A 32-year-old man underwent intralesional curettage with phenol and bone grafting for a giant cell tumor of the distal radius 18 months ago. He now presents with progressive swelling and pain in the wrist. Imaging shows a recurrent lesion measuring 3.5 cm × 2.8 cm at the same site, with erosion into the adjacent cortex. There is no evidence of pulmonary metastases. What is the most appropriate next step in management?