Abstract
AimsThe aim of this study was to develop a single-layer hybrid organic-inorganic sol-gel coating that is capable of a controlled antibiotic release for cementless hydroxyapatite (HA)-coated titanium orthopaedic prostheses.MethodsCoatings containing gentamicin at a concentration of 1.25% weight/volume (wt/vol), similar to that found in commercially available antibiotic-loaded bone cement, were prepared and tested in the laboratory for: kinetics of antibiotic release; activity against planktonic and biofilm bacterial cultures; biocompatibility with cultured mammalian cells; and physical bonding to the material (n = 3 in all tests). The sol-gel coatings and controls were then tested in vivo in a small animal healing model (four materials tested; n = 6 per material), and applied to the surface of commercially pure HA-coated titanium rods.ResultsThe coating released gentamicin at > 10 × minimum inhibitory concentration (MIC) for sensitive staphylococcal strains within one hour thereby potentially giving effective prophylaxis for arthroplasty surgery, and showed > 99% elution of the antibiotic within the coating after 48 hours. There was total eradication of both planktonic bacteria and established bacterial biofilms of a panel of clinically relevant staphylococci. Mesenchymal stem cells adhered to the coated surfaces and differentiated towards osteoblasts, depositing calcium and expressing the bone marker protein, osteopontin. In the in vivo small animal bone healing model, the antibiotic sol-gel coated titanium (Ti)/HA rod led to osseointegration equivalent to that of the conventional HA-coated surface.ConclusionIn this study we report a new sol-gel technology that can release gentamicin from a bioceramic-coated cementless arthroplasty material. In vitro, local gentamicin levels are in excess of what can be achieved by antibiotic-loaded bone cement. In vivo, bone healing in an animal model is not impaired. This, thus, represents a biomaterial modification that may have the potential to protect at-risk patients from implant-related deep infection.Cite this article: Bone Joint J 2021;103-B(3):522–529.
Highlights
The incidence of periprosthetic joint infection (PJI) is between 1% and 3% after primary arthroplasty and up to 15% after revision procedures.[1,2] With the number of primary arthroplasties expected to increase to 1.26 million annually in the USA by 2030, significantly more patients will be affected by infection in the future.[3]
Coatings containing gentamicin at a concentration of 1.25% weight/volume, similar to that found in commercially available antibiotic-loaded bone cement, were prepared and tested in the laboratory for: kinetics of antibiotic release; activity against planktonic and biofilm bacterial cultures; biocompatibility with cultured mammalian cells; and physical bonding to the material (n = 3 in all tests). the sol-gel coatings and controls were tested in vivo in a small animal healing model, and applied to the surface of commercially pure hA-coated titanium rods
Local gentamicin levels are in excess of what can be achieved by antibiotic-loaded bone cement
Summary
The incidence of periprosthetic joint infection (PJI) is between 1% and 3% after primary arthroplasty and up to 15% after revision procedures.[1,2] With the number of primary arthroplasties expected to increase to 1.26 million annually in the USA by 2030, significantly more patients will be affected by infection in the future.[3]. While prophylactic antibiotics are used to reduce the risk of PJI during primary surgery, once an infection becomes established on the prosthesis, antibiotics alone will not cure a PJI. This is because a biofilm has become established and the only solution is THE BONE & JOINT JOURNAL. Microorganisms entering the wound can be neutralized before a biofilm becomes established, the incidence of infection could be further reduced in both primary and revision surgery
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