The Value of Serial Metal Ion Levels in following up Patients with Metal-on-Metal Hip Arthroplasty

Background The sensitivity of cobalt (Co) and chromium (Cr) ion-levels in detecting poorly performing metal-on-metal hip implants is low. This study proposes that serial changes in ion-levels are a more accurate marker of arthroplasties at risk. Methods Serial metal ion-levels and implant data of 285 patients with ASR resurfacing or replacement were studied. Patient and implant characteristics were analysed using univariate and multivariate analyses. Results 111 (39%) had revision surgery. Time since index surgery (p≤0.001), acetabular inclination (p≤0.001), their interaction (p≤0.001) and femoral head size (p = 0.01) were significant variables. Head size (≤51 mm) had lower Co and Cr levels (p = 0.01). Cr/Co showed marginal decrease over time in the unrevised group and no decrease prerevision. Conclusions Repeated measurement of ion-levels were higher in the revision group suggesting that serial measurements rather than absolute values may have a role to play in predicting implant failure.

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Comparison between component designs with different femoral head size in metal-on-metal total hip arthroplasty; multicenter randomized prospective study

Journal of Orthopaedics ◽

10.1016/j.jor.2015.05.008 ◽

2015 ◽

Vol 12 (4) ◽

pp. 228-236 ◽

Cited By ~ 4

Author(s):

Wataru Ando ◽

Kengo Yamamoto ◽

Takashi Atsumi ◽

Satoshi Tamaoki ◽

Kazuhiro Oinuma ◽

...

Keyword(s):

Femoral Head ◽

Total Hip Arthroplasty ◽

Prospective Study ◽

Hip Arthroplasty ◽

Head Size ◽

Femoral Head Size ◽

Total Hip ◽

Metal On Metal

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Early Post-operative Rises in Serum Metal Ion Levels in Total Hip Arthroplasty

Reconstructive Review ◽

10.15438/rr.10.1.238 ◽

2020 ◽

Vol 10 ◽

Author(s):

Michael Le ◽

Dante Maestri ◽

Bob Jang ◽

Jason Chinnappa ◽

Sol Qurashi

Keyword(s):

Femoral Head ◽

Total Hip Arthroplasty ◽

Hip Arthroplasty ◽

Metal Ion ◽

Head Size ◽

Diagnostic Process ◽

Head Group ◽

Femoral Head Size ◽

Total Hip ◽

Metal Head

Background: Serum Cobalt (Co) and Chromium (Cr) forms part of the diagnostic process for metallosis following Total Hip Arthroplasty (THA). While knowledge exists on longer term metal ion levels, expected early post-operative rises in serum Co and Cr in Metal-on-Polyethylene (MoP) THAs are currently unknown. This study aims to describe early rises in serum Co and Cr at 6 months post-operatively. Methods: A prospective cohort study of 100 consecutive patients with an uncemented titanium stem from a single THA manufacturer was performed. Patients had either a metal (n=50) or ceramic (n=50) head articulating with a highly cross-linked polyethylene. Serum Co and Cr levels were measured 6 months post-operatively. Analysis compared mean values between groups and to determined baseline levels. Subgroup analysis investigated the effect of femoral head size and offset on metal ion levels. Results: A mean difference of 2.259 nmol/L (95% CI 0.449-4.069; p=0.015) was found when comparing 6-month serum Co in the metal head group compared to baseline. No significant differences were found in serum Cr (p=0.943). Mean serum Co levels were higher in the MoP group compared to the CoP (Ceramic-on-Polyethylene) comparator group (p=0.012). There were no differences in serum Cr (p=0.976). Variations in femoral head size and offset did not impact metal ion levels. Conclusion: At six months, a higher magnitude of serum Co exists in metal heads when compared to baseline (p=0.015) and to ceramic heads (p=0.012). Further study is required to determine whether serum concentrations of metal ions will continue to increase over time.

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