Intercalary Diaphyseal Endoprosthetic Reconstruction

Abstract

Intercalary endoprosthetic devices are a diaphyseal segmental reconstructive option for both primary tumors and skeletal metastases, most used for pathological fractures or failure of internal fixation. Numerous designs have been employed with varying success. These implants require adequate quality and length bone stock, both proximal and distal, to be employed. Alternative reconstructions may include vascularized fibula autograft, allograft reconstruction, acute shortening, and fixation with cement spacer augmentation with planning staged procedures. The reported functional results and complication profile of intercalary endoprostheses are acceptable, but their use is carefully considered, as aseptic loosening remains one of the most common risks for failure. Although successful at short follow-up, these devices are often used for patients with segmental destruction or tumor involvement of the upper extremity, particularly in cases with metastatic bone disease or myeloma. In this review, we discuss the numerous designs, indications and contraindications, alternative options, biomechanics, reported results, and complications.

Figure 1

the original Stryker intercalary humeral spacer design employed a male-female taper that was convenient in terms of achieving the desired rotational alignment of the two segments but required 2.04 cm of distraction to reduce the taper, resulting in 18% incidence of neurapraxia. This original design is shown here preassembled (A) and postassembly (B) (The figure used with permission from Wolters Kluwer Health.)

Figure 2

Although the female-male taper design in the Global Modular Replacement System (GMRS, Stryker) system has been abandoned for humeral intercalary spacers, it has been retained for the femoral intercalary spacers, where distraction is not as much of an issue due to the capacity of the thigh soft tissues and sciatic nerve to accommodate it. The intercalary GMRS femoral device shown here (right) has a female body component that can be assembled to any male stem (left) component (with or without body) to serve as an intercalary reconstructive endoprosthesis (Figures used with permission of Stryker)

Figure 3

Image showing lap joint articulating segments A lap joint set screw secured design (A) has replaced the original male-female taper design (Figure 1) for Stryker humeral intercalary endoprosthetic reconstruction to decrease the incidence of neurapraxia attributed to the need for distraction with the earlier design. Intraoperative photographs show the body portions attached to their corresponding stems, which have been cemented in place before the lap joint is closed and secured (B). After the lap joint is closed, two set screws are placed mediolateral and lateral medial (C). Care must be taken to ensure that the desired rotation is achieved before allowing cement to harden and that the final position of the screw holes is accessible. Postoperative anterior-posterior radiograph (D) shows the cemented stems and body in place within the humerus (The figure used with permission from Wolters Kluwer Health).

Figure 4

Radiographs showing the intramedullary diaphyseal segmental defect fixation system (Osteobridge IDSF; Merete) in the (A) femur, (B) tibia, and (C) humerus. In this system, the body segment is independent of the stems and is secured to them with screws. Intraoperative photograph (D) showing the body of the IDSF system in situ (The figure used with permission from Wolters Kluwer Health).

Figure 5

Intraoperative photograph (A) showing the compressive osteointegration device (Compress, Biomet, Warsaw, Indiana) in the proximal femur. The use of intercalary osteointegration devices has been reported in the femur. Postoperative anterior-posterior and lateral radiographs (B) showing the implanted compressive osteointegration device in the proximal femur. This device is particularly advantageous when limited intramedullary canal remains after bone resection (Adapted with permission from Wolters Kluwer Health).

Figure 6

Images showing custom, three-dimensional, printed, intercalary proximal tibial endoprostheses were used to preserve proximal tibial epiphyseal plate function following intercalary resection of a proximal, tibial, metadiaphyseal osteosarcoma. The (A) design planning, (B) custom device, and (C) postoperative anterior-posterior and lateral radiographs are shown. In (A), both the 3D model (left) and cross-sectional model (right) are shown (This work is licensed under a Creative Commons Attribution CC BY Generic License. It is attributed to Lu M, Li Y, Luo Y, Zhang W, Zhou Y, Tu C. Noncemented three-dimensional-printed prosthetic reconstruction for massive bone defects of the proximal tibia. World J Surg Oncol 2018;16(1):47. doi: 10.1186/s12957-018-1333-6. Figures 5–7).

Figure 7

Image showing a novel lap joint intercalary spacer design (Wego, Beijing, China) supplemented by a plate. The implant components and design plans are shown (Used with permission from John Wiley and Sons, Australia [Zhao LM, Tian DM, Wei Yet al. Biomechanical analysis of a novel intercalary prosthesis for humeral diaphyseal segmental defect reconstruction. Orthop Surg 2018;10(1):23-31. doi: 10.1111/os.12368. Figure 2]).

Figure 8

Lap joint intercalary spacer design supplemented by single plate affixed to body segment by two screws. Disassembled components (A) and assembled device (B) (Used with permission from Chinese Orthopaedic Association and John Wiley and Sons, Australia [Huang HC, Hu YC, Lun DX, Miao J, Wang F, Yang XG, Ma XL. Outcomes of intercalary prosthetic reconstruction for pathological diaphyseal femoral fractures secondary to metastatic tumors. Orthop Surg 2017;9(2):221-228. doi: 10.1111/os.12327]).