Wednesday, July 27, 2011

Review of the Cell biology surrounding metal on metal hips (9 of 9 in a series)

The material for this series of posts is sourced through the the following journal article:

Acta Orthop. 2008 Dec;79(6):734-47.
Metal-on-metal hip resurfacing arthroplasty: a review of periprosthetic biological reactions.
Mabilleau G, Kwon YM, Pandit H, Murray DW, Sabokbar A.
Conclusions from this series of 9 posts:

1. Although elevated levels of metal ions in the synovial fluid and in the peripheral blood after MoM atheroplasty are a common finding, the importance of these observations remain unclear.

2. These adverse biological responses to the metal ions produced can be local or systemic,

3.  Clinical cases of local tissue reactions (near the hip joint) are being increasingly reported.

4.  The precise biological pathway that leads to these localized effect of metal particles remain unknown.
5.  The high concentration of metal particles confined within the joint space may lead to activation of the T lymphocytes.

6.  In turn, this may may affect other local cell populations (as we discussed in the prior posts.)

7.  The individual biological response to the presence of wear debris appears to vary.

8.  This may reflect a different toxic-effect threshold or immunological intolerance.

9.  In some patients, the T cell-mediated interplay may lead to adverse clinical outcomes such as painful soft-tissue masses or other issues.

10.  The concerns about the unknown risks of  long-term exposure to metal debris remain.

11.  As the latency time of the metal on metal hip could be as long as 20 years, one can speculate that there may be development of tumors in response to excessive metal particles and metal ion production in these cases

12.  This highlights the importance of long-term clinical follow up and cellular research into the biological mechanisms involved in the pathogenesis of metal wear particle -induced adverse biological reactions.

[This concludes the series on these posts other than sharing some of the key papers referenced in this least insofar as I am concerned in the SYSTEMIC (other areas of the body away from the joint)  arena vs the LOCALIZED (near the joint) arena.  I will share those with you in the next posts.]

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