Study sets safe upper ion levels

[John C]

Here is a link to a recent study that suggests some key levels to look for in metal ion numbers.

http://www.healio.com/orthopedics/hip/news/print/orthopedics-today/%7B3FF58413-C747-4495-BA51-BBF8ECAA7FBA%7D/Researchers-set-safe-upper-limit-metal-ion-levels-for-metal-on-metal-hip-resurfacings

[hernanu]

Very interesting, John - that and the other followup articles. Nice to see that there are starting to be articles advising not to throw the baby out with the bathwater.

[John C]

Thanks Hernanu. Here is the direct link to the other article that you were referencing, in case others wanted to read it.

http://www.healio.com/orthopedics/hip/news/print/orthopaedics-today-europe/%7BCA5AC0A9-B228-482E-926A-FED352A32535%7D/Key-advantages-and-indications-for-metal-on-metal-hip-resurfacingshould-not-be-dismissed

[Neild5]

Thanks John!  Both articles are worth reading by all who visit this site.

[Pat Walter]

Researchers set safe upper limit metal ion levels for metal-on-metal hip resurfacings
Orthopedics Today, July 2012

Read complete article by clicking here
http://www.healio.com/orthopedics/hip/news/print/orthopaedics-today-europe/%7B3FF58413-C747-4495-BA51-BBF8ECAA7FBA%7D/Researchers-set-safe-upper-limit-metal-ion-levels-for-metal-on-metal-hip-resurfacings

An award-winning study by researchers from Belgium identified safe upper limits of 4.6 µg/L for chromium and 4.0 µg/L for cobalt in unilateral metal-on-metal hip resurfacing arthroplasties and 7.4 µg/L for chromium and 5.0 µg/L for cobalt in bilateral procedures.

"Levels higher than [these] established limits were significantly correlated with clinical symptoms, smaller component size, a smaller coverage arc, smaller contact patch to rim distance and a higher cup inclination," Catherine Van Der Straeten, MD, said. "Females and small head sizes are more at risk of having problematic hips."

"These upper acceptable limits are lower than the recommended threshold by the Medicines and Healthcare Products Regulatory Agency [in the United Kingdom]," Van Der Straeten said. "But, we had low tolerance for what we call the clinically problematic hip."

[hernanu]

Thanks, Pat - those are the limits I used when I got my readings a couple of weeks ago.

[cwg]

Okay, so please help me define mine, based on that report- In simple terms, please. Thank you in advance   

Chromium-Plasma  66.92    H (normal range) 1.90-5.80                    NMOL/L. (??)
Cobalt Plasma        25.62    H                       0.51-6.80   

I get tested every six months, and the results vary Cobalt pretty much the same but Chromium has been in the 40s

What is the difference betwee these and UG/L

* am finally ready to put this whole picture, together.

[cwg]

Should I assume that what they advise (in my report) as safe levels in "NMOL/L" s   is similar (to the reports posted here) that measure in UGLs?

I always appreciate the advice here and do not mind a simple "yes" or "no"

Next week I need to be in Palm Springs for an event and decided to have some tests done at "Medical Imaging" with a Dr John Feller as the radiologist. I will bring those results back to Vancouver for my Nov5 appointment with ortho surgeon,  Dr.Clive Duncan. Dr Duncan will compare my xrays from last year, to now

Last week during a business trip to Hong Kong, my BHR surgeon from five years ago took an xray that shows "failure of bone growth to in plant"-

Am taking advantage of being in California and doing my own investigations. I am advised to have a hip MR (which I thought was not possible) and a ct scan body scan...

If I am over reacting, that's fine, but.. am I missing anything?

Appreciate all advice

[Tim Bratten]

Okay, so please help me define mine, based on that report- In simple terms, please. Thank you in advance   

Chromium-Plasma  66.92    H (normal range) 1.90-5.80                    NMOL/L. (??)
Cobalt Plasma        25.62    H                       0.51-6.80   

I get tested every six months, and the results vary Cobalt pretty much the same but Chromium has been in the 40s

What is the difference betwee these and UG/L

* am finally ready to put this whole picture, together.

cwg:  you need to talk to the people who did these measurements to see what they measured. If your Chromium is 40 micrograms/liter that is way too high and you are in serious trouble. On the other hand if your Chromium  is 40 nano mols/ liter this converts to about 2 micro grams per liter and you are just fine unless you show other symptoms. The people who can best explain the numbers you are posting are the people who measured them.

Tim

[Tim Bratten]

Should I assume that what they advise (in my report) as safe levels in "NMOL/L" s   is similar (to the reports posted here) that measure in UGLs?

I always appreciate the advice here and do not mind a simple "yes" or "no"

Next week I need to be in Palm Springs for an event and decided to have some tests done at "Medical Imaging" with a Dr John Feller as the radiologist. I will bring those results back to Vancouver for my Nov5 appointment with ortho surgeon,  Dr.Clive Duncan. Dr Duncan will compare my xrays from last year, to now

Last week during a business trip to Hong Kong, my BHR surgeon from five years ago took an xray that shows "failure of bone growth to in plant"-

Am taking advantage of being in California and doing my own investigations. I am advised to have a hip MR (which I thought was not possible) and a ct scan body scan...

If I am over reacting, that's fine, but.. am I missing anything?

Appreciate all advice

I am not sure what the levels you posted should mean (talk to the people who measured them!) but here is the conversion from nano mols per lite to micro grams per liter for cobalt and chromium:

to convert to the more commonly used micrograms per litre (mg/l) you need to divide the nmol/L figure by 17 for cobalt and 19 for chromium. So, as an example, for a level of 100 nmol/L:

100 / 17= 5.88 mg/l for cobalt, and 100 / 19 = 5.26 mg/l for chromium.

[cwg]

chuckle- Thanks Tim- Think the "plasma" part is relevant here  too... Never mind. But appreciate your going at this

I will get back here, as soon as I know more, in order to "alert" or "relieve"

[Tim Bratten]

chuckle- Thanks Tim- Think the "plasma" part is relevant here  too... Never mind. But appreciate your going at this

I will get back here, as soon as I know more, in order to "alert" or "relieve"

I got these conversion numbers off a web site, but they are certainly roughly correct.  If you treated blood plasma like distilled water, to convert for Chromium you would simply multiply the 67 nanomols/liter that you report by .052 (there are 52 grams of Chromium in a mol) which amouns to dividing by 19.something.  Making a slight adjustment for the higher density of blood plasama shouldn't make a huge difference in the conversion. At any rate, if the figure for Chromium is what I think it is, it's a little high  but still well inside the safe range and should be OK unless you have other symptoms.

Good luck!

[hernanu]

Okay, so please help me define mine, based on that report- In simple terms, please. Thank you in advance   

Chromium-Plasma  66.92    H (normal range) 1.90-5.80                    NMOL/L. (??)
Cobalt Plasma        25.62    H                       0.51-6.80   

I get tested every six months, and the results vary Cobalt pretty much the same but Chromium has been in the 40s

What is the difference betwee these and UG/L

* am finally ready to put this whole picture, together.

I think Tim is roughly correct. What I came up with is if you start with nanomoles / liter:

• Convert nanomoles per liter to umoles per liter by dividing by 1000. This gets the correct scale.
• Multiply the umoles / liter x the molar mass of the chemical which gives the ugrams / liter.

From your report (assuming they are in nmol / L (nanomoles per liter) :

• Cobalt:        66.92 nmol/L  / 1000 * 58.9 molar mass (grams) = 3.94 ug/L
• Chromium :  25.62 nmol/L / 1000 * 52     molar mass (grams) = 1.33 ug/L

Are these your readings or what they consider safe limits? The strictest study I saw puts anything below 4 ug/L as safe for one hip, under 7 ug/L for two.

[Pat Walter]

To be safe, talk to your surgeon about your cobalt/chromium levels.  Ask them to explain and tell you if you should be worried.  They know where the test were sent and should know how to interpret them. If not, I would get to another experienced hip resurfacing surgeon and get input.

Pat

[cwg]

Thanks everyone, hope you are right..

 Have to say that people seem to be concerned by these levels  (tests performed  out east : London Health SC Ctr-University ) They seem to think I am way outside the safe zone.
 That plus the "failure of bone growth to inplant" based on new xrays....

I don't really understand either and  will be back in one week,  be better informed, and pass it along.