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A free-living female Korean water deer (Hydropotes inermis argyropus) was found with swelling in the left femur. Radiographic and histopathologic examination confirmed distal femoral osteosarcoma with metastases to the inguinal lymph node and the lungs; there are no previous reports of osteosarcoma in water deer., (© Wildlife Disease Association 2024.)

Background and Objective: Oncological distal femur resections can leave a proximal femur too short to host a stem. Reconstructive techniques are then challenging. The purpose of the study is to compare implant survival, complication rate and MSTS of two different options., Methods: We retrospectively divided 33 patients with primary bone tumours of distal femur in Group 1 (16 patients reconstructed with knee megaprosthesis with proximal bone augmentation, APC) and Group 2 (17 patients reconstructed with total femur prosthesis, TFP). Less than 12 cm of remaining proximal femur were planned for all resections., Results: MSTS score at 2 years is 25 ± 5 for Group 1 and 19 ± 7 for Group 2 (confidence interval [C.I.] 95%, p = 0.02). At 5 years it is 27 ± 2 for Group 1 and 22 ± 6 for Group 2 (C.I. 95%, p = 0.047). Failure and complication rates are lower for Group 1, but no statistical significance was reached. In APC reconstruction, union at the host-allograft junction was achieved in 16 out of 16 patients using the telescopic bone augmentation technique., Conclusions: APC provides higher functional results compared to TFP after extended distal femur resection. In APC reconstruction, telescopic augmentation is excellent for achieving union at the host-allograft junction., (© 2024 The Authors. Journal of Surgical Oncology published by Wiley Periodicals LLC.)

Introduction: conventional parosteal osteosarcoma is an uncommon malignant bone tumor, comprising 4% of all osteosarcomas. Although rare, parosteal osteosarcoma is the most common type of osteosarcoma of the bone surface. We present the clinical, histological and imaging characteristics of a rare histologic variant of a parosteal osteosarcoma, review the literature and emphasize the importance of radio-pathological correlation as well as the interpretation of a representative biopsy in order to obtain the correct diagnosis., Case Report: a 36-year old woman began her condition one year prior to admission to the hospital with increased volume in the left knee and pain. Image studies showed a juxtacortical heterogeneous tumor localized on the posterior surface of the distal femoral metaphysis. An incisional biopsy was performed, with the diagnosis of a Parosteal Osteosarcoma and a wide surgical resection was undertaken. According to the findings of the surgical specimen, the diagnosis of a Parosteal Osteosarcoma with low grade chondrosarcoma and liposarcoma components was made. The knowledge of this rare parosteal osteosarcoma variant can lead the orthopedic oncologists to avoid overlooking the adipose component and provide adequate surgical margins., Conclusion: we present the clinical, histological and imaging characteristics of a Parosteal Osteosarcoma with low grade liposarcoma and chondrosarcoma components.

Background: The advantages of distal femoral replacement prostheses for reconstructions after tumors are well known; one such implant, the Global Modular Replacement System (GMRS), has been widely used since 2003. Although implant breakage has been reported, the frequency of this event has varied across different studies., Questions/purposes: (1) What percentage of patients who underwent distal femur resection and replacement using the GMRS for primary bone tumors at one center experienced stem breakage? (2) At what timepoints did these breakages occur, and what factors were common among the stems that broke?, Methods: We performed a retrospective study of all patients who underwent distal femur resection and replacement using the GMRS for a diagnosis of primary bone sarcoma by the Queensland Bone and Soft-tissue Tumor service from 2003 to 2020 who had a minimum of 2 years of follow-up. Standard follow-up for primary bone sarcoma involves radiographic imaging of the femur at 6 weeks and 3 months postoperatively and yearly thereafter. From a chart review, we identified patients with femoral stem breakage. Patient and implant details were recorded and analyzed. A total of 116 patients had undergone a distal femoral replacement with the GMRS prosthesis for primary bone sarcoma; however, 6.9% (eight of 116 patients) died before completing the 2-year follow-up period and were excluded. Of the remaining 108 patients, 15% (16 patients) had died at the time of this review; however, given that they completed the 2-year follow-up period and did not experience stem breakage, they were included. Furthermore, 15% (16 patients) were considered lost to follow-up and excluded because they have not been seen in the past 5 years but were not known to have died or experienced stem breakage. This left 92 patients for analysis., Results: Stem breakages were identified in 5.4% (five of 92) of patients. All stem breakages occurred in stem diameters 11 mm or less with a porous body construct; the percentage of patients with breakage in this group was 16% (five of 31). All patients with stem fracture demonstrated minimal ongrowth to the porous coated body. The median time to stem fracture was 10 years (range 2 to 12 years); however, two of the five stems broke within 3 years., Conclusion: We recommend the use of a larger-diameter GMRS cemented stem (> 11 mm), and either the line-to-line cementing method or an uncemented stem from an alternative company should be considered in order to achieve this larger stem in smaller canals. If a stem less than 12 mm in diameter must be used or there is evidence of minimal ongrowth, then close follow-up and prompt investigation of new symptoms should occur., Level of Evidence: Level IV, therapeutic study., Competing Interests: Each author certifies that there are no funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article related to the author or any immediate family members. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request., (Copyright © 2023 by the Association of Bone and Joint Surgeons.)

Background: This study aimed to determine the prognostic outcome of hip joint replacement after resection of proximal femoral tumors by reviewing original studies., Methods: Two researchers independently searched PubMed, Embase, Cochrane Library, and Web of Science databases from inception to July 17, 2022. Then, the literature was screened by inclusion criteria. The basic information, primary outcomes, and secondary outcomes were extracted for weighted combined analysis. The quality of the included literature was evaluated using the Newcastle-Ottawa scale., Results: Twenty-four retrospective cohort studies comprising 2081 patients were included. The limb salvage rate was 98%. The survival rates at 1, 2, 3, 4, and 5 years were 80, 72, 65, 64, and 55% for patients with primary tumors and the rate at 1, 2, 3, 4, and 5 years were 44, 25, 17, 14, and 11% for patients with bone metastases, respectively., Conclusion: As chemotherapy and radiotherapy treatment progressed, joint reconstruction after proximal femoral tumor resection improved patients' function and quality of life., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Purpose: Limb salvage procedures for musculoskeletal tumors have inherent complications. Though most complications can be managed with retention of the reconstructions, occasionally salvaging these reconstructions is not possible. We evaluated the outcomes of patients undergoing rotationplasty after multiple failed revisions of limb salvage surgery and document the success rate of this "salvage" technique and the subsequent functional outcome of these patients., Method: Between January 1, 1999, and December 31, 2018, 14 patients (12 male and 2 female) with a median age of 24 years (11-51 years) underwent rotationplasty after multiple failed revisions of limb salvage surgery. Indication for rotationplasty was infection (10 patients), failed megaprosthesis (2 patients), unstable biological reconstruction (1 patient) and local recurrence (1 patient). The mean number of surgeries done before the patient underwent rotationplasty was 5 (range 2-7)., Results: One patient developed a vascular complication (venous congestion) immediately after rotationplasty and underwent an early amputation. The remaining 13 patients had no surgical complications. Mean Musculo Skeletal Tumor Society score in 13 evaluable patients was 26 (23-30)., Conclusion: Our study demonstrates the utility of rotationplasty as a "salvage" procedure after multiple failed lower limb salvage surgeries. It offers good success rates, low rates of complications and good functional outcomes in carefully selected cases., (© 2022. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Osteosarcoma is one of the most prevalent primary malignant bone tumors that affects teenagers more than adults. In recent years, artificial femoral replacement has become more and more common. The use of artificial total femoral replacement surgery prevents the need for amputating the damaged limb, preserves the patient's ability to move and bear weight on the leg, lessens the severity of the psychological trauma, and significantly raises the patient's quality of life. To explore the treatment methods and therapeutic effects of artificial femoral replacement in the treatment of femoral osteosarcoma. The clinical data of 11 patients with femoral malignant tumors who underwent artificial femoral replacement from January 2019 to March 2022 were retrospectively analyzed. Among them, 7 males and 4 females, 11 to 40 years old, average 19.36 ± 9.44 years old. The disease duration is 2 to 7 months, with an average of 4.7 months. Before and 3 months after operation, the patients who had tumors were given a score on the visual analog scale, and their quality of life was also measured. At the most recent follow-up, both the Musculoskeletal Tumor Society score and the Harris hip score were analyzed. Eleven patients were followed up for 6 to 58 months, and an average of 21 months. Complications such as wound infection, joint dislocation, and nerve damage did not occur. In 1 patient, popliteal vein thrombus formation, and in 2 patients with osteosarcoma died from tumor progression. Visual analog scale score at 3 months after surgery and the quality-of-life scores were 3.68 ± 1.39 and 40.04 ± 4.31, respectively, which were significantly improved compared to before surgery (5.94 ± 1.19 and 22.42 ± 3.63, respectively, P < .05). At the last interview, Musculoskeletal Tumor Society score is scored from 18 to 29 points, average 22.5 ± 5.9 points, and Harris hip score is scored from 42 to 90 points, with an average score of 69.0 ± 14.7. Artificial total femoral replacement is an effective limb salvage operation in the treatment of osteosarcoma., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.)

Adolescents and children worldwide are threatened by osteosarcoma, a tumor that predominantly affects the long bone epiphysis. Osteosarcoma is the most common and highly malignant bone tumor in youngsters. Early tumor detection is the key to effective treatment of this disease. The discovery of biomarkers and the growing understanding of molecules and their complex interactions have improved the outcome of clinical trials in osteosarcoma. This article describes biomarkers of osteosarcoma with the aim of positively influencing the progress of clinical treatment of osteosarcoma. Femoral bone tumor is a typical condition of osteosarcoma. Due to the wide range of femoral stem types, complexities in the distal femur, and tumors in the rotor part of femur, physicians following the traditional clinical approach face difficulties in removing the lesion and fixing the femur with resection of the tumor segment. In this paper, the effect of small doses of different concentrations of lidocaine anesthesia in patients undergoing lumpectomy for osteosarcoma femoral tumor segments is investigated. A computer-based artificial intelligence method for automated determination of different concentration levels of lidocaine anesthesia and amputation of osteosarcoma femoral tumor segment is proposed. Statistical analysis is carried on the empirical data including intraoperative bleeding, intraoperative and postoperative pain scores, surgical operation time, postoperative complications, patient satisfaction, and local anesthetic dose. The results showed that the patients in the study group had low intraoperative bleeding, short operation time, low postoperative hematoma formation rate, high patient satisfaction, higher dosage of anesthetic solution, and low dosage of lidocaine. Results revealed that mean arterial pressure and heart rate in extubating and intubating were significantly lower in the observation group than in the control group, and a significant difference ( P < 0.05) was observed between the two groups. This proves that the proposed algorithm can adequately reduce bleeding, alleviate postoperative pain, shorten operation time, reduce complications, accelerate recovery, and ensure better treatment results., Competing Interests: The authors solemnly declare that there are no conflicts of interest., (Copyright © 2022 Shuqin Ni et al.)

Giant cell tumor (GCT) of the bone is a locally aggressive and rarely metastasizing neoplasm. It is composed of neoplastic mononuclear stromal cells with a monotonous appearance admixed with macrophages and osteoclast-like giant cells. In a small subset of cases, GCT is malignant. Terminology previously related to this entity, and which is no longer supported by the World Health Organization, includes osteoclastoma and benign fibrous histiocytoma (BFH). Giant cells occur in numerous other pathologic conditions of the bone, which accounts for the misrepresentation of these non-GCT tumors in the early literature. Non-ossifying fibroma (NOF), aneurysmal bone cyst, and chondroblastoma have been erroneously labeled GCT for this reason. A single description of an ancient GCT was reported by Brothwell and Sandison and subsequently mentioned by Aufderheide and Rodrìguez-Martìn who were astonished that more of these tumors had not been identified in archaeological cases. To the best of our knowledge, no other cases of ancient GCT have been cited in the paleopathology literature. The study of this type of neoplasm in antiquity can be used as a means to better understand its characteristics and behavior and to expand the depth of time of the etiology of these lesions. We report a case of GCT of the left femur observed following the total body CT imaging of a partially mummified adult female, dating to eighteenth century., (© 2021. The Author(s).)

Background: Challenging emerging entities with distinctive molecular signatures may benefit from algorithms for diagnostic work-up., Methods: Fusion sarcomas (2020-2021, during pandemic) were diagnosed by clinicoradiology, morphology, phenotype, and next-generation sequencing (NGS)., Results: Six fusion sarcomas in two males and four females involved the chest-wall, neck, or extremities; ages ranged 2-73, median 18 years. Sizes ranged 5.3-25.0, median 9.1 cm. These include high grade 1) TPR-NTRK1 of proximal femur with a larger rounded soft tissue mass, previously considered osteosarcoma yet without convincing tumor matrix. A pathologic fracture necessitated emergency hemipelvectomy (NED) and 2) novel KANK1-NTRK2 sarcoma of bone and soft tissue with spindled pleomorphic to epithelioid features (AWD metastases). 3) Novel ERC1-ALK unaligned fusion, a low grade infiltrative deep soft tissue hand sarcoma with prominent-vascularity, myopericytoid/lipofibromatosis-like ovoid cells, and collagenized stroma, was successfully treated with ALK-inhibitor (Crizotinib), avoiding amputation. These NTRK and ALK tumors variably express S100 and CD34 and were negative for SOX10. 4) and 5) CIC-DUX4 round cell tumors (rapid metastases/demise), one with COVID superinfection, were previously treated as Ewing sarcoma. These demonstrated mild pleomorphism and necrosis, variable myxoid change and CD99 reactivity, and a distinctive dot-like-Golgi WT1 immunostaining pattern. 6) A chest wall/thoracic round cell sarcoma, focal CD34/ keratins/CK7, revealed nuclear-STAT6, STAT6-NAB2 by NGS, confirming malignant solitary fibrous tumor, intermediate-risk-stratification (AWD metastases)., Conclusions: Recent fusion sarcomas include new KANK1-NTRK2 and ERC1-ALK, the latter successfully treated by targeted-therapy. ALK/NTRK fusion partners TPR and KANK1 suggest unusual high-grade morphology/behavior. Clinicoradiologic, morphologic, and phenotypic algorithms can prompt molecular-targeted immunostains or NGS for final classification and promising inhibitor therapy., (Copyright © 2021. Published by Elsevier Inc.)

Introduction: Proximal femur replacement (PFR) in the setting of tumor resection is associated with a high rate of postoperative complication. The online American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) surgical risk calculator is approved by the Center of Medicare and Medicaid services to estimate 30-day postoperative complications. This study was to determine if the ACS-NSQIP can predict postoperative complications following PFR., Methods: We reviewed 103 (61 male and 42 female) patients undergoing PFR using the Current Procedural Terminology (CPT) codes available in the calculator: 27125 (hemiarthroplasty), 27130 (total hip), 27132 (conversion to total hip), 27134 (revision total hip), 27137 (revision acetabulum), 27138 (revision femur), and 27365 (excision tumor hip). The predicted rates of complications were compared with the observed rates., Results: Complications occurred in 54 (52%) of patients, with the predicted risk based on CPT codes: 27125 (21.5%); 27130 (7.8%); 27132 (16.6%), 27134 (17.8%), 27137 (14.4%), 274138 (22.7%), and 27365 (16.2%). The calculator was a poor predictor of complications (27125, area under the curve [AUC] 0.576); (27130, AUC 0.489); (27132, AUC 0.490); (27134, AUC 00.489); (27137, AUC 0.489); (27138, AUC 0.471); and (27365, AUC 0.538)., Conclusion: Oncologic PFR is known for complications. The ACS-NSQIP does not adequately predict the incidence of complications, and therefore cannot reliably be used in their shared decision-making process preoperative., (© 2021 Wiley Periodicals LLC.)

Introduction: There is currently no consensus regarding the best techniques or surgical strategies with which to maximize intercalary allograft reconstruction outcomes. The purpose of the current study was to assess which techniques and methods are being utilized by North American orthopaedic oncologists., Methods: Members of the Musculoskeletal Tumor Society (MSTS) were invited to complete an anonymous online questionnaire. The survey presented participants with two clinical scenarios and interrogated them on their preferred type of allograft, method of compression and fixation, and additional techniques used., Results: One hundred and twenty-six physicians completed the questionnaire. The majority studied in the United States (82%) and worked at an academic medical center (71%). Over half (54%) reported seeing over 10 primary bone tumors every year. Respondents were split between preferring a structural allograft alone or using a combined allograft-vascularized fibular graft. A majority indicated a preference for plate(s) and screw fixation but were divided between the use of two compression plates with a spanning plate, a single compression plate with a spanning plate, and two compression plates with an intramedullary nail. Screw fixation preferences were split between the use of unicortical locking only, bicortical locking only, and a combination of unicortical and bicortical locking. Almost equal percentages of respondents reported they would have used two, three, or four screws in both scenarios. Respondents were split between placing screws equidistantly and placing them peripherally within the allograft, adjacent to the allograft-host junction., Discussion: There is no clear surgical preference for intercalary reconstruction following tumor extirpation within this sample of orthopaedic oncologists. The current survey demonstrates variability across nearly every aspect of allograft reconstruction, which may, in part, explain the wide spectrum of outcomes reported within the literature. Prospective studies are warranted to better evaluate technique-specific outcomes in an effort to maximize reconstructive longevity and minimize allograft related complications., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: One of the challenges to surgical reconstruction following oncologic proximal femur resection is reliable re-establishment of the abductor mechanism. Surgical and functional outcomes following re-approximation of the abductor mechanism to a metallic endoprosthetic after tumor resection of the proximal femur have not been well established in the literature., Methods: A retrospective review was performed, inclusive of patients who received a proximal femur replacement with a metallic endoprosthesis following tumor resection. Patients were divided into two groups: (1) those that received an abductor repair involving a trochanteric osteotomy and osseous fixation of the greater trochanter/abductor mechanism to the endoprosthesis, and (2) those that did not have a trochanteric osteotomy and therefore had an abductor repair consisting of only soft tissue reattachment to the endoprosthesis. The two groups were assessed for demographic characteristics, diagnosis, surgical outcomes including rates of complication and failure, radiographic evidence of trochanteric failure, and functional outcomes. Descriptive statistics, comparative statistics, and logistic regression analyses were performed to discern differences between the two study groups., Results: Fifty-three patients were included in the analysis, 29 had abductor reconstructions involving reattachment of the greater trochanter to the metallic endoprosthesis and 24 had soft tissue reconstruction of the abductor mechanism without bony fixation. There were no differences between the two groups for demographic data, cancer diagnosis, follow up, or survivorship. Radiographic evidence of trochanteric dissociation from the endoprosthesis was observed in 45% of osteotomy cases. Only 10% of patients in the trochanter osteotomy group and 38% of the soft tissue only group were able to resume a normal, non-Trendelenburg gait at final postoperative visit (p = .024). Need for an assistive ambulatory device was seen in 83% and 67% of the osteotomy and soft-tissue-only patients, respectively (p = .21)., Conclusion: Re-establishing the abductor mechanism following proximal femur oncologic resection remains a challenge to orthopedic oncologists. Even when possible, salvage of the greater trochanter for reattachment to the endoprosthesis did not lead to improved function in this series, when compared to a similar cohort that received a soft-tissue-only abductor repair. Abductor mechanism reconstruction with a greater trochanteric osteotomy and subsequent fixation to the proximal femur endoprosthesis had a high rate of radiographic failure. Additionally, reattachment of the greater trochanter to the proximal femur endoprosthesis demonstrated no improvement in Trendelenburg gait or reliance on an assistive ambulatory device when compared to a soft-tissue-only abductor repair., (© 2021 Wiley Periodicals LLC.)

Tumour-to-tumour metastasis is very unusual and has been defined as a tumour metastasis into another histologically different tumour. It is extremely rare in bone. We report a case of lung squamous cell carcinoma metastasized to an enchondroma in the femur of a patient with Ollier disease. A 60-year-old female had a history of a poorly differentiated squamous cell carcinoma of the lung. She underwent a video-assisted thoracoscopic lobectomy, and a follow-up MRI scan showed three lesions in the left distal femur and proximal tibia, which were initially interpreted as metastasis on radiology. Resection of the left proximal tibial lesion was performed, and the pathological findings were consistent with enchondroma with no evidence of metastasis. Subsequent curettage of lesions in the distal left femur revealed metastatic poorly differentiated carcinoma with foci of hyaline cartilage, which was most consistent with metastatic carcinoma in a pre-existing enchondroma. The MRI films were re-reviewed. Characteristic MRI features of enchondroma were found in the lesion in the left proximal tibia and one of the lesions in the left distal femur, while the features of the other lesion in the left distal femur included cortical destruction and extensive oedema in surrounding soft tissue, which were consistent with a malignant tumour. In addition, the enchondroma in the lateral condyle showed blurring and irregular inner margin and adjacent bone oedema, which likely represents a co-existing metastatic tumour and enchondroma. The difference in lineage was confirmed by immunohistochemistry. The final diagnosis was metastatic poorly differentiated carcinoma of the lung into a co-existent enchondroma. The diagnosis can be challenging and could be easily overlooked both radiologically and histologically. Thorough clinical and radiological information is critical for the diagnosis, and despite a very unusual event, awareness of the tumour-to-tumour metastasis phenomenon can avoid an inaccurate diagnosis by the pathologist, therefore preventing inappropriate clinical intervention., (© 2020. The Author(s).)

Introduction: Rhabdomyosarcoma (RMS) is a malignant solid tumor of mesenchymal origin. It is the most com mon soft-tissue sarcoma in childhood and adolescence. 65% of cases are diagnosed before the age of 6. Histological subtypes include embryonal, alveolar, pleomorphic, and fused-cell RMS. The embryo nal subtype is more frequent in children, while the alveolar one is more frequent in adolescents and adults., Objective: To describe the clinical presentation of primary alveolar rhabdomyosarcoma in a schoolgirl., Clinical Case: 7-year-old schoolgirl with one-month history of progressive pain in her left thigh. X-ray shows a lytic lesion in the left femur diaphysis. A study was performed with 2 biopsies, immunohistochemistry, and PAX-FOXO1 studies which were compatible with alveolar RMS. Con clusion: Primary alveolar rhabdomyosarcoma of the bone is rare, but it should be considered within the differential diagnosis of primary small-round-blue cell bone tumors. Despite presenting a poor prognosis cytogenetic, this type of tumor seems to have better biological behavior, which for a successful treatment makes necessary to have a high index of suspicion in order to install a multimodal therapy in the context of a national protocol.

Aims: Osteosarcoma (OS) is the most common primary malignant tumour of the bone. However, further improvement in survival has not been achieved due to a lack of well-validated prognostic markers and more effective therapeutic agents. Recently, the c-Myc-phosphoribosyl pyrophosphate synthetase 2 (PRPS2) pathway has been shown to promote nucleic acid metabolism and cancer cell proliferation in malignant melanoma; phosphorylated mammalian target of rapamycin (p-mTOR) has been upregulated and an effective therapeutic target in OS. However, the p-mTOR-PRPS2 pathway has not been evaluated in OS., Methods: In this study, the expression level of PRPS2, p-mTOR and marker of proliferation (MKI-67) was observed in a cohort of specimens (including 236 OS cases and 56 control samples) using immunohistochemistry, and the association between expression level and clinicopathological characteristics of patients with OS was analysed., Results: PRPS2 protein level, which is related to tumour proliferation, was higher in OS cells (p=0.003) than in fibrous dysplasia, and the higher PRPS2 protein level was associated with a higher tumour recurrence (p=0.001). In addition, our statistical analysis confirmed that PRPS2 is a novel, independent prognostic indicator of OS. Finally, we found that the expression of p-mTOR was associated with the poor prognosis of patients with OS (p<0.05)., Conclusions: PRPS2 is an independent prognostic marker and a potential therapeutic target for OS., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: All-polyethylene (AP) tibial components have demonstrated equivalent or improved long-term survivorship and reduced cost compared with metal-backed (MB) components in primary total knee arthroplasty; however, there is a lack of data comparing these outcomes in the setting of an oncologic endoprosthetic reconstruction., Methods: A total of 115 (88 AP:27 MB) patients undergoing cemented distal femur endoprosthetic reconstruction following oncologic resection were reviewed. Mean age was 40 years and 51% were females. Cumulative incidences of all-cause revision, tibial component revision, reoperation, and infection were calculated utilizing a competing risk analysis with death as the competitor. Mean follow-up was 14 years., Results: The 10-year cumulative incidence of all-cause revision was 19.9% in the AP group and 16.3% in the MB group (hazard ratio [HR] = 0.93, p = 0.88). The cumulative incidence of tibial component revision was significantly lower in AP compared with MB at 10 years (1.1% vs. 12.5%, HR = 0.18, p = 0.03). There was no difference in infection-free survival when comparing the two groups (p = 0.72)., Conclusions: Reconstruction utilizing an MB or AP tibia component resulted in equivalent overall outcome; however, the tibial component in the AP group was less likely to be revised. AP tibial component should be considered for all primary oncologic reconstructions in the distal femur. LEVEL OF EVIDENCE: Level III Therapeutic., (© 2020 Wiley Periodicals LLC.)

Competing Interests: Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht.

Case: We report the case of a 78-year-old woman with undifferentiated pleomorphic sarcoma (UPS) of the proximal femur arising in a previous site of fibrous dysplasia (i.e., a liposclerosing myxofibrous tumor) that had been treated 4 years earlier with curetted surgery. GNAS mutation was detected in both the previous benign lesion and the UPS., Conclusion: Genetic analysis is useful in demonstrating the origin of the tumor especially in fibrous dysplasia with severe degeneration that have undergone malignant transformation., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSCC/B280)., (Copyright © 2020 by The Journal of Bone and Joint Surgery, Incorporated.)

Lower limb pathological fractures caused by bone metastases can severely impair activities of daily living, so recognizing fracture risk is essential. Medial cortical involvement (MCI) in the proximal femur has been demonstrated to affect bone strength in biomechanical studies, but it has not been investigated in real patients. Between 2012 and 2019, 161 bone metastases with computed tomography (CT) images were retrospectively examined. Twenty-nine fractures were observed including 14 metastases with pathological fractures at the first examination, and prophylactic surgery was performed for 50 metastases. We extracted clinicopathological data using CT images, including patient's background, MCI in the proximal femur, site, size, circumferential cortical involvement (CCI), pain, and nature of metastasis. Cox proportional hazard regression analyses were performed, and we created integer scores for predicting fractures. We revealed that MCI, CCI, lytic dominant lesion, and pain were significant factors by univariate analyses. By multivariable analysis, MCI and each 25% CCI were significant and integer score 1 was assigned based on hazard ratio. The full score was four points, with MCI in the proximal femur (one point) and ≥ 75% CCI (three points). With integer score two, sensitivity was 88.9% and specificity was 81.2% for predicting fracture within 60 days. In conclusion, MCI and CCI examined by CT images were the risk factors for pathological fracture. CCI ≥ 50% is a widely known risk factor, but in addition, it may be better to consider surgery if MCI in the proximal femur is observed in metastasis with 25-50% CCI.

This report describes a rare case of osteosarcoma of the right distal femur and secondary spontaneous pneumothorax in a 13-year-old girl. Secondary spontaneous pneumothorax complicating metastatic osteosarcoma is a rare but well-known phenomenon, with several suggested hypotheses for its pathogenesis. However, these hypotheses have not been confirmed. In the present case, the pathogenesis of secondary spontaneous pneumothorax complicating metastatic osteosarcoma was determined grossly, radiologically, and histopathologically. These findings may help to clarify further the pathogenesis of secondary spontaneous pneumothorax complicating metastatic osteosarcoma., (Copyright © 2020 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Rationale: Osteosarcoma is the most common primary malignant bone tumor in children. The prognosis of osteosarcoma has improved with the use of aggressive systemic chemotherapy in addition to surgery. The relapse of osteosarcomas is usually as lung metastasis observed within 2 to 3 years after the initial treatment. A relapse is rarely observed at >10 years., Patient Concerns: We report the case of a 51-year-old Japanese man who was treated for high-grade osteosarcoma of the femur at 13 years old. He was referred to our hospital with a suspicion of primary lung cancer based on back pain, respiratory distress, and an abnormal mass on chest radiograph., Diagnoses: Computed tomography-guided biopsy confirmed the lung lesion as a metastatic recurrence of high-grade osteosarcoma without local recurrence., Interventions: Chemotherapy was planned, but the patient's general condition rapidly deteriorated and thus palliative therapy was provided., Outcomes: The patient died 2 months after the initial consultation., Lessons: The survival durations of osteosarcoma patients have been prolonged by recent progress in multimodality therapy, and thus clinicians as well as osteosarcoma patients should always keep in mind the possibility of very late relapse.

Case: A 78-year-old man was followed for an incidentally found, asymptomatic lesion in his right proximal femur that was unchanged radiographically for 11 years. He developed pain and was believed to have experienced a stress fracture through the lesion. The lesion was biopsied, showing a high-grade pleomorphic sarcoma with an underlying senescent intraosseous lipoma. He was ultimately treated with wide excision and reconstruction of the proximal femur., Conclusion: This case highlights the importance of obtaining a tissue diagnosis for lesions that become symptomatic.

Osteosarcoma arising from cortical surface is classified into parosteal, periosteal and high-grade surface osteosarcoma. Along the spectrum, parosteal osteosarcoma occupies the well-differentiated end. It is a relatively rare disease entity, comprised only 4% of all osteosarcomas and barely reported in the literature. The objective of this study is to describe cases of parosteal osteosarcoma as well as a variety of treatment options amenable to such entity. Six cases of parosteal osteosarcoma were identified based on histopathological reports in a tertiary referral hospital in Jakarta, Indonesia between January 2001 and December 2019. The mean age was 29.8 years old; four of them (66.7%) were male. Distal end of femur was the most commonly involved bone (five cases, 83.3%). The patients were treated with wide excision followed by several different reconstruction methods: replacement with endoprosthesis, extracorporeal irradiation, knee arthrodesis, or prophylactic fixation. One of our patients presented with dedifferentiated component, and therefore was treated by limb ablation. While two cases died of pulmonary metastasis, other patients reported fair to excellent functional outcome., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2020 Yogi Prabowo et al.)

Osteosarcoma (OSA) is the most common primary bone malignancy overall and is responsible for considerable adolescent mortality. Approximately 850 patients are newly diagnosed with OSA in the United States each year. While the 5-year survival rate for localized OSA has improved from <20% over 40 years ago to over 65% today, progress has dwindled over the past three decades. Therapeutic stagnation has occurred, in part, as a result of limited preclinical models and the overall heterogeneity of OSA among patients. In this study, we report the establishment and characterization of a novel OSA cell line: OSA 1777. This cell line was isolated from the recurrent tumor specimen of a 19-year-old female who initially experienced 99% tumor necrosis after neoadjuvant chemotherapy and eventually had local recurrence and metastases. We present OSA 1777 growth characteristics, tumor markers, chemotherapeutic sensitivities, and oncogenic spheroid formation. In a two-dimensional (2D) monolayer culture, OSA 1777 exhibited a spindle shape and 60 h doubling time. STR DNA profiling revealed a unique genomic identity not matching any existing human cancer cell lines from the ATCC or DSMZ databases. Consistent with the mesenchymal origin, western blot was positive for vimentin and negative for the carcinoma marker cytokeratin. Within three-dimensional (3D) culture, the cells formed spheroids of similar patterning and smaller size compared with MNNG-HOS and U2OS cell lines. The chemotherapeutic drug sensitivity of OSA 1777 was evaluated in both 2D and 3D culture systems. In summary, we report OSA 1777 as a novel biological model of OSA amenable to future studies focused on OSA that recurs despite an initially strong chemotherapeutic response. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:902-910, 2020., (© 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Background: The femur is the most common site of metastasis in the appendicular skeleton, and metastatic bone disease negatively influences quality of life. Orthopaedic surgeons are often faced with deciding whether to prophylactically stabilize an impending fracture, and it is unclear if prophylactic fixation increases the likelihood of survival., Questions/purposes: Is prophylactic femur stabilization in patients with metastatic disease associated with different overall survival than fixation of a complete pathologic fracture?, Methods: We performed a retrospective, comparative study using the national Veterans Administration database. All patient records from September 30, 2010 to October 1, 2015 were queried. Only nonarthroplasty procedures were included. The final study sample included 950 patients (94% males); 362 (38%) received prophylactic stabilization of a femoral lesion, and 588 patients (62%) underwent fixation of a pathologic femur fracture. Mean followup duration was 2 years (range, 0-7 years). We created prophylactic stabilization and pathologic fracture fixation groups for comparison using Common Procedural Terminology and ICD-9 codes. The primary endpoint of the analysis was overall survival. Univariate survival was estimated using the Kaplan-Meier method; between-group differences were compared using the log-rank test. Covariate data were used to create a multivariate Cox proportional hazards model for survival to adjust for confounders in the two groups, including Gagne comorbidity score and cancer type., Results: After adjusting for comorbidities and cancer type, we found that patients treated with prophylactic stabilization had a lower risk of death than did patients treated for pathologic femur fracture (hazard ratio = 0.75, 95% CI, 0.62-0.89; p = 0.002)., Conclusions: In the national Veterans Administration database, we found greater overall survival between patients undergoing prophylactic stabilization of metastatic femoral lesions and those with fixation of complete pathologic fractures. We could not determine the cause of this association, and it is possible, if not likely, that patients treated for fracture had more aggressive disease causing the fracture than did those undergoing prophylactic stabilization. Currently, most orthopaedic surgeons who treat pathological fractures stabilize the fracture prophylactically when reasonable to do so. We may be improving survival in addition to preventing a pathological fracture; further study is needed to determine whether the association is cause-and-effect and whether additional efforts to identify and treat at-risk lesions improves patient outcomes., Level of Evidence: Level III, therapeutic study.

Background: Limb salvage surgery is becoming increasingly popular after tumor resection in the lower extremity. Biological reconstruction and use of megaprosthesis are main methods for malignant bone tumors of the proximal femur, which remain controversial due to short- and long-term complication in the proximal femur. Tumor-bearing bone treated by liquid nitrogen is one of biological reconstruction. This study aimed to evaluate the mid- and long-term functional outcomes and complications in patients treated with frozen autograft-prosthesis composite (FAPC) reconstructions in the proximal femur., Methods: This retrospective study included 19 patients (10 women, 9 men) with malignant tumors of the proximal femur who underwent tumor-wide resection and FAPC reconstruction (mean age, 46 years; range, 9-77 years). The mean follow-up period of 69 months (range, 9-179 months). Functional outcomes, oncological outcome and complications were evaluated by Musculoskeletal Tumor Society score, clinical and radiological examinations., Results: The overall survival rate was 68.4%, and the mean Musculoskeletal Tumor Society functional score was 26.4 points (88%). FAPC survival rates were 100 and 50% at 5 and 10 years, respectively. Five of the 19 patients (26%) had complications: 2 required prosthesis removal and 2 developed a deep infection around acetabular. Wear of the acetabulum occurred in 2 cases, while disease recurrence was occurred in 1 case. There were no cases of greater trochanter avulsion, obvious absorption around frozen bone, prosthesis loosening or leg length discrepancy., Conclusions: Due to without femoral osteotomy, this technique features satisfactory functional outcome and provide biomechanical stability that is comparable to those of other methods of biological reconstruction or megaprosthesis.

Case: A 60-year-old man presented with left hip pain, and a radiograph showed reduced joint space. During the surgical procedure for a total hip replacement, a proximal femur mass was identified and biopsy was subsequently interpreted as grade 2 chondrosarcoma. A wide resection was needed, but he developed local recurrence after 2 years and was treated with an external hemipelvectomy., Conclusions: Chondrosarcoma does not always present with a classical clinical picture or imaging, and it can be misdiagnosed. Practitioners should be highly suspicious of malignant disease as a cause for hip pain even if there is no direct indication of a neoplasm such as chondrosarcoma.

Case: A 64-year-old man diagnosed with prostate cancer was incidentally found to have a lesion in his distal femur. Although initially concerning for metastatic prostate cancer, after biopsy by an orthopaedic oncology specialist, a diagnosis of liposclerosing myxofibrous tumor (LSMFT) was confirmed. The lesion was treated with curettage and demineralized bone matrix grafting with close follow-up., Conclusions: This case report illustrates that LSMFT is not confined to the proximal femur and highlights the differences in radiographic appearance between LSMFT and more common metastatic bone lesions.

Background: Metastatic tumors of the penis are uncommon, and fewer than 500 cases have been reported since 1870. Most penile secondary tumors originate in organs of the genitourinary tract, followed by the gastrointestinal tract. Primary tumors of sarcoma origin are extremely rare. Herein, we present a teenager who had recurrent sarcoma of the right femur with penile metastasis., Case Presentation: The 20-year-old male patient was diagnosed with sarcoma of the right femur when he was 16 days old. He was stable following combination chemotherapy with the VAC regimen (vincristine, adriamycin, and cyclophosphamide) and debulking surgery. In January 2018, five months ago, he presented with right leg pain and swelling, and a recurrent tumor was found. Following excision of the tumor showed recurrent sarcoma. However, 2 months after the operation, right thigh swelling with tenderness occurred. A firm nodule on the glans of the penis was also noted. Penile metastasis was suspected and a biopsy was performed. The final pathology report disclosed pleomorphic sarcoma with penile metastasis. Symptoms including priapism and inguinal lymph node enlargement progressed rapidly within 2 weeks. He also complained of voiding difficulty with urine retention. The patient died 35 days after admission due to pneumonia with septic shock., Conclusion: Penile metasitasis largely occurs from organs in the pelvis. To the best of our knowledge, this is the first case of a teenager with a secondary penile tumor, metastasizing from sarcoma of the bone. It presented as a palpable mass, and then progressed into priapism. The patient had a dismal prognosis and the symptoms progressed faster than his physicians anticipated.

Background: To address large tumor-related defects and lower limb-length discrepancies during limb-salvage surgery in children with malignant tumors in the distal femur, a new custom-made dual-mobility semi-knee prosthesis (DMK) was made. This study aimed to provide a theory and references for further clinical applications of this prosthesis., Methods: Based on computed tomography data from adult knee joint samples, we used Mimics/Geomagic/Pro-E software and computer numerical control milling technology to design and manufacture the DMK. An in vitro study was carried out to examine the related kinematic parameters in the normal knee, total knee arthroplasty and DMK groups of cadaveric specimens. Then, a pilot clinical trial was performed., Results: The in vitro study revealed that the kinematics of the novel custom-made DMK are more similar to those of the normal knee than the total knee prosthesis. The pilot clinical trial showed that patients recovered well, and postoperative serial X-ray films did not demonstrate any disfigurations, loosening, dislocations or breaks in the prosthesis after a follow-up period ranging from 11 months to 5 years., Conclusion: The DMK is a novel concept and method for the treatment of malignant tumors in the distal femur in children, and the device used for ligament reattachment provides a solution for knee ligament reconstruction. However, DMK might be replaced by a total knee prosthesis after epiphyseal closure, because of incompatibility of tibial plateau with the prosthesis., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Aims: The aim of this study was to determine the risk of local recurrence and survival in patients with osteosarcoma based on the proximity of the tumour to the major vessels., Patients and Methods: A total of 226 patients with high-grade non-metastatic osteosarcoma in the limbs were investigated. Median age at diagnosis was 15 years (4 to 67) with the ratio of male to female patients being 1.5:1. The most common site of the tumour was the femur (n = 103) followed by tibia (n = 66). The vascular proximity was categorized based on the preoperative MRI after neoadjuvant chemotherapy into four types: type 1 > 5 mm; type 2 ≤ 5 mm, > 0 mm; type 3 attached; type 4 surrounded., Results: Limb salvage rate based on the proximity type was 92%, 88%, 51%, and 0% for types 1 to 4, respectively, and the overall survival at five years was 82%, 77%, 57%, and 67%, respectively (p < 0.001). Local recurrence rate in patients with limb-salvage surgery was 7%, 8%, and 22% for the types 1 to 3, respectively (p = 0.041), and local recurrence at the perivascular area was observed in 1% and 4% for type 2 and 3, respectively. The mean microscopic margin to the major vessels was 6.9 mm, 3.0 mm, and 1.4 mm for types 1 to 3, respectively. In type 3, local recurrence-free survival with limb salvage was significantly poorer compared with amputation (p = 0.025), while the latter offered no overall survival benefit. In this group of patients, factors such as good response to chemotherapy or limited vascular attachment to less than half circumference or longitudinal 10 mm reduced the risk of local recurrence., Conclusion: The proximity of osteosarcoma to major blood vessels is a poor prognostic factor for local control and survival. Amputation offers better local control for tumours attached to the blood vessels but does not improve survival. Limb salvage surgery offers similar local control if the tumour attachment to blood vessels is limited. Cite this article: Bone Joint J 2019;101-B:1024-1031.

Aims: The aim of this study is to assess outcomes of patients ≤12 years who undergo Stanmore noninvasive extendible endoprosthetic replacement of the distal femur (DF NIEPR)., Patients and Methods: A total of 101 children (mean age 9.6 years) were included. All complications which required further surgery were recorded. Clinical and functional outcomes were evaluated with Musculoskeletal Tumor Society (MSTS) scores at a mean follow-up of 64 months (range 6-174)., Results: Thirty-one (30.7%) patients died at a mean of 33 months. Forty had prosthesis removed after a mean of 43 months (range, 7-103). Attaining of the full lengthening potential before skeletal maturity was the most frequent reason for revision surgery, particularly in those with smaller lengthening potential (P  =  0.039). Implant survival rate for other causes was 61.7% at 5 years and 45.0% at 10 years. At final follow-up mean MSTS score was 26 (range, 13-29). Twenty-two (21.5%) patients had a final limb-length discrepancy (LLD)  > 2 cm., Conclusions: DF NIEPR produces a good functional outcome, with the prevention of major LLD at skeletal maturity in the majority of the cases. We suggest patient selection criteria to account for the stage of the disease due to the high cost of the NIEPR, and high percentage requiring revision, and a 60% mortality rate in those patients presenting with distant disease burden., (© 2019 Wiley Periodicals, Inc.)

Introduction: Osteosarcoma, a primary malignant bone tumor, has a well-recognised double peak of incidence in early adolescence and after 50 years. This study investigates the clinical features and prognostic factors of patients older than 50 years with osteosarcoma., Materiel and Methods: From January 2000 to December 2012, in one bone tumor reference center, 32 patients aged more than 50 years at the diagnosis (mean age: 62.4 years (50-85), sex ratio: 13 males, 19 females) diagnosed with osteosarcoma were included. Patients younger than 50 years at diagnosis or with a non-histologically proved osteosarcoma were excluded. For each patient, we registered medical history, tumor location, systemic and local extension, treatment, and survival., Results: 62% were located in the extremities and 28% in the axial skeleton. 6 were secondary sarcomas. Mean delay between first symptoms and biopsy was 7.4 months (range from 0 to 28 months). Ten patients had a systemic osteosarcoma with one or more pulmonary metastases. Six patients were treated with palliative care (18.8%). Eighteen patients received neodajuvant chemotherapy, sixteen of them received postoperative chemotherapy. Twenty-five patients had surgery. Postoperative complications were reported in eight cases (25%). Overall survival for all 31 patients was 25% at 5 years and 6.2% at 10 years. Survival without metastases was 15.6% at 5 years and nil at 10 years. Median survival time for the 22 localised osteosarcoma patients was 4 years (0.9-12.6) versus 1.2 years (0.3-12.3) for the 10 systemic osteosarcoma patients (p = 0.01)., Conclusion: Metastases at diagnosis, age, axial location are worse prognostic for survival., (Copyright © 2019 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

Aims: Aseptic loosening is a major cause of failure in cemented endoprosthetic reconstructions. This paper presents the long-term outcomes of a custom-designed cross-pin fixation construct designed to minimize rotational stress and subsequent aseptic loosening in selected patients. The paper will also examine the long-term survivorship and modes of failure when using this technique., Patients and Methods: A review of 658 consecutive, prospectively collected cemented endoprosthetic reconstructions for oncological diagnoses at a single centre between 1980 and 2017 was performed. A total of 51 patients were identified with 56 endoprosthetic implants with cross-pin fixation, 21 of which were implanted following primary resection of tumour. Locations included distal femoral (n = 36), proximal femoral (n = 7), intercalary (n = 6), proximal humeral (n = 3), proximal tibial (n = 3), and distal humeral (n = 1)., Results: The median follow-up was 132 months (interquartile range (IQR) 44 to 189). In all, 20 stems required revision: eight for infection, five for structural failure, five for aseptic loosening, and two for tumour progression. Mechanical survivorship at five, ten, and 15 years was 84%, 78%, and 78%, respectively. Mechanical failure rate varied by location, with no mechanical failures of proximal femoral constructs and distal femoral survivorship of 82%, 77%, and 77% at five, ten, and 15 years. The survivorship of primary constructs at five years was 74%, with no failure after 40 months, while the survivorship for revision constructs was 89%, 80%, and 80% at five, ten, and 15 years., Conclusion: The rate of mechanical survivorship in our series is similar to those reported for other methods of reconstruction for short diaphyseal segments, such as compressive osseointegration. The mechanical failure rate differed by location, while there was no substantial difference in long-term survival between primary and revision reconstructions. Overall, custom cross-pin fixation is a viable option for endoprosthetic reconstruction of short metaphyseal segments with an acceptable rate of mechanical failure. Cite this article: Bone Joint J 2019;101-B:724-731.

Mazabraud's syndrome is a rare disorder characterised by the association of fibrous dysplasia with intramuscular myxomas. We present a 36-year-old woman with right anterior knee pain and a buttock mass. Imaging showed aggressive bone destruction within an area of fibrous dysplasia in the right femur and a mass with myxoid signal characteristics in the right adductor region. Biopsy of the femur revealed both fibrous dysplasia and a high-grade spindle cell sarcoma. Biopsy of the adductor mass confirmed a soft-tissue myxoma. Molecular genetic analysis revealed an identical R201H substitution in the GNAS1 gene in the sarcoma, the myxoma, and also the conventional fibrous dysplasia.

Ewing's sarcoma (ES) is a small round cell tumor of adolescents or young adults that usually arises in the deep soft tissues of the extremities. The tumor cells have uniform round nuclei, fine powdery chromatin and indistinct nucleoli. CD99 (O13) is a product of the MIC 2 gene that is highly sensitive to ES but not specific. A panel of markers should be used for the differential diagnosis of small round cell tumors because nearly all others, on occasion, show membranous staining for CD99. One of the defining feature of ES is the presence of 22q12 gene rearrangement. The presented case is a 6 year-old boy complaining of swelling on his right leg. The biopsy was compatible with classic ES in terms of histopathological, immunohistochemical and cytogenetic criteria. Wide surgical resection was performed after chemotherapy. The posttreatment specimen was composed of uniformly small round cells mixed with areas of ganglion cells embedded in neurophil-like fibrillary background. Immunohistochemically, neoplastic cells revealed strong CD99 (O13) and NSE staining and the tumor had EWSR1 gene rearrangement. Morphologic alterations due to treatment are commonly seen in pediatric tumors. Single case reports have defined neural differentiation in ES but to the best of our knowledge this is the first report of ES in the literature with all histopathological, immunohistochemical, and cytogenetic criteria evaluated in both pretreatment and posttreatment specimens.

Tumor resection followed by reconstruction with a proximal femoral endoprosthesis or an allograft-prosthesis composite are the two main alternatives for treatment of proximal femoral malignancies. This review describes the revision rate, implant survival, limb salvage rate, and function. Overall revision rates are high and reasons for failure differ between treatment modalities. Rate and reasons for amputation are comparable between both methods. Functional outcome was reasonable to good on average for both treatment modalities. Level of evidence: IV, systematic review and meta-analysis., (© 2018 Wiley Periodicals, Inc.)

Competing Interests: Competing interests: None declared.

Background: Although cephalomedullary nail fixation is often used for metastatic peritrochanteric lesions of the femur, there is concern regarding the durability of the implant in comparison to endoprosthetic reconstruction. Previous studies have reported the proportion of patients who undergo reoperation for loss of stability, but the adequacy of the construct has not been critically evaluated in a competing risk analysis that incorporates death of the patient in the calculation., Questions/purposes: (1) What is the cumulative incidence of reoperation of cephalomedullary nails with death as a competing risk for metastatic lesions of the proximal femur? (2) What is the survival of patients with metastases to the proximal femur after cephalomedullary nailing? (3) What clinical factors are associated with implant stability in these patients?, Methods: Between 1990 and 2009, 11 surgeons at one center treated 217 patients with cephalomedullary nails for metastatic proximal femoral lesions. This represented 40% (217 of 544) of the patients undergoing surgery for metastases in this location during the study period. In general, we used cephalomedullary nails when there was normal bone in the femoral head, no fracture in the neck, and a moderate-sized lesion; we favored bipolar hemiarthroplasty for femoral neck fractures and disease affecting the femoral head; finally, we used proximal femoral endoprosthetic replacement for large lesions with severe bone destruction. A retrospective study was conducted of 199 patients with cephalomedullary nails for peritrochanteric metastases from 1990 to 2009. Pathologic fracture, defined as a breach in cortex with a clear fracture line either with or without displacement, was present in 61 patients. The most common primary cancers were breast (42 of 199 patients [21%]), lung (37 of 199 patients [18%]), and renal cell (34 of 199 patients [17%]). A competing risk analysis was performed to describe the cumulative incidence of implant revision. Patient overall survival was assessed by Kaplan-Meier survivorship. A univariate analysis was performed to determine whether there was an association between revision surgery and various patient factors, including tumor histology, pathologic fracture, cementation, and radiation., Results: Loss of implant stability necessitating revision surgery occurred in 19 of 199 patients (10%). In a competing risk analysis with death of the patient as the competing event, the cumulative incidence of revision surgery was 5% (95% confidence interval [CI], 3%-9%) at 12 months and 9% (95% CI, 5%-13%) at 5 years. Using Kaplan-Meier analysis, the overall patient survival was 31% (95% CI, 25%-37%) at 12 months and 5% (95% CI, 3%-9%) at 60 months. Patients with lung cancer had the shortest overall survival of 11% (95% CI, 1%-21%) at 12 months, and patients with multiple myeloma had the longest overall survival of 71% (95% CI, 49%-94%) at 12 months (p < 0.001). Duration of patient survival beyond the median 7 months was the only factor associated with a greater likelihood of revision surgery. Factors not associated with revision included tumor histology, pathologic fracture, closed versus open nailing, cementation, gender, age, and postoperative radiation., Conclusions: The competing risk analysis demonstrates a relatively low cumulative incidence of reoperation and suggests that cephalomedullary nailing is reasonable for patients with moderate-sized proximal femoral metastasis not affecting the femoral head. For the large majority of patients, the construct achieves the goal of stabilizing the femur for the duration of the patient's life. Longer patient survival was associated with greater risk of revision surgery, but no particular tumor histology was found to have a greater cumulative incidence of reoperation. Future work with a larger number of patients and stricter surgical indications may be needed to corroborate these findings., Level of Evidence: Level III, therapeutic study.

Rationale: Langerhans' cell histiocytosis (LCH), also called histiocytosis X, is an uncommon disorder manifesting in a variety of ways. Although LCH can involve various organs including bone, skin, and lymph nodes, multisystem involvement of LCH is rare in adults., Patient Concerns: A 31-year-old woman first presented to our hospital with left leg pain. She had a history of a 20-kg weight gain over three months., Diagnoses: X-ray, magnetic resonance imaging (MRI), computed tomography (CT), and bone scan images revealed enhancing lesions in the left femur and right temporal bone, multiple cystic lesions in the lung, enhancing mass in the pituitary stalk, and fat density lesions in the liver. The patient underwent excisional biopsy for the femoral lesion and histologic examination confirmed the diagnosis of LCH., Interventions: Excisional biopsy was performed for the bony lesion in the left femur. She received chemotherapy with vinblastine and prednisolone., Outcomes: The patient expired after 21 months from initial admission following recurrent episodes of pneumothorax, pneumonia, and sepsis., Lessons: Our case showed LCH involvement in bone, lung, central nervous system (CNS), and liver. Although it is occasionally difficult to discriminate LCH from other disorders, systemic evaluation might be helpful for differential diagnosis. Familiarity with the various multisystemic involvements of LCH on imaging is vital for diagnosing and managing patients in daily practice.

We report a rare case of giant periosteal osteoblastoma in the femur of a 21-year-old male. The patient presented with a painful, firm, non-tender mass in his left thigh. The pain was worse at night and was temporarily relieved with NSAIDS. He had no fevers, night sweats, or weight loss. The patient underwent preoperative radiological studies including plain radiographs, MRI, bone scan, and CT scan. An open biopsy was subsequently performed that was consistent with an aggressive, epithelioid osteoblastoma. Pathology demonstrated a neoplasm characterized by cohesive sheets of epithelioid osteoblasts, mixed with areas of conventional osteoblastoma displaying prominent osteoblastic rimming of woven bone trabeculae in a fibrovascular stroma. The patient subsequently underwent resection, cryosurgery, fixation, and bone grafting with cortical strut allografts. At final follow-up, 32 months postoperatively, there was no evidence of local recurrence. The patient had resumed all his normal activities. He could run without pain and had no restrictions with activities. The goal of this case report is to aid professionals in the diagnosis and treatment of highly uncommon aggressive osteoblastomas.

Objective: To investigate the radiological and histopathological features of giant cell tumor of bone treated with RANKL inhibitor denosumab. Methods: Eleven cases were retrieved from the surgical pathology records between March 2015 and June 2017 in Beijing Jishuitan Hospital. Formalin fixed, paraffin embedded specimens were collected and the histological features were evaluated. The imaging features including X ray, magnetic resonance imaging, and computed tomography were also reviewed. Results: These 11 cases of giant cell tumor of bone were derived from five female and six male patients, with age ranged from 20 to 62 years (mean age, 35 years). The tumors were located in the sacrum (6 cases), femur (2 cases), radius (1 case), tibia (1 case) and patella (1 case), respectively. Histologically, all cases showed depletion of giant cells, proliferation of mononuclear cells and different degrees of ossification 3 to 6 months after denosumab therapy. Radiography showed marked osteosclerosis and sclerotic rim formation. Three cases of the sacrum recurred after 5, 6 and 11 months of surgery, and the remaining cases showed no recurrence within follow-up of 1 to 14 months. Conclusions: Denosumab treated giant cell tumors morphologically differ from untreated tumors. Careful attention to a history of denosumab administration is crucial to avoid misdiagnosis and to allow proper differentiation from other tumors and tumor-like lesions.

Various methods for reconstructing large femur bone defects after tumor resection have been introduced. In this study, we reviewed the clinical outcomes of using a 1-barrel free vascularized fibular graft (FVFG) protected by a lateral locking plate for large femoral defects not involving the knee joint.Between August 2007 and August 2013, we treated 7 patients with large femoral bone defects after tumor resection. The mean age of the patients was 19 years (range, 12-36 years), and 3 were women. All defects were free of infection before the procedure. Femoral bone defects were reconstructed using a 1-barrel FVFG protected by a lateral locking plate. The mean bone defect size was 10.5 cm (range, 6-16 cm). We reviewed clinical outcomes at the last follow-up.All patients survived beyond the last follow-up; the mean follow-up period was 54 months (range, 26-100 months). Two patients sustained stress fractures of the FVFG, but the lateral locking plate protected the fractured graft until in situ bone healing obtained. Mean time to bone union of both host-graft junctions was 24 months (range, 18-31 months). The mean Musculoskeletal Tumor Society score (%) was 85.8% (range, 80-95%).A 1-barrel FVFG protected by a lateral locking plate maintained a stable graft-host bone construct, successfully leading to bone healing, even in cases of stress fractures of the graft, and appears to be a good option for large femur bone defects.