What is the difference among cemented, uncemented, and hybrid acetabular components in hip arthroplasty?

• A. Cemented uses screws for fixation; uncemented uses bone cement.
• B. Cemented uses porous coating for bone ingrowth; uncemented relies on bone cement.
• C. Cemented uses bone cement; uncemented relies on porous coating for bone ingrowth; hybrid combines cemented and uncemented fixation strategies across shell/stem.
• D. All rely on bone cement.

Answer: (C)

The key idea is how the acetabular cup attaches to the pelvis and how fixation is achieved. In a cemented cup, bone cement (usually polymethyl methacrylate) is used to bond the shell to the bone, providing immediate fixation once the cement cures. In contrast, an uncemented (cementless) cup relies on a porous coating or rough surface that allows bone to grow into or onto the shell over time, creating biological fixation; initial stability comes from a good press-fit and sometimes supplemental screws. A hybrid cup-stem approach mixes these strategies, using one component fixed with cement and the other relying on a porous surface for bone ingrowth, depending on surgeon preference and bone quality.

So the best description is that cemented uses bone cement; uncemented relies on porous coating for bone ingrowth; hybrid combines cemented and uncemented fixation strategies across shell and stem.