[Purpose] The purpose of this study is to provide fundamental information for efficient management of patients after a total knee replacement (TKR) through the evaluation of changes of range of motion, pain, functional level, and quality of life. [Subjects and Methods] For a total of 63 knee osteoarthritis patients, VAS, KSKS, KSFS, HSS, WOMAC scores and quality of life were evaluated for functional levels at pre-operation, post-operation, six months after operation, and 12 months after operation. [Results] After the TKR operations, participants showed significant improvement in KSKS, KSFS, WOMAC, and SF-36 scores when compared to pre-operation. [Conclusion] After a TKR operation, ROM, and pain management, along with a therapeutic program for improvement of function, should be conducted 6 months after the operation.