The Effect of Ischemic Preconditioning on Postoperative Pain After Total Knee Arthroplasty, a Randomized, Controlled Trial

The Effect of Ischemic Preconditioning on Postoperative Pain After Total Knee Arthroplasty, a Randomized, Controlled Trial

The Effect of Ischemic Preconditioning on Postoperative Pain After Total Knee Arthroplasty, a Randomized, Controlled Trial

The application of a tourniquet for 5 minutes and subsequent reperfusion before actual inflation of the tourniquet for total knee arthroplasty (ischemic preconditioning) decreases the level of local inflammation and therefore postoperative pain in response to reperfusion of the ischemic extremity.

During knee surgery your surgeon routinely uses a device called a tourniquet that allows us to temporarily cut of blood supply to the site of surgery. This helps to reduce blood loss and improves operating conditions. When allowing blood back into your leg at the end of the procedure, debris (bone, fat, tissue breakdown products and cement from the surgery) gets washed out and gains access to the rest of your body. In the vast majority of cases this event bares no major clinical consequences, but can rarely result in signs of inflammation of various body systems. Patients with evidence of impaired organ system function such as pre-existing lung and heart disease may be more vulnerable. Previous studies suggest that cutting off the blood supply for a short period of time just before a prolonged episode, could lead to a decrease in the extent of tissue breakdown products in this extremity and may thus be associated with a decrease in the inflammation of other organ systems. We propose to study this theory in knee surgery patients by looking at levels of markers of inflammation present in the blood before and after surgery.

In the study group, the patients' operative limb will be preconditioned by inflating the tourniquet for 5 minutes, followed by deflation and a 5-minute reperfusion period. Subsequently, the tourniquet will be inflated for the entire length of the operation (before skin incision to after insertion of the final components).

In the control group, the tourniquet will be used for the entire length of the operation without a preconditioning phase.

In the study group, the patients' operative limb will be preconditioned by inflating the tourniquet for 5 minutes, followed by deflation and a 5-minute reperfusion period. Subsequently, the tourniquet will be inflated for the entire length of the operation (before skin incision to after insertion of the final components). In the control group, the tourniquet will be used for the entire length of the operation without a preconditioning phase.

Muscle oxygenation over calf as measured by non-invasive infrared spectroscopy pre-surgery, 6h, 24h, and 48h after surgery

Levels of leukocytes and tumor necrosis factor-alpha (TNF) and Interleukin 6 (IL6) in drainage fluid at 24hr postoperatively

Periarticular circumference of the knee as compared to contralateral side as curde marker of swelling at 6h, 24, and 48h postoperatively

Inclusion Criteria: All patients undergoing primary total knee arthroplasty Exclusion Criteria: Patients who chronically use narcotics (<1 month). Patients with contraindications (severe peripheral vascular disease, presence of femoral-popliteal bypass grafts, etc.) or no plan for tourniquet use as determined by the clinical care team. Patients who are on corticosteroids prior to their surgery