Does Limited Tourniquet Usage in Primary Total Knee Arthroplasty Result in Better Functional Outcomes?

Dear Editor, Pneumatic tourniquet use has gained popularity in peripheral limb operations since its advent in 1904 by Harvey Cushing, permitting tourniquet pressure to be monitored and manually controlled throughout surgery. In total knee arthroplasty (TKA), application of a mid-thigh pneumatic tourniquet offers the possible benefi ts of providing a dry operating fi eld, reducing intraoperative blood loss, allowing cement to set in an optimal and completely dry environment thus potentially improving bone-cement inter-digitation and reducing operative time.1-4 There is ongoing controversy with regard to risks associated with tourniquet use in TKA surgery.2,5-10 Many authors have advocated that tourniquet usage compromises the ability to perform early straight-leg-raise and knee fl exion after surgery, increases risks of nerve, muscle and vascular injury, as well as postoperative swelling, stiffness and pain.5,11-13 Cardiorespiratory function may be affected by tourniquet infl ation and defl ation, which could lead to intraoperative hypoxia, pulmonary embolic events and cardiac arrest.9 Reactive hyperaemia has also been noted on tourniquet defl ation, which may cause substantial bleeding and affect operation time.2,8,10 Tourniquets may also be related to an increased incidence of early infection and wound healing disorders due to perioperative hypoxia and reduced postoperative tissue perfusion.5,7,8 Several authors have correlated tourniquet use and an increased incidence of venous thromboembolic phenomena. 6,7,8 Arthroplasty surgeons continue to face a dilemma on the ideal time of tourniquet release. The relationship between duration of tourniquet use and development of postoperative complications also remains controversial. This has resulted in variations in the profi le of tourniquet use; either throughout the procedure, use for part of the procedure, or none at all. There have been few prospective studies evaluating clinical outcomes of partial or limited tourniquet use in TKA surgery. There is scant literature on the effects of cement interdigitation, or long-term outcomes of implant loosening or radiolucency between patients who received conventional tourniquet compared to limited tourniquet and non-tourniquet assisted TKA surgery. The aim of this study is to determine whether the limited use of a tourniquet during TKA surgery affects predefi ned clinical outcomes. Materials and Methods We reviewed 121 cases of TKA performed by single surgeon (senior author) over a 4-year period between 2005 to 2008 and had been prospectively entered into a database. Using preliminary data, we calculated that our group sizes are adequately powered to detect an effect size of 0.4 at 80% power. All operations were done for osteoarthritis. Only unilateral surgeries were performed. Patients with infl ammatory arthritis on potential procoagulant medications were excluded. There were no anticoagulated patients in this cohort. The fi rst 68 patients underwent surgery with limited tourniquet use and the subsequent 53 patients underwent surgery with conventional tourniquet use. Tourniquets used were automatic pneumatic tourniquets and pressures were standardised at 300 mmHg. We defi ned “limited tourniquet use” as defl ation of tourniquet until cementation of implants and “conventional tourniquet use” as tourniquet use throughout surgery and defl ation after wound closure and application of initial dressings. The following data parameters were recorded: age, gender, race, coexisting medical problems, type of anaesthesia, use of tourniquet and tourniquet time, operating time and drain volumes postoperatively. Institutional review board (IRB) approval was obtained for the study and informed consent was taken from all patients. The 2 groups were well-matched in terms of age, gender, ethnicity, comorbidities, use of aspirin, type of anaesthesia, and preoperative range-of-motion. Postoperative incidence of deep vein thrombosis (DVT) was evaluated. Preoperative and postoperative pain scores using the visual analogue scale (VAS), joint range-of-motion, and radiographic evidence of implant loosening, were assessed over a period of 2 years postoperatively.