Development of a 3D scan posture-correction procedure to facilitate the direct-digital splinting approach

The direct-digital upper-limb orthopaedic splinting process employs portable 3D scanning systems to capture anatomical surface geometry. However, the resultant quality of a complete upper-limb scan geometry may be detrimentally affected by involuntary movements of an unsupported limb, and the inability to maintain the correct posture due to patient disability. The aim of this research study is to develop an upper-limb 3D scanning posture-correction procedure that addresses these limitations. The methodology covers four stages: (a) 3D scanning; (b) rigging; (c) posture correction; and (d) geometry inspection. Manual and semi-automated rigging procedures were developed to define segments and joints of the wrist on the upper-limb scans. A semi-automated definition was developed to precisely and repeatedly articulate the defined hand segment. To assess feasibility and accuracy of the developed posture-correction procedure, the hand segment on scans in neutral hand posture were articulated with the developed posture-correction procedure as closely as possible to the corresponding hand positions on the scans in extended hand postures. The reported virtual posture-correction procedure provides a basis for research into anatomy articulation and the optimisation of complex splints and orthoses.