uncemented

Uncemented, in the context of arthroplasty and other implants, refers to fixation methods that do not use bone cement to secure the implant to bone. Instead, uncemented implants rely on a precise press-fit at implantation and subsequent biological fixation via bone in-growth into porous or textured surfaces, or on-growth around the implant.

In hip arthroplasty, shoulder, knee prostheses, and other joint replacements, uncemented designs use porous titanium or cobalt-chromium surfaces often with hydroxyapatite coatings to promote osseointegration. The goal is to achieve stable fixation initially by press-fit and later by bone ingrowth, allowing load transfer to living bone.

Advantages include preservation of bone stock, avoidance of cement-related debris, and potentially long-term stability if osseointegration succeeds. Disadvantages include the need for adequate bone quality for initial fixation, a longer period to achieve full fixation, and higher risk of early loosening or periprosthetic fracture if fixation is inadequate. Patient selection and surgical technique are important factors in success.

Compared with cemented implants, uncemented devices may have different failure profiles: cemented components provide immediate fixation with a cement mantle but can complicate revisions due to cement versus bone interface. Modern cementless implants have improved survival rates in younger, active patients and in those with good bone quality, while cemented implants remain common in older patients with osteoporosis or poor bone stock.