 This study will include non-hysterectomised women aged 40 to 65 years who have undergone breast surgery and then commenced on aromatase inhibitors within the preceding 12 weeks. The control group which has been fully recruited included non-hysterectomised, healthy women aged 40 to 65 years. A MRI of the dominant knee will be used to compare changes in knee articular volume over time. A MRI will be done at baseline and again at 2 years. Changes in knee articular volume is the primary outcome. We will also use this opportunity to compare menopausal symptoms assessed using the Menopause Quality of Life MENQOL questionnaire between women treated with aromatase inhibitors and those who are not. Well-being will also be assessed using the Psychological General Well-Being index. 