Table 2.

Kaplan-Meier survivorship results computed using the time to revision for any reason as the end point

Followup	Osteonecrosis group		Control group
	Survivorship	95% confidence interval	Survivorship	95% confidence interval
3 years	97.5%	90.3%–99.4%	98.4%	97.1%–99.1%
5 years	95.7%	87.0%–98.6%	95.4%	93.1%–96.9%
8 years	93.9%	84.1%–97.7%	93.4%	90.4%–95.5%