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[Repair of the knee extension apparatus in the treatment of "extension contracture" after femoral lengthening].

UNLABELLED
Restriction of the knee flexion is one of the most frequent complications during femoral lengthening with Ilizarov method. In most severe cases the knee flexion reaches less than 90 degrees, which leads to impairment of patient's activity ("extension knee contracture") and represents difficult clinical problem to manage.


MATERIAL
We reviewed 4 patients at the age of 14 to 22 years (mean 19), treated surgically because of severe knee flexion limitation as a complication of femoral lengthening with the Ilizarov method. The mean age at femoral lengthening was 17 years (12 to 20). The indication for lengthening was femoral shortening from 5 to 12 cm (mean 7.5) because of myelodysplasia with club foot deformity (1 case), fibular hemimelia (1 case), sequelae of septic arthritis (1 case) and Ollier disease (1 case). Lengthening with Italian modification of Ilizarov device was used in all cases. In two patients with knee instability the apparatus was extended to stabilize the knee joint (in one case tibial and femoral lengthening was made simultaneously). Femoral lengthening of 5 to 12 cm (mean 7.5) was achieved. Knee flexion before lengthening varied from 90 degrees to 150 degrees (mean 135 degrees) and after femoral lengthening decreased to 41 degrees (20 to 75 degrees).


METHOD
Plasty of knee extension apparatus was done 16 months after removal of the Ilizarov device. The procedure includes extensive release of subcutaneous and fascial adhesions around the knee joint (4 patient), patellar retinaculum and ilio-tibial tract release (4 patient), lengthening of vastus lateralis muscle (4 patients), vastus medialis (2 patients) and vastus intermedius (1 patient), mobilization of patello-femoral joint (3 patients), fractional, intramuscular lengthening of rectus femoris 15 cm above the knee joint (2 patients). Intraoperatively 90 degrees flexion was achieved (80 degrees to 100 degrees). In after treatment plaster cast with knee flexion 45 degrees was used. After 4-5 days passive exercises were started using K2 apparatus (continuous passive knee motion) and posterior slabs: one with knee extension for walking and second with knee flexion at the night were used. Active exercises began at the 10th day after surgery.


RESULTS
At follow up 10 to 47 months (mean 36) after surgery 105 degrees to 120 degrees of knee flexion (mean 114 degrees) was achieved with full passive and active knee extension at good muscle power. All joints were evaluated as stable in sagittal and coronal planes (including 2 joints with mild instability in coronal plane before surgery).


CONCLUSIONS
1. Femoral lengthening procedure should be realized with proper attention to prophylaxis of knee extension contracture. 2. Knee extension apparatus plasty is effective and save procedure for treatment of so called "extension knee contracture" as a complication of femoral lengthening.