Low Profile Ilizarov Frame in Correction of Varus Deformity in Patients with Adolescent Blount's Disease

Abstract

Background: Adolescent Blount disease or late onset tibia vara constitutes the most common cause of pathologic genu varum in late childhood and adolescence. It is a developmental condition characterized by disordered endochondral ossification of the posteromedial part of the proximal tibial physis resulting in multiplanar deformities of the lower limb. Objective: the aim of This work was to evaluate the results of treatment of acute correction of varus deformity in patients with Blount disease by using low profile Ilizarov frame. Patients and Methods: It is a retrospective and a prospective study for 10 patients who had adolescent Blount disease treated by acute correction using low profile Ilizarov frame. We looked principally into the following variables to evaluate the results of the treatment: Deformity correction (expressed as mechanical axis restoration), the average normal values were used as a reference (medial proximal tibial angle, 85–90; posterior proximal tibial angle, 77–84; thigh–foot angle, +10 external rotation) Results: the patients were 9 boys (90%) and one girl (10%). The mean age at presentation was 13.60 years, range ( 11- 17 years) , 6 patients (60%) presented with unilateral affections and 4 patients (40%) presented with bilateral affection. Mean preoperative to postoperative changes of MPTA from 74.57 (range 65-80) improved to 89.21 (range 86-95), Mean preoperative to postoperative changes of PPTA from 74.21 (range 66-80) improved to 79.07 (range 77-82) , Mean preoperative to postoperative changes of MAD from 31.14 mm (range 18-45 mm) improved to 3.64 mm (range 0-8 mm). Mean preoperative to postoperative changes of TFA from -23.57 (range -30 -15) of internal tibial torsion improved to 5.36 (range 0-10) of external tibial torsion Conclusion: Management of adolescent Blount disease by acute correction strategy using a low profile Ilizarov is a safe technique offering excellent results with low incidence of complications. ,Low profile Ilizarov is lighter and less bulky so more comfortable for patients than classic Ilizarov external fixation , Acute correction technique can achieve the same result of correction as gradual correction technique in patient with no limb length discrepancy , Acute correction offers a shorter time in frame as compared to gradual correction with fewer follow-up visits and exposure to radiation.