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The distal femur is the predominant site for benign bone tumours and a common site for fracture following tumour removal or cementation. However, the lack of conclusive assessment criterion for post-operative fracture risk and appropriate devices for cement augmentation are serious concerns. Hence, a validated biomechanical tool was developed to assess bone strength, depending on the size and location of artificially created tumorous defects in the distal femora. The mechanics of the bone-cement interface was investigated to determine the main causes of reconstruction failure. Based on quantitative-CT images, non-linear and heterogeneous finite element (FE) models of human cadaveric distal femora with simulated tumourous defects were created and validated using in vitro mechanical tests from 14 cadaveric samples. Statistical analyses demonstrated a strong linear relationship (R 2  = 0.95, slope = 1.12) with no significant difference between bone strengths predicted by in silico analyses and in vitro tests (P = 0.174). FE analyses showed little reduction in bone strength until the defect was 35% or more of epiphyseal volume, and reduction in bone strength was less pronounced for laterally located defects than medial side defects. Moreover, the proximal end of the cortical window and the most interior wall of the bone-cement interface were the most vulnerable sites for reconstruction failure.

Background: Reconstruction of defects after resection of malignant bone tumors with liquid nitrogen-sterilized recycled autografts is an alternative to bone allografts and endoprostheses in resource-constrained environments. Most studies reporting favorable outcomes with liquid nitrogen-sterilized autografts for bone reconstruction are geographically restricted to a few countries, and the technical challenges of routinely using liquid nitrogen intraoperatively, especially when using the pedicle freezing technique, has not been documented., Questions/purposes: (1) What are the technical challenges of liquid nitrogen sterilization of bone tumors for inexperienced surgeons? (2) What are the complications associated with the procedure?, Methods: Between May 2017 and October 2019, 88 patients underwent limb salvage procedures for malignant bone tumors of the extremities at our institution. An endoprosthesis was used for reconstruction of the defect following resection in 45% (40 of 88) of these patients, mostly in adults (median age 21 years; range 9 to 68). In the remaining 55% (48 of 88) of patients undergoing biological reconstruction, liquid nitrogen-sterilized autograft was used in 90% (43 of 48), extracorporeal irradiation-sterilized autograft was used in 4% (2 of 48) and allograft was used in 6% (3 of 48). Of the 43 patients receiving liquid nitrogen-sterilized autograft, 5% (2 of 43) were excluded due to loss to follow-up and the remaining 95% (41 of 43) were included for the analysis. Liquid nitrogen-sterilized autograft was the preferred method of reconstruction at our institution during the study period, unless the patient had an indication for prosthesis reconstruction; extracorporeal irradiation-sterilized autograft was used due to resource constraints with liquid nitrogen and allograft was used when patients insisted.All surgical procedures were performed by the same team of trained orthopaedic oncology surgeons. The medical records of the included 41 patients were retrieved using an institutional database search in this retrospective study, and all were used to ascertain technical challenges associated with the operations as well as early (within 3 weeks of the index procedure) and late complications (those occurring 3 weeks or more after surgery). The technical challenges were defined as follows: the quantity of liquid nitrogen to be used; arranging, storing and handling of liquid nitrogen in the operating room, type and size of the container to be used for sterilization, the positioning of the container during pedicle freezing, level of fibular osteotomy for pedicle freezing of tibia, soft tissue protection, limb rotation during pedicle freezing, managing tourniquet time, and any other intraoperative factors with the use of liquid nitrogen for sterilizing the autograft. As our experience with the technique gradually grew, the answers to the above-mentioned factors were determined. Considering the removal of autograft as the endpoint of interest, survival of the autograft was determined by Kaplan-Meier analysis.The median (range) patient age was 14 years (2 to 49), and 54% (22 of 41) were males. Osteosarcoma was the most common diagnosis (68%, [28 of 41]) followed by Ewing's sarcoma (20%, [8 of 41]). On presentation, 27% of patients (11 of 41) had radiological evidence of pulmonary metastasis. Tumors were seen frequently around the knee (39% [16 of 41] proximal tibia and 22% [9 of 41] distal femur). Before resection 85% (35 of 41) underwent neoadjuvant chemotherapy. Sixty-six percent (27 of 41) underwent pedicle-freezing and the remaining 34% (14 of 41) underwent free-freezing of the tumor segment of the bone. The median (range) duration of surgery was 280 minutes (210 to 510). The patients were followed up for a median (range) duration of 21 months (5 to 30); two patients were lost to follow-up., Results: With gradual experience using liquid nitrogen-sterilization over time at our institution, we determined that the following factors helped us in performing liquid nitrogen-sterilization more efficiently. For every operation 15 L to 20 L of unsterilized liquid nitrogen was arranged, 1 or 2 days before the procedure, and stored in industrial-grade cryocylinders in the operating complex. During the procedure, the operating surgeons wore additional plastic aprons under the surgical gowns, surgical goggles, and rubber boots. The staff managing the liquid nitrogen in the operating room wore thermal protective gloves. For most of the pedicle freezing procedures, we used a cylindrical stainless-steel container that was 30 cm in height and 15 cm in diameter, with a narrow opening. The container was kept on a separate moveable cart that was placed next to the operating table at a slightly lower level, and it was wrapped in multiple cotton rolls, plastic sheets, surgical sheets, and a crepe bandage. For pedicle freezing of the tibia, we performed the fibular osteotomy at least 5 cm away from the planned surgical margin, roughly around the axis of rotation of the limb. The soft tissue at the base of the delivered bone segment was dissected for at least 5 cm beyond the planned surgical margin of bone, and was protected with multiple layers of cotton rolls, plastic drapes, a single roll of Esmarch and crepe bandage. The tumor segment was externally rotated during pedicle freezing for all anatomic sites (proximal tibia, distal tibia, proximal humerus, and proximal femur). The tourniquet was inflated just before pedicle freezing to prevent tumor dissemination and not before the initial incision in all pedicle freezing procedures.Thirty-nine percent of patients (16 of 41) experienced complications associated with the procedures, and 15% (6 of 41) underwent revision surgery. Early complications (occurring within 3 weeks of the index procedure) were skin necrosis in four of 16 patients, intraoperative fracture in one of 16, superficial infection in one of 16, and neurapraxia in one of 16 patients. Late complications (occurring 3 weeks or more after surgery) were resorption of the recycled bone in four of 16 patients, nonunion of the osteotomy site in two of 12, delayed union of the osteotomy site in one of 16, collapse of the recycled bone in one of 16, and local recurrence in 1 of 16 patients. Kaplan-Meier survivorship free from removal of autograft at 2 years after surgery was 92% (95% confidence interval 89 to 96)., Conclusion: Liquid nitrogen-sterilization is an alternative technique that requires some training and experience for the surgeon to become proficient in treating primary malignant bone tumors. Because it is widely available, it may be an option worth exploring in resource-constrained environments, where allografts and endoprostheses cannot be procured. The methods we developed to address the technical challenges will require more study and experience, but we believe these observations will aid others who may wish to use and evaluate liquid nitrogen sterilization of extremity bone sarcomas., Level of Evidence: Level IV, therapeutic study.

A 7-year-old neutered male domestic shorthair cat was presented with chronic lameness in the right forelimb. A cystic bony lesion was identified in the distal right humerus and amputation was performed. The epiphyseal trabecular bones of the capitulum and trochlea was replaced by a tan to pink, expansile mass that was surrounded by a thin rim of cortical bone. Microscopically, the tumour was composed of a bland, osteoid producing spindle cell population within a well-vascularized fibrous stroma. Radiographical and histological features were consistent with osteoblastoma. Osteoblastoma and the related osteoid osteoma are uncommon, benign osteoblastic tumours that are reported rarely in animals. These tumours should be considered as differential diagnoses for slow growing, cystic bony lesions in cats., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Tumor induced osteomalacia (TIO) are extremely rare paraneoplastic syndrome with less than 300 reported cases. This report highlights the pitfalls and challenges in diagnosing and localizing TIO in patients with refractory and resistant osteomalacia., Patient and Methods: 41- year gentleman with 4-year history of musculoskeletal weakness and pathologic fractures presented in wheelchair bound incapacitated state of 1-year duration. Investigations were significant for severe hypophosphatemia, severe phosphaturia, normal serum calcium, reduced 1,25-dihydroxy vitamin-D, elevated ALP, elevated intact parathyroid hormone (iPTH), and pseudo-fractures involving pelvis and bilateral femur. Whole body MRI and 99mTc methylene diphosphonate bone-scan were also normal. Whole body FDG-PET scan involving all 4 limbs revealed a small FDG avid lesion at lateral border of lower end of left femur (SUV max 3.9), which was well characterized on 3-dimensional CT reconstruction. Plasma C-terminal fibroblast growth factor (FGF)-23 was 698 RU/ mL (normal < 150 RU/ml). Wide surgical excision of the tumor was done. Histopathology confirmed mesenchymal tumor of mixed connective tissue variant. Serum phosphorous normalized post-surgery day-1. High dose oral calcium and vitamin-D was continued. FGF-23 normalized post surgery (73RU/ml). Physical strength improved significantly and now he is able to walk independently., Conclusion: TIO is frequently confused with normocalcemic hyperparathyroidism and vitamin-D resistant rickets/osteomalacia, which increases patient morbidity. Imaging for tumor localization should involve whole body from head to tip of digits, cause these tumors are notoriously small and frequently involve digits of hands and legs. Complete surgical removal of the localized tumor is key to good clinical outcomes.

Objective: To assess the clinical success and costs of computed tomography (CT)-guided radiofrequency ablation (RFA) of osteoblastoma (OB) and spinal osteoid osteoma (OO)., Materials and Methods: Nineteen patients with OB and eight patients with spinal OO were treated with CT-guided RFA. The OBs were localized in the extremities (n = 10), the vertebral column (n = 2), and (juxta-)articular (n = 7). Dedicated procedural techniques included three-dimensional CT-guided access planning in all cases, overlapping RFA needle positions (median, two positions; range, 1-6 RF-electrode positions) within the OB nidus (multiple ablation technique, n = 15), and thermal protection in case of adjacent neural structure in four spinal OO. The data of eight operated OB and ten operated spinal OO patients were used for comparison. Long-term success was assessed by clinical examination and using a questionnaire sent to all operated and RFA-treated patients including visual analogue scales (VAS) regarding the effect of RFA on severity of pain and limitations of daily activities (0-10, with 0 = no pain/limitation up to 10 = maximum or most imaginable pain/limitation)., Results: All patients had a clear and persistent pain reduction until the end of follow-up. The mean VAS score for all spinal OO patients and all OB patients treated either with RFA or with surgical excision significantly decreased for severity of pain at night, severity of pain during the day, and both for limitations of daily and of sports activities., Conclusions: RFA is an efficient method for treating OB and spinal OO and should be regarded as the first-line therapy after interdisciplinary individual case discussion.

Background: Few studies have systematically identified factors associated with blood loss in musculoskeletal tumor surgery. We aimed to identify risk factors for requiring large-volume transfusion in musculoskeletal tumor surgery and created an interactive model to predict red blood cell transfusion requirements based on patient characteristics. These data will facilitate planning in hospital blood banks and aid identification of specific groups for future interventions targeted at reducing blood utilization. Only one similar study has been published and there are minimal data surrounding interventions designed to minimize blood loss in musculoskeletal tumor surgery., Study Design and Methods: We retrospectively analyzed a database containing 1322 consecutive surgeries, performed at a quaternary referral center in Melbourne, Australia. Using logistic regression analysis and a negative truncated binomial logistic regression model, we developed prediction models for transfusion requirement., Results: The following factors were associated with large-volume transfusion: malignant tumors, bone tumors, sacral and pelvic tumors, high American Society of Anesthesiologists (ASA) score, and tumor size of more than 5 cm. High ASA score was also strongly associated with 30-day mortality., Conclusions: Preoperative planning in high-risk patients is critical to ensure adequate blood product supply, minimize wastage, and optimize the patient's general health before surgery. These patients would be ideal targets for future randomized studies aimed at reducing blood utilization., (© 2014 AABB.)

Background: Surgical options for treatment of extremity musculoskeletal tumours include excision [limb sparing] surgery or amputation [limb ablation]. Ablative surgery is for advanced extremity musculoskeletal tumours when limb salvage surgery is not feasible., Objective: To determine the indications for ablative surgery in extremity musculoskeletal tumours in our centre., Method: This is a 6 year prospective study of patients presenting with extremity musculoskeletal tumours at National Orthopaedic Hospital Lagos. Data such as age, gender, presenting complaints, anatomic location of the tumour, clinical stage, type of ablative surgery and adjuvant treatment offered, histologic type of tumour, and treatment outcome were documented., Results: Nineteen patients had ablative surgery as a mode of treatment. 11 were male while 8 were female with a M:F of 1.3:1. The age range was 3 - 69 years. Seven patients [6 males and 1 female] refused ablative surgery and voluntarily discontinued treatment. Most tumours were located in the lower limb and all patients that had ablative treatment presented with stage 3 or 4 disease. Osteogenic sarcoma was the most common diagnosis, accounting for 4 cases [21.1%]. Six patients [31.6%] with non-malignant tumours had ablative surgery due to either late presentation or inaccurate preoperative diagnosis. Trans-femoral amputation was the most common level of amputation and this was done in 9 patients [47.4%]. Adjuvant chemotherapy was prescribed for all patients. The recurrence and survival rates could not be determined for each tumour as the patients were lost to follow-up soon after surgery with average post operative follow up of 5.5 months., Conclusion: Late presentation with locally advanced disease remains the dominant indication for ablative surgery in extremity musculoskeletal tumours.

The study presents clinical and diagnostic problems in patients with malignant bone metaplasia. Material is composed of 13 patients treated surgically between april 2002 and august 2007. In three cases tumors were localised in tibia, in 5 patients around distal femur, in 2 in pelvis, in 2 in humerus and in 1 in lumbar spine. None of the patients has had recurrence by february 2006 r, 12 patients have been free of the disease so far. However, one individual diagnosed with giant cell tumor metaplasia to osteosarcoma did not accept proposed therapy. The authors have particularly emphasized thorough clinical and radiological evaluation and the need of team work before surgical procedure.

Introduction: The authors present the results of nine patients (two females, seven males) who had bone tumors that were treated with en bloc resection and distraction osteogenesis between 1991-2000., Materials and Methods: The average age of the patients was 19.3 years (14-42 years). The histological diagnosis was osteosarcoma in four cases, Ewing's sarcoma in two, giant cell tumor in one, osteofibrous dysplasia in one and osteoblastoma in one. A uniplanar external fixator was applied to one case and circular external fixator to the other eight cases., Results: The average follow-up period was 59.1 months (27-129 months). The external fixator was removed at an average of 18.1 months (range, 4-19 months). The average bone defect after resection was 14 cm (8-24 cm) and the average external fixation index, distraction index, and maturation index were 31.5 (18.7-40.0), 11.2 (10.9-11.2) and 17.8 (7.5-32.7), respectively. The function of the affected leg was excellent in four patients, good in three, fair in one and poor in one according to the Enneking scoring system. We did not observe any early consolidation or osseous binding in the defect area in any patient. Frequent complications were pin tract infection and non-union at the docking site., Conclusion: Our results indicate that the Ilizarov method allows effective restoration of bone defects in the treatment of bone tumors despite various disadvantages.

Thirteen patients had skeletal reconstruction using vascularised fibula graft following resection of the diseased bone. Eleven patients had reconstruction of the lower limbs and two patients of the upper limbs. Clinical and radiographical evidence union were achieved with the average time of 32 weeks (earliest eight weeks). Six out of 11 patients (54%) in lower limb reconstruction started weight bearing at the average of 27 weeks. Bony union in this study is comparable with other studies using vascularised fibula graft.

This study investigated the concept of using plates to attach endoprostheses to bone after segmental resection for bone tumours in an animal model. Titanium alloy plates integrated with the prosthesis and coated with hydroxyapatite were attached to bone by screws. This type of uncemented fixation relied on the induction of periosteal bone formation into and around the plates to secure the implant to bone. Two, three, and six-slotted plate designs were investigated. On retrieval, each plate was securely fixed by new bone. Bone apposition on the external surface of the plates occurred through a combination of periosteal bone production, invasion of bone through slots in the plate, and bone growth over the ends of the plates. Most plates became incorporated into a remodelled cortex. Higher bone turnover rates (microm day(-1)) were seen in bone in the slots of the plate compared with normal cortical bone turnover (p < 0.05). Significantly higher rates of turnover were measured beneath slotted parts of the plates compared with regions below the unslotted parts (p < 0.05). The cross-sectional area of bone surrounding the six-plate implant design was significantly higher than that of the three-plate (p < 0.05) and two-plate (p < 0.05) designs. In addition, significantly more bone formed adjacent to the six-plated implant design compared with that in the contralateral limb (p = 0.002). However, no significant difference was found when the total cortical area around the three-plated design was compared with that of the contralateral limb (p = 0.63). In contrast, significantly less bone was measured adjacent to the two-plate design than in the untreated limb (p = 0.001). Image analysis also demonstrated increased cortical porosity adjacent to the six-plate design compared with the three-plate (p = 0.004) and two-plate (p < 0.05) designs. Finite element analysis demonstrated that the six and three-plate designs increased the second moment of area compared with that in the left tibia (p = 0.003 and 0.066, respectively). However, the attachment of the more flexible two-plate design did not significantly increase the second moment of area compared with that in the contralateral limb (p = 0.235). It was concluded that due to both mechanical and biological effects, the hydroxyapatite-coated plate designs generated new bone that enhanced fixation and encouraged plate integration into the load-bearing structure of the cortex. This method of fixation may be an alternative to the use of intramedullary cemented stems in patients requiring bone tumour implants and may be the only way to preserve the joint in difficult cases where only short segments of bone remain.

Dense calcification and psammomatous bodies are common in spinal meningioma, but are rarely reported in osteogenic meningioma. We present a 73-year-old woman with an extramedullary, intradural tumor located at the T5 vertebra. The tumor showed mixed intensity and heterogeneous enhancement on the T1-weighted image and hypointensity on the T2-weighted image, and was situated near the spinal nerve root. The tumor's initial symptom was myelopathy, as is usual with spinal meningioma. We successfully removed the tumor under microscopy and found it to be separated from the vertebral column by the epidural space. The symptoms and signs improved gradually after the operation. Because the pathologic examination revealed areas of lamellar bone with bone marrow in the transitional meningioma, and because these were not related to the psammomatous bodies, osteogenic meningioma was diagnosed. Metaplasia of arachnoid cells is considered to be the putative etiology of osteogenic meningioma.

Metaplastic breast carcinoma, a rare entity, accounts for only about 0.02% of all breast carcinomas. It involves the transformation of mammary neoplasms into osteoid and chondroid substances. Because of the relatively small patient population and the limited number of controlled studies, there is confusion regarding its classification and staging. Its histogenesis is unknown. The authors describe a 65-year-old woman with findings consistent with metaplastic breast carcinoma. Theories as to etiology and prognosis as well as treatment are discussed.

Twelve patients presenting with a bone tumor were operated on using autoclaved bone autografts for reconstruction following carcinologic resection. According to the Enneking grading system, 6 were high malignancy tumors (3 osteosarcomas and 3 grade 2 chondrosarcomas), 4 were low grade tumors (1 paraosteal sarcoma, 1 chondrosarcoma, 1 secondary chondrosarcoma, 1 liposarcoma). One was a metastasis from a kidney tumor. The last patient had a femoral osteoid osteoma. Six local recurrences were responsible for 4 reoperations: 2 disarticulations and 2 iterative resections. With a 1-6 years range of follow-up (average follow-up 2.5 years), osseointegration of autoclaved grafts was studied. Fusion at the host/graft junction was roentgenographically observed. In three cases, proximal resorption of the humeral graft occurred. Five biopsies were obtained during reoperation after 1 year, which showed partial revascularization of autoclaved bone autografts. The authors conclude that autoclaved tumoral bone grafts, are reliable and discuss indications. They point out the main contraindication, represented by chemosensitive bone tumors, in which conservation of the removed tumor is necessary to quantify the response to chemotherapy.