The reverse planning method for lengthening of the lower limb using a straight intramedullary nail with or without deformity correction. A new method

Abstract

Objective: Lengthening of the lower limb with or without correction of angular deformity using an intramedullary nail with new correction strategies to restore or maintain a normal mechanical axis and orientation of the joints compared to traditional strategies using external fixation. Postsurgical lengthening will occur along the axis of the straight nail.

Planning technique: The "reverse planning method" starts with the "ideal" final result of the projected correction and goes back to the preexistent deformity. The mechanical axis of the lower limb as well as the bone and joint orientation to it are well-defined geometrically measured. Technical considerations like the entry point of the nail, the diameter and geometry of the diaphyseal canal, the curvature of the bone, the apex of deformity, the level of osteotomy, and the creation of adequate bone segment size to allow for stable "locking" to the intramedullary nail are accommodated.

Results: The reverse planning method was used in the author's center in more than 500 cases of deformity correction and lower extremity lengthening using the Fitbone intramedullary lengthening nail, but the planning and surgical principles are applicable to lengthening and deformity correction with other intramedullary straight devices or for "lengthening over a nail" procedures.