A curvature on a limb in one or in several planes is defined as deformity. The curve may be present in frontal, sagittal or rotationel plane and may be seen in multiple planes at the same time. The deformity may be present as angulation, translation or torsion.

Deformities may be congenital and may develop due to other health problems. In children, the deformities develop due to particular genetic and metabolic disorders or as a consequence of fractures and bone infections. Deformities may develop on any bone in human body. The physicians must keep in mind that each deformity and the treatment must be organised specific for the patient

The deformities may not cause any discomfort, or in advanced cases the patients could not walk. In such severe conditions, geometric and biomechanic measurements must be taken. In addition, simulation of the deformity and the  treatment plan must be performed on a template before surgery. Then, the operation procedure is performed in particular periods; acute or gradual.

Ilizarov, a breakthrough method which was introduced to the world in 1970s, has frequently been used for fixations. The center of the deformity, the position of the hinge and the algorithm of the fixation are determined with a good deformity analysis before surgery. Then, the plan for acute or gradual correction and the choice of implant for fixation of the bone after osteotomy(cutting out the bone) are discussed. Then, the operation is performed in accordance with the plan. The deformity with such a plan will be fixated at about hundred percent  accuracy and the operation will be a total success. However, performing such a complex surgery will require quite much experience. Otherwise, patients may not be happy with the outcomes after surgery.