The symptoms of knee osteoarthritis include knee joint pain, impaired proprioception, and etc. Knee arthroplasty is commonly recommended for the patient with severe knee osteoarthritis to relieve pain and regain function. But the effects of arthroplasty on the proprioception and gait performance, which were related to the risk of falling, were not fully understood. Recently, the concept of enhancing the rotational movement has been introduced into the design of the knee joint prosthesis for mimicking the kinematic performance of the healthy knee. However, study on the functional performance after using these rotational designed arthroplasties was still scarce. So, the purpose of this study aims to evaluate the differences in the proprioception, balance function and gait performance among different designs of the knee arthroplasties with mobile bearing (MB), medial congruent (MC) and posterior stabilized (PS) design. This study is divided into the retrospective and prospective parts.

Investigators will enroll the patients who already replaced their knee joint by one of the above knee arthroplasties for the retrospective part; other patients who plans to receive one of the above knee arthroplasties, twenty participants for each design and each part. The assessment of proprioception, balance function and gait performance will be performed before the knee arthroplasty, and followed at the post-surgery time points of six weeks and three months. The one-way ANOVA will be used to compare the group differences in the retrospective part, and the two-way mixed model ANOVA for the prospective part.

Ultimately, the results of this study could help to have better knowledge of the treatment effects from the different designed knee arthroplasties.

Inclusion Criteria:

• Diagnosed as knee joint osteoarthritis and will receive knee joint arthroplasty.

Exclusion Criteria:

• Already receiving a knee joint arthroplasty surgery
• Can not walk independently for 20 m
• Can not stand for 5 min
• With neurological degenerative disease
• Lower limb received any surgery within recent 2 years

Out patient department