A 32-year-old man with a known giant cell tumor of the distal femur underwent curettage 18 months ago. He now presents with recurrent pain and swelling over the same site. Repeat radiographs show a new lytic lesion at the previous surgical site with a similar soap bubble pattern. Histology confirms recurrent GCT. Which of the following adjuvant techniques would have been most effective in reducing recurrence risk at the time of initial surgery?