Unusual soft tissue metastases in a patient with chondrosarcoma: a case report.

Chondrosarcoma (CS) is the second most frequent primary malignant bone tumour, characterized by production of non-osteoid cartilage matrix. Up to more than 30% of patients with CS present distant metastases, and the lungs represent the preferred site. Hence, CS soft tissue metastases and superficial cutaneous lesions are extremely rare. We report the case of a female who developed unusual multiple soft tissue CS metastases. This patient underwent left hindquarter amputation for recurrent grade 3 chondrosarcoma of the femoral neck with extension to the pelvis approximately 4 years after internal fixation with an intramedullary nail for pathological fracture of left proximal femur and subsequent total proximal femoral endoprosthetic replacement for grade 1-2 chondrosarcoma. In the following years, she underwent metastasectomy for several grade 2 pulmonary metastatic chondrosarcomas. More than 14 years after the amputation, she presented with multiple unusual superficial cutaneous lesions, and a whole-body magnetic resonance imaging demonstrated multiple soft tissue foci of metastatic disease. The histology of multiple soft tissue lesions excised confirmed metastatic chondrosarcoma. Then, she underwent marginal excision of further multifocal soft tissue metastatic high-grade chondrosarcoma. Unlike the poor survival from the onset of these metastases in the other cases reported in the literature, our patient is still alive 2 years after the first multiple soft tissue excision of metastatic chondrosarcoma, and approximately 20 years after the diagnosis of chondrosarcoma. Soft tissue CS metastases are a rare entity with few cases described in literature. This study aims to make the reader aware of this lesser-known CS manifestation.

Can the Cartilaginous Thickness Determine the Risk of Malignancy in Pelvic Cartilaginous Tumors, and How Accurate is the Preoperative Biopsy of These Tumors?

BACKGROUND: Peripheral osteochondral tumors are common, and the management of tumors presenting in the pelvis is challenging and a controversial topic. Some have suggested that cartilage cap thickness may indicate malignant potential, but this supposition is not well validated. QUESTIONS/PURPOSES: (1) How accurate is preoperative biopsy in determining whether a peripheral cartilage tumor of the pelvis is benign or malignant? (2) Is the thickness of the cartilage cap as determined by MRI associated with the likelihood that a given peripheral cartilage tumor is malignant? (3) What is local recurrence-free survival (LRFS), metastasis-free survival (MFS), and disease-specific survival (DSS) in peripheral chondrosarcoma of the pelvis and is it associated with surgical margin? METHODS: Between 2005 and 2022, 289 patients had diagnoses of peripheral cartilage tumors of the pelvis (either pedunculated or sessile) and were treated at one tertiary sarcoma center (the Royal Orthopaedic Hospital, Birmingham, UK). These patients were identified retrospectively from a longitudinally maintained institutional database. Those whose tumors were asymptomatic and discovered incidentally and had cartilage caps ≤ 1.5 cm were discharged (95 patients), leaving 194 patients with tumors that were either symptomatic or had cartilage caps > 1.5 cm. Tumors that were asymptomatic and had a cartilage cap > 1.5 cm were followed with MRIs for 2 years and discharged without biopsy if the tumors did not grow or change in appearance (15 patients). Patients with symptomatic tumors that had cartilage caps ≤ 1.5 cm underwent removal without biopsy (63 patients). A total of 82 patients (63 with caps ≤ 1.5 cm and 19 with caps > 1.5 cm, whose treatment deviated from the routine at the time) had their tumors removed without biopsy. This left 97 patients who underwent biopsy before removal of peripheral cartilage tumors of the pelvis, and this was the group we used to answer research question 1. The thickness of the cartilage cap was recorded from MRI and measuring to the nearest millimeter, with measurements taken perpendicular in the plane that best allowed the greatest measurement. Patient survival rates were assessed using the Kaplan-Meier method with 95% confidence intervals as median observation times to estimate MFS, LRFS, and DSS. RESULTS: Of malignant tumors biopsied, in 49% (40 of 82), the biopsy result was recorded as benign (or was considered uncertain regarding malignancy). A malignant diagnosis was correctly reported in biopsy reports in 51% (42 of 82) of patients, and if biopsy samples with uncertainty regarding malignancy were excluded, the biopsy identified a lesion as being malignant in 84% (42 of 50) of patients. The biopsy results correlated with the final histologic grade as recorded from the resected specimen in only 33% (27 of 82) of patients. Among these 82 patients, 15 biopsies underestimated the final histologic grade. The median cartilage cap thickness for all benign osteochondromas was 0.5 cm (range 0.1 to 4.0 cm), and the median cartilage cap thickness for malignant peripheral chondrosarcomas was 8.0 cm (range 3.0 to 19 cm, difference of medians 7.5 cm; p < 0.01). LRFS was 49% (95% CI 35% to 63%) at 3 years for patients with malignant peripheral tumors with < 1-mm margins, and LRFS was 97% (95% CI 92% to 100%) for patients with malignant peripheral tumors with ≥ 1-mm margins (p < 0.01). DSS was 100% at 3 years for Grade 1 chondrosarcomas, 94% (95% CI 86% to 100%) at 3 years for Grade 2 chondrosarcomas, 73% (95% CI 47% to 99%) at 3 and 5 years for Grade 3 chondrosarcomas, and 20% (95% CI 0% to 55%) at 3 and 5 years for dedifferentiated chondrosarcomas (p < 0.01). DSS was 87% (95% CI 78% to 96%) at 3 years for patients with malignant peripheral tumors with < 1-mm margin, and DSS was 100% at 3 years for patients with malignant peripheral tumors with ≥ 1-mm margins (p = 0.01). CONCLUSION: A thin cartilage cap (< 3 cm) is characteristic of benign osteochondroma. The likelihood of a cartilage tumor being malignant increases after the cartilage cap thickness exceeds 3 cm. In our experience, preoperative biopsy results were not reliably associated with the final histologic grade or malignancy, being accurate in only 33% of patients. We therefore recommend observation for 2 years for patients with pelvic osteochondromas in which the cap thickness is < 1.5 cm and there is no associated pain. For patients with tumors in which the cap thickness is 1.5 to 3 cm, we recommend either close observation for 2 years or resection, depending on the treating physician's decision. We recommend excision in patients whose pelvic osteochondromas show an increase in thickness or pain, preferably before the cartilage cap thickness is 3 cm. We propose that surgical resection of peripheral cartilage tumors in which the cartilage cap exceeds 3 cm (aiming for clear margins) is reasonable without preoperative biopsy; the role of preoperative biopsy is less helpful because radiologic measurement of the cartilage cap thickness appears to be accurately associated with malignancy. Biopsy might be helpful in patients in whom there is diagnostic uncertainty or when confirming the necessity of extensive surgical procedures. Future studies should evaluate other preoperative tumor qualities in differentiating malignant peripheral cartilage tumors from benign tumors. LEVEL OF EVIDENCE: Level III, diagnostic study.

Controversies in orthopaedic oncology.

Chondrosarcoma is the second most common surgically treated primary bone sarcoma. Despite a large number of scientific papers in the literature, there is still significant controversy about diagnostics, treatment of the primary tumour, subtypes, and complications. Therefore, consensus on its day-to-day treatment decisions is needed. In January 2024, the Birmingham Orthopaedic Oncology Meeting (BOOM) attempted to gain global consensus from 300 delegates from over 50 countries. The meeting focused on these critical areas and aimed to generate consensus statements based on evidence amalgamation and expert opinion from diverse geographical regions. In parallel, periprosthetic joint infection (PJI) in oncological reconstructions poses unique challenges due to factors such as adjuvant treatments, large exposures, and the complexity of surgery. The meeting debated two-stage revisions, antibiotic prophylaxis, managing acute PJI in patients undergoing chemotherapy, and defining the best strategies for wound management and allograft reconstruction. The objectives of the meeting extended beyond resolving immediate controversies. It sought to foster global collaboration among specialists attending the meeting, and to encourage future research projects to address unsolved dilemmas. By highlighting areas of disagreement and promoting collaborative research endeavours, this initiative aims to enhance treatment standards and potentially improve outcomes for patients globally. This paper sets out some of the controversies and questions that were debated in the meeting.

An unusual cystic presentation of pelvic skeletal Ewing sarcoma: a case series.

Ewing sarcoma (ES) is the second most common primary malignant bone tumour in children and adolescents. About 14.5% of primary malignancies develop in pelvic bones, where they typically have worse prognoses than extremity or acral sarcomas. It usually presents with aggressive features on radiology scans, but may also present with different radiological characteristics. In this series, we describe rare appearances of pelvic skeletal Ewing sarcoma, with large extraosseous cystic component on imaging, defined by the presence of fluid-filled spaces in the extraosseous tumour lesion, which distinguishes it from the solid nature of conventional ES. We report 3 cases of cystic presentation of ES, with imaging features supporting diagnosis of a primary malignant bone tumour arising from the superior pubic ramus with associated massive intrapelvic solid and cystic mass. CT-guided biopsy provided diagnosis of ES, with large intrapelvic soft tissue and cystic component. These patients underwent neo-adjuvant chemotherapy and proton beam therapy with significant reduction in size of the solid components, while the cystic components remained relatively unchanged. Two patients underwent surgical resection of the tumour (navigated P3 internal hemipelvectomy and hemipelvis P2/P3 resection, respectively), and one patient died while on treatment. In both who underwent surgery, histology showed ES with margins clear and more than 99% of treatment-induced necrosis. To the authors' knowledge, this unusual presentation of pelvic ES is described for the first time in the literature as a case series, with particular reference to atypical extraosseous cystic changes, along with the clinical and radiological characteristics, and their treatment.

Incidence of avascular necrosis of native femur following hip transposition surgery for periacetabular malignancies: a single-centre experience.

BACKGROUND: Hip transposition surgery after surgical resection of large pelvic tumours is a well-established alternate to endoprosthetic reconstruction. The major goals of surgery are to ensure adequate resection margins with limb salvation, albeit with acceptable levels of morbidity. While surveillance is aimed at diagnosing local recurrence or distant metastasis primarily, other complications may occasionally be seen.The aim of this study was to assess incidence of avascular necrosis (AVN) in the preserved native femoral heads after hip transposition surgery for periacetabular malignancies, also known as hanging hip surgery. PATIENTS AND METHODS: Patient records and follow-up imaging of 22 patients who had undergone hanging hip surgery from 1999 to 2020 were retrospectively analysed to assess for any probable causes of AVN. RESULTS: Of the 22 patients, 5 (22.7%) had developed AVN on follow-up with a mean time of onset of about 10.5 months from surgery (5 months-2 years). A review of the patient demographics, surgical notes, preoperative management did not offer any clues as to the cause of AVN in these patients. Osteopenia was the most common radiological finding (59%) in most patients, but this also did not herald AVN onset. CONCLUSIONS: The theory that loss of major vascular supply to the femoral head from capsular disruption during hip transposition surgery would lead to AVN in most patients did not hold true as AVN occurred in a small number of patients.

An unusual case of metastatic melanoma in subcutaneous tissue presenting as a solitary cystic mass with fluid levels.

Malignant melanoma is a common and often aggressive neoplasm of the skin arising from melanocytes. Metastatic melanoma is known for its diverse clinical manifestations, and can present with atypical features prior to diagnosis of the primary lesion, which can pose a diagnostic challenge. We report a rare case of metastatic melanoma in a 67 year-old male who presented with a painless, enlarging mass in the right axilla over a 4 week period. Ultrasound and magnetic resonance imaging (MRI) scans revealed a well-defined solitary, cystic appearing lesion in the right axilla with a distinct fluid-fluid level. An ultrasound guided biopsy of the lesion diagnosed a metastatic melanoma. While haemorrhagic distant metastases are a well-recognised complication of malignant melanoma, particularly in the brain and lung, soft tissue metastases presenting with fluid-fluid levels is not well described in the literature. The case highlights the importance of considering the differential of melanoma metastasis when encountered with such a lesion and importance of ultrasound guided biopsy for histopathological confirmation, as the imaging features can mimic that of a haemorrhagic soft tissue sarcoma, the management of which differs substantially from that of melanoma.

Periostitis Ossificans: Largest Case Series with Review of Literature.

Background Periostitis ossificans (PO) are rare, benign ossifying surface lesions characterized by the centripetal ossification with osseous and soft-tissue edema. Their clinicoradiological appearances can easily mimic those of more sinister or infective surface lesion. Objective This study aimed to explore the various anatomical locations and muscle attachment at the site of PO, and evaluate the role of complementary image findings in patients presenting at our tertiary orthopaedic referral center. Patients and Methods A retrospective review of our oncology and radiology databases was undertaken to identify patients with PO reported on radiographs, magnetic resonance imaging (MRI) and computed tomography (CT) over the past 13 years (2007-2020). Patient demographics, sites of PO, muscle attachment at the site of PO, findings on complementary imaging, and clinical management outcome were documented. Results We identified 38 patients with PO with a mean age of 24 years (range: 4-66 years). Muscle attachment was seen at the site of PO in the majority of cases (89%). The majority of PO were in the lower limb and commonly seen around the attachment of quadriceps. Deltoid attachment was commonly involved in the upper limb. Conclusion Muscle attachment is commonly seen at the site of PO, which results in stripping of the periosteum resulting in soft-tissue and osseous edema and centripetal ossification.

Intraosseous conventional central chondrosarcoma does not metastasise irrespective of grade in pelvis, scapula and in long bone locations.

Background: Histological grade has been regarded as the most important prognostic factor in conventional central chondrosarcoma. To evaluate whether the presence of an extraosseous tumour component is associated with a decreased metastasis-free survival or disease-specific survival and alternatively to develop a simple prognostic and clinical decision-making tool. Material and methods: We searched two prospectively maintained international sarcoma centre databases for primary non metastatic central conventional chondrosarcomas of all grades in pelvis, scapula or long bone location, undergoing curative treatment, diagnosed between 2000 and 2020. Pre-treatment MRI scans were reviewed for the presence of an extraosseous mass. The metastasis-free survival (MFS) and disease-specific survival (DSS) were estimated by the Kaplan-Meier method from surgery to event, death or last follow-up. Results: 336 patients were identified between 2000 and 2020, undergoing surgical treatment for conventional central chondrosarcoma. 111 patients (33 %) had grade 1 tumours, 149 patients (44 %) had grade 2, and 76 patient (23 %) had grade 3 chondrosarcomas determined as the highest grade in the final resected specimen. An extraosseous soft tissue component was more frequent in higher grade tumours (p < 0.001) and present in 200 cases (60 %). None of the patients with an intraosseous tumour developed metastases or died of the disease. For patients with extraosseous tumour component, MFS was 92 % (95 % CI, 96-100) at 2-years and 74 % (95 % CI, 67-81) at 10-years and DSS was 91 % (95 % CI, 87-95) at 2-years and 75 % (95 % CI, 68-82) at 10-years. The MFS and DSS was significantly different (p < 0.001) for those patients with or without an extraosseous tumour component, irrespective of grade or anatomical location. Discussion: The results of this study has shown that the metastatic potential of intraosseous conventional central chondrosarcoma is negligible. The presence of an extraosseous soft tissue component may be used for prognostication and to guide treatment pathways for patients with central cartilage tumours.

Current role and future applications of image-guided interventional procedures in musculoskeletal oncology - A narrative review.

Background: Musculoskeletal (MSK) image-guided interventional procedures have been increasingly used in and remain crucial in the diagnosis and treatment of musculoskeletal tumours. Aims: In this article, we aim to describe commonly performed interventional procedures in the subspeciality of MSK oncology drawing experience from our tertiary referral centre. Recent advances, emerging techniques and future applications of image-guided interventional procedures in the field of MSK oncology are highlighted. Material and methods: A retrospective search using the keyword 'musculoskeletal system', 'neoplasms', 'biopsy', and 'interventional radiology' was performed at our tertiary care oncology orthopaedic referral centre radiology database. The radiology images were collected from our Picture Archiving and Communication System (PACS) and Radiology Information System (RIS). Electronic Patient Records, histopathology laboratory records and patient characteristics were collaborated to generate this narrative experience at our centre. Results: Image-guided interventional procedures have been utilised in a spectrum of primary and secondary MSK tumours. Current applications include diagnosis of bone and soft tissue MSK neoplastic lesions with biopsies, thermal, cryotherapy and Radiofrequency ablations and augmentation procedures. Conclusion: Musculoskeletal (MSK) image-guided interventions have increasing applications in the diagnosis, management, treatment and monitoring of patients with MSK tumours. The emergence of newer imaging technologies with enhanced skills of interventional radiologists will allow a range of therapeutic MSK interventions in both effective control of primary lesions and palliative care of metastatic lesions.

Assessing ChatGPT's ability to pass the FRCS orthopaedic part A exam: A critical analysis.

AI technology has made significant advancements in recent years, with the notable development of ChatGPT in November 2022. Users have observed evidence of deductive reasoning, logical thinking, and coherent thought in ChatGPT's responses. This study aimed to determine if ChatGPT has the capability to pass the Orthopaedic Fellow of the Royal College of Surgeons (FRCS Orth) Part A exam. METHODS: To assess ChatGPT4's ability to pass the Orthopaedic FRCS Orth Part A exam, a study was conducted using 240 mock FRCS Orth Part A questions. The study evaluated the accuracy of ChatGPT's answers and the response time for each question. Descriptive statistics were employed to analyse the chatbot's performance. RESULTS: The evaluation revealed that ChatGPT4 achieved an overall score of 67.5% on Part A of the exam. However, ChatGPT4 did not meet the overall pass mark required for the FRCS Orth Part A exam. CONCLUSION: This study demonstrates that ChatGPT was unable to pass the FRCS Orthopaedic examination. Several factors contributed to this outcome, including the lack of critical or high-order thinking abilities, limited clinical expertise, and the inability to meet the rigorous requirements of the exam.

Iliotibial band friction syndrome after knee cementoplasty: a case report.

Iliotibial band pathologies can result in lateral knee pain. These are commonly seen in runners and cyclists. Lateral knee pain following knee arthroplasty can be due to distal iliotibial band enthesopathy or impingement by the femoral component. Cementoplasty is a common procedure performed during treatment of osseous lesions. We describe a case of ITB friction syndrome due to small focus of cement following cementoplasty for GCT (giant cell tumour).

Accuracy of MRI scans in predicting intra-articular joint involvement in high-grade sarcomas around the knee.

Aims: Intra-articular (IA) tumours around the knee are treated with extra-articular (EA) resection, which is associated with poor functional outcomes. We aim to evaluate the accuracy of MRI in predicting IA involvement around the knee. Methods: We identified 63 cases of high-grade sarcomas in or around the distal femur that underwent an EA resection from a prospectively maintained database (January 1996 to April 2020). Suspicion of IA disease was noted in 52 cases, six had IA pathological fracture, two had an effusion, two had prior surgical intervention (curettage/IA intervention), and one had an osseous metastasis in the proximal tibia. To ascertain validity, two musculoskeletal radiologists (R1, R2) reviewed the preoperative imaging (MRI) of 63 consecutive cases on two occasions six weeks apart. The radiological criteria for IA disease comprised evidence of tumour extension within the suprapatellar pouch, intercondylar notch, extension along medial/lateral retinaculum, and presence of IA fracture. The radiological predictions were then confirmed with the final histopathology of the resected specimens. Results: The resection histology revealed 23 cases (36.5%) showing IA disease involvement compared with 40 cases without (62%). The intraobserver variability of R1 was 0.85 (p < 0.001) compared to R2 with κ = 0.21 (p = 0.007). The interobserver variability was κ = 0.264 (p = 0.003). Knee effusion was found to be the most sensitive indicator of IA involvement, with a sensitivity of 91.3% but specificity of only 35%. However, when combined with a pathological fracture, this rose to 97.5% and 100% when disease was visible in Hoffa's fat pad. Conclusion: MRI imaging can sometimes overestimate IA joint involvement and needs to be correlated with clinical signs. In the light of our findings, we would recommend EA resections when imaging shows effusion combined with either disease in Hoffa's fat pad or retinaculum, or pathological fractures.

Outcomes of distal radial endoprostheses for tumour reconstruction: a single centre experience over 15 years.

We report a retrospective study over a 15-year period, between 2005 and 2020, evaluating clinical and functional outcomes in patients who underwent reconstruction of the distal radius with an endoprosthetic replacement following excision of both malignant and aggressive benign bone tumours. Data was collected retrospectively from a prospectively maintained electronic database, and prospectively via telephone patient consultation. Musculoskeletal Tumour Society and patient-rated wrist evaluation scores were assessed at a minimum of 1 year postoperatively. Of nine implants, five were arthrodeses and four were arthroplasties. One patient required amputation within 6 months for proximal metastatic disease. At last follow-up, eight patients subjectively reported good function. Five patients returned to high functionally demanding jobs. Mean Musculoskeletal Tumour Society and patient-rated wrist evaluation scores were 72% and 50/100, respectively. We conclude that distal radius endoprosthetic replacements offer acceptable functional outcomes and remain a viable option when biological reconstruction is not possible.Level of evidence: IV.

Clear Cell Chondrosarcoma-Oncological Outcomes in an Asian Cohort.

Clear cell chondrosarcoma is a rare subtype of chondrosarcoma, included in the category of low-grade (grade 1) sarcomas of the bone. We evaluated the results of treatment of these rare tumours at our institute and documented their outcomes in a hitherto unreported ethnic (Asian) cohort. Of the 480 extremity and pelvic chondrosarcomas diagnosed between January 2006 and December 2017 at our institute, 12 (2.5%) were clear cell chondrosarcoma. There were 11 male patients and one female patient. The mean age was 35 years (range 24-51 years). Mean duration of symptoms was 6 months and all cases were in the long bones; 8 cases in the femur, 2 in the humerus, and 1 each in the tibia and fibula. All cases were non metastatic at presentation Three patients were excluded from final analysis as they did not seek treatment at our hospital after initial presentation. Seven of nine cases had elevated alkaline phosphatase levels (mean value of 342 and range of 94-1353). Eight cases underwent wide excision while one case who had curettage elsewhere and presented to us with no evidence of residual disease was managed with watchful observation. None of the patients received adjuvant chemotherapy or radiotherapy. There were no local or distant recurrences at a median follow-up of 73 months (range 43-244 months). Seven of nine cases had elevated alkaline phosphatase levels (mean value of 342 and range of 94-1353). Eight patients were alive and disease free at last follow-up while one had died due to an unrelated cause at 76 months after index surgery. Clear cell chondrosarcomas comprised only 2.5% (12 of 480) of all chondrosarcomas in our study. Elevated serum alkaline phosphatase levels may serve as a surrogate marker to help in diagnosis. Wide excision in clear cell chondrosarcomas is recommended and provides excellent oncological outcomes.

Outcomes of soft-tissue sarcoma in nonagenarians.

AIMS: Current literature suggests that survival outcomes and local recurrence rates of primary soft-tissue sarcoma diagnosed in the very elderly age range, (over 90 years), are comparable with those in patients diagnosed under the age of 75 years. Our aim is to quantify these outcomes with a view to rationalizing management and follow-up for very elderly patients. METHODS: Retrospective access to our prospectively maintained oncology database yielded a cohort of 48 patients across 23 years with a median follow-up of 12 months (0 to 78) and mean age at diagnosis of 92 years (90 to 99). Overall, 42 of 48 of 48 patients (87.5%) were managed surgically with either limb salvage or amputation. RESULTS: A lower overall local recurrence rate (LRR) was seen with primary amputations compared with limb salvage (p > 0.050). The LRR was comparable between free (R0), microscopically (R1), and macroscopically positive (R2) resection margins in the limb salvage group. Amputation was also associated with longer survival times (p < 0.050). Overall median survival time was limited to 20 months (0 to 80). CONCLUSION: Early and aggressive treatment with appropriate oncological surgery confers the lowest LRR and a survival advantage versus conservative treatment in this cohort of patients. With limited survival, follow-up can be rationalized on a patient-by-patient basis using alternative means, such as GP, local oncology, and/or patient-led follow-up. Cite this article: Bone Joint J 2022;104-B(1):177-182.

Importance of Skeletal Staging in Chondrosarcoma of Bone: Results of Survey on Current Practices Among Musculoskeletal Oncologists.

PURPOSE: There are no clear guidelines for staging of conventional chondrosarcoma. We conducted an online survey to determine the current practices for skeletal staging for conventional chondrosarcoma among practicing oncologists and to assess any discrepancy in practices and with the published literature. METHODOLOGY: A simple ten-question online survey (e-mails and WhatsApp) was conducted among practicing oncologists over a period of 3 weeks using online portal (surveymonkey.com). It was followed by analysis based on each question to find current practices. RESULTS: 139 members participated in the survey (84% surgeons, 9% radiologists, 3% medical and 3% radiation oncologists and 1% nuclear medicine). 65% have been treating chondrosarcoma for more than 5 years. 88% opined that biopsy is mandatory even if the radiology is suggestive of a chondrosarcoma. 66% said that solitary skeletal metastasis is seen in less than 2% of the cases but 84% of participants were in favour of performing an investigation (bone scan/PET scan) for skeletal survey. While 43% opined skeletal metastasis is more common in recurrent chondrosarcoma, 26% said that performing a bone scan was likely to impact management, 28% said it will not impact management and 46% were unsure. Of the group who thought that a bone scan would impact management or were unsure, the majority (56%) opined that this was relevant only in grade 2 and grade 3 chondrosarcoma. CONCLUSION: There was lack of consensus regarding staging for chondrosarcoma. Only 26% of respondents were convinced that performing a bone scan was likely to impact management of chondrosarcoma. There is a need to analyze large data sets (retrospective/prospective) to arrive at an evidence-based staging algorithm for chondrosarcoma.

Is 2 mm a wide margin in high-grade conventional chondrosarcomas of the pelvis?

AIMS: Controversy exists as to what should be considered a safe resection margin to minimize local recurrence in high-grade pelvic chondrosarcomas (CS). The aim of this study is to quantify what is a safe margin of resection for high-grade CS of the pelvis. METHODS: We retrospectively identified 105 non-metastatic patients with high-grade pelvic CS of bone who underwent surgery (limb salvage/amputations) between 2000 and 2018. There were 82 (78%) male and 23 (22%) female patients with a mean age of 55 years (26 to 84). The majority of the patients underwent limb salvage surgery (n = 82; 78%) compared to 23 (22%) who had amputation. In total, 66 (64%) patients were grade 2 CS compared to 38 (36%) grade 3 CS. All patients were assessed for stage, pelvic anatomical classification, type of resection and reconstruction, margin status, local recurrence, distant recurrence, and overall survival. Surgical margins were stratified into millimetres: < 1 mm; > 1 mm but < 2 mm; and > 2 mm. RESULTS: The disease--specific survival (DSS) at five years was 69% (95% confidence interval (CI) 56% to 81%) and 51% (95% CI 31% to 70%) for grade 2 and 3 CS, respectively (p = 0.092). The local recurrence-free survival (LRFS) at five years was 59% (95% CI 45% to 72%) for grade 2 CS and 42% (95% CI 21% to 63%) for grade 3 CS (p = 0.318). A margin of more than 2 mm was a significant predictor of increased LRFS (p = 0.001). There was a tendency, but without statistical significance, for a > 2 mm margin to be a predictor of improved DSS. Local recurrence (LR) was a highly significant predictor of DSS, analyzed in a competing risk model (p = 0.001). CONCLUSION: Obtaining wide margins in the pelvis remains challenging for high-grade pelvic CS. On the basis of our study, we conclude that it is necessary to achieve at least a 2 mm margin for optimal oncological outcomes in patients with high-grade CS of the pelvis. Cite this article: Bone Joint J 2021;103-B(6):1150-1154.

Pelvic Ewing sarcoma: Should all patients receive pre-operative radiotherapy, or should it be delivered selectively?

BACKGROUND: Locally recurrent disease following surgical resection of Ewing sarcoma (ES) confers a poor prognosis. Limited evidence is available evaluating non-selective use of pre-operative radiotherapy (RT) for patients with pelvic ES and its effect on local control and survival. PATIENTS AND METHODS: 49 consecutive patients with pelvic ES were identified retrospectively from a prospectively collated database. Patients either received non-selective pre-operative RT and surgery (n = 27), or selective post-operative RT (n = 22) (surgery alone (n = 11) or surgery and post-operative RT (n = 11)). RESULTS: Patients who had non-selective pre-operative radiotherapy appeared to have a higher LRFS, 88.0% compared to 66.5% in the selective RT group (p = 0.096, Kaplan Meier; p = 0.028, Chi-squared). Administration of non-selective, pre-operative RT to all patients with pelvic ES elevates the LFRS to that of the good responder group (≥90% tumour necrosis and margins, p = 0.880). There was no difference in metastasis-free survival, 60.0% and 54.5% (p = 0.728) and overall survival (OS), 57.7% and 63.6% (p = 0.893). The majority of pre-operative RT patients had both good necrosis (≥90%) (p = 0.003) and widely excised tumours, 81.5% vs 59.1% (p = 0.080). Tumour volume ≥250 ml was associated with worse LRFS (p = 0.045) and post-operative complications (p = 0.017). There may be improved LRFS (p = 0.057) with pre-operative proton-beam RT compared to surgery and selective post-operative RT. CONCLUSION: Pre-operative photon or proton-beam RT to all pelvic ES may improve LRFS compared to the selective delivery of post-operative RT. Radiotherapy delivered to all patients results in a greater percentage of highly necrotic tumours at surgical excision, enabling a greater proportion of patients with wide resection margins.

'Umbrella construct' - an innovative technique for reconstruction of the proximal humerus after curettage in locally aggressive benign bone tumours.

AIM: Reconstructing locally aggressive benign bone tumours of the proximal humerus after intralesional curettage is a challenge. We present a novel reconstruction technique 'Umbrella construct' where a femoral head and a strut allograft are combined to reconstruct the cavity. Complications, graft incorporation time, functional (Musculoskeletal Tumor Society score [MSTS]) and oncological outcomes were evaluated. METHODS: Between January 2006 and June 2017, 11 cases (10 giant cell tumours, 1 chondroblastoma) underwent curettage followed by reconstruction with Umbrella construct. There were six females and five males with a mean age of 23 years (range 14-36 years). The maximum longitudinal extent of disease was 9 cm (range 5-9 cm). RESULTS: The median follow-up was 54 months (range 34-122 months). The mean allograft incorporation time was 7 months (5-8 months). One patient had a graft fracture which was managed conservatively. Two cases developed local recurrence and the construct was revised to a prosthesis in both. The mean MSTS score for the nine cases with retained graft was 27 (23-29). CONCLUSIONS: Umbrella construct is an effective reconstruction modality which helps to maintain joint congruity and limb length. It has acceptable oncological outcomes with good function.

Navigation-assisted pelvic resections and reconstructions for periacetabular chondrosarcomas.

OBJECTIVES: Survival in patients with chondrosarcomas has not improved over 40 years. Although emerging evidence has documented the efficacy of navigation-assisted surgery, the prognostic significance in chondrosarcomas remains unknown. We aimed to assess the clinical benefit of navigation-assisted surgery for pelvic chondrosarcomas involving the peri-acetabulum. METHODS: We studied 50 patients who underwent limb-sparing surgery for periacetabular chondrosarcomas performed with navigation (n = 13) without it (n = 37) at a referral musculoskeletal oncology centre between 2000 and 2015. RESULTS: The intralesional resection rates in the navigated and non-navigated groups were 8% (n = 1) and 19% (n = 7), respectively; all bone resection margins were clear in the navigated group. The 5-year cumulative incidence of local recurrence was 23% and 56% in the navigated and non-navigated groups, respectively (p = 0.035). There were no intra-operative complications related to use of navigation. There was a trend toward better functional outcomes in the navigated group (mean MSTS score, 67%) than the non-navigated group (mean MSTS score, 60%; p = 0.412). At a mean follow-up of 63 months, the 5-year disease-specific survival was 76% and 53% in the navigated and non-navigated group, respectively (p = 0.085), whilst the 5-year progression-free survival was 62% and 28% in the navigated and non-navigated group, respectively (p = 0.032). CONCLUSION: This study confirmed improved local control and progression-free survival with the use of computer navigation in patients with limb-salvage surgery for periacetabular chondrosarcomas, although the advancement in other treatment modalities is required for improvement of disease-specific survival.