Comparing Prefabricated and 3D Printed Foot Orthoses for the Management of Flat Foot Condition: A Randomized Controlled Trial.

OBJECTIVE: To investigate the short-term effects of 3D-printed and prefabricated foot orthoses on the management of flat feet. DESIGN: In this single-blinded study, 63 patients with flat feet were enrolled via convenience sampling. They were randomly assigned to the control and experimental groups, receiving prefabricated and customized 3D-printed foot orthoses, respectively. The assessment tools included a Visual analog scale (VAS) and a modified Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST) questionnaire. The patients scored their pain at weeks 0 and 4 using the VAS. At the end of week 4, patients completed the modified version of the QUEST questionnaire to record their satisfaction with the orthosis. RESULTS: VAS scores at week 0 for the two groups were not statistically significant (p > 0.05). At week 4, the VAS scores of the experimental group reduced significantly (p < 0.001), whereas the VAS scores of the control group remained statistically insignificant (p > 0.05). Modified QUEST questionnaire analysis revealed higher satisfaction with orthosis comfort and effectiveness in the experimental group than in the control, while factors like orthosis dimensions, weight, and durability did not differ significantly between groups. CONCLUSIONS: Customized 3D-printed orthoses effectively reduced pain and enhanced patient satisfaction with comfort and effectiveness in 4 weeks.

Comparison of multiple 3D scanners to capture foot, ankle, and lower leg morphology.

BACKGROUND: 3D scanning of the foot and ankle is gaining popularity as an alternative method to traditional plaster casting to fabricate ankle-foot orthoses (AFOs). However, comparisons between different types of 3D scanners are limited. OBJECTIVES: The aim of this study was to evaluate the accuracy and speed of seven 3D scanners to capture foot, ankle, and lower leg morphology to fabricate AFOs. STUDY DESIGN: Repeated-measures design. METHODS: The lower leg region of 10 healthy participants (mean age 27.8 years, standard deviation [SD] 9.3) was assessed with 7 different 3D scanners: Artec Eva (Eva), Structure Sensor (SS I), Structure Sensor Mark II (SS II), Sense 3D Scanner (Sense), Vorum Spectra (Spectra), Trnio 3D Scanner App on iPhone 11 (Trnio 11), and Trnio 3D Scanner App on iPhone 12 (Trnio 12). The reliability of the measurement protocol was confirmed initially. The accuracy was calculated by comparing the digital scan with clinical measures. A percentage difference of #5% was considered acceptable. Bland and Altman plots were used to show the mean bias and limit of agreement (LoA) for each 3D scanner. Speed was the time needed for 1 complete scan. RESULTS: The mean accuracy ranged from 6.4% (SD 10.0) to 230.8% (SD 8.4), with the SS I (21.1%, SD 6.8), SS II (21.7%, SD 7.5), and Eva (2.5%, SD 4.5) within an acceptable range. Similarly, Bland and Altman plots for Eva, SS I, and SS II showed the smallest mean bias and LoA 21.7 mm (LoA 25.8 to 9.3), 21.0 mm (LoA 210.3 to 8.3), and 0.7 mm (LoA 213 to 11.5), respectively. The mean speed of the 3D scanners ranged from 20.8 seconds (SD 8.1, SS I) to 329.6 seconds (SD 200.2, Spectra). CONCLUSIONS: Eva, SS I, and SS II appear to be the most accurate and fastest 3D scanners for capturing foot, ankle, and lower leg morphology, which could be used for AFO fabrication.

Digital mapping of a manual fabrication method for paediatric ankle-foot orthoses.

Ankle-foot orthoses (AFOs) are devices prescribed to improve mobility in people with neuromuscular disorders. Traditionally, AFOs are manually fabricated by an orthotist based on a plaster impression of the lower leg which is modified to correct for impairments. This study aimed to digitally analyse this manual modification process, an important first step in understanding the craftsmanship of AFO fabrication to inform the digital workflows (i.e. 3D scanning and 3D printing), as viable alternatives for AFO fabrication. Pre- and post-modified lower limb plaster casts of 50 children aged 1-18 years from a single orthotist were 3D scanned and registered. The Euclidean distance between the pre- and post-modified plaster casts was calculated, and relationships with participant characteristics (age, height, AFO type, and diagnosis) were analysed. Modification maps demonstrated that participant-specific modifications were combined with universally applied modifications on the cast's anterior and plantar surfaces. Positive differences (additions) ranged 2.12-3.81 mm, negative differences (subtractions) ranged 0.76-3.60 mm, with mean differences ranging from 1.37 to 3.12 mm. Height had a medium effect on plaster additions (rs = 0.35). We quantified the manual plaster modification process and demonstrated a reliable method to map and compare pre- and post-modified casts used to fabricate children's AFOs.

Comparison of 3D scanning versus traditional methods of capturing foot and ankle morphology for the fabrication of orthoses: a systematic review.

BACKGROUND: In the production of ankle-foot orthoses and in-shoe foot orthoses, lower leg morphology is traditionally captured using a plaster cast or foam impression box. Plaster-based processes are a time-consuming and labour-intensive fabrication method. 3D scanning is a promising alternative, however how these new technologies compare with traditional methods is unclear. The aim of this systematic review was to compare the speed, accuracy and reliability of 3D scanning with traditional methods of capturing foot and ankle morphology for fabricating orthoses. METHODS: PRISMA guidelines were followed and electronic databases were searched to March 2020 using keywords related to 3D scanning technologies and traditional foot and ankle morphology capture methods. Studies of any design from healthy or clinical populations of any age and gender were eligible for inclusion. Studies must have compared 3D scanning to another form of capturing morphology of the foot and/or ankle. Data relating to speed, accuracy and reliability as well as study design, 3D scanner specifications and comparative capture techniques were extracted by two authors (M.F. and Z.W.). Study quality was assessed using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) and Consensus-Based Standards for the Selection of Health Measurement Instruments (COSMIN). RESULTS: Six articles met the inclusion criteria, whereby 3D scanning was compared to five traditional methods (plaster cast, foam impression box, ink footprint, digital footprint and clinical assessment). The quality of study outcomes was rated low to moderate (GRADE) and doubtful to adequate (COSMIN). Compared to traditional methods, 3D scanning appeared to be faster than casting (2 to 11 min vs 11 to 16 min). Inter-rater reliability (ICC 0.18-0.99) and intra-rater reliability (ICCs 0.25-0.99) were highly variable for both 3D scanning and traditional techniques, with higher agreement generally dependent on the foot parameter measured. CONCLUSIONS: The quality and quantity of literature comparing the speed, accuracy and reliability of 3D scanning with traditional methods of capturing foot and ankle morphology is low. 3D scanning appears to be faster especially for experienced users, however accuracy and reliability between methods is variable.