Monday, July 18, 2011

Review of the Cell biology surrounding metal on metal hips (2 of x in a series)

Fascinating Review.

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.

first interesting point from this paper:
Unlike most organic chemicals, metal can not be eliminated from the tissues by metabolic degradation. [ I never knew before reading this why the kidney and liver were the key organs that might be affected]  Thus, they can only me eliminated from tissues by renal or gastronintestinal excretion.  There is evidence from a recent animal study to suggest that Chromium ions can accumulate in the liver.  Others have investigated potential long-term effects on the the kidney function resulting from Co and Cr wear in metal-on metal total hip replacements by measuring the serum metal ion levels and creatinine clearance  at 10- year follow -up in 75 patients conducted in 2007.

In this study, the serum creatinine clearance was normal indicating the kidney functioning is normal.

[comments by connie.  Just recently there was a much larger study conducted at Stanford and was published this year:

Nine-Year Incidence of Kidney Disease in Patients Who Have had Total Hip Arthroplasty. 

Chandran SE, Giori NJ. J Arthroplasty. 2011 Apr 18. [Epub ahead of print]
Department of Orthopedic Surgery, Stanford University, Stanford, California.


Metal-metal total hip arthroplasty (THA) is contraindicated in patients with impaired renal function due to increased metal ion output relative to other bearings and renal excretion of metal ions. Although one can avoid a metal-metal THA in a patient with renal disease, a patient may be destined to develop renal disease later in life. In this study, we sought to determine the incidence of newly diagnosed renal disease in the 9 years after THA. Using the Department of Veterans Affairs national database, we identified 1709 patients who had a primary THA in 2000 without preexisting renal disease. We found the 9-year risk of developing chronic renal disease after primary THA to be 14% and severe or end-stage renal disease to be 6%
What a difference 3 years make!  Very interesting indeed.

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