Patient controlled oral analgesia (PCOA) has been utilitzed in several centers in the US and Germany. Preliminary evidence from the literature seems to indicate that the benefits of PCOA are similar to IV PCA including increased patient satisfaction and better pain control (Striebel, Romer, Kopf, Schwagmeier ,1996; Striebel, Scheitza, Philippi, Behrens, Toussaint, 1998). At the Toronto Western Hospital, University Health Network, we have successfully implemented a PCOA program on two surgical units (Orthopedics/Rheumatology and Spinal). The purpose of this study is to compare usual nurse administered oral analgesia to PCOA with respect to pain, patient satisfaction, and passive range of knee motion in postoperative total knee replacement patients.