Pseudotumours, cobalt and clinical outcome in small head metal-on-metal versus conventional metal-on-polyethylene total hip arthroplasty

van der Veen, H. C., Reininga, I. H., Zijlstra, W. P., Boomsma, M. F., Bulstra, S. K. & van Raay, J. J., Jan-2020, In : Hip international. 30, 1, p. 56-63 8 p.

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BACKGROUND:: Metal-on-metal total hip arthroplasty (MoM THA) is associated with the formation of pseudotumours. Studies mainly concern pseudotumour formation in large head MoM THA. We performed a long-term follow-up study, comparing pseudotumour incidence in small head metal-on-metal (SHMoM) THA with conventional metal-on-polyethylene (MoP) THA. Predisposing factors to pseudotumour formation were assessed.

METHODS:: From a previous randomised controlled trial comparing SHMoM (28 mm) cemented THA with conventional MoP cemented THA, patients were screened using a standardised CT protocol for the presence of pseudotumours. Serum cobalt levels and functional outcome were assessed.

RESULTS:: 56 patients (33 MoP and 23 MoM) were recruited after mean follow-up of 13.4 years (SD 0.5). The incidence of pseudotumours was 1 (5%) in the SHMoM THA cohort and 3 (9%) in the MoP THA cohort. Prosthesis survival was 96% for both SHMoM and MoP THAs. Serum cobalt levels did not exceed acceptable clinical values (<5 µg/L) whereas no differences in cobalt levels were detected at follow-up between both groups. Oxford and Harris Hip Scores were good and did not differ between SHMoM and MoP THA.

CONCLUSIONS:: This long-term follow-up study shows a low incidence of pseudotumour formation and good functional outcome in cemented head-taper matched SHMoM and MoP THA.

Original languageEnglish
Pages (from-to)56-63
Number of pages8
JournalHip international
Issue number1
Early online date2019
Publication statusPublished - Jan-2020


  • Cobalt, metal-on-metal, pseudotumour, small head, total hip arthroplasty, REPLACEMENT, VALIDATION, EXPERIENCE, CORROSION, BEARING, COHORT, AGE

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