 Secondary outcomes: Functional tests timed up and go, 30s sit and stand, forward reach, forward step down, 6 min walk and 40 m walk test, knee strength Biodex isokinetic dynamometer and patient reported pain on a visual analogue scale VAS. A number of PROMs: Health related quality of life EQ-5D, Knee injury and Osteoarthritis Outcome Score KOOS, Oxford Knee Score OKS and Forgotten Joint Score FJS as well as 3D movement and gait analysis. 