Tourniquet-induced wound hypoxia after total knee replacement

We have investigated whether the thigh tourniquet used during total knee re placement (TKR) influenced the development of postoperative wound hypoxia a nd was a cause of delayed wound healing. We allocated randomly 31 patients (31 TKRs) to one of three groups: 1) no tourniquet; 2) tourniquet inflated at low pressure (about 225 mmHg); and 3) tourniquet inflated to high pressu re of about 350 mmHg. Wound oxygenation was measured using transcutaneous o xygen electrodes. In the first week after surgery, patients with a tourniquet inflated to a h igh pressure had greater wound hypoxia than those with a low pressure. Thos e without a tourniquet also had wound hypoxia, but the degree and duration were less pronounced than in either of the groups with a tourniquet. Use of a tourniquet during TKR can increase postoperative wound hypoxia, es pecially when inflated to high pressures. Our findings may be relevant to w ound healing and the development of wound infection.