Patterns of cement distribution in total hip resurfacing arthroplasty.

In this in vitro study, 4 different resurfacing implants have been evaluated with a simulated femoral head: 2 types of cement have been used (low and high viscosity) and 2 different cementing techniques have been performed: direct (cement apposition directly on the femoral head) and indirect (cement poured into the femoral component). High-viscosity cement shows a homogeneous distribution all over the femoral head. Low-viscosity cement shows a massive polar concentration with insufficient if not absent distribution in the equatorial zone. Polar cement concentration could be held as a risk factor for early implant failure. It could have 2 effects on femoral head: biologic (excessive local exothermic reaction could cause necrosis of the osteocytes) and biomechanical (it could lead to uneven load distribution on the femoral head).