Minimum Age: 60 years Maximum Age: 85years Gender-Based: All Accepts Healthy Volunteers:No  Criteria:  Inclusion Criteria:  Age between 60 and 85 years Informed consent Receipt of elective unilateral primary knee arthroplasty surgery.  Exclusion Criteria:  Non-degenerative arthritis, including rheumatoid arthritis, or traumatic arthritis Patients receiving rehabilitation simultaneously Patients with other musculoskeletal or neurological problems, including fractures, Parkinsonism, cerebrovascular events, or patients with multiple comorbidities Cancer patients receive chemotherapy Patients with the peri-operative complication that has an adverse effect on outcomes,for example: intra-operative fractures, thromboembolism, peri-operative infections, or phlebitis