I got a right hip resurfacing using the Biomet Magnum Recap by Dr. Gross in SC in June 2006. My clunking/shifting has gotten progressively worse over the years; it is so frequent now (I estimate more than one hundred/day) I often don't think about it. It occurs primarily when my hip is extended. When standing, slight shifts in position can set off a series of clunks - almost like a ratchet. When walking, there is often a clunk as the implanted hip reaches full extension. The hip does not bother me much other than the clunking; the clunking causes no pain. I am a very active 59 year old male, 5'-8", 163 lbs.
In February 2011, I had blood levels of chromium and cobalt measured on my own - Dr. Gross did not suggest it. Cr was 38 mcg/l ("normal" <1.4mcg/l) and Co was 81 mcg/l ("normal" <0.5 mcg/l), both extremely high. I reported this to Dr. Gross who asked me to have them rechecked with a lab he uses - results there were virtually identical. (Note: mcg/l means micrograms/liter; one lab measured serum metal levels and one measured plasma levels with very little difference between the two.)
I talked to Dr. Gross after the elevated blood metal levels were confirmed. He said my cup inclination angle is to steep ~ 60 degrees (optimum is closer to 40 degrees) which is associated with excessive wear, probably due to edge loading of the cup. He said steep inclination angles weren't known to be a problem in 2006 when I had the resurfacing, and that he didn't have a way then to set the angle during the operation. He now uses an intra-operative x-ray to measure the angle at which the cup is placed and now never has cup angles > 50 degrees. I recommend reading Dr. Gross's article on Acetabular Component Inclination Angle on his website (
http://www.grossortho.com/). Given that my hip is functioning well, he didn't feel my blood metal levels were a serious health issue, and said the options were to continue to track metal levels, get an MRI to check surrounding tissues for signs of metallosis, or to revise the cup.
I opted for a metal-shielding MRI (MARS protocol) (May 2011) to see if there were abnormalities around the implant. The MRI showed abnormal fluid accumulation around the hip; the radiologist's report concluded it was most likely a "psuedotumor due Particle Disease."
I met with Dr. Gross in May 2011 right after the radiologist reported the MRI results. Dr. Gross recommended replacement of the acetabular cup to correct the steep inclination angle. As a side note, he believes my clunking is due to the temporary loss of "lubricating" fluid in the implant due to the excessive wear on the edge of the cup, causing the hip to catch or stick - he feels this probably accelerating the wear.
Dr. Gross feels that replacing the cup at the correct angle will resolve the excessive wear, metallosis, and psuedotumor. He said that total hip replacement is also an option, but that since the femoral component looks good, he recommends cup replacement. Even though the femoral component likely also has wear, he feels that when placed in a new cup at the proper angle, it will function well. He says he has revised 3 HSRs in his patients who had steep cup angles (>60 degrees), one of whom had metallosis. In one revision he replaced cup only (very recently) and in one case did a THR (about a year ago). He said the revisions went smoothly and both patients are doing well. I don't recall him mentioning the outcome with the third revision.
I originally posted this account under the "clunking and shifting" thread to provide some perspective to those who have these symptoms, but want to be clear that the clunking/shifting alone is not significantly affecting the quality of my life and I would not consider surgery to eliminate it. I am considering the "revision" surgery to address the high blood metal levels and metallosis. I'll also try to post this under "serious post op problems thread."
I'd appreciate any insights from those of you who have had similar issues, particularly from any of you who have had a cup-only revision due to metallosis. Thanks.
Brian
Black Mt., NC