Background: Soft tissue sarcomas (STSs) are rare, highly malignant mesenchymal tumours, comprising approximately 1% of all adult cancers and about 15% of paediatric solid tumours. STSs exhibit considerable genomic complexity with diverse subtypes, posing significant clinical challenges. Objectives: This study aims to characterise the molecular signature of primary STS through liquid biopsies and the untargeted metabolomic profiling of 75 patients, providing deep insights into cellular processes and potential therapeutic targets. Methods: This study analysed serum samples using nuclear magnetic resonance (NMR) spectroscopy for metabolomic profiling. Multivariate data analysis and machine learning classifiers were employed to identify biomarkers. Results: A panel of eleven significant deregulated metabolites were discovered in serum samples of patients with STS, with potential implications for cancer diagnosis and treatment. Conclusions: Choline decrease emerged as a marker for cancer progression, highlighting the potential of targeting its metabolism for therapeutic approaches in STS. The NMR analysis protocol proved effective for determining circulating biomarkers from liquid biopsies, making it suitable for rare disease research.

Background: Joint-sparing resection of juxta-articular knee tumors is challenging. With the development of 3D printing technology, custom-made cutting guides were introduced with the aim to improve the accuracy of tumor resection margins and to shape the allograft for adequate matching in biological reconstruction. Materials and Methods: Between December 2017 and July 2023, 13 patients underwent joint-sparing juxta-articular resection of the knee for a primary bone tumor at our institution. Resection was performed using a custom-made 3D-printed titanium alloy cutting guide and reconstruction was performed using a custom-shaped allograft. The mean follow up was 50 months (min 14–max 81). The study of cutting accuracy was performed by digital examination of CT images of the resection specimen in eight patients. Results: The average cutting error was 2.3 mm. Surgical margins were wide in all patients. Four patients developed postoperative complications that led to the removal of the allograft in one case. The average functional result according to the Musculoskeletal Tumor Society Score was 26 (min 14–max 30), and according to the Oxford Knee Score it was 44 (min 22–max 48). Conclusions: Custom-made titanium cutting guides resulted effective in improving the accuracy of joint-sparing juxta-articular resection of the knee and allograft matching.

Aims: Various reconstructions of the distal radius after tumour resection have been proposed. Osteoarticular allografts can restore a functional joint, but the long-term durability of this reconstruction has been questioned. Data on long-term results are scarce in the literature. The aim of our study was to answer the following questions: What is the long-term survival of osteoarticular distal radius allografts with a minimum follow-up of ten years? What is the long-term patient satisfaction? Methods: From 1999 to 2013, we performed 23 reconstructions with osteoarticular allografts after distal radius resection. Patients had a mean age of 36 years (14 to 69); 17 had giant cell tumour, three Ewing's sarcoma, two osteosarcoma, and one osteoblastoma. All patients were evaluated for allograft survival and functional outcome (Musculoskeletal Tumor Society (MSTS) score and Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire score). Results: One patient was lost to follow-up at 53 months. One patient died for concomitant disease at 44 months. Of the remaining 21 patients, one underwent revision arthrodesis at 48 months. A total of 20 allografts remained in situ at follow-up for a mean of 213 months (22 to 293). The mean MSTS was 25.7 (18 to 30), and the mean DASH was 10.4 (0 to 30). According to the MSTS parameter of emotional acceptance, all patients with a surviving allograft scored still satisfied or higher. Conclusion: In our experience, osteoarticular allografts in distal radius reconstruction can be a long-lasting procedure with long-term patient satisfaction. Few and conflicting results are reported in the literature; even when comparing series, it is difficult to clearly identify factors that may explain the differences in reported results. Cite this article: Bone Jt Open 2025;6(12):1523–1531.

Introduction Two-stage revision for chronic periprosthetic joint infections (PJI) of knee megaprostheses is complex and often results in significant bone loss. DAIR-Plus and other partial exchange procedures, involving debridement with partial prosthesis removal but retaining stems, are typically used for acute PJI but may benefit select chronic cases. This study aimed to: (i) assess DAIR-Plus and partial two-stage exchange outcomes in chronic megaprosthesis infections; and (ii) identify prognostic factors to guide their use versus full component removal. Materials and methods Twenty-three patients underwent DAIR-Plus or partial two-stage exchange (PTSE) procedures for chronic knee megaprosthetic PJI between 2000 and 2022. Nineteen patients, were included. Targeted antibiotics were administered based on Infectious Disease Specialist recommendations. Infection eradication was evaluated using clinical and serologic parameters. Results Nineteen patients (mean age 53.4 years) underwent 13 DAIR-Plus and 7 PTSE. PJI-free survival was 57.9% at 1 year, 47.4% at 2 and 5 years, and 42% beyond 5 years. Among failures, 6 had persistent infection and 5 relapsed (mean time to relapse: 13.75 months). Four additional patients achieved infection control after further two-stage revisions; 7 remained uncontrolled, leading to 6 amputations and 1 chronic suppressive treatment. Outcomes did not differ significantly by age, gender, host status, oncological history, radiotherapy, or surgical approach. Staphylococcus spp. caused 63% of infections and were associated with significantly lower PJI-free survival at final follow-up (25% vs. 62% for other organisms, p = 0.048). Conclusions DAIR-Plus provided lasting infection control in selected chronic PJI cases, with nearly half remaining infection-free long term with notable advantages such as bone stock preservation and faster recovery. Partial two-stage exchange does not appear to offer additional advantages over DAIR-Plus. Outcomes were not influenced by clinical factors, but Staphylococcus spp. infections showed significantly lower success.