Comparison of different pinning techniques for 3D-printed radius with Salter-Harris type I fracture

Abstract

The purpose of the present study was to compare different pinning techniques for distal radius with Salter-Harris type I fracture. Computed Tomography (CT) images of a distal antebrachium of the 6.5 kg, growing, 6-month-old intact male mongrel dog were 3D-printed with Polycarbonate (PC) material. Twenty-one synthetic bones were classified into three groups. Cross pinning, Parallel pinning, and HK2 pinning techniques were applied to each group. A compressive shear test was applied to each group, and the results at 1 mm, 2 mm, and 3 mm displacement and the load at failure were analyzed through statistical software. It was found that there was no significant difference (p = 0.156) among the three groups at 1 mm displacement load. When comparing loads at 2 mm displacement, a significant difference (p = 0.024) was observed between the HK2 pinning group (224.6 ± 21.8 N) and the Parallel pinning group (188.1 ± 18.2 N). When comparing loads at 3 mm displacement, the HK2 pinning group (392.9 ± 35.6 N) and Cross pinning group (379.4 ± 37.6 N) showed significantly higher (p = 0.006, p = 0.028) loads than the Parallel pinning group (329.1 ± 25.1 N). In the comparison of maximum failure loads, a significant difference (p = 0.029) was observed between the HK2 pinning group (546.6 ± 47.5 N) and the Parallel pinning group (478.6 ± 44.3 N). In conclusions, the reduction of the distal radius with Salter-Harris type I fractures using the novel HK2 pinning technique in 3D-printed bones was similar or superior to other pinning techniques.