Intercalary femur allografts are an acceptable alternative after tumor resection

Abstract

Background: With the improved survival for patients with malignant bone tumors, there is a trend to reconstruct defects using biologic techniques. While the use of an intercalary allograft is an option, the procedures are technically demanding and it is unclear whether the complication rates and survival are similar to other approaches.

Questions/purposes: We evaluated survivorship, complications, and functional scores of patients after receiving intercalary femur segmental allografts.

Patients and methods: We retrospectively reviewed 83 patients who underwent an intercalary femur segmental allograft reconstruction. We determined allograft survival using the Kaplan-Meier method. We evaluated patient function with the Musculoskeletal Tumor Society scoring system. Minimum followup was 24 months (median, 61 months; range, 24-182 months).

Results: Survivorship was 85% (95% confidence interval: 93%-77%) at 5 years and 76% (95% confidence interval: 89%-63%) at 10 years. Allografts were removed in 15 of the 83 patients: one with infection, one with local recurrence, and 13 with fractures. Of the 166 host-donor junctions, 22 (13%) did not initially heal. Nonunion rate was 19% for diaphyseal junctions and 3% for metaphyseal junctions. We observed an increase in the diaphysis nonunion rate in patients fixed with nails (28%) compared to those fixed with plates (15%). Fracture rate was 17% and related to areas of the allograft not adequately protected with internal fixation. All patients without complications had mainly good or excellent Musculoskeletal Tumor Society functional results.

Conclusions: Diaphyseal junctions have higher nonunion rates than metaphyseal junctions. The internal fixation should span the entire allograft to avoid the risk of fracture. Our observations suggest segmental allograft of the femur provides an acceptable alternative in reconstructing tumor resections.

Level of evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Fig. 1A–B

(A) An AP radiograph shows a patient with a diaphyseal osteosarcoma. (B) An AP radiograph shows a 4-year followup control with an intercalary allograft stabilized with two-plate fixation in the proximal and distal metaphyseal osteotomies. The entire length of the allograft is protected with lateral plate fixation.

Fig. 2A–C

(A) A MR image shows a 36-year-old patient with a diaphyseal chondrosarcoma. (B) An AP radiograph shows a 6-month followup control with an intercalary allograft stabilized with a locked intramedullary nail. (C) An AP radiograph shows a 7-year control of the intercalary allograft with incorporation of the graft and healing of both osteotomies.

Fig. 3

A graph shows a Kaplan-Meier curve for survival of the intercalary allografts. The overall survival rate of the 83 intercalary allografts was 85% at 5 years (95% CI: 93%–77%) and 76% at 10 years (95% CI: 89%–63%).

Fig. 4A–C

In a patient who was reconstructed after tumor resection with an intercalary femur allograft stabilized with an intramedullary nail and screws, a fracture occurred at the level where the allograft was not covered by the internal fixation. (A) AP and (B) lateral radiographs show the metaphyseal area is not protected with internal fixation. (C) A lateral radiograph shows the knee after a metaphyseal fracture in the area not protected with internal fixation.