INFLUENCE OF FEMORAL COMPONENT DESIGN ON CEMENT PENETRATION IN HIP RESURFACING ARTHROPLASTY

Wadih Y. Matar, MSc, M.D.
Ottawa, ON

P. Poitras
K. Smit
O. May
P.E. Beaulé

Introduction: Retrieval analyses of failed hip resurfacings have shown variability in cement penetration and mantle. Multiple factors have been shown to influence cement penetration. The objective of this study is to determine the effect of femoral component design on cement penetration.

Methods and Materials: Six femoral heads were resurfaced for each of the four designs: BHR®, ASR®, Conserve® and ReCap® using the manufacturer's recommended cementing technique. In addition, the BHR was implanted using the Conserve cementing technique "BHR(Conserve)" and vice-versa for the Conserve "Conserve(BHR)". Statistical analysis was completed using a one-way ANOVA (p<0.05).

Results: Average cement penetration was statistically highest with BHR (65.6+/-15.2%) compared to Recap (26.1+/-5.2%), Conserve (19.4+/-5.3%) and ASR (12.2+/-5.1%) (p<0.05). Cement penetration in BHR(Conserve) group remained statistically higher than all other implants (36.7+/-6.6%) (p<0.05), whereas Conserve(BHR) group did not show a difference. Mantle thickness was greatest with BHR(Conserve) group 2.92+/-0.72mm (p<0.05).

Conclusion: Cement penetration was greatest with the BHR using its low-viscosity cementing technique. When tested with the Conserve's high viscosity cementing technique, cement penetration was still greater than the remaining four groups. This suggests that the implant design itself, and more specifically, its clearance play a critical role. Hip resurfacing surgeons need to understand this since excessive or insufficient penetration can lead to early failure.