Saturday, January 8, 2011

Additional Information on Complications Associated with Hip Arthroplasty.

Things I didn't know until reading this journal article by the Melbourne Orthopaedic Group in Australia (2005.)

1)       Metal-on-Metal implants produce higher serum cobalt and chromium levels than conventional metal-on-polyethylene.

2)      It is difficult to compare metal levels between patients because the tests used to measure the blood levels vary in measurement parameters and measurements.  These are various things that are measured:
a.       Serum
b.      Blood
c.       Urine
d.      Red blood cells

3)      Cobalt levels might rise to a peak at 6 months or so post procedure and may decline over a 3 year period. [While this is a resurface procedure they are referring to, I have not heard this claim before.]

4)      It is unclear as to whether metal sensitivity actually contributes to implant failure.  [This is interesting because I wondered myself whether these two things were related.  I think there are a number of patients who are having their hip removed because the hip itself failed but do not necessarily have toxic metal levels in their blood.  I am betting the opposite will also hold true.  There are patients who have a functioning hip and are asymptomatic in terms of visible pain but may have elevated and toxic levels of Cr and Co in their blood.  I think it is so important for this reason that every patient who received one of these implants get tested regardless of whether they are symptomatic or not.]

5)      5 years ago when this article was written, there was no reliable pre-op test to predict hypersensitivity of the metal alloys in these implants. [I was never given any such test 5 years ago.  I wonder if there is one now?  I would imagine you could get a red blood test pre-op but I will have to research this.]

6)      Titanium is now available to provide better integration between the femur head and the acetablum. [I wonder what issues there have been in the last 5 years with titanium sensitivities.]  

1 comment:

  1. Thank you, thank you for all the great information. The comments are excellent too. Thank you all for sharing. My own situation is in between. I am not in agony, but I am in constant state of discomfort. A dull ache in the hip. Slightly elevated cobalt levels. 17.6. I have some dizziness, which docs suspect could be related to elevated cobalt levels. But there is so little known about all this as yet. I value other comments. I'd like to know about all the facts related to revision. Thanks Louise