Long-term Results of Intercalary Endoprosthetic Short Segment Fixation Following Extended Diaphysectomy

Intercalary endoprosthetic reconstruction following diaphyseal resection of osseous tumors offers functional advantages through preservation of native joints adjacent to the resected defect. Use of such implants is restricted by the amount of bone available for stem fixation adjacent to the defect. This study aimed to determine whether short osseous segment fixation with acceptable outcomes and complication rate can be reliably achieved with a customized intercalary endoprosthesis following extended diaphysectomy. A retrospective review of prospectively collected data was performed on 6 patients receiving customized anchor plugs for short segment fixation with a double compressive osseointegration intercalary implant to reconstruct segmental defects. Five of the implants were augmented with cement to support fixation in metaphyseal bone. Patient age at surgery ranged from 12 to 86 years. At mean follow-up of 39 months, mean Musculoskeletal Tumor Society functional score was 26.3, with 5 of 6 patients achieving scores of 27 or greater. Stable fixation was achieved in all patients, with the shortest segment of bone 3.7 cm in length. Three mechanical implant failures requiring revision surgery occurred. No patient required revision of the entire implant, secondary adjacent joint replacement, or secondary amputation. No patient exhibited aseptic loosening, and no case was complicated by infection. Excellent functional outcomes were seen with follow-up out to 9 years. This suggests that cement-augmented double compressive osseointegration intercalary endoprosthetic reconstruction can extend the benefits of intercalary replacement to many patients who otherwise might require adjacent joint or physeal sacrifice. However, patients should be counseled on the high risk of implant failure with subsequent need for revision surgery. [Orthopedics. 2017; 40(6):e964-e970.].