Correlation of postoperative bone scintigraphy with healing of vascularized fibula transfer: a clinical study

This study examines the usefulness and reliability of bone scintigraphy in correlation with radiological and clinical evidence of bone healing in 15 patients who underwent microvascular transfer of the fibula. All patients were followed for a minimum of 18 months postoperatively. Technetium-99 methylene diphosphonate bone scans and the most recent radiographs were blindly rereviewed. Bone scintigraphic results were characterized as (1) clearly positive (i.e., excellent visualization of the fibula), (2) clearly negative (i.e., no evidence of tracer uptake in the fibula), or (3) indeterminate (i.e., artifact present as a result of metallic or soft tissue interference). Bone radiographs were classified into three typical patterns: (1) complete bony union and graft hypertrophy, (2) incomplete union (either distal or proximal) requiring a second procedure), and (3) nonunion, with increased proximal and distal lucency (with or without pathological fracture) and loss of graft definition. Eleven patients had positive scintigraphic scans postoperatively. In 8 no subsequent procedure was necessary; 2 patients required additional bone grafts to augment the osseous reconstruction; viable fibulas were seen at reoperation. One patient with a positive scan showed decreased graft definition at four months followed by autograft fracture. Three patients had indeterminate scans, 2 of whom evidenced uncomplicated clinical and radiological union. One patient had a clearly negative scan and ultimately tibia-fibula synostosis was required to attain stability. Bone scintigraphy appears to correlate with survival, but not necessarily union, of a vascularized fibula autograft. Additional monitoring techniques should be used in combination with a one-time bone scan to both monitor the patency of the microanastomoses and to prioritize the orthopedic management of the patient.