|   Polyethylene | Zirconia | N | Mean followup | Steady-state wear rate | P value | |
---|---|---|---|---|---|---|---|
 |  |  |  | (years) | Yttria stabilized zirconia | Cobalt chromium |  |
 |  |  |  |  | (mm/year) |  | |
Nakahara et al. [13] | Longevity (Zimmer) | (NGK) | 51 | 7 | −0.01 | −0.01 | 0.83 |
Kawate et al. [16] | Aeonian (JMM) | (JMM) | 32 | 5 | 0.00 | 0.01 | 0.36 |
Fukui et al. [17] | Longevity (Zimmer) | (NGK) | 45 | 5 | 0.01 | Â | Â |
Miyanishi et al. [15] | Aeonian (JMM) | (JMM) | 95 | 2 | 0.06 | Â | Â |
Present study | Excellink (JMM) | (JMM) | 91 | 7 | 0.02 | Â | Â |