Do Children With Osteosarcoma Benefit From Pulmonary Metastasectomy?: A Systematic Review of Published Studies and "Real World" Outcomes.

OBJECTIVE: To critically examine the evidence-base for survival benefit of pulmonary metastasectomy (PM) for osteosarcoma (OS) in the pediatric population. BACKGROUND: PM for OS is recommended as the standard of care in both pediatric and adult treatment protocols. Recent results from the "Pulmonary Metastasectomy in Colorectal Cancer" trial demonstrate no survival benefit from PM in colorectal cancer in adults. METHODS: A systematic review was undertaken according to "Preferred Reporting Items for Systematic Reviews and Meta-Analysis" guidelines. Medline, Embase, and 2 clinical trial registers were searched for all studies detailing pediatric patients with OS (<18 years) undergoing PM with a comparison cohort group that did not receive PM. RESULTS: Eleven studies met inclusion criteria dating from 1984 to 2017. All studies were retrospective and none directly compared PM versus no PM in pediatric patients as its main objective(s). Three-year survival rates ranged from 0% to 54% for PM and 0% to 16% for no PM. No patients receiving PM were usually those with unresectable disease and/or considered to have a poor prognosis. All studies were at high risk of bias and there was marked heterogeneity in the patient selection. CONCLUSIONS: There is a weak evidence base (level IV) for a survival benefit of PM for OS in pediatric patients likely due to selection bias of "favorable cases." The included studies many of which detailed outdated treatment protocols were not designed in their reporting to specifically address the questions directly. A randomized controlled trial-while ethically challenging in a pediatric population-incorporating modern OS chemotherapy protocols is needed to crucially address any "survival benefit."

ctDNA quantification improves estimation of outcomes in patients with high-grade osteosarcoma: a translational study from the OS2006 trial.

BACKGROUND: Osteosarcoma stratification relies on clinical parameters and histological response. We developed a new personalized stratification using less invasive circulating tumor DNA (ctDNA) quantification. PATIENTS AND METHODS: Plasma from patients homogeneously treated in the prospective protocol OS2006, at diagnosis, before surgery and end of treatment, were sequenced using low-passage whole-genome sequencing (lpWGS) for copy number alteration detection. We developed a prediction tool including ctDNA quantification and known clinical parameters to estimate patients' individual risk of event. RESULTS: ctDNA quantification at diagnosis (diagCPA) was evaluated for 183 patients of the protocol OS2006. diagCPA as a continuous variable was a major prognostic factor, independent of other clinical parameters, including metastatic status [diagCPA hazard ratio (HR) = 3.5, P = 0.002 and 3.51, P = 0.012, for progression-free survival (PFS) and overall survival (OS)]. At the time of surgery and until the end of treatment, diagCPA was also a major prognostic factor independent of histological response (diagCPA HR = 9.2, P < 0.001 and 11.6, P < 0.001, for PFS and OS). Therefore, the addition of diagCPA to metastatic status at diagnosis or poor histological response after surgery improved the prognostic stratification of patients with osteosarcoma. We developed the prediction tool PRONOS to generate individual risk estimations, showing great performance ctDNA quantification at the time of surgery and the end of treatment still required improvement to overcome the low sensitivity of lpWGS and to enable the follow-up of disease progression. CONCLUSIONS: The addition of ctDNA quantification to known risk factors improves the estimation of prognosis calculated by our prediction tool PRONOS. To confirm its value, an external validation in the Sarcoma 13 trial is underway.

Recycled bone grafts treated with extracorporeal irradiation or liquid nitrogen freezing after malignant tumor resection.

INTRODUCTION: Recycled bone autografts prepared using extracorporeal irradiation (ECIR) or liquid nitrogen freezing (LNF) methods have been used for the reconstruction of skeletal elements after wide resection of sarcomas involving bone tissues. Few reports include long-term follow-up data for histological analyses of recycled autografts, particularly in the case of ECIR autografts. MATERIALS: A total of 34 malignant bone and soft tissue tumors were resected and reconstructed using 11 ECIR- and 23 LNF-recycled autografts; the mean postoperative follow-ups were 14 and 8 years, respectively. ECIR was used for either osteosarcomas or Ewing sarcomas, whereas in addition to these tumors LNF was used for chondrosarcomas and soft tissue sarcomas involving bone tissues. Recycled bone was implanted as total bone, osteoarticular, or intercalary grafts, with or without prosthesis or vascularized fibular grafts. RESULTS: The 10-year graft survival rate was similar between groups, 81.8% using ECIR and 70.2% using LNF. There were no autograft-related tumor recurrences in either group. Graft survival was unrelated to type of graft or additional procedures. Complication rates tended to be higher using ECIR (64%) compared with LNF (52%) and the infection rate was significantly higher with ECIR (27%) versus LNF (0%). At the final assessment, plain radiographs revealed original recycled bone was present in 7 of 11 ECIR cases and in zero cases treated with LNF autografts, indicating that recycled bone treated with LNF autografts was remodeled into new bone. Histological examination of ECIR-treated bones revealed a delayed and incomplete endochondral ossification process, necrosis and empty lacunae. Conversely, LNF autografts showed remodeled bones with normal trabecular structures. CONCLUSIONS: ECIR and LNF treatment of autografts provided adequate tumor control with acceptable clinical results as a reconstruction method.

Predictors of pulmonary metastases on chest computed tomography in children and adolescents with osteosarcoma-tips for qualifying patients for thoracotomy.

BACKGROUND: Osteosarcoma is the most common primary malignant bone tumour in children and adolescents. Lungs are the most frequent and often the only site of metastatic disease. The presence of pulmonary metastases is a significant unfavourable prognostic factor. Thoracotomy is strongly recommended in these patients, while computed tomography (CT) remains the gold imaging standard. The purpose of our study was to create tools for the CT-based qualification for thoracotomy in osteosarcoma patients in order to reduce the rate of useless thoracotomies. METHODS: Sixty-four osteosarcoma paediatric patients suspected of lung metastases on CT and their first-time thoracotomies (n = 100) were included in this retrospective analysis. All CT scans were analysed using a compartmental evaluation method based on the number and size of nodules. Calcification and location of lung lesions were also analysed. Inter-observer reliability between two experienced radiologists was assessed. The CT findings were then correlated with the histopathological results of thoracotomies. Various multivariate predictive models (logistic regression, classification tree and random forest) were built and predictors of lung metastases were identified. RESULTS: All applied models proved that calcified nodules on the preoperative CT scan best predict the presence of pulmonary metastases. The rating of the operated lung on the preoperative CT scan, dependent on the number and size of nodules, and the total number of nodules on this scan were also found to be important predictors. All three models achieved a relatively high sensitivity (72-92%), positive predictive value (81-90%) and accuracy (74-79%). The positive predictive value of each model was higher than of the qualification for thoracotomy performed at the time of treatment. Inter-observer reliability was at least substantial for qualitative variables and excellent for quantitative variables. CONCLUSIONS: The multivariate models built and tested in our study may be useful in the qualification of osteosarcoma patients for metastasectomy through thoracotomy and may contribute to reducing the rate of unnecessary invasive procedures in the future.

Endoprosthetic replacement with preservation of the epiphysis for proximal tibial reconstruction after osteosarcoma resection in children: a case report.

BACKGROUND: Limb salvage surgery is an important method for treating malignant tumors of the bone involving the adjacent parts of the major joints in children. This technique allows for preservation of limb function, especially in the lower limb. However, the reconstruction of the proximal end of the tibia after removing the tumor mass with a rational scale to preserve the total knee joint and reduce limb length discrepancy presents a challenge. CASE PRESENTATION: We present a case of osteosarcoma of the proximal tibia. After being treated with an extended tumor resection, the proximal tibia of the child was restructured using endoprosthetic replacement with epiphyseal preservation. This procedure preserves the entire articular surface and growth plate of the knee joint of the affected limb and provides a feasible alternative protocol for retaining the function and growth potential of the affected limb. The patient remained disease-free and normal limb motor function was observed during the 3.5 year follow-up since the initial surgery. CONCLUSIONS: Preservation of the epiphysis enabled our patient to perform better limb function after limb-saving surgery as a result of his undamaged knee joint and minimized limb-length discrepancy. We believe that endoprosthetic replacement with preservation of the epiphysis can provide the best strategy for reconstruction after resection of focal malignant tumors in long bones without epiphytic involvement.

Controversies in Oncologic Pediatric Limb Salvage.

With advances in chemotherapy and radiation therapy, surgical treatment of patients with bone sarcomas has advanced from most patients undergoing an amputation to now most patients undergoing a limb salvage procedure. With the advances of limb salvage surgical techniques, reconstructive procedures have expanded to include autografts, allografts, endoprosthetic replacements, and rotationplasty. In a growing child, the decision to perform each of these reconstructive options is individualized and each needs to be considered to provide the patient with the optimal oncologic and functional outcome, while being durable to minimize the risk of complications and subsequent surgeries.

Incidence and management of secondary deformities after megaendoprosthetic proximal femur replacement in skeletally immature bone sarcoma patients.

INTRODUCTION: Megaendoprosthetic reconstruction of bone defects in skeletally immature patients has led to the development of unique complications and secondary deformities not observed in adult patient cohorts. With an increasing number of megaendoprosthetic replacements performed, orthopedic oncologists still gain experience in the incidence and type of secondary deformities caused. In this study, we report the incidence, probable cause and management outcome of two secondary deformities after megaendoprosthetic reconstruction of the proximal femur: hip dysplasia and genu valgum. MATERIALS AND METHODS: Retrospective analysis of 14 patients who underwent primary and/or repeat reconstruction/surgery with a megaendoprosthetic proximal femur replacement between 2018 and 2022. RESULTS: Mean patient age was 9.1 years (range 4-17 years). Stress shielding was observed in 71.4%. Hip dislocation was the most frequent complication (50%). While four dislocations occurred without an underlying deformity, secondary hip dysplasia was identified in 58.3% (n = 7/12) of intraarticular resections and reconstructions, leading to dislocation in 71.4% (n = 5/7). A genu valgum deformity was observed in 41.6% (n = 5/12). The incidence of secondary hip dysplasia and concomitant genu valgum was 42.9% (n = 3/7). Triple pelvic osteotomy led to rebound hip dysplasia in two cases (patients aged < 10 years), whereas acetabular socket replacement led to stable hip joints over the course of follow-up. Temporary hemiepiphyseodesis was applied to address secondary genu valgum. CONCLUSIONS: Patients aged < 10 years were prone to develop secondary hip dysplasia and genu valgum following proximal femur replacement in this study. Management of secondary deformities should depend on remaining skeletal growth. Stress shielding was observed in almost all skeletally immature patients.

Successful surgical resection of a multilobular osteochondrosarcoma arising from the costal cartilage in a cat.

A 10-year-old neutered male cross-bred cat was referred to our clinic for a solid mass tightly fixed to the right side of the thoracic wall from the 2nd to 4th ribs. Computed tomography revealed the mass had remarkable calcifications and arose from the 3rd costal cartilage. After removal, it was diagnosed histopathologically as a multilobular osteochondrosarcoma (MLO). For tumor resection, extremely wide surgical margins included 6 costal cartilages and 3 sternal segments were required; however, the tumor was successfully resected, followed by reconstruction of the thoracic wall using artificial materials. The cat recovered uneventfully and was good in health for ~4 y. This is apparently the first report of surgical resection of MLO from the costal cartilage of a cat. Key clinical message: To our knowledge, this is the first report of MLO from the costal cartilage in a cat, demonstrating aggressive surgical resection despite extremely wide surgical margins.

Résection chirurgicale réussie d'un ostéochondrosarcome multilobulaire provenant du cartilage costal chez un chatUn chat croisé mâle castré de 10 ans a été référé à notre clinique pour une masse solide bien fixée sur le côté droit de la paroi thoracique de la 2e à la 4e côte. La tomodensitométrie a révélé que la masse présentait des calcifications remarquables et provenait du 3e cartilage costal. Après retrait, il a été diagnostiqué histopathologiquement comme un ostéochondrosarcome multilobulaire (MLO). Pour la résection tumorale, des marges chirurgicales extrêmement larges comprenaient 6 cartilages costaux et 3 segments sternaux; cependant, la tumeur a été réséquée avec succès, suivie d'une reconstruction de la paroi thoracique à l'aide de matériaux artificiels. Le chat s'est rétabli sans incident et était en bonne santé pendant environ 4 ans. Il s'agit apparemment du premier rapport de résection chirurgicale de MLO du cartilage costal d'un chat.Message clinique clé:À notre connaissance, il s'agit du premier rapport de MLO du cartilage costal chez un chat, démontrant une résection chirurgicale agressive malgré des marges chirurgicales extrêmement larges.(Traduit par Dr Serge Messier).

Use of a haired angularis oris axial pattern flap in a dog to correct a large oronasal fistula secondary to resection of a hard palate multilobular osteochondrosarcoma.

A 6-year-old neutered male mixed-breed dog underwent curative-intent surgical resection of a hard palatal multilobular osteochondrosarcoma and closure of the defect using bilateral buccal mucosal flaps. However, failure of the flaps resulted in a massive hard palatal defect that was subsequently repaired using a haired skin angularis oris axial pattern flap. This report describes the clinical outcome using this surgical approach and novel complications encountered. Key clinical message: The haired skin angularis oris axial pattern flap appears to be a suitable and robust option for reconstruction of large palatal defects.

Utilisation d'un lambeau cutanée poilus avec rotation axiale au niveau de l'artère angularis oris chez un chien pour corriger une fistule oronasale volumineuse secondaire à la résection d'un ostéochondrosarcome multilobulaire du palais dur. Un chien croisé mâle castré de 6 ans a subi une résection chirurgicale à visée curative d'un ostéochondrosarcome multilobulaire du palais dur et une fermeture de l'anomalie par des lambeaux de la muqueuse buccale. Cependant, la défaillance des lambeaux a entraîné un défaut important du palais dur qui a ensuite été réparé à l'aide d'un lambeau de peau avec poils avec rotation axiale au niveau de l'artère angularis oris. Ce rapport décrit les résultats cliniques de cette approche chirurgicale et les nouvelles complications rencontrées.Message clinique clé :L'utilisation d'un lambeau de peau avec poils avec rotation axiale au niveau de l'artère angularis oris semble être une option appropriée et robuste pour la reconstruction des défauts importants du palais.(Traduit par Dr Serge Messier).

Cross-Cultural Adaptation and Validation of the Romanian Musculoskeletal Tumor Society Scoring System for Patients with Extremity Bone Sarcomas.

Background and Objectives: Primary malignant bone tumors are rare lesions, and their complex treatment can lead to functional impairment. It is important to have a postoperative assessment tool for patients' functional outcomes to be evaluated and to consequently adapt future treatments in the pursuit of a continuous improvement of their quality of life. The Musculoskeletal Tumor Society Score (MSTS) is a validated specific system score that is used frequently in the follow-up of these patients. We found no information about a valid translated Romanian version of this score neither for the upper limb nor for the lower limb. We proposed in this study to translate the original version of the MSTS Score into Romanian and to perform validation analysis of the Romanian-language MSTS Score. Materials and Methods: We selected 48 patients who underwent limb-salvage surgery after resection of bone sarcomas. Patients were interrogated twice according to the translated Romanian version of the MSTS Score during their follow-up. The translation was performed according to the recommended guidelines. A total number of 96 questionnaires were valid for statistical analysis. Results: Internal consistency and reliability were good for both sets of questionnaires' analytic measurements, with Cronbach's alpha values of 0.848 (test) and 0.802 (retest). The test-retest evaluation proved to be statistically strong for reproducibility and validity with Spearman's rho = 0.9 (p < 0.01, 95% CI). Conclusions: This study permitted the translation of this score and the validation of psychometric data. Our results showed that the Romanian version of the MSTS is a reliable means of assessment of the functional outcome of patients who received limb-salvage surgery for the upper and lower extremities.

[Osteosarcoma Secondary to Polyostotoic Fibrous Dysplasia of the Ribs].

Sarcomatous transformation of fibrous dysplasia is extremely rare. We present the case of a 54-yearold man with multiple rib masses, multiple enlarged lymph nodes throughout the body, and multiple osteolytic lesions on computed tomography( CT). A positron emission tomography( PET) scan showed abnormal enhancement in each. A needle biopsy of the right supraclavicular fossa lymph node revealed sarcoidosis. Considering the possibility of malignancy associated with sarcoidosis, a rib tumor resection and mediastinal lymph node biopsy were performed to confirm the diagnosis of the rib lesion. The pathology results showed that the rib mass was a low-grade central osteosarcoma and the mediastinal lymph node was sarcoidosis. The distribution of the lesions was consistent with osteosarcoma secondary to multiple fibrous bone dysplasia. As the osteosarcoma was low grade, the patient was followed up. Three years after surgery, there was no increase in residual disease.

Clinical application of LARS tumor tube in joint function reconstruction of tumor type artificial hip replacement. / LARSè‚¿ç˜¤ç®¡åœ¨è‚¿ç˜¤åž‹äººå·¥é«‹å ³èŠ‚ç½®æ¢æœ¯å ³èŠ‚åŠŸèƒ½é‡å»ºä¸­çš„ä¸´åºŠåº”ç”¨.

OBJECTIVES: Proximal femur tumor resection often leads to hip joint instability and functional loss. Various methods have been clinically applied to repair hip joint soft tissue function, but deficiencies remain. This study aims to evaluate the advantages and disadvantages of the ligament advanced reinforcement system (LARS) tumor tube in assisting soft tissue function reconstruction in patients undergoing tumor type artificial hip replacement surgery. METHODS: This study included 85 patients (41 males, 44 females) with proximal femoral tumors treated at the Xiangya Bone Tumor Treatment Center from January 2012 to January 2022, aged 10 to 79 (38.5±18.2) years. Among them, 13 cases had benign aggressive tumors, 45 had primary malignant bone tumors, and 27 had bone metastases. Clinical data, imaging data, and intraoperative photos were collected. Patients were followed up and postoperative functional evaluations were conducted using the Musculoskeletal Tumor Society (MSTS) scoring system and Harris hip joint scoring system to assess limb function and hip joint function. RESULTS: Preoperative pathological fractures were present in 37 cases (43.5%), with a lesion length of (9.4±2.9) cm. Among non-metastatic tumor patients, 7 experienced postoperative recurrence, including 6 cases of osteosarcoma and 1 case of fibrosarcoma. Pulmonary metastases occurred in 9 osteosarcoma patients. Five patients required reoperation due to postoperative complications, including 3 cases of deep vein thrombosis, 1 case of giant cell granuloma, and 1 case of prosthesis infection. Postoperatively, 5 patients exhibited Trendelenburg gait, and 6 had leg length discrepancies. The postoperative MSTS score was 26.7±1.4, and the Harris score was 89.6±5.3. CONCLUSIONS: The LARS tumor tube can effectively assist in reconstructing the soft tissue function of the hip joint and greatly reduce postoperative complications, making it an effective technical improvement in joint function reconstruction in tumor type artificial hip replacement surgery.

Functional and oncological outcomes of patients with proximal humerus osteosarcoma managed by limb salvage.

BACKGROUND: Osteosarcoma is the most common primary bone malignancy in skeletally immature patients. The proximal humerus is the third most common site of osteosarcoma. The literature shows a paucity of published data concerning the outcome of proximal humerus osteosarcoma managed by limb salvage. The purpose of this study was to answer the following questions: (1) do patients with proximal humerus osteosarcoma managed by limb salvage and neoadjuvant chemotherapy show good functional and oncological outcomes, and (2) are there any prognostic factors that are associated with better oncological and functional outcomes? MATERIALS AND METHODS: The study was a retrospective case series study assessing the overall outcome of 34 patients with proximal humerus osteosarcoma. Eighteen patients were males (53%) while 16 were females. Biological reconstruction was done in 15 patients (44%), while nonbiological reconstruction was done in 19 patients. Resections were mainly intraarticular (82%). Functional outcome was assessed using the Musculoskeletal Tumor Society (MSTS) score, while oncological outcome was assessed based on local recurrence and development of chest metastasis. Comparisons between quantitative variables were done using the nonparametric Mann-Whitney test. To compare categorical data, the chi-square (χ2) test was performed. The exact test was used instead when the expected frequency was less than 5. Correlations between quantitative variables were examined using the Spearman correlation coefficient. RESULTS: The mean MSTS score was 25.5 (range 23-29). A younger age was statistically correlated with a poorer MSTS score (P = 0.0016). Six patients out of 34 (17.6%) had local recurrence and four of them (67%) were treated by forequarter amputation. 41% of patients developed chest metastasis, and the majority of them were treated by chemotherapy (71%). In comparison with patients with osteosarcoma at other sites who were also managed in our institution, proximal humerus osteosarcoma patients showed higher incidence rates of local recurrence and chest metastasis along with lower 5-year patient and limb survivorships compared to distal femur, proximal tibia and proximal femur osteosarcoma patients. CONCLUSION: Treatment of osteosarcoma of the proximal humerus by limb salvage and chemotherapy yields a good functional outcome. The method of reconstruction does not impact the resultant function. The 5-year survivorship of these patients is 65%. Younger patients have a better oncological outcome and an inferior functional outcome. LEVEL OF EVIDENCE: Level IV therapeutic study.

Functional and Oncological Outcome of Patients with Distal Femoral Osteosarcoma Managed by Limb Salvage Using Modular Endoprosthesis.

BACKGROUND: The aim of the study was to assess the functional and oncological outcomes of patients with distal femoral osteosarcoma managed by limb salvage using modular endoprosthesis as well as to assess related complications. PATIENTS AND METHODS: A total of 82 patients were included in our study. Functional outcome was assessed using MSTS score and knee range of motion. Oncological outcome was assessed regarding local recurrence, chest metastasis, and patient survivorship. Complications were classified according to Henderson et al. RESULTS: The mean MSTS score was 26.21 (87.4%) (range 8-30 points) with 70.7% of patients having more than 90° of flexion. The incidence of local recurrence was 3.7% (3 patients), while the incidence of chest metastasis was 14.6% (12 patients). Aseptic loosening (type 2 failure) was the commonest complication (19.5%), followed by infection (15.9%). The 5- and 10-year survivorships of the limb were 98.8%, while the 5- and 10-year survivorships of the prosthesis were 67.7% and 52.4%, respectively. CONCLUSION: This study showed that patients with osteosarcoma distal femur who are treated by chemotherapy and limb salvage have an excellent long-term prognosis in terms of patient as well as limb survivorship. The use of modular endoprosthesis in these patients offer an acceptable function, with two-thirds of the patients retaining their prosthesis after 5 years and more than half retaining them after 10 years.

Functional Outcome Following Proximal Tibial Osteosarcoma Resection and Reconstruction by Modular Endoprosthesis.

PURPOSE: The proximal tibia is a common location for osteosarcoma. Modular endoprosthesis is a popular reconstructive option, yet it has been associated with many complications. Our study aimed to evaluate the functional outcome and complications of proximal tibial osteosarcoma patients treated by limb salvage using modular endoprosthesis. METHODS: A retrospective study of a prospective database was performed during the period between January 2000 and July 2017. Fifty-five patients with proximal tibial osteosarcoma underwent resection and modular endoprosthetic reconstruction. The functional outcome was evaluated using the Musculoskeletal tumor society scoring system and knee range of motion. Postoperative complications were classified according to Henderson classification; Type 1 (soft tissue failure), Type 2 (aseptic loosening), Type 3 (structural failure), Type 4 (infection) and Type 5 (local tumor progression). RESULTS: The mean follow-up period was 71.69 ± 49.76 months. The mean musculoskeletal tumor society score was 26.5 ± 2.22; the mean range of motion was 72.63 ± 25.07, and the mean extension lag was 15.09 ± 15.38. Type 1, type 2, type 3, type 4, and type 5 complications occurred in 7.3%, 14.5%, 21.8%, 23.6%, and 5.5%, respectively. Chest metastasis developed in 10 patients (18.2%). The estimated 5-year and 10-year survival rates for the treated patients were 83.6% and 79.9%. CONCLUSIONS: Proximal tibial osteosarcoma reconstruction with a modular endoprosthesis is a reliable treatment option for retaining limb function. Most complications are manageable.

Joint-preservation surgery for bone sarcoma in adolescents and young adults.

Bone sarcoma often occurs in childhood, as well as in adolescents and young adults (AYAs). AYAs differ from pediatric patients in that their bone is skeletally mature and the physis has almost disappeared with the completion of growth. Although AYAs spend less time outside, they often participate in sports activities, as well as driving, working, and raising a family, which are natural activities in daily living. Multidisciplinary approaches involving imaging, multi-agent chemotherapy, surgical procedures, and careful postoperative care has facilitated an increase in limb-sparing surgery for bone sarcoma. In addition, recent advances in imaging modalities and surgical techniques enables joint-preservation surgery, preserving the adjacent epiphysis, for selected patients following the careful assessment of the tumor margins and precise tumor excision. An advantage of this type of surgery is that it retains the native function of the adjacent joint, which differs from joint-prosthesis replacement, and provides excellent limb function. Various reconstruction procedures are available for joint-preserving surgery, including allograft, vascularized fibula graft, distraction osteogenesis, and tumor-devitalized autografts. However, procedure-related complications may occur, including non-union, infection, fracture, and implant failure, and surgeons should fully understand the advantages and disadvantages of these procedures. The longevity of the normal limb function for natural activities and the curative treatment without debilitation from late toxicities should be considered as a treatment goal for AYA patients. This review discusses the concept of joint-preservation surgery, types of reconstruction procedures associated with joint-preservation surgery, and current treatment outcomes.

Does primary tumor resection improve survival for patients with sarcomas of pelvic bones, sacrum, and coccyx who have metastasis at diagnosis ?

BACKGROUND: Recent studies demonstrated that primary tumor resection (PTR) improves survival of patients with metastatic bone sarcomas. However, it remains quite unclear regarding the role of PTR in the treatment of sarcomas of pelvic bones with synchronous metastasis at diagnosis. METHODS: Using the Surveillance, Epidemiology, and End Results Program, we enrolled a total of 385 patients with sarcomas of pelvic bones, sacrum, and coccyx who have metastasis at initial diagnosis, including 139 patients with osteosarcoma, 176 with Ewing sarcoma, and 70 with chondrosarcoma. Association between PTR and disease-specific survival (DSS) were investigated using the univariable and multivariable Cox regression models. Hazard ratio (HR) and 95% confidence interval (CI) were reported. Representative institutional PTR strategies and clinical outcomes for patients with metastatic pelvic sarcomas from our cancer center were displayed. RESULTS: The usage rate of PTR was 28.1% (39/139) in osteosarcoma, 13.6% (24/176) in Ewing sarcoma, and 41.4% (29/70) in chondrosarcoma with synchronous metastatic lesions. PTR was not associated with an improved DSS for metastatic pelvic osteosarcoma (HR = 0.686, 95% CI = 0.430 ~ 1.094, P = 0.113) and Ewing sarcoma (HR = 0.580, 95% CI = 0.291 ~ 1.154, P = 0.121). The use of PTR was associated with an improved DSS for metastatic pelvic chondrosarcoma (HR = 0.464, 95% CI = 0.225 ~ 0.954, P = 0.037). CONCLUSION: Primary lesion resection may provide a survival benefit for metastatic chondrosarcoma, but not for osteosarcoma and Ewing sarcoma of pelvic bones, sacrum, and coccyx. This population-based study recommends an active surgical intervention for metastatic chondrosarcoma while non-surgical treatment for metastatic osteosarcoma and Ewing sarcoma of the pelvis in terms of survival improvement.

What Is the Long-term Survivorship of Primary and Revision Cemented Distal Femoral Replacements for Limb Salvage of Patients With Sarcoma?

BACKGROUND: Cemented endoprosthetic reconstruction after resection of primary bone sarcomas has been in common use for decades. Although multiple studies have reported the survivorship of primary endoprostheses, implant survivorship after revision surgery is less well established. Given that earlier advances in systemic therapy improved survival of patients with sarcoma, the usage of revision endoprostheses can be expected to increase and, as such, understanding revision implant survivorship will help to inform patient and surgeon expectations. Additionally, as new implants are developed that allow alternative reconstruction options, a normative dataset establishing accurate expectations for revision cemented endoprostheses is a critical benchmark by which to measure progress. QUESTIONS/PURPOSES: (1) What is the implant survivorship free of all-cause revision for primary and revision cemented distal femoral replacements (DFRs) used in the treatment of malignant or benign tumors? (2) What are the most common indications for revision of primary and revision DFRs in an oncology population with mean follow-up of more than 10 years? (3) How does the indication for revision of a primary DFR affect the subsequent risk for and type of revision DFR complication? (4) What patient, tumor, or implant characteristics are associated with improved survivorship free of revision in cemented DFRs used in patients treated initially for primary malignant or benign tumors? METHODS: This was a retrospective, comparative study using our institution's longitudinally-maintained database of 806 cemented endoprostheses starting in 1980 and assessed through December 31, 2018. In all, 365 DFRs were inserted during this time, but 14% (51 of 365) were placed for nonprimary bone tumors and 1% (5 of 365) were cementless reconstructions, leaving 309 cemented DFRs. Seventy-one percent (218 of 309) were primary implants and 29 percent (91 of 309) were revision implants (used to revise a prior DFR in all patients). During this time period, our strong bias was to use cemented stems and, thus, nearly all of our patients had cemented stems. Six percent (13 of 218) of primary DFRs were implanted more than 2 years before the study end; however, they lacked 2 years of follow-up data and, thus, were considered lost to follow-up, leaving 205 implants in the primary DFR analysis group. Only the first revision after primary DFR revision surgery was included in the revision cohort analysis. Thirty-two percent (29 of 91) of revision DFRs were second or more revision patients and were excluded, leaving 62 implants in the revision analysis group. Most patients in both groups were men (57% [117 of 205] for primary and 71% [44 of 62] for revision) who had been diagnosed with osteosarcoma (75% [153 of 205] and 73% [45 of 62] for primary and revision, respectively). The primary cohort had mean age of 26 ± 16 years with a mean follow-up of 136 ± 122 months, and the revision cohort had mean age of 31 ± 13 years (p = 0.02) with 141 ± 101 months of follow-up. Study endpoints included all-cause implant revision and cause-specific revision for soft tissue complications, aseptic loosening, structural complications (defined as periprosthetic or implant fracture), infection, or tumor progression. Planned surgery for implant lengthening procedures was excluded. Implant survivorship free from all-cause revision was calculated using a competing risk (cumulative incidence) estimator with death as a competing risk. A log-rank test using chi-square analysis was used to evaluate the differences in implant survivorship between primary DFRs and first revisions. The cause-specific incidences of implant revision were tabulated for primary and revision DFRs. Cox regression analysis investigated the odds of subsequent all-cause revision surgery for revision cemented DFRs based on the primary implant complication. A binary logistic regression analysis using age, gender, indication for revision, tumor type, infection, perioperative chemotherapy, and radiation was performed to identify factors associated with a second DFR reoperation. Relative effect sizes are reported as ORs. RESULTS: The revision DFR cohort had a shorter mean survival to all-cause revision than the primary cohort (mean 10 years [95% CI 7 to 12] versus 18 years [95% CI 15 to 20]; p < 0.001). The most common complications necessitating revision for revision implants were periprosthetic or implant fracture in 37% (23 of 62) and aseptic loosening in 15% (9 of 62), and the type of primary implant complication was not associated with risk of subsequent all-cause revision surgery for revision implants. Stem diameter less than 15 mm was associated with repeat all-cause revision in cemented revision DFRs after controlling for resection length, stem length, implant fabrication (custom or modular), and presence of a porous collar (OR 4 [95% CI 1 to 17]; p = 0.03). No other parameters that we explored, including patient age, gender, chemoradiation history, or primary tumor diagnosis, were associated with repeat revision surgery. CONCLUSION: Understanding modifiable factors that can improve revision DFR survival is critical to achieving long-term limb salvage for patients with tumors around the knee. Our data suggest that utilizing implants with the largest possible stems-or at a minimum increasing the stem size over the primary implant-is important to revision cemented DFR survivorship and is an important part of our revision practice. Improving revision implants' resistance to aseptic loosening through designs that resist torsion (a common mode of cemented fixation failure)-such as with the use of custom cross-pin fabrication-may be one method to improve survivorship. Another will be improved implant metallurgy that is resistant to fatigue fracture. Next steps may include understanding the optimal ratio of femoral diaphyseal width to implant diameter in patients where anatomic constraints preclude the insertion of cemented stems 15 mm or more in diameter. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Is Dissection and Preservation of Adherent Popliteal Vessels From a Posterior Soft Tissue Mass Associated With a Higher Proportion of Local Recurrence in Patients With a Distal Femoral Osteosarcoma?

BACKGROUND: In patients who have osteosarcoma of the distal femur, there is concern that when dissecting the popliteal vessels from the posterior soft tissue extent of the tumor, a less-than-wide margin of resection may be achieved depending on the extent of the posterior soft tissue mass. Surgeons have little information to guide them when deciding whether dissecting the popliteal vessels in a patient in whom the vessels are in direct contact with a posterior mass will result in an increased likelihood of local recurrence compared with patients in whom the popliteal vessels are not in contact with the tumor mass. QUESTIONS/PURPOSES: (1) Is dissecting the adherent popliteal artery and vein away from the posterior soft tissue extent of a distal femoral osteosarcoma by stripping them from their adventitia associated with an increased risk of local recurrence compared with patients in whom there is normal tissue between the tumor and vessels? (2) Is there an association with the type of tumor resection and the development of chest metastases and overall survivorship in this anatomic location? METHODS: We retrospectively studied our patient database. From August 1, 1994, until December 31, 2019, all patients with conventional distal femoral osteosarcomas treated with chemotherapy and surgery were identified. A minimum of 2 years of follow-up was required for patients who were alive. A total of 545 patients matched these criteria. We excluded 7% (37 patients) who did not have a posterior soft tissue mass, 9% (51 patients) who has metastases, 0.7% (four patients) who had osteosarcomas in multiple sites, 1% (five patients) who died of chemotherapy complications, and 6% (30 patients) who were lost to follow-up. A total of 418 patients (211 men and 207 women) were eligible for this study. The mean age of the patients was 17 ± 6.6 years. All patients underwent routine staging (plain radiographs, MRI, chest CT, and bone scan) and received preoperative chemotherapy. The patients were divided into two groups according to the relationship between the popliteal vessels and the posterior extent of the extraosseous tumor. Axial MRI slices (T1, T1 with contrast, T2, and short tau inversion recovery) were analyzed separately by the two senior authors. Disputes were settled by a senior musculoskeletal radiologist and confirmed by the patient's operative report. In Group 1, which included 229 patients, there was a clear plane between the popliteal vessels and tumor. All patients underwent limb salvage. In Group 2, which had 189 patients, the popliteal vessels adhered to the tumor. This group was further subdivided into Groups 2a (patients in whom the vessels were dissected and limb salvage was performed; dissection of the popliteal vessels from the tumor entailed stripping the vessels from its adventitia in some areas) and 2b (patients in whom no attempt was made to dissect the vessels, and amputation or rotationplasty was performed). When rotationplasty was performed, the vessels were resected and reanastomosed. The decision to perform limb salvage in Group 1 was not debatable; however, in patients in Group 2, who had adherent vessels, the decision was made by the tumor board. Tumors with complete encasement of the vessels or nerves, nonunited pathologic fractures, and fungating of the tumor through the skin were treated by amputation or rotationplasty. Patients with tumors with adherent vessels that were not encased were offered limb salvage. This was often a shared decision with the patient. We performed a pathologic evaluation of the resected specimens to evaluate margins and tumor necrosis in all specimens. RESULTS: Local recurrence-free survivorship was worse in patients with adherent tumors who underwent dissection of the vessels by stripping them from their adventitia (Group 2a; 68% at 5 years [95% CI 57% to 78%]) than in those without adherent tumors (Group 1: 96% [95% CI 93% to 99%]) and patients with adherent tumors who had amputation or rotationplasty (Group 2b: 99% [95% CI 96 to 100]; p < 0.01). Chest metastases developed in 142 patients. The proportion of chest metastases was higher in Group 2a (59% [60 of 101]) than in Group 1 (24% [55 of 229]) and Group 2b (31% [27 of 88]; p < 0.01). Five-year overall survivorship was worse in patients with adherent tumors who underwent dissection of the vessels by stripping them from their adventitia (Group 2a: 51% at 5 years [95% CI 40% to 63%]) than in those without adherent tumors (Group 1: 78% [95% CI 72% to 84%]) and patients with adherent tumors who had amputation or rotationplasty (Group 2b: 71% [95% CI 60% to 82%]; p < 0.01). CONCLUSION: In light of these findings, when performing limb salvage for distal femoral osteosarcoma with adherent vessels, leaving an adventitial margin is associated with an increase in the incidence of local recurrence and poorer overall survivorship. Surgeons should refrain from dissecting these adherent vessels or at minimum discuss the expected outcomes with the patient. Future studies could target the outcome of vascular resection and bypass graft in the management of osteosarcoma. LEVEL OF EVIDENCE: Level III, therapeutic study.

Accuracy of bony resection under computer-assisted navigation for bone sarcomas around the knee.

BACKGROUND: Computer-assisted navigation has made bone sarcoma resections more precise. However, further clinical studies involving accuracy analyses under navigation are still warranted. METHODS: A retrospective study for analysis of computer-assisted navigation accuracy was carried out. Between September 2008 and November 2017, 39 cases of bone sarcomas around the knee joint were resected under computer-assisted navigation. The control group comprised 117 cases of bone sarcomas around the knee treated by limb salvage surgery wherein bony cutting was achieved freehand. The length difference (LD) was defined as the specimen length minus the planned resection length. The LDs were detected in both groups and compared. The margin accuracy (MA) was defined as the achieved margin minus the desired margin at the bone cutting site and was detected in the navigation group. RESULTS: The LDs between the postoperative specimen length and the preoperative planned length were compared. In the navigation group, the LD was 0.5 ± 2.5 mm (range, - 5 to 5 mm), while in the freehand group, the LD was 3.4 ± 9.6 mm (range, - 20 to 29 mm), with a significant difference (P < 0.01). In the absolute value analysis, the LD absolute value was 2.0 ± 1.6 mm in the navigation group and 8.3 ± 6.0 mm in the freehand group, with a significant difference (P < 0.01). In the navigation group, the MA was 0.3 ± 1.5 mm (range, - 3 to 3 mm) and the MA absolute value was 1.1 ± 1.0 mm. CONCLUSIONS: Better accuracy can be achieved when computer-assisted navigation is conducted for bone sarcoma resection around the knee. LEVEL OF EVIDENCE: IV.