Abstract
Aim: presentation of a new lengthening device which is reliable and overcomes the problems seen with the classical Ilizarov frame, based on the principle of fluid mechanics.
Methods: we followed ten cases until bone healing. After corticotomy, the telescoping nail is brought into the femur or tibia like a normal IM nail. Diameter for the femoral nail 13 mm, 12mm for the tibia nail. In the proximal sector of the nail, the sterile arachid oil presses the plunger of the hydraulic actuator (pressure cell) out of the piston. It pushes against the distal nail which is locked in the distal femur with two screws. In all but one case, lengthening was done because of post-traumatic shorthening. In one femur with a defect of 10 cm a bone transport was performed using this system to fill the gap.
The pressure in the nail was increased with an external syringe-pump, attached two times daily via a quick coupling (swage lock) mechanism to the inlet port of the nail (60 Bar for the femur and 40 Bar for the tibia). Lengthening at a rate of 1.8 mm day was possible with remarkable comfort for the patient. The silver coated inlet port (tube of 2mm) gave no skin reaction in nine cases. In one femur there was slight drainage of fluid which stopped spontaneously after two weeks. While lengthening, patients were allowed to walk with partial weight bearing.
After lengthening, the oil was released and the inlet port cut off underneath the skin.
Results: all cases could be brought up to length in the desired time frame. Additional surgery was necessary in two cases to enhance bone healing (one autologous bone graft, one bone marrow injection). No implant failure or other undesired side effects were noticed with this method.
Conclusion: preliminary good results were achieved with this new apparatus, which seems to give reproducible results with less burden to the patient. Lengthening can be achieved much faster than with the classical distraction method of Ilizarov.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
