A study to evaluate the harmful effects of metal ions on eyesight in patients with an ASR total hip replacement.

A study on the ASR metal on metal hip resurfacing: Impact of cobalt toxicity on visual pathways and the presence of soft tissue destruction in the symptomatic hip.

Status

Not yet recruiting

Phases

Unknown

Study type

Observational

Source

ANZCTR

Registry ID

ACTRN12612000589886

Enrollment

Registered

2012-06-01

Start date

2013-01-01

Completion date

Unknown

Last updated

2020-01-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

Total hip replacement is now a well established operation to reliably alleviate pain from osteoarthritis of the hip joint. Over the years a number of bearing surfaces have been used in order to minimise the wear within the joint itself. One such bearing surface is a metal socket articulating with a metal ball. However we know now that although this provides very low wear rates, it can result in metal ions being released into the blood stream as a result of this wear process. It is the precise effects of these metal ions within the blood stream that we are beginning to understand more about. In particular we know very little about the effect that metal ions have on the eyesight and if metal ion levels are high whether this can cause changes in visual acuity. This study aims to measure blood levels of Cobalt and Chrome in your blood stream and then potentially carry out specific tests to look at the functioning of the cells within the eyes to assess whether this is abnormal.

Interventions

The harmful effects of elevated metal ion levels in the systemic circulation are increasingly being realised. There have been isolated case reports of disturbance of visual pathways as a result of elevated metal ion levels however this has never been investigated in relation to elevated metal ion levels resulting from a hip replacement. The ASR total hip replacement used a metal on metal bearing surface and has now been identified as failing early and in the process result in elevated metal ion levels. This study aims to investigate visual pathways using electrophysiological techniques and then correlate these findings with metal ion levels in a cohort of patients who have undergone an ASR total hip replacement. The electrophysiological assessments on the eye will take approximately 4 1/2 hours to complete. The metal ion levels will be taken at the point of recruitment and no long term follow up will be part of this study.

Eligibility

Sex/Gender

All

Age

0 to No maximum

Healthy volunteers

Inclusion criteria

Patients recruited will have undergone an ASR total hip replacement or an ASR hip resurfacing. For the control group patients will have undergone a total hip replacement with a non metal on metal bearing surface (i.e. metal on polyethylene)

Exclusion criteria

Not relevant

Outcome results