The treatment of periprosthetic infection remains one of the most difficult and challenging problems in orthopaedic surgery. Conventional approaches such as the use of tissue and/or fluid cultures to identify and treat organisms are not nearly as successful as they need to be in order to address these conditions. The limitations of treatment, including the inaccessibility of microorganisms at the time of irrigation and debridement, the development of resistant strains of microorganisms, and the elaboration by microorganisms of protective biofilms, have led to unsuccessful outcomes in a large number of cases.
In this issue of JBJS Reviews, Chen and Parvizi provide an update on some of the new methods that may possibly advance this field. Molecular methods such as polymerase chain reaction to amplify bacteria can improve the likelihood of identifying the pathogen in a patient with a periprosthetic joint infection. Synovial markers such as C-reactive protein, leukocyte esterase, α-defensin, human β-defensin-2 (HBD-2) and HBD-3, and cathelicidin LL-37 are known to be elevated in patients with periprosthetic joint infection and may be used as markers for diagnosing infection at the time of operative management. Serum markers such as interleukin-4 (IL-4) and IL-6, and others such as soluble intracellular adhesion molecule-1 (sICAM-1) and procalcitonin (PCT), have been shown to be elevated in patients with periprosthetic joint infection.
Molecular detection methods probably have received the most attention and interest as an advancement that may improve our ability to diagnose periprosthetic infections. The limitations of these methods, however, include their high sensitivity and an increased rate of false-positive results. Methods to reduce the number of false-positive results are currently in development and include, among other things, the measurement of 16S ribosomal RNA in the belief that targeting RNA will result in amplification of only the genetic material of live bacteria. In addition, use of the mecA gene for identifying methicillin-resistant Staphylococcus aureus (MRSA) can reduce this rate.
Although this article does not provide definitive new approaches to the problem, the review of recent advances with the development of promising biomarkers and molecular techniques provides optimism that this field is evolving in a positive way.