Introduction Forearm fractures of the radius and ulna account for approximately 45% of pediatric fractures. Unfortunately, after adequate reduction and casting, these fractures have a risk of re-displacement in the cast within the first 3 weeks. While some re-displacement may be acceptable due to remodeling capabilities of children, significant re-displacement requires repeat manipulation or internal fixation to prevent deformity and range of motion deficits. Previous literature suggests that conservatively managed mid-shaft both-bone forearm fractures have a re-manipulation rate of 10-70%. The purpose of this study is to compare the re-displacement rate of displaced mid-shaft both-bone forearm fractures in children treated with closed reduction and casting with or without a loop and sling applied to the cast proximal to the fracture site (Rang technique—see figure). Methods The study was approved by the medical school IRB. A retrospective review was performed of 42 patients under the age of 14 with displaced mid-shaft both-bone forearm fractures treated over a 4-year period (25 males and 17 females). The average age was 7 years (range 1 to 13). Data analyzed included: demographics, mechanism of injury (MOI), presence of a pulse, presence of nerve injury, incidence of compartment syndrome, use of a loop and sling, loss of reduction, need for re-manipulation, need for ORIF. Patients with pathologic or additional fractures were excluded. Results The most common MOI was a fall on the outstretched arm. Treatment in each case was closed reduction and casting without internal fixation. One patient presented with trace distal pulses and three presented with neurological symptoms. Post op immobilization was performed with well-molded casting in forty cases and sugar-tong splints followed by casting in 2 cases. The casts were applied with the elbow flexed to 90 degrees and the forearm in neutral. In 15 patients (36%) a loop and sling were attached to the cast proximal to the fracture site (‘Rang’ method). 27 patients (64%) were given a standard sling. Only one patient (7%) managed with the Rang method lost reduction while 17 patients (63%) given a regular sling lost reduction and required a second fracture manipulation (P = 0.0004). No patient was indicated for ORIF. No patients developed a compartment syndrome. All cases went on to radiographic union without the need for additional procedures. The weak pulse returned after fracture reduction; the nerve palsies recovered within 1-month observation. Discussion/conclusion Treatment of displaced both-bone forearm fracture in a child age < 14 years typically involves closed reduction and casting. The ‘Rang’ method of placing a loop and attached sling proximal to the fracture site creates support for the well molded cast and minimizes deforming force at the fracture site. In the current study, this casting ‘pearl’ resulted in significantly less fracture re-displacement.

Long arm cast with loop/sling attached proximal to the fracture site.