The Impact of Tourniquet Use During Total Knee Arthroplasty: From Gene Expression to Clinical Outcomes

Abstract

Total knee arthroplasty (TKA) aims to improve function and quality of life for patients with advanced knee osteoarthritis. Despite advances in new implants and surgical techniques, around 10-15% of patients are dissatisfied after the operation. A tourniquet is often used during TKA to improve visualisation of the surgical field, reduce bleeding, optimise cementation, and decrease operative time. However, it can negatively affect postoperative pain, muscle recovery, length of hospital stay, and lead to adverse events. This doctoral thesis investigates how the use of a tourniquet affects skeletal muscle cells and clinical outcomes after surgery. Patients were randomised into two groups, with half undergoing surgery with a tourniquet. Biopsies were taken from the patients’ thigh muscle to determine the impact of tourniquet use on expression of genes and proteins. These were taken at the end of surgery and 8 weeks later. The specific genes and proteins analysed are associated with hypoxic response, cell death, inflammation, pain, and muscle regeneration. Analyses were performed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), tissue microarray (TMA), and immunohistochemistry (IHC). The results revealed that tourniquet use increased the expression of proteins associated with muscle regeneration, which may positively impact postoperative strength. Notably, one of these proteins is also linked with pain. Tourniquet use did not increase the expression of genes or proteins related to cell death, inflammation, or hypoxic response. Furthermore, clinical outcomes assessments were conducted at the first day, 8 weeks, and 1 year postoperatively. The results revealed that tourniquet use reduced blood loss and could potentially improve muscle strength 8 weeks after surgery. Tourniquet use did not negatively impact knee function, pain, patient satisfaction, duration of surgery, or the length of hospital stay.