TABLE IV.

Results from the Random-Effects Model^*

	Hazard Ratio†	P Value
Time
One year	Reference	—
More than one year to two years	4.249 (3.819 to 4.727)	<0.001
More than two years to three years	5.479 (4.920 to 6.100)	<0.001
More than three years to four years	6.499 (5.834 to 7.240)	<0.001
More than four years to five years	7.374 (6.615 to 8.220)	<0.001
More than five years to six years	8.263 (7.407 to 9.218)	<0.001
More than six years to seven years	9.397 (8.413 to 10.496)	<0.001
More than seven years to eight years	10.497 (9.383 to 11.743)	<0.001
More than eight years to nine years	12.036 (10.717 to 13.518)	<0.001
More than nine years to ten years	15.057 (13.102 to 17.304)	<0.001
Sex
Male	Reference	—
Female	0.805 (0.763 to 0.850)	<0.001
Head size
<32 mm	Reference	—
≥32 mm	0.836 (0.775 to 0.902)	<0.001
Bearing type
Ceramic on ceramic	Reference	—
Ceramic on conventional polyethylene	0.969 (0.846 to 1.111)	0.655
Ceramic on highly cross-linked polyethylene	1.084 (0.952 to 1.234)	0.226
Metal on conventional polyethylene	1.046 (0.936 to 1.169)	0.426
Metal on highly cross-linked polyethylene	0.830 (0.760 to 0.907)	<0.001
Fixation effects by age
Hybrid, forty-five to more than seventy-five years	Reference	—
Uncemented, forty-five to sixty-four years	1.206 (1.021 to 1.423)	0.028
Cemented, forty-five to sixty-four years	1.095 (0.884 to 1.357)	0.406
Uncemented, sixty-five to seventy-four years	1.160 (1.032 to 1.304)	0.013
Cemented, sixty-five to seventy-four years	1.051 (0.907 to 1.217)	0.511
Uncemented, seventy-five years or more	1.559 (1.387 to 1.751)	<0.001
Cemented, seventy-five years or more	0.913 (0.790 to 1.055)	0.217

^*The estimate (and the standard error) was −5.049 ± 0.091 for the fixed intercept and 0.013 ± 0.018 for the random intercept.

^†The values are given as the hazard ratio, with the 95% CI in parentheses.