Manufacturing and Analysis of a Knee Ankle Foot Orthosis for Acquired Anisomelia by Using a Finite Elements Strategy

Anisomelia is a leg length discrepancy and is an anatomical condition that can be caused by congenital or acquired disorders. A particular case of acquired severe anisomelia is caused by surgical treatment of femoral osteosarcomas, leading to a reduction in leg length. In this paper, we present and analyze a personalized ortheses manufacturing process (KAFO). To do that, the orthoses are designed based on biomechanical requirements for a particular case of severe anisomelia (more than 6 cm) caused by surgical treatment of femoral osteosarcoma. Then, custom-made KAFO is manufactured by a handcrafted process; thus a digitized 3D model of KAFO is carried out to optimize its thigh shell design using a numerical analysis based on the finite elements method. For this, a distribution of the weight force of 257.51 N in the ischial support is analyzed, obtaining a Von Mises criterion of 170, 15, the safety factor of 2, 03, a total deformation of 64,48, and an equivalent elastic strain of 0, 02, respectively. Finally, the design and manufacturing of KAFO are analyzed during the patient’s gait. The results obtained report that the use of proposed KAFO reduces gait abnormalities, in contrast to the test without KAFO.