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Background Tumor-associated fibroblast growth factor 23 (FGF-23)-induced hypophosphatemic rickets is a rare but known pediatric entity first described in 1959. It results from local production of phosphatonins by benign and malignant mesenchymal tumors. Case-Diagnosis/Treatment We report an 8-year-old boy with tumor-associated hypophosphatemic rickets due to paraneoplastic FGF-23 secretion from a benign mesenchymal pelvic-bone tumor. Excessive FGF-23 production was visualized by immunohistochemistry in the resected tumor. Phosphate wasting stopped immediately after tumor resection. We reviewed 26 reports of pediatric patients with tumor-induced hypophosphatemic rickets; paraneoplastic FGF-23 secretion was documented in only three of them. All tumors developed inside bone, were benign in 21/26 cases, and were localized in femur/tibia (13/26), radius/ulna/humerus (7/26), pelvis (4/26), rib (1/26), and craniofacial (1/26) bones. Mean interval between onset of signs and/or symptoms and diagnosis was 34 months. Conclusions In patients with hypophosphatemic rickets acquired beyond infancy, radiologic investigations for bone tumors need to be performed rapidly. In contrast to biochemical screening for increased circulating FGF-23 levels, immunohistochemical confirmation of FGF-23 production in resected tumor tissue can be regarded as being well established. Keywords Children * Hypophosphatemic rickets * Fibroblast growth factor 23 * Tumor-induced rickets, Introduction Tumor-induced hypophosphatemic rickets (TIR) is a rare condition first described in 1959 [1]. In adults, the same pathogenetic mechanism results in tumor-induced osteomalacia (TIO), which has been reported in [...]

Osteosarcoma is the most common primary malignant bone tumour in children and adolescents. More than a third of patients do not respond to standard therapy and urgently require alternative treatment options. Due to a high degree of inter‐ and intra‐tumoural genomic heterogeneity and complexity, recurrent molecular alterations that could serve as prognostic predictors or therapeutic targets are still lacking in osteosarcoma. Copy number (CN) gains involving the IGF1R gene, however, have been suggested as a potential surrogate marker for treating a subset of patients with IGF1R inhibitors. In this study, we screened a large set of osteosarcomas and found specific CN gains of the IGF1R gene in 18 of 253 (7.1%) cases with corresponding IGF1R overexpression. Despite the discouraging results observed in clinical trials in other tumours so far, focusing only on selected patients with osteosarcoma that show evidence of IGF pathway activation might represent a promising new and innovative treatment approach. [ABSTRACT FROM AUTHOR]

Introduction Simple bone cysts (SBCs) are common in children and adolescents. The risk of refracture and the probability of spontaneous healing in SBCs are mainly dependent on the activity of the cyst and can be quantified with the Cyst-Index. Avoiding pathological fractures is the primary goal. Our study presents a comparison of two different bioresorbable bone graft substitutes (BGSs) in the minimally-invasive treatment of SBC in the active stage by percutaneous cyst aspiration and injection. Methods Between 2006 and 2017, 38 patients (aged two to 37 years; mean age 12.4 (sd 5.6)) were treated with percutaneous cyst aspiration and refilled with bioresorbable BGSs in three hospitals. The cysts of 21 patients (11 humerus, five femur, four calcaneus, one fibula) were refilled with porous beta- tricalcium phosphate (PB-TP group) (ChronOS Inject) and of 17 patients (nine humerus, six femur, one calcaneus, one fibula) with hydroxyapatite/calcium sulphate (H/CS group) (CERAMENT|BONE VOID FILLER). There were 13 (62%) preceding fractures in the PB-TP group and eight (47%) in the H/CS group. The follow-up of all patients was at least two years. During follow-up, radiological healing (modified Neer classification), activity level, refracture rates, recurrence rates, resorption period and complications were analyzed. Results In all, 21 patients treated with PB-TP group experienced 27 operations (one refracture, three recurrences and one persistent cyst). A total of 17 patients treated with H/CS experienced 20 operations (one refracture and one 1 Department of Pediatric Orthopedics, University Children's Hospital Basel, Basel, Switzerland 2 Cantonal Hospital Aarau, Aarau, Switzerland 3 Cantonal Hospital Bellinzona, Bellinzona, Switzerland Correspondence should be sent to Andreas Krieg, University Children's Hospital, Switzerland, Spitalstrasse 33, CH-4053, Basel. E-mail: andreas.krieg@ukbb.ch recurrence). After six weeks, 95% in the PB-TP group returned to unrestricted activity with one refracture in the femur due to insufficient biomechanical stability and all returned to unrestricted activity in the H/CS group. Partial or complete radiological response was observed in 81% after 13 months (sd 3.4). Three recurrences (14%) occurred in the PB-TP group and one recurrence (6%) occurred in the H/CS group. The refracture rates were similar in both groups; one (5%) in the PBTP group and one (6%) in the H/CS group. All H/CS treated cysts showed completed resorption after two years, whilst in PB-TP treated cysts no resorption occurred in five cases (25%) (p = 0.031). Two (10%) wound infections occurred in the PBTP group and no infections occurred in the H/CS group. Conclusion Both PB-TP and H/CS can provide stability and prevent refracture in patients with single bone cysts at the upper extremity or the foot. For the proximal femur, additional stabilization is necessary, due to the weight-bearing and associated high refracture rate. The H/CS bone graft substitute has a better resorption rate than the PB-TP graft. [ABSTRACT FROM AUTHOR]

Primary bone tumors are rare but more frequently seen during childhood and with predilection for the distal femur and proximal tibia. Therapy of benign tumors-if indicated-includes surgical resection in most cases, whereas malignant bone tumors such as osteo- and Ewing's sarcomas are treated with chemotherapy, wide resection and/or radiation therapy (Ewing's sarcoma). The reconstruction of emerging bone defects is significantly influenced by surgeon-related preferences and tumor-associated factors, respectively. Double-barrel vascularized fibula grafts or extracorporeally irradiated autografts in combination with a free fibula transplant are preferred biological reconstruction techniques around the knee joint. In cases in which the knee joint cannot be preserved, reconstruction is performed using tumor endoprostheses, but potentially emerging leg length discrepancies after resection of a potent physis must be taken into account. In considerably young patients, rotationplasty might represent a viable option with promising functional results., (© 2024. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

This study aimed to determine the alteration in maximum isokinetic torque in patients after intramedullary femoral leg lengthening. Thirty patients with a median leg-length discrepancy of 3.0 cm underwent femoral limb lengthening with an intramedullary motorized device. Maximum isokinetic, concentric torque of the extensors, and flexors of the knee was measured before (n=30) and 2 years after surgery (n=21). Postoperatively, a significant difference remained for the maximum isokinetic torque of the extensors (22%) between the lengthened and the normal leg, which might have been caused by muscle response to the distraction procedure itself in the form of higher stiffness, less immediate displacement, and inconsistent force relaxation properties. However, we provide evidence that physiotherapy after limb lengthening should focus on extensors to prevent loss of strength.

Congenital pseudarthrosis of the clavicle (CPC) is a very rare condition with a predilection for the right clavicle. Young children are often only symptomatic with activities and as they grow. Operative management in an asymptomatic child is debatable, with various techniques reported in the literature. This is a retrospective, single-centre case series study. All children with CPC treated surgically by resection, bone grafting (nonvascular iliac crest) and plate fixation between 2004 and 2012 at our centre were included. Excluded conditions were traumatic or obstetric fractures of the clavicle, children with musculoskeletal or neurological disorders and children lost to follow-up. Clinical and radiological examination was performed at 6 weeks, 3 months and between 6 and 12 months postoperatively. A total of eight clavicles in seven children (four girls and three boys), with a mean age of 7.1 years (5-8 years), were operated with a mean follow-up of 7 years (4-10 years). In six children, the right (dominant) side was affected, with one child affected bilaterally. Overall, 85% of our patients showed good functional results 6 weeks postoperatively and complete radiographic consolidation at a mean of 8.5 months (3-25 months) postoperatively. One female child showed delayed union, but without clinical deficit. There was low donor-site morbidity. We recommend early operative treatment of CPC with a nonvascularized bone graft from the iliac crest and plate fixation., Level of Evidence: IV.