ASSESSING THE EFFICACY OF A SILVER-DOPED ANTIMICROBIAL COATINGS ON PROSTHETIC LINERS

Background

Problems with Day to Day Prosthetic Liner Wear

  • In the United States, roughly one in every 180 Americans is currently living with a lost limb after amputation.1
  • There are currently two million patients in the United States living with amputation, and with over 130,000 new amputations each year, this number is estimated to nearly double in the next 35 years as projections call for a total amputee population of 3.9 million in the United States by 2050.1
  • Unfortunately, much of the focus for a surgeon while performing amputation is on the short-term outcome of the patient. Currently, a successful amputation means a complication-free procedure which leaves the patient with a properly sealed limb-end fit for prosthesis attachment.2
  • Due to the ease of this bacterial growth in the prosthetic socket, amputation is often coupled with long term bacteria-related complications, most notably skin irritation, ulceration, infection, sepsis, or in extreme cases, death.3
    • Chronic malodor.

Hypothesized Advantages of Coating on Prosthetic Liners

  • Titanium dioxide has been demonstrated to have anti-inflammatory properties.
  • Polydimethylsiloxane (PDMS) confers flexibility and strong binding adherence to soft liners.
  • When dried, coating is approximately 100nm thick.
  • Sweat and humidity generated in the enclosed stump-liner interface will drive silver release.

Methodology

Liners Pathogens
– Alpha Hybrid
– Ottobock Thermoplastic TPE
– Proteor Keasy
– Alpha Silicone
– MRSA
– P. acnes
– VR E. faecalis
– MSSA
– CoNS epidermidis
– MDR A. baumannii
  • 8mm plugs of liners excised with biopsy punch.
  • Plugs stored in 70% ethanol overnight.
  • Dip coated in each respective condition and allowed to cure in the hood overnight.
  • Plates inoculated with a lawn of bacteria at 2×107 CFU/ml.
  • Plugs placed on plate (liner side down) for 72hrs.

Results

Fig 1. Liner surface interaction with coating

Fig 2. A. baumannii dose response curve

Fig 3. Kirby Bauer Assay showing inhibition at the 10X and 100% Ag-doped liner plug

Keasy Kirby Bauer A. baumannii

Thermoplastic Kirby Bauer A. baumannii

Silicone Kirby Bauer A. baumannii

Hybrid Kirby Bauer A. baumannii