 Patients who are undergoing unilateral total knee replacement TKR and choose to participate will be randomly assigned to a treatment group.Patients in group one treatment group will receive a 30ml dose of .5 bupivacaine solution injected into the local anesthetic infiltration catheter immediately prior to its removal on postoperative day one. Patients in group two control group will receive no additional medication during local anesthetic infiltration catheter removal. 