Type-B-IIIa hip rotationplasty: an alternative operation for the treatment of malignant tumors of the femur in early childhood.
BACKGROUND: The biological plasticity of the cartilaginous proximal part of the tibia in children makes it possible to use the tibia to reconstruct the lower extremity after excision of a sarcoma of the thigh. A type-B-IIIa rotationplasty is an alternative to prosthetic replacement in very young children who have a malignant tumor of the femur that requires extensive resection. METHODS: A type-B-IIIa rotationplasty was done in eight patients who had a femoral tumor: four had a Ewing sarcoma; three, an osteosarcoma; and one, a primitive neuroectodermal tumor. The ages ranged from two years and eight months to ten years and six months at the time of the procedure. RESULTS: All eight patients were able to bear full weight and had a good range of motion of the hip joint at a median of five years and one month (range, two years and four months to eight years) postoperatively. They also were able to participate in sports activities. Radiographs and magnetic resonance imaging studies confirmed that the lateral part of the tibial plateau had remodeled to form a structure that resembled a developing femoral head. Seven patients were operated on only once, and a second hospital stay was not necessary. The remaining patient had a prolonged hospitalization for revision of the wound. CONCLUSIONS: As an alternative to amputation or an extendable tumor prosthesis, a type-B-IIIa rotationplasty offers not only a better functional result but also biological reconstruction. Placement of the cartilaginous head of the tibia into the acetabulum permits development of a new femoral head. Thus, not only is the foot preserved as a functional knee joint but a newly formed hip joint develops as well.