Orthopaedic applications of cold physical plasma

Abstract

Cold physical plasma (CPP) technology is of high promise for various medical applications. The interplay of specific components of physical plasma with living cells, tissues and organs on a structural and functional level is of paramount interest with the aim to induce therapeutic effects in a controlled and replicable fashion. In contrast to other medical disciplines such as dermatology and oromaxillofacial surgery, research reports on CPP application in orthopaedics are scarce. The present implementation of CPP in orthopaedics involves surface modifications of orthopaedic materials and biomaterials to optimize osseointegration. In addition, the influence of CPP on musculoskeletal cells and tissues is a focus of research, including possible adverse reactions and side effects. Its bactericidal aspects make CPP an attractive supplement to current treatment regimens in case of microbial inflammations such as periprosthetic joint infections. Attributed anticancerogenic and pro-apoptotic effects underline the clinical relevance of CPP as an additive in treating malignant bone lesions. The present review outlines ongoing research in orthopaedics involving CPP; it distinguishes considerations for safe application and the need for more evidence-based research to facilitate robust clinical implementation.

Keywords: antimicrobial therapy; cancer therapy; cold physical plasma; plasma medicine; reactive oxygen species; skeletal regeneration; surface modification.

Figure 1

CPP is generated by adding energy to a neutral gas to yield a partially ionized gas that can be operated at or below body temperature (<40°C). In pen-like CPP devices, the transition of a neutral feeding gas (e.g. argon) through a strong electric field (HF electrode) results in the discharge of ions (Ar*) and electrons (e–). The interaction with ambient air species (O₂, N₂ and H₂O) leads to the generation of bioreactive short-living oxygen species (ROS). Side products of this complex physiochemical process are low amounts of ultraviolet (UV) and electromagnetic (em) radiation.

Figure 2

Possible CPP applications in musculoskeletal medicine. Due to modifications of treatment parameters, CPP can be utilized in several different clinical applications in musculoskeletal medicine. These include skeletal tumour therapy, biomaterial modification and cell regenerative approaches at lower treatment intensity. Besides this, CPP´s antiseptic properties are promising for the antibiofilm treatment in septic surgery and the conditioning of antiseptic irrigation fluids, e.g. in arthroscopy.