking. This study aimed to delineate age-associated transcriptional differences and develop a pediatric-specific prognostic signature. Methods: Bulk RNA sequencing was performed on tumor specimens from 70 osteosarcoma patients stratified into pediatric (≤14 years, n = 37), adolescent (15–18 years, n = 22), and adult (≥19 years, n = 11) groups. Differential expression, functional enrichment, and immune infiltration analyses were conducted. A pediatric-specific signature was validated in the TARGET-OS cohort (n = 87). Results: Pediatric osteosarcoma exhibited a hyperproliferative phenotype, enriched in E2F targets, G2M checkpoint, and DNA replication pathways. Adolescent tumors showed heightened immune–inflammatory signatures, while adult tumors activated osteogenic differentiation programs. Regarding the immune microenvironment, only adolescent tumors demonstrated active immune infiltration; pediatric and adult groups exhibited immunologically “cold” features. We identified a 10-gene pediatric-specific transcriptomic signature that declined with increasing age. High signature scores were significantly associated with inferior overall survival (hazard ratio [HR] = 5.6, 95% confidence interval [CI]: 1.2–26.2, p = 0.01) and progression-free survival (HR = 2.1, 95% CI: 1.1–4.2, p = 0.03). These findings showed concordant trends in the independent TARGET-OS cohort. Conclusions: Pediatric, adolescent, and adult osteosarcoma harbor distinct transcriptional profiles representing biologically different disease entities. The pediatric-specific 10-gene signature may serve as a clinically actionable biomarker for risk stratification and guide age-adapted therapeutic strategies.