Oncologic reconstruction of the proximal femur in children younger than 9 years using a proximal humerus allograft and a hip prosthesis: Report of two cases and description of the surgical technique.

IntroductionProximal femoral tumor resection poses a major challenge in orthopaedic oncology, particularly in very young pediatric patients (<9 years), where the need to preserve function and limb length collides with the limited availability of reconstructive options (3D-printed implants, endoprostheses, biological constructs such as vascularized fibular grafts, and allograft-prosthetic composites) or leads to amputation.ObjectiveTo describe in detail the surgical technique for proximal femoral tumor resection and reconstruction using an allograft-prosthetic composite (APC) with a proximal humerus allograft plus a hip prosthesis, documenting its applicability and outcomes regarding function, allograft survival, and oncologic disease status in two pediatric cases treated at a national cancer referral center in Bogotá, Colombia.MethodsWe report two pediatric cases and detail the surgical technique used for proximal femoral reconstruction after tumor resection, based on an APC (proximal humerus allograft + hip prosthesis). Data were collected from medical records with radiological and functional follow-up.ResultsIn both patients, proximal femoral reconstruction using our technique yielded a stable construct with preservation of limb function (MSTS >72), documented graft incorporation at 3 months, local disease control, and only one recorded complication (contact dermatitis).ConclusionProximal femoral reconstruction using an APC with a proximal humerus allograft is a viable and safe surgical option in pediatric patients with Ewing sarcoma. In our experience, the technique was successfully applied in two patients, allowing limb preservation with a favorable course. Thus, it offers a functional and reliable option for limb salvage in selected cases.