The effects of technique changes on aseptic loosening of the femoral component in hip resurfacing. Results of 600 Conserve Plus with a 3 to 9 year follow-up

The purpose of the present study vas to determine the effectiveness of modifications in the surgical technique loosening of the femoral component in the first 600 consecutive Conserve Plus metal-on-metal hybrid resurfacings (Wright Medical Technologies, Arlington, Tenn). These modifications were gradually introduced over time, but all the changes were implemented after the first 300 hips. The average age of the patients was 48.9 years, and 74% were male. The average follow-up vas 70.5 months for the first 300 hips and 42.4 months for the second 300, and there was a significant improvement (P =.016) of the second 300 hips over the first 300 in a time-dependant analysis using as an end point the time to appearance of a radiolucency, suggesting potential femoral component loosening. None of the components with cemented stems showed femoral radiolucencies or were revised for aseptic loosening. Adding fixation holes in the dome and chamfered areas and cleansing and drying using a suction tip in the dome hole were significantly related to the improvement of the results. Positioning the femoral component in a more valgus position did not show any effect as an independent variable.