The disease-specific quality of life is assessed using a validated questionnaire, the Western Ontario Shoulder Instability Index, measured at baseline, and 3, 6, 12 and 24 months. The WOSI index has 21 questions, divided into four categories to assess physical symptoms, sport/recreation/work, lifestyle and emotions. Each question is scored out of 100 using a visual analog scale response format. A lower score reflects a better quality of life.