Kolbitsch P, Noebauer-Huhmann I, Giurea A, et al. - In the present study, the researchers sought to check for a significant association between MRI findings, serum metal levels and clinical scores in patients with small-head metal-on-metal implants and whether serum cobalt and chromium levels are sufficient in detecting patients with pseudotumors in the long-term follow-up. At a minimum follow-up of 20 years, 26 patients (29 THAs) of the originally 98 patients (105 THAs), involved in this research between November 1992 and May 1994 were available for a follow-up examination. In the long-term follow-up, authors observed mean serum cobalt levels of 1.87 μg/L (± 3.44) and chromium levels of 2.23 μg/L (± 2.96), as well as very good clinical and functional results (mean HHS 88.6). This investigation gives the first published data on small-head metal-on-metal hips, comparing metal ion levels, pseudotumors, clinical and radiological outcomes in a follow-up period of more than 20 years and shows that serum metal levels are not significantly higher in patients with pseudotumors.