Zusammenfassung: Denosumab ist für die Therapie der Osteoporose und ausgewählter Knochentumoren zugelassen, und seine Wirksamkeit ist in der Literatur gut dokumentiert. Bei Kindern erfolgt der Einsatz zur Behandlung benigner Knochentumoren jedoch off-label. Wir berichten über einen 13-jährigen Jungen mit aneurysmatischer Knochenzyste des Humerus, der nach Beendigung einer supportiven Denosumab-Therapie eine ausgeprägte Hyperkalzämie entwickelte. Der Patient wurde erfolgreich mit intravenöser Flüssigkeitstherapie, Kaliumsubstitution, Zoledronat und Furosemid behandelt. Dieser Fall verdeutlicht die Notwendigkeit einer engmaschigen Kontrolle des Calcium- und Knochenstoffwechsels bei Kindern und Jugendlichen während und nach Denosumab-Therapie.

Background: Although survival rates for patients with malignant bone tumors have improved significantly, complications following tumor resection and limb-sparing reconstruction remain a major clinical challenge, particularly in young individuals. Intercalary resection often results in large bone defects, necessitating complex reconstructions. Fibula grafts offer biological advantages; however, their long-term outcomes, especially regarding mechanical complications and comprehensive patient-reported well-being, require further detailed exploration, particularly in cohorts utilizing non-vascularized grafts. Objective: This retrospective study evaluated the complication rates, bone hypertrophy, limb function, and quality of life following non-vascularized fibular graft reconstruction for malignant bone tumors in a single-center cohort. This study offers insights into long-term success and patient well-being, with a particular focus on correlations with systemic therapy and defect size, factors that remain insufficiently explored in the current literature. Methods: In this single-center retrospective study, twenty-four non-vascularized fibular grafts were used to reconstruct intercalary bone defects following malignant tumor resection. Complications were categorized using the Clavien–Dindo classification. Graft hypertrophy was evaluated according to the method described by Weiland and de Boer. Functional outcomes were assessed using the MSTSs and TESSs, while quality of life was measured using the SF-36 questionnaire. Notably, the cohort analyzed represents a relatively large single-center series focusing exclusively on the outcomes of non-vascularized fibular grafts. Results: Our findings revealed significant rates of mechanical complications, with osteosynthesis material failure occurring in 50.0% of cases, pseudarthrosis in 47.6%, and fractures of the fibular grafts in 38.1% of cases. Importantly, there were significant correlations between mechanical complications and systemic therapy (p = 0.017), as well as between defect size and fractures (p = 0.013), identifying critical risk factors. Despite these considerable complication rates, patients achieved satisfactory limb function (MSTS: 74 ± 17; TESS: 83 ± 15) and quality of life scores comparable to national norms, with notably higher mental health indices, highlighting their psychological resilience. Conclusions: Non-vascularized fibular graft reconstruction, despite high mechanical complication rates, significantly facilitates long-term functional recovery and psychological well-being. These findings emphasize the necessity of risk-adapted surgical strategies and long-term follow-up protocols to mitigate complications, optimize long-term function, and ultimately advance patient-centered care.

Background: Breech presentation is considered one of the main risk factors for developmental dysplasia of the hip (DDH) in singleton pregnancies; however, data regarding twins are limited. The aim of this study was to evaluate whether breech presentation in twins is associated with abnormal hip ultrasound findings and to assess the influence of delivery mode, sex and gestational age. Methods: Obstetric and ultrasound data from twin births at Frankfurt University Hospital between 2010 and 2014 were retrospectively analyzed. A total of 130 twins in whom at least 1 infant with breech presentation and both infants underwent hip ultrasound according to Graf’s technique within the first 14 days after birth were included. Twins were divided into breech-breech, breech-vertex and breech-transverse groups. Hip findings were categorized as normal (Graf type Ia/Ib) or abnormal/immature (Graf type IIa or higher). Statistical analysis was performed using Fisher-Freeman-Halton exact testing. Results: No infant demonstrated manifest DDH (Graf type IIc or higher). Overall, 5.4% of infants showed physiologically immature or abnormal hip ultrasound findings classified as Graf type IIa. No significant association was found between breech presentation and abnormal hip findings; however, abnormal findings were more common in the breech-transverse group compared to the breech-breech group ( p = 0.037). Infants delivered via cesarean section demonstrated a higher rate of abnormal findings than vaginally delivered infants ( p = 0.041). Conclusion: In this cohort, breech presentation in twins was not associated with an increased rate of abnormal hip ultrasound findings. The combination of breech and transverse presentation may represent a higher risk constellation. Due to the retrospective design and lack of a singleton control group, conclusions regarding a modifying effect of twin pregnancy on the occurrence of DDH cannot be drawn. Level of evidence: Retrospective cohort study. Level III evidence.

Background: Pathologic fractures of the humerus due to metastatic disease cause severe pain, loss of function and reduced quality of life. Surgical treatment is predominantly palliative and aims to achieve rapid pain relief, early functional recovery and minimal treatment-related morbidity. The photodynamic bone stabilization system (IlluminOss^®) is a minimally invasive, radiolucent, intramedullary device that may address these needs. Methods: This retrospective analysis of prospectively collected data from two centers included 51 patients with 52 pathologic humeral lesions (completed or impending fractures) treated with photodynamic intramedullary stabilization between 2013 and 2025. Baseline variables comprised demographics, Eastern Cooperative Oncology Group (ECOG) performance status, comorbidities, pain (numeric rating scale, NRS) and function (Musculoskeletal Tumor Society Upper Extremity Score, MSTS-UE; Toronto Extremity Salvage Score, TESS). Lesion characteristics, operative details, in-hospital course, follow-up outcomes (TESS, patient satisfaction/quality of life) and long-term endpoints (survival, complications) were recorded. Results: The study cohort (25 women, 26 men; mean age 68.5 years) represented a highly palliative population with advanced, disseminated malignant disease. Of the 52 humeral lesions, 35 (67.3%) presented as pathological fractures, whereas 17 lesions (32.7%) were classified as impending fractures due to extensive osteolysis. Among the impending fractures, Mirels scores ranged from 8 to 10, with three lesions scoring 8, eight lesions scoring 9, and six lesions scoring 10. ECOG performance status was 0–2 in 75.0% and 3–4 in 25.0% of patients. Preoperative pain was high (mean NRS 7.1) and function markedly reduced (median MSTS-UE 9.5/30; median TESS 36.5/100). Postoperatively, pain improved significantly from NRS 7.1 to 2.0 (p < 0.001). MSTS-UE increased from a median of 9.5 to 20 (p < 0.001). Follow-up showed further functional improvement with an increased TESS of 36.5 to 61 (p < 0.001), high patient satisfaction and subjective improvement in quality of life. Kaplan–Meier analysis (n = 44) demonstrated a median survival of 6 months for ECOG 0–2 and 3 months for ECOG 3–4. Implant failure (Henderson type III) occurred four times (7.7%) and was successfully revised with plate and/or screw osteosynthesis or diaphyseal replacement. Conclusions: Photodynamic intramedullary stabilization provides effective treatment for selected pathologic humeral lesions with low implant failure rate, offering rapid pain relief, functional improvement and low perioperative morbidity. Implant failure in complex fracture morphologies highlights the need for morphology-adapted indication and consideration of supplemental fixation in high-risk cases.