Metal ion levels in ceramic-on-ceramic THR with cobalt-chrome modular necks: analysis of cobalt and chromium serum levels in 23 healthy hip patients



Modular necks in total hip replacement (THR) can be a source of metal ion release.


We measured the level of cobalt (Co) and chromium (Cr) ions in the serum of 23 healthy volunteers with a well-functioning ceramic-on-ceramic THR of a particular design, containing a cobalt-chrome (Co-Cr) stem and a Co-Cr modular neck.


Average Co in serum was 1,71 µg/l; median Co was 1.50 µg/l. No patient had Co levels higher than 3.70 µg/l. Average Cr level was 0.49 µg/l; in all but one patient Cr was below the detection limit (<0.50 µg/l). Co was higher for varus necks compared to all other subtypes: 2.14 µg/l vs 1.58 µg/l (p<0.05). The same system with Titanium modular necks shows lower Co serum levels: 1.26 µg/l (p<0.01 ). In conclusion, the hybrid THR Profemur Xm® – Procotyle L® with a Co-Cr modular neck on a Co-Cr stem design shows very low Cr ion serum levels in a randomly selected group of well-functioning hip patients.


Co ion serum levels are low, but significantly higher for 8° varus necks, and Co levels are significantly higher than values of this system with a Titanium modular neck.

Hip Int 2017; 27(1): 21 - 25




Jan F.A. Somers, Lieven Dedrye, Sofie Goeminne

Article History


Financial support: None.
Conflict of interest: None.

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  • Department of Orthopaedic and General Surgery, Jan Yperman Hospital, Ypres - Belgium
  • Department of Orthopaedic Surgery, Catholic University of Leuven, Leuven - Belgium

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