Durom Femoral Component Cementing Rationale

The Durom Femoral Component is fixed with PALACOS®* bone cement.  The implant and instruments are designed to produce an even cement mantle of approximately 1mm.  A thin cement mantle (<0.75mm) is a risk of fatigue fracture under physiological cyclical loading.  This could lead to implant loosening.  On the other hand, a thick cement mantle results in more bone resection.1  Finite element analysis (FEA) indicates the optimal cement mantle thickness for a femoral resurfacing component is between 0.75mm – 1.0mm2 .  An even cement mantle around the cylindrical milled femoral head is critical for optimal force transmission, 

If the femoral implant fits “line-to-line” with the reamed femoral head, as in many hip resurfacing systems, the cement pools around the top of the head – thus providing little or no cement mantle around the cylindrical portion of the head. This leads to an unfavorable pattern of stress transmission, as the entire load is carried down a central column of bone in the head.  The consequent peripheral stress shielding may result in neck thinning and neck fracture.  In additions, “line-to-line” femoral components can often be difficult to fully seat, resulting in leg lengthening and exposure of cancellous bone at the head-neck junction, which may increase the subsequent incidence of neck fracture.

*PALACOS® is a trademark of Heraeus Kulzer GmbH.  Under license from Heraeus Kulzer GmbH, Hanau, Geramany.

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Overview
Design Rationale Key Points
Distinct Instrumentation

References

  1. Grigoris, et al. The development of the Durom metal-on-metal hip resurfacing. Hip International. 2006; 16:S65-72.<?>
  2. Soulhat j, Hertig D, Ploeg H, O’Keane M, Roberts P, Grigoris P. Finite element analysis of a cemented hip resurfacing. JBJS Br 2003; 85 (suppl1); S7.