In Vitro Elution Characteristics of Vancomycin in a Composite Calcium Phosphate/Calcium Sulfate Bone Substitute

Xu Yang, MD
Hospital for Special Surgery

Liza Osagie, MBBS
Hospital for Special Surgery


Mathias P. Bostrom, MD

Attending Orthopaedic Surgeon, Hospital for Special Surgery
Professor of Orthopaedic Surgery, Weill Cornell Medical College

Abstract

Background

Periprosthetic joint infection is a particularly difficult orthopedic problem, complicating a growing number of revision procedures. Joint debridement and systemic antibiotics are the mainstay of treatment, yet difficulty remains in maintaining a minimum inhibitory concentration of antibiotic at the localized site of infection.

Study Aims

This study analyzes the elution characteristics of a 40%bwt calcium phosphate–60%bwt calcium sulfate composite, at varying concentrations of vancomycin.

Methods

Four groups of varying concentrations of vancomycin (2.63%bwt, 5.13%, 9.76%, and 17.78%) were mixed with one pack of the composite cement. At designated time intervals up to 28 days, the antibiotic concentration was detected using fluorescence polarization immunoassay and the elution trends compared.

Results

The elution rate of each of the four groups decreased over time. At almost all of the intervals, the elution rates of the higher concentration groups were significantly higher than the lower concentration groups (P<0.05).

Conclusions

Calcium sulfate reabsorbs over a prolonged period, producing porosity which allows for new bone ingrowth through occupation of osteoprogenitor cells and osteoblasts; while calcium phosphate acts as a long-term osteoconductive matrix.

Clinical Relevance

The results of this study suggest that vancomycin can be mixed affectively with a calcium sulfate/phosphate composite, both maintaining stability and eluting gradually over a clinically relevant period of time.

This article appears in HSS Journal: Volume 8, Number 2.
View the full article at springerlink.com.

About the HSS Journal

HSS Journal, an academic peer-reviewed journal published three times a year, February, July and October. The Journal accepts and publishes peer reviewed articles from around the world that contribute to the advancement of the knowledge of musculoskeletal diseases and disorders.


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