An ‘osteotomy’ is the surgical division of a bone to improve alignment of the limb. This may be done to improve function, pain or the cosmetic appearance of a limb. Osteotomies around the knee may be considered in young patients with localised arthritis of the joint, enabling knee replacement surgery to be delayed until later in life. The specifics of the procedure will vary from patient to patient and will be discussed when the surgery is planned.