Healing of femoral fractures by the meaning of an innovative intramedullary nail.

In this paper, an innovative design of nail, conceived to heal fractures of long bones has been investigated. Its functioning is based essentially on sliding of conical surfaces located in a spindle and in a series of holding pins radially disposed around it. Spindle and holding pins are connected together by means of a sleeve. Medial and distal screws are not necessary. Rotational and longitudinal motions of the spindle are transformed in a radial expansion of the holding pins by the sliding of conical surfaces. A complete numerical FE model of an implanted femur was realized and analyzed by the mean of two loading configurations: LC1 by imposing a vertical load of 980 N, and LC2 by considering resultants of the muscle actions. Analyses confirmed results, in terms of mechanical performances, comparable with the others traditional systems of prosthesis.