[Contribution of Ilizarov's equipment in the treatment of congenital pseudarthrosis of the lower limb].

INTRODUCTION

Risks and benefits of using Ilizarov apparatus in the treatment of congenital tibial or fibular pseudarthrosis (CTFP) are presented in this retrospective study.

MATERIALS AND METHODS

We reviewed with an average follow-up of 3 years and 4 months, the outcome of twenty consecutive patients treated between 1985 and 1993, for a CTFP using the Ilizarov apparatus. Sixteen patients were treated for non union of both tibia and fibula, 1 patient for an isolated non union of the fibula, and 3 patients for correction of a previously treated, malunited pseudarthrosis. The apparatus was used in four different ways: Realignement, end to end compression, and leg lengthening in 14 cases, Simple external fixation in association with another method of treatment in 2 cases, Progressive correction of malunion in 3 cases, Progressive diaphyseal reconstruction in 1 case (fibula).

RESULTS

The mean fixation duration was 7.3 months. Union was achieved with the initial treatment in 11 out of 20 cases (including the 3 cases of malunion correction). Bone grafting was used in 7 out of the 9 remaining cases, and led to bone healing in 3 of them. Five complications were encountered: deep infection in 1 case, repeated stress fracture in 1 case, repeated fracture of the pins in 1 case, malunion in 6 cases, and less than 3 cm leg length discrepancy in 4 cases.

DISCUSSION

Ilizarov external fixator is an efficient solution for many cases of CTFP, in which healing did not occur with other methods of treatment. The best indication for its use are the normotrophic and the hypertrophic types of non union (Apoil II), after the age of 4 or 5. Secondary massive bone grafting is to be considered in some cases, since it can either achieve bone union or strengthen it. The major disadvantage of this method is the lack of excision of the dystrophic tissue at the non union site. So, even after the non union is healed, the bone remains dystrophic and fragile, and necessitates a permanente protective orthosis, until the end of bone growth.