<1 | Optimally functioning joints. Co concentrations in the range of normal physiological values |
1–2 | ‘Normal/expected wear’ and the majority of published studies involving well-functioning hip resurfacing devices report median Co levels in this range31 32 |
2–5 | ‘Equivocal wear’. The significance of Co concentrations in this range are not currently well understood |
5–10 | ‘Increased wear’. A Co concentration ≥5 µg/l is highly sensitive and specific for increased wear of explanted components8 |
>10 | ‘Excessive wear’. In a healthy individual, Co concentrations >10 µg/l signify unequivocally high rates of wear8 |