Factors affecting re-displacement in pediatric forearm fractures and the role of cast indices

Abstract

Pediatric forearm fractures are among the most common reasons for presenting to the orthopedic emergency and pose challenges for orthopedists due to the complexity of their treatment and the frequency of complications. [1] The majority of the childhood diaphyseal forearm fractures are treated with manipulative reductions and loss of reduction is one of the most commonly reported complications. [2,3] The factors that cause loss of reduction can be categorized under three headings, related to the fracture, the surgeon or the patient. Fracture-based factors can be summarized as previous displacement, fracture localization, and the obliquity of the fracture, while surgeon-related factors are inadequate fracture reduction and poor casting technique, and patientrelated factors are muscle atrophy and the regression of the soft tissue edema in the cast. [2-4] The part we need to focus on as trauma surgeons is the employment of an appropriate casting following a successful fracture reduction. Although the importance of radiological indices in measuring the success of the treatment in distal radius fractures has been examined in many studies, studies on these indices in diaphyseal forearm fractures are very limited. Alemdaroğlu et al. [5] described the three-point index (TPI) in adult and pediatric radius distal end fractures and reported Objectives: This study aims to investigate the factors affecting the loss of reduction in pediatric diaphyseal forearm fractures and to compare the three-point index (TPI) with the cast index, padding index, Canterbury index, and gap index. Patients and methods: This retrospective study, which was conducted between January 2016 and December 2016, included 159 patients (134 males, 25 females; mean age 8.1±2.8 years; range, 3 to 13 years) with diaphyseal forearm fracture. Patients' age, gender, and the level, displacement, and location of the fractures were recorded. The presence of anatomic reduction, a straight ulnar border, and the cast type (banana or box type) were checked after the reduction. The TPI, cast index, padding index, Canterbury index, and gap index were measured. Results: Fifty-two patients (32.7%) experienced loss of reduction during the follow-up. Displaced fractures of both the radius and the ulna, cast type-banana, anatomical reduction, straight ulnar border, TPI, cast index, padding index, and Canterbury index were found to be associated with re-displacement. Conclusion: Although cast indices can be used as a beneficial clinical tool in predicting the loss of reduction in the treatment of pediatric forearm fractures, they may not be sufficient when used alone. Obtaining a more accurate result may be possible by assessing several parameters such as the presence of an anatomic reduction, box-type casting, and TPI together.

Increase in gap index over time after reduction of unstable paediatric both-bone forearm fracture does not cause displacement

“…Another important index is the three-point index, which measures the gap amount using a different method. Although some studies have touted it as a displacement predictive method, its superiority over the cast index remains unclear 4,15 . Our findings suggest that the gap index does not predict displacement; we argue that the effect of the gap amount increasing over time in the three-point index method is small.…”

“…Many casting indices are used to predict reduction loss, the most common being the cast index, three-point index and gap index 4,5 . These indexes are routinely and successfully applied during plaster application.…”

“…Values below the cut-off have been demonstrated to prevent reduction loss. 4,5 The cast index was calculated by dividing the inner diameter of the cast on the lateral view by the inner diameter of the cast on the AP view (Figure 1). The cut-off was 0.8.…”

“…Gap index 8 : It is the amount of distance between the skin and the plaster in the X-ray taken after the reduction. Maintaining the gap index below the cutoff values can prevent reduction loss 4,5 . This value is calculated as follows: (Radial fracture site gap + Ulnar fracture site gap/Inner diameter of cast in AP plane) + (Dorsal site gap + Volar fracture site gap/Inner diameter of cast in lateral plane) (Figure 2a and b).…”

Radiographic prediction of Colles fracture displacement after splint fixation-a prospective study of 97 patients

“…According to Wolff's law, repetitive loads on the bone cause adaptive responses that allow the bone to better cope with these loads. In the case of the radius, most of these loads may come from muscle strength, and the volar cortex is responsible for maintaining the stress of the musculoskeletal system [11,12] . The stabilization acts as a support rod like an angle iron pulley system.…”