James Aronson, M.D.

In part one of this two-part presentation (August VJO), Dr. James Aronson reviewed the compression-distraction histogenesis of bone and soft tissues, the basis for treatment when applying the principles of circular external fixation as first defined by Professor G. A. Ilizarov of the Soviet Union in the 1950s. In addition, Dr. Aronson addressed the complexities involved when applying circular external fixation to the femur.

The femur is the most difficult bone to lengthen because:

• It is both the largest bone in the body and the bone surrounded by the greatest muscle mass, therefore creating the potential for extensive resistance against lengthening;
• It has built-in angular and torsional changes created by the normal anatomy requiring complex three-dimensional planning and treatment;
• The anatomical and mechanical axes differ by approximately 6 to 7 degrees

Part two of this extensive review includes the surgical technique for femoral lengthening while focusing on the intraoperative considerations involved with the application of the Ilizarov circular external fixator. The viewer will see "new" carbon fiber circular fixation rings being used. The composite reduces the weight of these often bulky femoral frames, and more importantly, they afford clear unobliterated radiographic visualization. In addition, Dr. Aronson makes a point of reviewing perhaps the most important consideration, that of wire and half-pin placement, which is important not only to the success of the procedure, but also to the safety and comfort of the patient and successful rehabilitation of the limb during distraction. Ilizarov places strong emphasis on the perfect pin placement that means not only placing the pin through the skin, soft tissue, and bone and out the other side without injuring a neurovascular structure, but also it means being not even close to a neurovascular structure since the wire or half-pin could erode into the structure, causing considerable damage.

This case presentation involves a 15-year-old female who in 1986 had an open fracture of the right femur with a segmental right tibial fracture. She was treated initially with external fixation and standard split-thickness skin grafting techniques. Mixed gram-negative osteomyelitis developed and subsequently healed by means of debridements, which resulted in significant femoral bone loss. The initial external fixation was replaced with an intramedullary rod and was removed once bone incorporation was achieved. The patient now has significant soft tissue defects on her medial thigh as well as femoral shortening of 2 inches.

References
1. Aronson J Posttraumatic femoral lengthening. Part 1: Tension-stress phenomenon and circular frame construct for the femur MVP Video J Orthop 1991;6(4):segment 1
2. Maiocchi AB, Aronson J, eds. Operative Principles of Ilizarov Baltimore:Williams & Wilkins 1991
3. Bagnoli GF, Paley D The Ilizarov Method Philadeophia:B.C. Decker 1990
4. Ilizarov GA The tension-stress effect on the genesis and growth of tissues Clin Orthop 1989;238:249-281
5. Paley D, et al. Treatment of malunions and mal-nonunions of the femur and tibia by detailed preoperative planning and the Ilizarov techniques Orthop Clin North Am 1990;21(4):667-691

• Total Run Time: 26:13 minutes
• Catalog Number: 6010
• Publication Date: October 1991

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