Rotationplasty is a useful option for limb salvage surgery in pediatric patients with malignant bone and soft tissue tumors. However, bone growth after rotationplasty remains poorly characterized. We present a case of a 3-year-old boy with extraskeletal Ewing sarcoma who underwent multidrug chemotherapy (vincristine, doxorubicin, ifosfamide and etoposide), wide resection and functional reconstruction with rotationplasty. No radiotherapy was administered during the treatment course and the patient has been followed up for 16 years after rotationplasty. Leg length at skeletal maturity was predicted using postoperative radiograph measurements of the affected leg at the age of 4 years. Two conventional prediction methods, the multiplier and straight-line graph methods were used for prediction. The predicted leg length was compared with the actual leg length to assess bone growth after rotationplasty. Immediately after surgery, the lengths of the affected lower leg, femur and tibia were 32.5, 15.0 and 17.6 cm, respectively, and the predicted leg length of the affected leg at skeletal maturity using the multiplier and straight-line graph methods was 44.6 and 44.2 cm, respectively. However, the actual length of the affected leg at skeletal maturity was 49.8 cm, and the gap between actual and predicted lengths was more than 5 cm. In conclusion, the affected leg after rotationplasty showed more than expected bone overgrowth compared with the predictions of the conventional methods.
Keywords: Ewing sarcoma; bone development; limb salvage.
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