Obesity is a global epidemic of 2.1 billion people and a well known cause of osteoarthritis. Joint replacement in the obese attracts more complications, poorer outcomes and higher revision rates. It is a reversible condition and the fundamental principles of dealing with reversible medical conditions prior to elective total joint replacement should apply to obesity. The dilemma for orthopaedic surgeons is when to offer surgery in the face of a reversible condition, which if treated may obviate joint replacement and reduce the risk and severity of obesity related disease in both the medical arena and the field of orthopaedics.

Clinical studies evaluating the effects of vitamin D alone or in combination with calcium on physical function, falls and fractures have been inconsistent. Vitamin D has, however, been the focus of much orthopaedic, trauma and endocrine research. Playing a central role in muscle and bone metabolism, some studies on Vitamin D therapies offer the tantalising suggestion of a reduction in falls and fractures simply with vitamin D supplementation. We review the background and evidence behind vitamin D.