The word “osteotomy” refers to a division of a bone. It is like a controlled fracture.
This operation is less common than it used to be but it is used to redirect load bearing forces around the knee joint. Sometimes patients have arthritis on the inside of the knee which gives rise to a marked bowing of the joint as though they had been riding a horse for too long. An osteotomy can be performed through the upper end of the shin bone. A wedge of bone can be removed and rather than being bow-legged, the patient can be reconverted to the usual knock-kneed alignment.
A similar approach can be adopted with the lower end of the thigh bone if excessive knock-kneedness is experienced by the patient. A wedge of bone can be taken from the medial side or inner side of the lower end of the thigh bone and convert the knock-kneed alignment into a limb which is now straight.
Whilst uncommon, osteotomies still have a role to play. They are typically used in patients who have quite significant deformity, who are suffering pain and who are too young to consider or should consider a joint replacement.