Use of extendable total femoral replacements in children with malignant bone tumors

Although rarely required, extendable reconstruction devices for replacing t he entire femur offer children with malignant bone tumors the opportunity o f a nearly normal development by overcoming an expected leg length discrepa ncy. Femoral integrity can be restored, allowing most patients to walk with out the use of aids. There are no data available to provide evidence regard ing long term results and morbidity in such patients. Six patients (range 2 -12 years of age), three with osteogenic osteosarcoma and three with Ewing' s sarcoma, were treated between 1988 and 1996 with custom made Stanmore ext endable prosthetic total femoral replacements. One patient died 12 months a fter surgery because of complications relating to pulmonary metastasis. The remaining five patients were observed be tween 2.7 and 8.9 years (average, 5 years). No tumor recurrence has been recorded and no amputation has been performed. All surviving patients underwent an average of 9.4 operative pr ocedures (range, 4-16 procedures) including 6.4 extension procedures (range , 3-10 procedures), and one prosthetic revision (range, 0-3 procedures). Fi ve revisions in two patients were necessary because of infection, loosening of the prosthesis, mismatch between femoral head and acetabulum, or full e xtension of the extending mechanism. The functional results were measured i n accordance with the Musculoskeletal Tumor Society rating score, with an a verage result of 77.3 %, Total femoral replacement in a growing individual achieves good functional results yet has various risks for an uncertain out come. Careful selection of the patient and realistic appraisal of the long term prospects are essential for successful treatment.