 Participants will be asked to attend movement analysis testing sessions at the University of Strathclyde in Glasgow on three separate occasions; preoperatively, at 4 to 8 weeks postoperatively and at one year postoperatively. Each of these sessions will follow the same procedure. Prior to data collection, participants will be asked to change into the tight fitting shorts and vest tops provided male participants will be asked to forego the vest tops in the changing rooms within the laboratory facility. Measurements of weight and body dimensions will be taken required for processing the data and then reflective markers will be attached to the legs, pelvis, torso and arms. These will be attached using toupee tape or elasticated straps as required. They will be asked to wear a headband provided with another four markers attached on their head. There will be eight activities of daily living ADLs in the test protocol, which will be carried out in one of two laboratories; one a standard motion capture laboratory S and the other in a laboratory with a CAREN system Motek Medical, Amsterdam, Netherlands which consists of a virtual reality screen, moving platform and treadmill M. The ADLs will be: 