A 14-year-old boy was treated for nonmetastasized femoral Ewing sarcoma with inductive and consolidation chemotherapy with surgical resection of the diaphysis and with interposition of an allograft. During follow-up, a remarkable increase in osteoblastic activity in the distal osteotomy plane was observed on Tc-99m disodium hydroxymethylene diphosphonate (HDP) scintigraphy 29 months after surgery that was highly suspicious of recurrence. Revision of radiographs showed delayed consolidation, induced by failure of hardware as the cause of increased tracer uptake. This was confirmed 6 months later by scintigraphy. It is concluded that bone scintigrams should be interpreted with available conventional x-rays to avoid false-positive results.