Comparison of sit-to-stand and static standing balance ability between patients with total knee arthroplasty and elderly healthy subjects.

Background: Identifying the functional status of patients after total knee arthroplasty is important. This study aimed to examine the differences in sit-to-stand and static standing ability balance between patients who underwent total knee arthroplasty and healthy participants.

Methods: Twenty patients (mean age 70.05 years) who underwent total knee arthroplasty and 20 healthy participants (mean age 69.20 years) participated in this study. To assess the participants' sit-to-stand, the Good Balance System (Metitur Ltd, Finland) was used to measure each participant's mediolateral center of pressure (COP) displacement and time required to complete the sit-to-stand movement. To assess the participants' static standing balance, the Good Balance System was used to measure each patient's mediolateral COP displacement, anteroposterior COP displacement, and velocity moment when standing with eyes open and with eyes closed.

Results: A significant difference was found in the mediolateral COP displacement and the time required to complete the sit-to-stand movement in the two groups (P< 0.05). A significant difference was also found in the mediolateral and anteroposterior COP displacement and the velocity moment when standing with eyes open and with eyes closed in the two groups (P< 0.05).

Conclusions: Patients who had total knee arthroplasty showed decreased sit-to-stand and static standing balance ability compared with the control group in the initial period after surgery.