Abstract

Background: Adolescent Blount disease is the commonest cause of genu varum in old children. It is a multiplanar deformity consisting of varus, procurvatum and internal tibial torsion. Ilizarov frame can be used for both acute and gradual correction. Acute correction has the benefit of shorter time to healing and more comfortable to the patient. Gradual correction needs more patient compliance but is more forgiving.

Objective: the aim of this work to evaluate the results of acute correction of adolescent Blount’s disease using a hinged Ilizarov frame constructed for gradual correction taking the benefits of acute correction and using a hinged frame making it possible to correct any overcorrection or under correction in the clinic.

Patients and Methods: It was a prospective study for 23 boys with adolescent Blount disease treated by acute correction using a hinged Ilizarov frame. The average age at presentation was 14 years (range 11- 17 years), 3 patients (13%) had bilateral affection. 6 patients had limb length discrepancy.

Results: Average preoperative to postoperative changes of MPTA from 70º (range 60-80) improved to 90º (range 85-95), Average preoperative to postoperative changes of PPTA from 72 (range 64-80) improved to 80º (range 78-82), Average preoperative to postoperative changes of MAD from 35 mm (range 20-50mm) improved to 5mm (range 0-10mm). Average preoperative to postoperative changes of TFA from -25 (range -30-20) of internal tibial torsion improved to 5.36 (range 0-10) of external tibial torsion.

Conclusion: Acute correction of adolescent Blount’s disease using a hinged two rings Ilizarov frame constructed for gradual correction is a safe technique combining the benefits of acute and gradual correction, allows the surgeon to correct any error at the clinic and decreasing the need for operative fluoroscopy.

Keywords: Blount disease; Hinged ilizarov; Acute correction

Abbreviations: MPTA: Medial Proximal Tibial Angle; PPTA: Posterior Proximal Tibial Angle; MAD: Mechanical Axis Deviation; LLD: Limb Length Discrepancy; TFA: Thigh Foot Angle