Is palpation essential in the digital era of orthotic designing?

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.