The goal of this observational study is to investigate the potential of wearable sensors for monitoring the postoperative recovery of patients after TKA. The main question the study aims to answer is: • whether alterations in gait characteristics and the changes in PA levels measured by wearable PA trackers can accurately reflect a patient's postoperative recovery status and provide clinically relevant information to aid their management. Participants will wear PA trackers during the perioperative period of TKA (2 weeks before until 3 months after, and then agin for 2 weeks one year after the surgery) and we will analyze their gait and PA and correlate them with their recovery after surgery.