Masamitsu Kido1, Kazuya Ikoma2, Yusuke Hara1, Kan Imai1, Masahiro Maki1, Takumi Ikeda1, Hiroyoshi Fujiwara1, Daisaku Tokunaga1, Nozomu Inoue3, Toshikazu Kubo1. 1. Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan. 2. Department of Orthopaedics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan. Electronic address: kazuya@koto.kpu-m.ac.jp. 3. Department of Orthopedic Surgery, Rush University Medical Center, Chicago, USA.
Abstract
BACKGROUND: Insoles are frequently used in orthotic therapy as the standard conservative treatment for symptomatic flatfoot deformity to rebuild the arch and stabilize the foot. However, the effectiveness of therapeutic insoles remains unclear. In this study, we assessed the effectiveness of therapeutic insoles for flatfoot deformity using subject-based three-dimensional (3D) computed tomography (CT) models by evaluating the load responses of the bones in the medial longitudinal arch in vivo in 3D. METHODS: We studied eight individuals (16 feet) with mild flatfoot deformity. CT scans were performed on both feet under non-loaded and full-body-loaded conditions, first with accessory insoles and then with therapeutic insoles under the same conditions. Three-dimensional CT models were constructed for the tibia and the tarsal and metatarsal bones of the medial longitudinal arch (i.e., first metatarsal bone, cuneiforms, navicular, talus, and calcaneus). The rotational angles between the tarsal bones were calculated under loading with accessory insoles or therapeutic insoles and compared. FINDINGS: Compared with the accessory insoles, the therapeutic insoles significantly suppressed the eversion of the talocalcaneal joint. INTERPRETATION: This is the first study to precisely verify the usefulness of therapeutic insoles (arch support and inner wedges) in vivo.
BACKGROUND: Insoles are frequently used in orthotic therapy as the standard conservative treatment for symptomatic flatfoot deformity to rebuild the arch and stabilize the foot. However, the effectiveness of therapeutic insoles remains unclear. In this study, we assessed the effectiveness of therapeutic insoles for flatfoot deformity using subject-based three-dimensional (3D) computed tomography (CT) models by evaluating the load responses of the bones in the medial longitudinal arch in vivo in 3D. METHODS: We studied eight individuals (16 feet) with mild flatfoot deformity. CT scans were performed on both feet under non-loaded and full-body-loaded conditions, first with accessory insoles and then with therapeutic insoles under the same conditions. Three-dimensional CT models were constructed for the tibia and the tarsal and metatarsal bones of the medial longitudinal arch (i.e., first metatarsal bone, cuneiforms, navicular, talus, and calcaneus). The rotational angles between the tarsal bones were calculated under loading with accessory insoles or therapeutic insoles and compared. FINDINGS: Compared with the accessory insoles, the therapeutic insoles significantly suppressed the eversion of the talocalcaneal joint. INTERPRETATION: This is the first study to precisely verify the usefulness of therapeutic insoles (arch support and inner wedges) in vivo.