BACKGROUND: Venous thromboembolism (VTE) and the subsequent development of pulmonary embolism (PE) is a major cause of post-operative mortality in total knee arthroplasty (TKA). We evaluated whether the addition of an ultrasound-guided femoral nerve block with general anesthesia affected the incidence in the development of VTE following TKA. METHODS: This was a retrospective non-randomized comparative study with patients assigned to groups based on the surgery date (pre-femoral nerve block versus post-femoral nerve block periods). All anesthesia and medical records of the patients who had undergone computer-navigated TKA in our facility between January 2009 and March 2010 were retrospectively reviewed. RESULTS: Forty patients were identified; 15 patients underwent computer-navigated TKA under general anesthesia alone (Group G) and 25 patients underwent surgery under general anesthesia combined with ultrasound-guided femoral nerve block (Group F). The incidence of development of VTE post-operatively was significantly lower in Group F (P = 0.037). Logistic regression analysis identified the use of a femoral nerve block as the most significant variable correlating with the incidence of post-operative development of VTE, and the odds ratio for VTE development in Group G was 3.12 (95% CI, 0.57-20.56). CONCLUSIONS: We suggest the possibility that the addition of a femoral nerve block on general anesthesia may reduce the incidence of the development of VTE following TKA.
Anesthesia ; Anesthesia, General ; Arthroplasty ; Femoral Nerve ; Humans ; Incidence ; Knee ; Logistic Models ; Medical Records ; Nerve Block ; Odds Ratio ; Pulmonary Embolism ; Retrospective Studies ; Venous Thromboembolism

This study investigated the physiological responses and effects of exercise training under hypoxic conditions at the skeletal muscle level induced by reducing muscle temperature in cold water environment. Participants were divided into two intervention groups, cooling and control conditions, according to the water temperature of 15°C and 33°C where the training were conducted in. Eight participants in each group performed submaximal cycling exercise in the water for 30 minutes at the lactate threshold (LT) intensity, three times a week for four weeks (12 sessions). LT intensity was assessed at pre- and post-intervention in a 33°C water temperature environment. A progressive load cycling test was performed on land to assess maximal oxygen uptake (VO2max) and Wingate test was conducted to measure anaerobic power. In the cooling group, working muscle deoxygenation increased during submaximal and maximal exercise, suggesting an improvement in the muscle oxygen extraction capacity. However, no effects on aerobic capacity such as VO2max or LT intensity were observed. The improvement in mean power and time to peak during the Wingate test in the cooling group indicated that LT intensity exercise training in a cold water environment would increase anaerobic power.