Is Palpation Essential in The Digital Era of Orthotic Designing?

Komal Chhikara^1,2,3,4*Scott Morrison⁵Marie-Luise Wille^1,2,3Buddhi Herath^1,2,3Kerrie Evans^6,7Dean Hartley^5,6Müge Belek Fialho Teixeira⁸Bridget Hughes⁹Natalie Haskell^10,11Amanda Beatson¹²Marianella Chamorro-Koc^10,13Judith Paige Little^1,2,3,4Sinduja Suresh^1,2,3,4

• ¹School of Mechanical, Medical and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, Queensland 4000, Australia, Brisbane, Australia
• ²Centre for Biomedical Technologies, Faculty of Engineering, Queensland University of Technology, Brisbane, Queensland 4000, Australia, Brisbane, Australia
• ³Australian Research Council Training Centre for Multiscale 3D Imaging, Modelling, and Manufacturing, Queensland University of Technology, Brisbane, Queensland 4000, Australia, Brisbane, Australia
• ⁴Biomechanics & Spine Research Group at the Centre for Children’s Health Research, Faculty of Engineering, Queensland University of Technology, Brisbane, Queensland 4000, Australia, Brisbane, Australia
• ⁵iOrthotics, Brisbane, Queensland 4030, Australia, Brisbane, Australia
• ⁶Healthia Limited, Brisbane, Queensland 4006, Australia, Brisbane, Australia
• ⁷Faculty of Medicine and Health, School of Health Sciences, The University of Sydney, Sydney 2006, Australia, Sydney, Australia
• ⁸School of Architecture and Built Environment, Faculty of Engineering, Queensland University of Technology, Brisbane, Queensland 4000, Australia, Brisbane, Australia
• ⁹School of Education, Faculty of Creative Industries, Education, and Social Justice, Queensland University of Technology, Brisbane, Queensland 4000, Australia, Brisbane, Australia
• ¹⁰School of Design, Faculty of Creative Industries, Education and Social Justice, Queensland University of Technology, Brisbane, Queensland 4000, Australia, Brisbane, Australia
• ¹¹School of Architecture, Industrial Design and Planning, Griffith University, Gold Coast, Australia, Gold coast, Australia
• ¹²QUT Business School, Centre for Decent Work and Industry (CDWI), Queensland University of Technology, Brisbane, Queensland 4000, Australia, Brisbane, Australia
• ¹³QUT Design Lab, Faculty of Creative Industries, Education and Social Justice, Queensland University of Technology, Brisbane, Queensland 4059, Australia, Brisbane, Australia

Custom foot orthotics require identification of anatomical landmarks in the foot to facilitate accurate alignment and precise foot measurements. Traditionally, these landmarks are identified through manual palpation, however, with the advent of digital scanning, it may not be necessary. Therefore, this study aimed to determine whether guidance from manual palpation to identify anatomical landmarks affects (a) reliability of foot measurements and (b) consistency in digitally designed orthotic insoles. For reliability, 3D foot scans were obtained under non-weight-bearing (NWB) (n=24) and weight-bearing (WB) (n=24) conditions from 12 healthy adult participants (9 females and 3 males; age 29 ± 4 years; height 164 ± 8 cm; weight 60 ± 6 kg). 15 key dorsal and plantar foot measurements were extracted based on the palpation-guided and scan-derived landmarks. Following this, a preliminary assessment of orthotic design consistency was evaluated using a reference participant (n=1), with 24 orthotic insoles designed (3 designers designed insoles using scan-derived and palpation-guided landmarks (by 3 podiatrists), in NWB and WB). Intra-and inter-user reliability of palpation-guided landmarks were good to excellent (ICC = 0.90-1). Measurements for scan-derived landmarking showed good to excellent intra-user reliability (0.83-0.92) but poor to moderate inter-user reliability (0.31-0.75) for clinically relevant plantar measurements. While palpation improves landmark reliability, translating these into consistent orthotic designs requires clinical expertise and standardised design workflows. Palpation, while not always essential, improves landmarking identification in variable clinical conditions. Collaborative training and further studies across varied clinician and designer experience levels are essential to optimize digital orthotic design.