Follow-up time, completed years | Metal-on-metal prosthesis (n = 579) | Metal-on-polyethylene prosthesis (n = 1585) | Â | Â | ||||
---|---|---|---|---|---|---|---|---|
 | Obs | SMR | 95% CI‡ | Obs | SMR | 95% CI | RR | 95% CI |
0-1 | 7 | 0.46 | 0.04-1.27 | 27 | 0.50 | 0.03-0.41*** | 0.91 | 0.98 - 1.163 |
2-9 | 75 | 0.81 | 0.62-1.32 | 193 | 0.70 | 0.61-0.96* | 1.16 | 0.88 - 1.52 |
10-19 | 103 | 0.85 | 0.86-1.59 | 326 | 0.97 | 0.67-1.02 | 0.87 | 0.69 - 1.10 |
20+ | 115 | 1.40 | 0.50-1.30 | 156 | 1.40 | 0.61-1.24 | 1.00 | 0.78 - 1.28 |
Total | 300 | 0.96 | 0.78-1.18 | 702 | 0.90 | 0.66-0.87 *** | 1.07 | 0.93 - 1.22 |