Background: Consensus on method of treatment of displaced supracondylar fracture of the humerus in children is still lacking. Purpose of this prospective randomized controlled study is to compare closed reduction and long arm slab application with closed reduction and percutaneous crossed Kirschner wires  fixation.

Materials and methods: Children of age less than 12 years presented in B.P. Koirala institute of health sciences, Dharan in one year were randomly allocated to group A and group B consisting 30 patients in each group. Closed reduction and long arm posterior slab was applied in group A and in group B, closed reduction was followed by crossed Kirschner wires  fixation. Clinical and radiological evaluation of reduction was performed immediately after procedure and at the end of  first week, third week, third month and sixth month.

Results: The groups were matched for pre fracture characteristics and post reduction evaluation. The mean follow up period in group A was 6.9 months and in group B was 7.1 months. Closed reduction failed in two patients at the  first attempt and one patient failed to retain reduction at  rst week in group A. 11 patients (5 in group A and 6 in group B) were lost to follow up. Range of movement, valgus, varus and carrying angle of elbow in two groups were not significantly different. The mean difference of carrying angle of affected elbow as compare to normal elbow was significant in group A (p>  0.05). Flynn’s overall rating showed 32% excellent, 36% good, 18% fair and14 % poor result in patents treated with long arm slab as compared to 58% excellent, 29% good, 13 % fair and no poor results in patients with crossed Kirschner wires  fixation.

Conclusion: The outcome of displaced extension type supracondylar fracture of the humerus in children, managed with closed reduction and slab application are comparable with closed reduction and crossed Kirschner wire  fixation in terms of range of motion but is inferior in restoration of carrying angle. Good to excellent cosmetic and functional results are higher with crossed percutaneous Kirschner wires  fixation than with slab immobilization.