endoprostheses

Endoprosthesis is an internal prosthetic device implanted to replace a missing biological structure or to restore function of a damaged organ or limb. Endoprostheses are placed inside the body during surgery and are designed to withstand mechanical loads while maintaining biocompatibility with surrounding tissues. The term encompasses a range of devices used across multiple medical specialties, including orthopedic and vascular procedures.

Orthopedic endoprostheses are the most widespread. They include total or partial joint replacements such as hip, knee, and shoulder prostheses, as well as replacements for the elbow or ankle. Vascular endoprostheses include stent implants and endovascular grafts used to treat conditions such as aneurysms or arterial occlusive disease.

Design and materials: Endoprostheses are typically constructed from metallic alloys (such as titanium, cobalt-chromium, or stainless steel), ceramics, and get bearing surfaces from polymers like ultra-high-molecular-weight polyethylene. Many devices employ porous or textured surfaces to promote bone ingrowth for cementless fixation, or are mastic with bone cement for cemented fixation. Modularity allows surgeons to mix components.

Clinical considerations: Indications include pain relief, restoration of joint function, and stabilization of the limb. Outcomes vary by device and patient, but joint endoprostheses generally improve mobility and quality of life. Complications can include infection, loosening or wear leading to osteolysis, mechanical failure, fracture of the prosthesis, thrombosis or endoleaks in vascular devices, and rarely allergic reactions to materials.

History and regulation: Modern endoprostheses emerged in the mid-20th century and have evolved with advances in biomaterials and surgical techniques. Regulatory oversight and post-market surveillance govern their approval and long-term performance, with ongoing research focused on durability, wear resistance, and biocompatibility.