Reconstruction options in children after bone tumor resection are as varied as they are challenging. Advances in biologic and endoprosthetic design have led to many choices, all of which must be considered in the context of prognosis, treatment limitations, and patient/family expectations. The current experience and results of limb-sparing surgery following bone sarcoma resection in growing children are discussed, including allograft, autograft, and metallic prostheses alone and in combination, especially as they pertain to the knee. In some cases, the ablative options of amputation and rotationplasty must be seen as equal and, at times, superior choices to limb salvage.