After the approval of institutional review board and the provision of informed consent , @ patients over @ years old , undergoing acute replacement of femoral head under combined spinal and epidural anesthesia and midazolam sedation at Qingdao Municipal Hospital and Qingdao Hiser Medical Center from January @ to May @ , were randomly assigned into control group ( group C , n = @ ) and parecoxib group ( group P , n = @ ) .