Outcome of the intramedullary diaphyseal segmental defect fixation system for bone tumors

Resection of diaphyseal malignant bone tumors is indicated for local control and impending pathological fracture or failure of prophylactic internal fixation. However, there are no large, long-term studies analyzing the results of intercalary reconstruction using segmental metallic spacers.

We present 24 patients treated with wide resection for primary or metastatic bone tumors involving the diaphysis of the femur, tibia, or humerus and reconstruction using a modular intramedullary diaphyseal segmental defect fixation system. The mean length of bone resection was 10 cm. The postoperative complications and outcome were evaluated.

At a mean follow-up of 29 months, 17 patients were alive and 7 patients were dead of disease; no patient had local recurrence. Implant-related complications occurred in 8 patients, the most common being mechanical loosening and rotational instability. Loosening was most common in reconstructions of more than 10 cm length of bone resection. In all femoral reconstructions, mechanical failure occurred at the proximal stem. True limb length discrepancy of 2.0 cm was observed in one patient. Wound healing complications were not observed; range of motion and function of the adjacent joints was within normal limits.

The modularity, ease of application and preservation of the adjacent joints are major advantages of segmental modular prostheses; however, the complications' rate is high. Complications occur most often at the proximal stem in femoral reconstructions and reconstructions for more than 10 cm length of bone resection. In these cases, the use of these implants should be reconsidered or not recommended.