MEASUREABLE ENDPOINTS - Objective outcomes from performance based testing will be assessed, OARSI (OARSI: Osteoarthritis Research Society International) recommended physical function tests (6 minute walk test). Secondary outcomes: Pain, reported physical function in daily activities/sport/recreation, knee related quality of life measures from the above mentioned questionnaires and 4 other OARSI recommended functional tests (30sec chair stand test, 40m fast paced walk test, stair climb test and up and go test) in addition to age, sex, BMI (Body Mass Index), ethnicity and occupation.