Introduction: Surgical site infection is a growing and expensive complication. Surgical site surveillance is performed with the aid of laboratory tests and clinical evaluation; the latter has some limits, including reproducibility and validation of results and, as suggested by many authors, the need of a dedicated well trained staff. At present no imaging instruments are available for routine objective monitoring of “normal” or complicated surgical site healing. Recently, technological improvement made available for clinical use high resolution portable digital telethermocameras at relatively low-costs. No data are available in the literature, concerning the “physiological” thermographic pattern of surgical wounds in orthopaedics. The aim of this study is then to evaluate the physiological telethermographic pattern of surgical site healing after hip and knee prosthetic surgery, to provide a reference value for further analysis.
Methods: The surgical site of 60 consecutive patients undergoing total hip replacement and 40 patients unde-going total knee replacements were examined at fixed intervals from the day before surgery to six weeks after intervention, using a portable telethermographic camera (AVIO TVS-200EX). Results were compared with contralateral side and with laboratory data.
Results: A physiological “telethermographic pattern” of wound healing was observed and showed to be remarkably reproducible among different patients. A thermographic peak was observed at day 3, with a mean temperature elevation (hottest spot) of 2.3 +− 1.3 ^C after hip replacement and of 2.8 +− 1.5 ^C after total knee replacement. Similar results were obtained when considering the mean surface temperature in a 10 cm rectangle area identified around the surgical wound. Temperature at the surgical site slowly returned to baseline (contralateral side as reference) in a six weeks period.
Discussion and Conclusion: Telethermography through a portable camera appears a reliable, not invasive, not irradiating and easy-to-use tool to monitor surgical site following hip or knee arthroplasty at the patient’s bed. Surgical site show a highly reproducible physiological thermographic pattern, with peak values at day 3 and a constant decrease until normal values at week 6 after surgery. This findings may be used as a reference for further studies, to establish the relevance of abnormal thermographic patterns in connection with surgical site complications.
