Given the differences between biopsy techniques, especially regarding the representativeness and amount of tissue obtained upon diagnostic workup of suspicious bone and soft tissue lesions, this study aimed at evaluating the diagnostic conclusiveness of different biopsy techniques at a tertiary sarcoma centre. Overall, 222 consecutive patients (50.9

Pathological fractures in children are uncommon manifestations of underlying bone lesions. Differences in biomechanical loading and lesion distribution between the upper and lower extremities may result in distinct fracture characteristics and clinical presentations. The aim of this study was to characterize pathological fractures in the growing skeleton and to identify location-specific differences between upper- and lower-extremity fractures regarding patient demographics, trauma mechanisms, fracture characteristics, and underlying lesion types. This retrospective single-center study included 235 pediatric patients (0–17 years) with radiologically confirmed pathological fractures treated between 1999 and 2021. Demographic, clinical, and radiographic data were extracted from institutional records. Fractures were classified according to trauma mechanism, accident setting, anatomical location and underlying pathology. Statistical comparisons between upper- and lower-extremity fractures were performed using standard statistical tests, with statistical significance defined as p < 0.05. A total of 235 pathological fractures were analyzed, including 120 fractures of the upper extremity (51.1

Aims:Surgical management of intermediate and malignant tumours in the pelvis is complex. Complications are frequent and either related to the surgery itself or to post-surgical failure of the reconstruction technique. This systematic review and meta-analysis aims at analyzing all reported complications following PI to PIII pelvic resections for intermediate and malignant tumours. Methods:Based on a systematic literature search on PubMed adhering to the PRISMA guidelines, 1,683 study records were identified, of which we included 90 original studies published until 22 July 2025. Overall complication rates were assessed with random-effects meta-analysis. Differences in complication rates between reconstruction types (i.e. megaprosthetic, mostly biological, none) were evaluated with meta regression analysis. Results:Data on 2,199 patients (1,250 males (57%)) with mainly PI to PIII pelvic resections were analyzed. The most common reconstruction types were custom-made implants (21%; n = 451) and ice-cream cone prostheses (14%; n = 312). Pooled rates of infections, wound healing problems, nerve injuries, and deep vein thrombosis (DVT) amounted to 15% (95% CI 12% to 18%), 13% (95% CI 10% to 15%), 7% (95% CI 5% to 9%), and 4% (95% CI 2% to 6%), respectively. Further, pooled implant revision/removal and secondary external hemipelvectomy rates were 14% (95% CI 11% to 17%) and 4% (95% CI 3% to 5%). Mostly biological reconstructions were associated with higher rates of nerve injuries (p < 0.001), construct failures (p = 0.010), and secondary implant revision/removal (p = 0.003) compared to megaprosthetic reconstruction. Further, biological reconstructions were associated with increased secondary external hemipelvectomy rates compared to megaprosthetic reconstructions (p = 0.005) or no reconstructions (p = 0.001). Conclusion:Treatment of pelvic malignancies is challenging, with technically demanding resections and complex reconstructions. Across all reconstruction techniques following sacrum-sparing pelvic resections, infections and wound healing problems are the most common complications, yet there is also a considerable proportion of patients with neurovascular complications and DVTs.

[This corrects the article DOI: 10.1371/journal.pone.0066300.].

Purpose: Neoadjuvant radiotherapy (NRTX) is recommended for soft tissue sarcomas (STS) by current European Society of Medical Oncology (ESMO) guidelines. Histological response to preoperative treatment (including NRTX) is a well-established prognostic parameter in patients with osteosarcoma and Ewing sarcoma. In patients with STS, however, the relevance of histological – and radiological – necrosis rate following neoadjuvant treatment is less well known. Methods: We conducted a systematic PubMed search and obtained 2,433 potentially relevant entries, of which 30 original articles were finally included. Histological and radiological tumour necrosis following NRTX of STS was systematically studied, as was the potential association between the histological necrosis rate and oncological outcome (local recurrence-free survival (LRFS), distant metastasis-free survival (DMFS) and overall survival (OS)) using random-effects meta-analysis. Results: Information on 2,346 patients (1,257 males; 53.6%) of whom 2,228 (95.0%) had received NRTX was summarised. Most STS were located in the extremities (n = 2016; 85.9%). A histological necrosis rate of ≥90% was present in 22.8%. On imaging, the mean necrosis rate ranged between 14.7 and 67.7%. There was a significant association between higher histological necrosis rate and improved DMFS (HR = 0.29; 95% CI: 0.12–0.71; P = 0.018), while no associations for LRFS (HR = 0.54; 95% CI: 0.06–5.17; P = 0.181) or OS (HR = 0.60; 95% CI: 0.10–3.64; P = 0.437) were found. Conclusions: Tumour necrosis is frequently observed following NRTX in STS. Higher histological necrosis seems to be associated with improved DMFS. Overall, varying reporting of the histological and radiological necrosis rate following NRTX in STS calls for improved estimation of treatment response, considering histological and radiological features alike.

Femoral fractures in children are uncommon and are usually trauma-related; however, some occur secondary to underlying bone pathology. Early differentiation between traumatic and pathological fractures is essential to avoid delayed diagnosis. This study aimed to identify clinical predictors associated with pathological femoral fractures in children. In this retrospective single-center comparative study, 432 pediatric patients (0–17 years) with femoral fractures were included. These fractures were classified as traumatic (n = 386, 89.4

BACKGROUND:Enchondromas (EC) present cartilaginous tumors that are difficult to differentiate from their intermediate counterpart, atypical cartilaginous tumors (ACT). Histologically, tumor distinction of these entities is limited by sampling bias, while radiologically, similar lesion features render classification challenging. Therefore, the aim of this study is to investigate whether machine learning- or radiomics-based image analysis tools can reliably differentiate between EC and ACT using MRI data and corresponding expert annotations. METHODS:Based on an MRI dataset of 206 unique patients (79 controls, 104 EC, 23 ACT), we develop a machine learning-based AI image analysis tool that uses the state-of-the-art nnU-Net framework for medical image segmentation and extends it for tumor classification. Two nnU-Net models (Scout and Specialist) are applied sequentially. Scout first detects images without tumor tissue and removes them from further analysis, whereas Specialist performs the final tumor classification on the remaining images. Alternatively, our tool supports radiomics-based classification using hand-crafted tumor characteristics. RESULTS:In our cross-validation experiments, when using the two models approach, where Specialist follows Scout, we achieved 87% Sensitivity (95% CI [0.67, 0.96]) for the ACT class and 93% Sensitivity (95% CI [0.87, 0.97]) for the EC class. Furthermore, no image containing an ACT was classified as non-tumor. CONCLUSIONS:In this pilot study, we demonstrated that MRI information alone can be used to differentiate between ACT and EC with high accuracy. These results seem promising that in future, machine learning and AI can be used for better orthopedic diagnosis of cartilaginous tumors in clinical practice.

Graft choice in primary anterior cruciate ligament (ACL) reconstruction remains controversial. While hamstring autografts are common, allografts offer advantages such as no donor site morbidity and reduced operation time. This study aimed to compare the clinical, functional and health-related quality of life (HRQOL) outcomes of hamstring allografts vs. autografts in primary ACL reconstruction. In this single-center randomized controlled trial, patients undergoing primary ACL reconstruction were randomized to receive either a hamstring allograft or autograft. Clinical evaluation and patient-reported outcome measures (PROMs), including the International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Outcome Score (KOOS), and Short Form (SF)-36 Health survey, were collected preoperatively and at multiple follow-ups to 12 months. Operation time and postoperative magnetic resonance imaging (MRI) scans at 12 months were also analyzed. The final cohort included 25 patients (13 allograft, 12 autograft). At 12 months, no statistically significant differences between groups were detected for any PROM. Mean IKDC scores were 83.0 ± 7.2 in the allograft group and 87.2 ± 5.0 in the autograft group (p = 0.12). Both groups demonstrated improvement in patient-reported functional outcomes; however, objective instrumented laxity testing was not performed. Mean operation time was significantly shorter for the allograft group (61.6 ± 11.4 min) compared to the autograft group (83.0 ± 13.6 min; p < 0.001). In this small pilot randomized cohort of patients aged 27 years and older, no statistically significant short-term differences in PROMs were detected between hamstring allograft and autograft ACL reconstruction at 12 months. Allograft use was associated with significantly shorter operative time. These findings should be interpreted cautiously because the study was not powered to demonstrate equivalence or noninferiority and longer term follow-up with objective laxity testing is required to assess graft durability and stability.

Aims:The aim of this study was to achieve consensus on important topics related to tenosynovial giant cell tumour (TGCT) and giant cell tumour of bone (GCTB), and to identify areas for future research. Methods:In January 2026, a consensus meeting, The Birmingham Orthopaedic Oncology Meeting (BOOM), held in Cape Town, South Africa, gathered 314 delegates from 59 countries to debate 21 consensus statements on tenosynovial giant cell tumour (TGCT) and giant cell tumour of bone (GCTB) through a modified Delphi process. Results:Of the 21 statements, two achieved unanimous consensus, 18 strong consensus, and one moderate consensus. Unanimous consensus was reached for prioritizing joint-preserving intralesional curettage in GCTB when feasible, and for supporting non-surgical approaches in anatomically challenging cases, particularly sacral lesions. The statement addressing the role of denosumab in GCTB achieved only moderate consensus. The use of adjuvants in GCTB, as well as the management of recurrent and systemic GCTB, including long-term use of denosumab, reached strong consensus. Strong consensus was achieved in the surgical and non-surgical management for both primary and recurrent TGCT. Surveillance strategies for both TGCT and GCTB generated substantial discussion despite strong consensus, reflecting ongoing uncertainty and lack in evidence. Conclusion:This international consensus provides practical guidance for the management of TGCT and GCTB while identifying important gaps in evidence. Joint-preserving surgery remains central to the treatment of GCTB, with selective integration of systemic therapies and individualized surveillance. The consensus framework highlights priorities for future collaborative research in orthopaedic oncology.

Aims Surgical management of intermediate and malignant tumours in the pelvis is complex. Complications are frequent and either related to the surgery itself or to post-surgical failure of the reconstruction technique. This systematic review and meta-analysis aims at analyzing all reported complications following PI to PIII pelvic resections for intermediate and malignant tumours. Methods Based on a systematic literature search on PubMed adhering to the PRISMA guidelines, 1,683 study records were identified, of which we included 90 original studies published until 22 July 2025. Overall complication rates were assessed with random-effects meta-analysis. Differences in complication rates between reconstruction types (i.e. megaprosthetic, mostly biological, none) were evaluated with meta regression analysis. Results Data on 2,199 patients (1,250 males (57%)) with mainly PI to PIII pelvic resections were analyzed. The most common reconstruction types were custom-made implants (21%; n = 451) and ice-cream cone prostheses (14%; n = 312). Pooled rates of infections, wound healing problems, nerve injuries, and deep vein thrombosis (DVT) amounted to 15% (95% CI 12% to 18%), 13% (95% CI 10% to 15%), 7% (95% CI 5% to 9%), and 4% (95% CI 2% to 6%), respectively. Further, pooled implant revision/removal and secondary external hemipelvectomy rates were 14% (95% CI 11% to 17%) and 4% (95% CI 3% to 5%). Mostly biological reconstructions were associated with higher rates of nerve injuries (p < 0.001), construct failures (p = 0.010), and secondary implant revision/removal (p = 0.003) compared to megaprosthetic reconstruction. Further, biological reconstructions were associated with increased secondary external hemipelvectomy rates compared to megaprosthetic reconstructions (p = 0.005) or no reconstructions (p = 0.001). Conclusion Treatment of pelvic malignancies is challenging, with technically demanding resections and complex reconstructions. Across all reconstruction techniques following sacrum-sparing pelvic resections, infections and wound healing problems are the most common complications, yet there is also a considerable proportion of patients with neurovascular complications and DVTs. Cite this article: Bone Jt Open 2026;7(6):713–723.

Background: As the use of artificial intelligence (AI) and large language models (LLMs) is increasingly adopted into scientific writing, it is important to understand AI's ability to produce clear and accurate content that is on par with human-authored content in the field of orthopaedics, including orthopaedic oncology. The aim of this study was to compare a series of editorials written by orthopaedic oncologists with those written by a single LLM (ChatGPT 4.0) using a variety of quality metrics. Methods: Volunteer orthopaedic oncologists submitted a 3- to 4-paragraph persuasive editorial on a topic of their choice in the field of musculoskeletal oncology. ChatGPT 4.0 was then prompted to write a corresponding editorial for each topic. Each editorial was evaluated by two blinded peer reviewers and graded using a 25-point scale on the following quality metrics: content, clarity, grammar, persuasiveness, and creativity. The evaluators were also asked to indicate whether they believed the editorials were written by humans or by AI. Results: A total of 20 editorials were submitted by human authors and matched with 20 prompted AI editorials. No notable difference in average total quality score for human versus AI submissions was observed. AI-generated articles scored markedly higher in grammar, but there were no notable differences in any other quality metric. Reviewers correctly identified author type 59% of the time. Discussion: LLMs such as ChatGPT can generate editorial content in orthopaedic oncology that matches human-written quality, suggesting a potential supportive role for AI in scientific communication, with implications for authorship standards, editorial practices, and peer review.

PURPOSE:Graft choice in primary anterior cruciate ligament (ACL) reconstruction remains controversial. While hamstring autografts are common, allografts offer advantages such as no donor site morbidity and reduced operation time. This study aimed to compare the clinical, functional and health-related quality of life (HRQOL) outcomes of hamstring allografts vs. autografts in primary ACL reconstruction. METHODS:In this single-center randomized controlled trial, patients undergoing primary ACL reconstruction were randomized to receive either a hamstring allograft or autograft. Clinical evaluation and patient-reported outcome measures (PROMs), including the International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Outcome Score (KOOS), and Short Form (SF)-36 Health survey, were collected preoperatively and at multiple follow-ups to 12 months. Operation time and postoperative magnetic resonance imaging (MRI) scans at 12 months were also analyzed. RESULTS:The final cohort included 25 patients (13 allograft, 12 autograft). At 12 months, no statistically significant differences between groups were detected for any PROM. Mean IKDC scores were 83.0 ± 7.2 in the allograft group and 87.2 ± 5.0 in the autograft group (p = 0.12). Both groups demonstrated improvement in patient-reported functional outcomes; however, objective instrumented laxity testing was not performed. Mean operation time was significantly shorter for the allograft group (61.6 ± 11.4 min) compared to the autograft group (83.0 ± 13.6 min; p < 0.001). CONCLUSION:In this small pilot randomized cohort of patients aged 27 years and older, no statistically significant short-term differences in PROMs were detected between hamstring allograft and autograft ACL reconstruction at 12 months. Allograft use was associated with significantly shorter operative time. These findings should be interpreted cautiously because the study was not powered to demonstrate equivalence or noninferiority and longer term follow-up with objective laxity testing is required to assess graft durability and stability.

Population-based cancer registries provide incidence and survival data but lack granular treatment-specific information. However, this information can be critical for rare malignancies as soft tissue sarcoma (STS). The Austrian Sarcoma Registry (ASR) has been established to close this gap by capturing detailed clinical and therapeutic data across Austria. Data of 748 patients (median age 65 years) with localised extremity or trunk STS diagnosed between 1999 and 2024 at six Austrian institutions were retrospectively analysed. Prognostic factors for local recurrence (LR), distant metastasis (DM), and overall survival (OS) were assessed using competing risk regression and Cox regression models. Perioperative RTX and RTX, respectively, had been applied in 57

Purpose:To evaluate imaging features and clinicopathologic correlation in florid reactive periostitis (FP) and parosteal osteosarcoma (PO), emphasizing diagnostic pitfalls in surface bone lesions. Patients and Methods:Four patients (two FP, two PO) underwent radiography, CT, and MRI, including dynamic contrast-enhanced sequences in selected cases. Histopathology with immunohistochemical analysis of MDM2 and CDK4, including gene amplification testing, was performed in all cases. Results:FP demonstrated solid or layered periosteal reaction, soft-tissue swelling, and bone marrow edema without atypia or MDM2/CDK4 amplification. PO presented as lobulated ossified masses with cortical attachment or cleavage plane and positive MDM2/CDK4 expression. DCE-MRI showed overlapping enhancement patterns and did not reliably differentiate the entities. Conclusion:Differentiation between FP and PO requires careful evaluation of conventional imaging features combined with histopathological confirmation. Multidisciplinary assessment remains essential to prevent diagnostic overtreatment or undertreatment. Key Points:· FP may mimic PO on MRI. · Cleavage plane favors parosteal osteosarcoma. · DCE-MRI shows overlapping enhancement patterns. · MDM2/CDK4 are essential in equivocal cases. Citation Format:· Igrec J, Stranger N, Puseljic M et al. Imaging Pitfalls in Surface Bone Lesions: Florid Reactive Periostitis Mimicking Parosteal Osteosarcoma - A Multimodality Case Series. Rofo 2026; DOI 10.1055/a-2864-1949.

Total femur replacements (TFRs) involve the replacement of the whole femoral bone, reconstruction of the hip and knee joints, and soft tissue reconstruction for function and joint stability. The aim of this multicentric European Musculo-Skeletal Oncology Society (EMSOS) study is to report on the functional outcome, quality of life, as well as gait analysis in patients with TFR. Retrospective data from 12 international participating centers were collected. In total, 65 patients [median (IQR) age at surgery 40 (18–56) years, 60

Extraskeletal osteosarcoma (ESOS) is a rare, aggressive mesenchymal tumor with limited therapeutic options and a poor prognosis due to frequent metastases. Identifying targetable genetic alterations could improve treatment outcomes. The objective is to report the first worldwide case of ESOS harboring an ETV6::NTRK3 fusion and describe the clinical response to larotrectinib, a selective TRK inhibitor. Case report of a 74-year-old man with a rapidly enlarging, inoperable neck tumor measuring 7.9 ×7.1 ×6.6 cm. The case underwent histopathological, immunohistochemical, and molecular analyses, including targeted RNA sequencing using the Archer Fusion Plex Pan Solid Tumor v2 panel and DNA-based targeted analysis with the Ion Torrent Oncomine Comprehensive Assay Plus. The clinical course was monitored over an 8-month treatment period. Molecular analysis revealed an actionable, in ESOS previously not described, ETV6::NTRK3 fusion. Treatment with larotrectinib (100 mg twice daily) led to a rapid clinical response within 3 weeks. MRI demonstrated partial remission after 2 months (4.7 ×3.9 ×2.8 cm), with further tumor shrinkage at 8 months (4.4 ×3.7 ×2.4 cm). Despite complications, including urothelial carcinoma recurrence requiring chemotherapy and surgery, larotrectinib was resumed with dose adjustments. No significant adverse effects related to TRK inhibition were observed. This case represents the first reported instance of ESOS with an NTRK fusion. The rapid and sustained response to larotrectinib highlights the potential of precision medicine in managing rare and aggressive tumors, emphasizing the importance of molecular profiling to identify actionable targets. Extraskeletal osteosarcoma (ESOS) is a rare and aggressive form of cancer that grows in soft tissue. It is hard to treat and often spreads to other parts of the body. In this report, we describe a 74-year-old patient with a large, fast-growing tumor in the neck. Genetic testing found a rare change in the tumor’s DNA called an ETV6::NTRK3 fusion, which had never been reported in this type of cancer before. The patient was treated with a targeted medicine called Larotrectinib. The tumor quickly shrank and continued to get smaller over several months. This case shows how genetic testing can help find new treatment options, especially for patients with rare or difficult-to-treat cancers. Skok, Ochsenhofer et al. present the first reported instance of extraskeletal osteosarcoma with an NTRK fusion. The rapid and sustained response to larotrectinib highlights the potential of precision medicine in managing rare and aggressive tumors, emphasizing the importance of molecular profiling to identify actionable targets.

Advancements in diagnostic and therapeutic modalities for giant cell tumors of bone (GCTB) have introduced molecular and radiological tools that refine clinical decision-making. H3.3 G34W immunohistochemical staining has become a routine diagnostic marker, while H3F3A mutational analysis enhances prognostic insights. Treatment primarily involves surgical methods such as curettage or en bloc resection, with denosumab serving as an adjunct in high-risk or inoperable cases. We retrospectively analyzed 55 patients with GCTB, focusing on clinicopathologic and radiological findings. Tumors were evaluated using the Campanacci grading system. Immunohistochemical analysis with H3.3 G34W antibody and next-generation sequencing (NGS) were performed to detect H3F3A mutations. A subgroup of nine patients treated with denosumab was further analyzed for clinical outcomes and histological changes. The cohort had a mean age of 37.7 years, with tumors most commonly affecting the knee joint (55