METHODS	Before wound closure , patients were given intra-synovial injections of the following solutions : patients in group I received 40mL of 300mg ropivacaine with 1:200,000 epinephrine and 5mg morphine ; patients in Group II received 40mL of 300mg ropivacaine with epinephrine ; and patients in Group III received 50mL normal saline as a control .\