Changes in Postural Stability Following THA for OA

The purpose of this study is to evaluate the changes in postural stability and balance confidence during the initial three months after elective unilateral total hip arthroplasty for osteoarthritis. Specifically, the investigators aim to: 1. To evaluate change in postural stability between the DA and DL surgical approaches during the first three months after elective unilateral THA for OA, using both a clinical measure and an instrumented measure. 2. To evaluate change in balance confidence between the DA and DL surgical approaches during the first three months after elective unilateral THA for OA. Secondary objective 3. To compare the DA and DL approaches for activity levels, function, quality of life and pain during the first three months after elective unilateral THA for OA.