It was well known that total knee arthroplasty could improve the previously impaired proprioception in degenerative osteoarthritis. Most current researches have been focused on the change of the proprioception. However, the evaluation of the proprioception is based on the surrogated end.

Double or single limb standing balance is considered functional scale. It is very important view for the prevention of slipping down injury in evidence-based approaches for knee osteoarthritis.

Unfortunately, few study have been performed for figuring proprioceptive change after surgery out.

Considering the similarity between the proprioception and the standing balance and reported positive result in proprioception after total knee arthroplasty, the investigators supposed that total knee arthroplasty might give an influence on the recovery of single limb standing balance.

Inclusion Criteria:

• Medial compartment degenerative knee osteoarthritis showing the varus deformity

Exclusion Criteria:

• History of surgery on the lower extremity except for arthroscopy or menisectomy
• Hip arthritis or, hip or back pain disturbing the standing
• History of participation in sport rehabilitation program within less than 6 months
• Presence of neurological or musculoskeletal disease disturbing the standing
• Patient to reject the participation

patients to be scheduled to take a elective unilateral total knee arthroplasty