Correspondence (reply): In Reply

We would like to thank our colleagues both for their interest, positive feedback, and valuable additional information, as well as for their critical comments, on our article (1).

Dr. Birkenhauer points to the value of procalcitonin (PCT) determination as a possible laboratory test to differentiate between inflammatory activities due to disorders (and in particular, to rheumatism) or infection. This laboratory value has long been a topic of investigation for the surgical disciplines. Of note, procalcitonin values have highly divergent specificities and sensitivities in various examinations of patients who receive joint replacements. According to recommendations, procalcitonin should only be tested in combination with CRP, if at all (2, 3). However, neither various older studies nor a current study by Sousa et al. (2017) found differences between the preoperative procalcitonin values for septic versus aseptic loosening (4). Overall, the reliability of procalcitonin determination as an adequate marker for periprosthetic infection is not yet certain. Due to the lack of sufficient studies, the PCT assessment is not included in the current international guidelines and consensus recommendations. Further studies for this are necessary.

Professor Dunkelberg points out the difficulty of maintaining sterility in sterile goods that are stored in air-permeable packaging. There are high quality requirements for this in place in Germany; nevertheless, he is correct to refer to the necessary monitoring required to ensure sterility even after prolonged storage. Whether using cabinets with additional measures to reduce the airborne pathogen load (for instance, plasma sterilization) can also further reduce the contamination risk of sterile products remains the subject of future studies.