Study Procedure and Outcome Measures
STS
All outcomes were measured at the preoperative assessment, which took place immediately before the surgical intervention, and two postoperative follow-ups at three and six months after surgery. After arrival at the laboratory, participants had to fill in the EQ-5D and WOMAC questionnaires followed by the TUG and STS tests. Subsequently, the gait analysis was conducted.To assess the quality of life, the German EQ-5D questionnaire was used. According to Schulenburg et al. [Strength of the lower extremities was measured with the STS test, which has been shown to be a reliable and valid indicator of lower body strength in older adults [Functional mobility was measured with the TUG test. It is a common test in physiotherapy and clinical trials to measure the walking ability and functional mobility of patients [Gait parameters were measured using a six-meter electronic walkway (OptoGait, Microgate Corporation, Bolzano, Italy). To ensure a constant walking velocity during the measurement, a two-meter acceleration and deceleration area was given on each end of the walkway [