Wednesday, March 28, 2012

Who said there were no suspicions surrounding these metal-on metal hips until late? Not so.

I think you will find this article interesting because of the date of publication of it: 1973!!!  39 YEARS AGO!


Br Med J. 1973 Mar 3;1(5852):527-9.

Concentration of wear products in hair, blood, and urine after total hip replacement.



Abstract


Raised levels of cobalt and chromium are found in the blood and urine of patients with metallic total hip replacements. When one of the hip components is made of polyethylene much less metal seems to be released from the joint. The long-term effects of the accumulation of chromium in the body need to be studied further.

Now fast forward to 1998


J Bone Joint Surg Am. 1998 Oct;80(10):1447-58.




Metal release in patients who have had a primary total hip arthroplasty. A prospective, controlled, longitudinal study.



Source


Department of Orthopedic Surgery, Rush Arthritis and Orthopedics Institute, Rush Medical College, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois 60612, USA. jacobs@ortho4.pro.rpslmc.edu

Abstract


There is an increasing recognition that, in the long term, total joint replacement may be associated with adverse local and remote tissue responses that are mediated by the degradation products of prosthetic materials. Particular interest has centered on the metal-degradation products of total joint replacements because of the known toxicities of the metal elements that make up the alloys used in the implants. We measured the concentrations of titanium, aluminum, cobalt, and chromium in the serum and the concentration of chromium in the urine of seventy-five patients during a three-year prospective, longitudinal study. Twenty patients had had a so-called hybrid total hip replacement (insertion of a modular cobalt-alloy femoral stem and head with cement and a titanium acetabular cup without cement), fifteen had had insertion of an extensively porous-coated cobalt-alloy stem with a cobalt-alloy head and a titanium-alloy socket without cement, and twenty had had insertion of a proximally porous-coated titanium-alloy stem with a cobalt-alloy head and a titanium socket without cement. The remaining twenty patients did not have an implant and served as controls. The results of our study showed that, thirty-six months postoperatively, patients who have a well functioning prosthesis with components containing titanium have as much as a threefold increase in the concentration of titanium in the serum and those who have a well functioning prosthesis with cobalt-alloy components have as much as a fivefold and an eightfold increase in the concentrations of chromium in the serum and urine, respectively. The predominant source of the disseminated chromium-degradation products is probably the modular head-neck junction and may be a function of the geometry of the coupling. Passive dissolution of extensively porous-coated cobalt-alloy stems was not found to be a dominant mode of metal release. CLINICAL RELEVANCE: Increased concentrations of circulating metal-degradation products derived from orthopaedic implants may have deleterious biological effects over the long term that warrant investigation. This is a particularly timely concern because of recent clinical trends, including the reintroduction of metal-on-metal bearing surfaces and the increasing popularity of extensively porous-coated devices with large surface areas of exposed metal. Accurate monitoring of the concentrations of metal in the serum and urine after total hip replacement also can provide insights into the mechanisms of metal release. Our findings suggest that fretting corrosion at the head-neck coupling is an important source of metal release that can lead to increased concentrations of chromium in the serum. Determinations of the concentrations of metal in the serum and urine may be useful in the diagnosis of patients who are symptomatic after a total joint replacement as increased levels are indicative of at least one mode of mechanical dysfunction (for example, fretting corrosion) of the device.

2 comments:

  1. Connie, this is dreadful. It's one thing to develop a metal on metal hip without knowing of the potential or likely deleterious effects. But the effects were out there for anyone with reasonable research skills to find.

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  2. It's alot like deja vu all over again.......I wonder how this will be addressed in the litagation.Kinda shoots a big 'ole hole in the "We had no idea"defense.

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