For patients too young to be fitted with an expandable prosthesis, limb salvage surgery requires other strategies. The main problems are related to the impossibility of implanting an expandable prosthesis to the residual bone growth that is much too big in relation to the bone size, with the precocious implant loosening and/or the residual absence of bone growth, as well as the problem of limb length and shape difference. In this paper, we report a possible reconstruction solution using a composite prosthesis for an Ewing’s sarcoma of the proximal femur in an infant patient. After resection, a femoral stem was cemented into the distal third of a homoplastic humerus; a carbon fiber plate was used to stabilize the bone/homograft interface. At the one-year follow-up, the patient was free of disease and able to walk with only a slight limp. This case report describes a possible solution for very small patients. An adult humerus is of the right size to replace a child’s lower limb segments, and the distal humerus can be shaped, maintaining a cortex stiff enough to support a prosthesis. Very young patients might obtain a faster osteointegration of the graft than adults, due to their higher biological activity and, in this case, the diapasonal shape of the allograft might also have contributed to accelerated fusion. Moreover, the use of a graft to fit the prosthesis avoids loosening issues due to canal widening, hypothetically providing more growing time before system failure and revision surgery. However, although this technique is promising, further studies are necessary to confirm our findings and to verify if this procedure allows easier future prosthesis implantation.

Background: Heel pain in children is a common condition. The aetiology can be ascribed to fractures, osteochondrosis, tendinitis, calcaneal-navicular or talo-calcaneal coalition, osteomyelitis, rheumatic diseases, anatomic variants, malignant tumours (osteosarcoma, Ewing’s sarcoma), and benign lesions (bone cyst, aneurismal bone cyst, osteoid osteoma, or exostosis). In particular, this manuscript focuses on a case of calcaneal exostosis in the paediatric age, aiming to highlight its rarity. Osteochondromas are benign tumours of the surface of the bone and the overlying cartilage. They grow until skeletal maturity and can cause stiffness, pain, cosmetic alterations, tendinitis, and neuro-vascular compression. The calcaneus is an extremely rare site for these tumours. Only two case reports of paediatric exostosis of the calcaneus bone are available. Methods: We describe a case of a girl of 16 years of age, affected by multiple cartilaginous exostosis, who presented with a painful mass on the inferior margin of the foot in the calcaneal region, which was diagnosed as an exostosis. The neoformation was excised, and the girl underwent clinical follow-up. Results: The patient was promptly discharged in good condition, and on the 25th postoperative day, she was completely pain-free and allowed weight bearing. Conclusions: In the case of heel pain resistant to conservative treatment, the presence of an osteochondroma should be considered after excluding more common causes. If symptomatic, calcaneal osteochondromas could require surgical excision.