Exploring the mechanical properties of 3D-printed multilayer lattice structures for use in accommodative insoles

The effectiveness of custom hard-shell 3D-printed foot orthoses in a cohort of patients who did not respond to treatment with custom ethylene-vinyl-acetate (EVA) foot orthoses

BACKGROUND

Patients who do not achieve positive outcomes with custom ethylene-vinyl-acetate (EVA) foot orthoses will often be escalated to other services for treatment, which may include surgery.

OBJECTIVE

This study aimed to explore the effectiveness of custom hard-shell 3D-printed foot orthoses for patients who did not respond to treatment with custom EVA foot orthoses and were being considered for treatment escalation.

DESIGN

An eight-week clinical evaluation and a two-year review of relevant medical records.

METHOD

Thirty-six consecutive patients with a range of musculoskeletal lower limb pathology who remained symptomatic after 12-weeks use of custom EVA foot orthoses were fitted with custom hard-shell 3D-printed foot orthoses. The Foot Health Status Questionnaire was used to assess patients at baseline and eight-week follow-up in conjunction with the Client Satisfaction with Device module of the Orthotics and Prosthetics User Survey. Patients were categorised as responders or non-responders based on their change in pain scores. A review of relevant medical records two years after receiving their orthoses determined if patients required further treatment for their initial condition.

RESULTS

Across the full cohort there were significant improvements in pain, function and foot health. At follow-up, responders reported significantly improved pain, function and foot health compared with non-responders. Twenty-six patients (12 responders, 14 non-responders) required no further treatment for their original condition after two years.

CONCLUSIONS

Custom hard-shell 3D-printed foot orthoses have the potential to improve pain, function, foot health, and provide satisfaction in patients with lower limb musculoskeletal conditions which do not improve with custom EVA foot orthoses.

From Design to Clinical Translation: Unraveling Orthotist Perspectives on 3D Printed Accommodative Insoles

Background

Custom accommodative insoles have become the gold standard for managing plantar pressures and reducing ulceration risk in persons with diabetes. With advances in 3D printing technologies, methods of fabricating 3D printed accommodative insoles have emerged. Clinician feedback is imperative to developing a 3D printed accommodative insole that meets clinical needs and is more effective than the current standard of care.

Objective

To inform the development of 3D printed accommodative insoles by gaining clinician perspective on insole requirements and application of the digital workflow for seamless translation into the clinical setting.

Study Design

Qualitative study.

Methods

Four focus groups with a total of 16 Orthotists were held, prompting discussions on the current standard of care accommodative insole and other 3D printed insoles we have developed. Sessions were recorded, transcribed, and main themes were derived from transcriptions.

Results

Review and analysis of the transcripts resulted in four main themes: 1) Reimbursement, 2) Durability, 3) Effectiveness, and 4) Workflow application in clinic.

Conclusions

The responses showed areas to focus improvements on the 3D printed insole design and ways to ease the transition into a clinical setting. Clinician support is crucial in the adoption of a new device to clinical practice. Their feedback is essential to ensuring the item meets the clinical needs and the workflow is not disruptive to the clinical setting.

Clinical relevance

Understanding clinician perspective on current SoC disadvantages and shortcomings, areas for improvement in the 3D printed insole fabrication, and what is feasible in clinic appointments will help inform insole design and aid in translating new 3D-printing technology to clinical care for improved patient outcomes.

Flatfoot arch correction with generic 3D-printed orthoses at different body weight percentages

BACKGROUND

Flatfoot can be associated with foot pathologies and treated conservatively with foot orthoses to correct arch collapse and alleviate painful symptoms. Recently, 3D printing has become more popular and is widely used for medical device manufacturing, such as orthoses. This study aims at quantifying the effect of generic 3D-printed foot orthoses on flatfoot arch correction under different static loading conditions.

METHODS

Participants with normal and flatfeet were recruited for this cross-sectional study. Clinical evaluation included arch height, foot posture index, and Beighton flexibility score. Surface imaging was performed in different loading conditions: 1) 0% when sitting, 2) 50% when standing on both feet, and 3) 125% when standing on one foot with a weighted vest. For flatfoot participants, three configurations were tested: without an orthosis, with a soft generic 3D printed orthosis, and with a rigid 3D printed orthosis. Arch heights and medial arch angles were calculated and compared for the different loading conditions and with or without orthoses. The differences between groups, with and without orthoses, were analyzed with Kruskal-Wallis tests, and a p < 0.05 was considered significant.

RESULTS

A total of 10 normal feet and 10 flatfeet were analyzed. The 3D printed orthosis significantly increased arch height in all loading conditions, compared to flatfeet without orthosis. Wearing an orthosis reduced the medial arch angle, although not significantly. Our technique was found to have good to excellent intra and interclass correlation coefficients.

CONCLUSIONS

Generic 3D printed orthoses corrected arch collapse in static loading conditions, including 125% body weight to simulate functional tasks like walking. Our protocol was found to be reliable and easier to implement in a clinical setting compared to previously reported methods.

LEVEL OF EVIDENCE

II.