Aims

Orthopaedic and reconstructive surgeons are faced with large defects after the resection of malignant tumours of the sacrum. Spinopelvic reconstruction is advocated for resections above the level of the S1 neural foramina or involving the sacroiliac joint. Fixation may be augmented with either free vascularized fibular flaps (FVFs) or allograft fibular struts (AFSs) in a cathedral style. However, there are no studies comparing these reconstructive techniques.

The rate of fracture and subsequent nonunion after radiation therapy for soft-tissue sarcomas and bone tumors has been demonstrated to quite high. There is a paucity of data describing the optimal treatment for these nonunions. Free vascularized fibular grafts (FVFG) have been used successfully in the treatment of large segmental bone defects in the axial and appendicular skeleton, however, their efficacy with respect to treatment of radiated nonunions remains unclear. The purpose of the study was to assess the 1) union rate, 2) clinical outcomes, and 3) complications following FVFG for radiation-induced femoral fracture nonunions.

We identified 24 patients who underwent FVFG for the treatment of radiation-induced femoral fracture nonunion between 1991 and 2015. Medical records were reviewed in order to determine oncologic diagnosis, total preoperative radiation dose, type of surgical treatment for the nonunion, clinical outcomes, and postoperative complications. There were 11 males and 13 females, with a mean age of 59 years (range, 29 – 78) and a mean follow-up duration of 61 months (range, 10 – 183 months). Three patients had a history of diabetes mellitus and three were current tobacco users at the time of FVFG. No patient was receiving chemotherapy during recovery from FVFG. Oncologic diagnoses included unspecified soft tissue sarcomas (n = 5), undifferentiated pleomorphic sarcoma (UPS) (n = 3), myxofibrosarcoma (n = 3), liposarcoma (n = 2), Ewing's sarcoma (n = 2), lymphoma (n = 2), hemangiopericytoma, leiomyosarcoma, multiple myeloma, myxoid chondrosarcoma, myxoid liposarcoma, neurofibrosarcoma, and renal cell carcinoma.

Mean total radiation dose was 56.3 Gy (range, 39 – 72.5), given at a mean of 10.2 years prior to FVFG. The average FVFG length was 16.4 cm. In addition to FVFG, 13 patients underwent simultaneous autogenous iliac crest bone grafting, nine had other cancellous autografting, one received cancellous allograft, and three were treated with synthetic graft products. The FVFG was fixed as an onlay graft using lag screws in all cases, additional fixation was obtained with an intramedullary nail (n = 19), dynamic compression plate (n = 2), blade plate (n = 2), or lateral locking plate (n = 1).

Nineteen (79%) fractures went on to union at a mean of 13.1 months (range, 4.8 – 28.1 months). Musculoskeletal Tumor Society scores improved from eight preoperatively to 22 at latest follow-up (p < 0.0001). Among the five fractures that failed to unite, two were converted to proximal femoral replacements (PFR), two remained stable pseudarthroses, and one was converted to a total hip arthroplasty. A 6th case did unite initially, however, subsequent failure lead to PFR. Seven patients (29%) required a second operative grafting. There were five additional complications including three infections, one wound dehiscence, and one screw fracture. No patient required amputation.

Free vascularized fibular grafts are a reliable treatment option for radiation-induced pathologic femoral fracture nonunions, providing a union rate of 79%. Surgeons should remain cognizant, however, of the elevated rate of infectious complications and need for additional operative grafting procedures.