What is the function of a cement restrictor in cemented arthroplasty, and when is it used?

• A. Increases cement viscosity during curing
• B. Is used in acetabular cementing to fix the cup
• C. Reduces thermal risk during cement curing
• D. Limits cement mantle depth and helps achieve proper pressurization; used in femoral canal cementing

Answer: (D)

A cement restrictor is placed in the femoral canal during cemented arthroplasty to trap the cement and define how far it can flow. By creating a distal stop, it sets and limits the cement mantle depth around the stem and allows intentional pressurization of the cement as it is inserted. This pressurization pushes cement into the cancellous bone, promoting good interdigitation and a solid proximal fixation. It is specifically used for the femoral side of the cemented procedure, not for acetabular cementing. While it may incidentally influence heat generation by limiting cement mass, its primary role is controlling mantle depth and enabling proper pressurization.