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Systemic metal-protein binding associated with total joint replacement arthroplasty.
N J Hallab1, J J Jacobs, A Skipor
1Department of Orthopedic Surgery, Rush-Presbyterian-St. Lukes Medical Center, 1653 West Congress Avenue, Chicago, Illinois 60612, USA. nhallab@rush.edu
Journal of Biomedical Materials Research
|December 22, 1999
Summary
Titanium and chromium from joint replacements bind to specific serum proteins. This metal-protein binding likely begins near the implant due to higher local metal concentrations, impacting long-term health.
Area of Science:
- Biomaterials Science
- Orthopedic Surgery
- Clinical Chemistry
Background:
- Total joint replacements often contain cobalt-chromium (CoCr) or titanium (Ti) alloys.
- Understanding metal ion distribution and protein binding is crucial for assessing implant safety and longevity.
- Elevated systemic metal levels can indicate implant wear or corrosion.
Purpose of the Study:
- To investigate the distribution of titanium and chromium in serum protein fractions.
- To identify specific serum proteins that bind to metal ions released from joint implants.
- To explore the mechanism and location of initial metal-protein binding.
Main Methods:
- Serum samples from patients with CoCr or Ti implants and healthy controls were analyzed.
- Metal-protein binding was studied in vivo and in vitro using serum.
- Chromium(+3) (CrCl(3)) was added to control serum to replicate metal-protein interactions.
Main Results:
- Chromium (Cr) bound to serum proteins at approximately 70 and 180 kDa in CoCr implant patients.
- Titanium (Ti) bound to serum proteins at approximately 70 kDa in Ti implant patients.
- In vitro studies confirmed Cr binding to high molecular weight proteins like immunoglobulins, with binding occurring at significantly higher metal concentrations than found systemically.
Conclusions:
- Metal-protein binding occurs in specific molecular weight ranges for both Cr and Ti released from joint replacements.
- Protein binding of metals is likely initiated in the periprosthetic space due to localized high metal concentrations.
- Identifying specific protein carriers of metal degradation products is essential for evaluating the long-term biological effects of joint replacement devices.