Abstract: Objective To compare the perioperative outcomes of total knee arthroplasty (TKA) between osteoarthritis (OA) and rheumatoid arthritis (RA) patients. Methods Clinical data about osteoarthritis patients (n=65) and rheumatoid arthritis patients (n=43) who underwent unilateral TKA in our department of orthopedics from September 2012 to August 2013 were recorded. The knee functional outcomes were compared between the two groups in preoperative period and 3 or 5 days after operation, including VAS score, range of motion (ROM), length of hospitalization and complication rates. The knee functional outcomes were compared between the two groups in preoperative period or 1, 3 months after operation according to Hospital for Special Surgery (HSS) score. Results The differences of preoperative condition between two groups were not significant (P＞ 0.05). The 3, 5 day postoperative ROM of OA group were higher than that of the RA group (P＜ 0.05). While, the 3, 5 day postoperative VAS scores of OA group were lower than that of the RA group (P＜ 0.05). Drainage volume, increasing rate of circumference length above 10 cm of the knee, length of hospitalization and wound related complication occurred more often in RA group than in OA group (P＜ 0.05). The 1 and 3 months postoperative HSS score of RA groups were lower than that of OA group (P＞ 0.05). Conclusion The TKA effects of RA patients in perioperative period are worse than that of OA patients.