Assessment of Safety and Performances of a 3D Printed Prosthetic Foot: A Pilot Study

Pilot Study to Assess Safety and Performances of a Energy Storing and Return (ESAR) Prosthetic Foot Made in Additive Manufacturing

A dynamic energy storage and return foot prosthesis is a type of prosthesis designed to mimic and restore the functionality and natural movement of the limb that has been amputated. This type of prosthesis is designed to allow patients to perform daily activities, even very dynamic ones, with greater ease and efficiency. The distinguishing feature of a dynamic energy storage and return prosthesis is the presence of a system that accumulates mechanical energy during the support phase on the ground and returns it during the push phase, increasing the amount of push itself. In foot prostheses, it is common to use carbon fiber blades or springs that deform during the support of the foot and then restore themselves, returning elastic energy during the subsequent push. This helps reduce the effort required to walk and allows for more fluid and natural movements. Additive Manufacturing (AM) technology is ideal for highly customized and high-value production. Orthoses/prostheses are particularly suited to exploit the potential of this technology. However, the lack of functional materials that meet different design needs, such as structure and comfort of the devices, has limited the use of AM mainly in orthoses. AM is promising for orthoses due to its customization capability and reduced production costs compared to traditional solutions. In particular, it has been shown how continuous filament carbon printing can lead to the creation of prostheses that have dynamic and energy return characteristics similar to or even superior to commercial ones. The present pilot clinical investigation aims to provide indications regarding the safety and performance of the 3D printed prosthesis - named PROFIL - in a real-world scenario. The state of the art has not yet defined the performance and safety of 3D printed prostheses with thermoplastic materials and continuous carbon fiber. Since greater comfort and the possibility of performing physical activity more easily with the use of these devices is expected, it is considered of interest for clinical practice to evaluate these prostheses. The primary objective of the study is therefore to evaluate the safety and performance of the device during walking on flat surfaces and more demanding tasks. The secondary objectives aims at evaluate usability and deformation of the 3D printed prosthesis under different loading conditions (slow and fast walking, ascending and descending ramps or steps) by mean of fiber-glass sensors integrated in the prosthesis foot.

Study Overview

• Status: Completed
• Conditions: Amputation of Lower Limb
• Intervention / Treatment: Device: 3D printed prosthesis foot; Device: Current prosthesis foot

• Study Type: Interventional
• Enrollment (Actual): 3
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Italy
  • Bologna
    • Vigorso Di Budrio, Bologna, Italy, 40054
      • Centro Protesi Inail

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Monolateral below knee amputation
• Mobility level: K3 or K4
• Age: 18-65 years old
• Maximum weigth: 100 Kg
• Collaborative subject
• Clinically stable stump

Exclusion Criteria:

• Pregnant
• Not able to understand written and oral instructions
• Problems to the stump

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: PROFIL prosthesis foot; Recruited subjects with below kenen amputation wearing the experimental prosthesis foot (PROFIL)	Device: 3D printed prosthesis foot; Energy storage and restoration 3D printed prosthesis foot
Active Comparator: Current prosthesis foot (PROFLEX XC); Recruited subjects with below knee amputation wearing the currently used prosthesis foot (PROFIL)	Device: Current prosthesis foot; Energy storage and restitution prosthesis foot made in carbon fibers blades

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Adverse Events Occurred During Use of the Intervention Prosthesis Foot	Adverse events may be: falling, stumbling, lower back pain as consequence of the prosthesis foot use, stump pain as consequence of the prosthesis foot use, breakage of the prosthesis foot	Day 1 and Day 2
Change From Comparator of Lower Limb Joint Angles Measured With Inertial Measurements Units (IMUs)	The IMUs record joints kinematics while subjects perform a series of motor tasks, i.e. walk of flat surfaces at a self-selected speed and ascend/descend stairs and ramps. In particular, the following variables are measured: range of motion of ankle joint (prosthetic ankle), knee joint, and hip joint of the impaired lower limb. The measured angles are normalized on a gait cycle (0% = heel strike, 100% = toe off). The outocome variable is computed as mean difference between the normalized measured angles and the normalized reference value taken from the literature.	Day 1 and Day 2
Change From Comparator of Lower Limb Joint Angles Measured With an Optoelectronic System	The optoelectronic system records joints kinematics while subjects walk of a flat surfaces at a self-selected speed. In particular, the following variables are measured: range of motion of ankle joint (prosthetic ankle), knee joint, and hip joint of the impaired lower limb. The measured angles are normalized on a gait cycle (0% = heel strike, 100% = toe off). The outocome variable is computed as mean difference between the normalized measured angles and the normalized reference value taken from the literature.	Day 1 and Day 2
Change From Comparator of Gait Quality Wihile Ascending Ramps With Hill Assessment Index (HAI)	Hill Assessment Index (HAI) is a 12-points ordinal scale used to evaluate ramp ascending quality; the higher the score the better the gait quality while ascending ramps (0 = cannot do/refuse to do, 11 = even step, without assistive device) .	Day 1 and Day 2
Change From Comparator of Gait Quality While Ascending Stairs With Stair Ascending Index (SAI)	Stair Ascending Index (SAI) is 14-points ordinal scale used to quantify stair ascending qualty; the higher the score the better the gait quality while ascending stairs (0 = cannot do/refuse to do, 13 = Without rail or assistive device, step-over-step pattern)	Day 1 and Day 2
Change From Comparator of Equilibrium in Orthostatism by Mean of Force Plates	The subject is asked to stand still on a force plate for 30 seconds. The sway path of the Centre of Pressure (COP) is recorded. The higher the valure the sway path, the lower the equilibrium in orthostatism. This outcome measure is performed with the eyes open and closed	Day 1 and Day 2
Change From Comparator of Load Simmetry While Standing up/Sitting Down From/on a Chiar by Mean of Force Plates	The subject is asked to sit on a chair with both the feets (sound foot and prosthesis foot) on different force plates. At the "Start" signal, the subject stands up, stands still for 5 seconds and sits down. The weigth distribution on the lower limbs is recorded during the entire task. The symmetry index is computed as the ratio between: the difference between the load peak of the ground reaction force (GRF) measured in the sound side and the load peak of the ground reaction force (GRF) measured in the impaired side ON the sum between the load peak of the ground reaction force (GRF) measured in the sound side and the load peak of the ground reaction force (GRF) measured in the impaired side. Asymmetry index = [(peak GRF sound - peak GRF impaired) / (peak GRF sound + peak GRF impaired)]*100%	Day 1 and Day 2
Change From Comparator of Amputee Mobility Predictor (AMP-PRO)	AMP is a 21-item objectve measure in which static and dynamic sitting and standing activities, as well as transfer and gait skills of progressing difficulty are performed. Score range is 0-47. Higher scores indicate better mobility. Based on the final score, 4 groups are defined (K1 = 15-26, K2 = 27-36, K3 = 37-42, K4 = 43-47).	Day 1 and Day 2
Change From Comparator of Functional Mobility Measured With the L-test	The subject starts from a sitting position. At the "Start" signal, the subject stands up from the chair, walks in a closed 10-meters L-shaped path, and sits down on the same chair. The time necessary to complete the path is measured with a stopwatch. The lower the time to complete the path, the higher the functional mobility.	Day 1 and Day 2

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change From Comparator of Usability of the Prosthesis Foot	Usability is measured with an ad hoc custom-made 6-items questionnaire. Each item ranges 1 to 5. To compute the final score, each item is summed up (total range: 6-30). The higher the score, the better the usability.	Day 1 and Day 2

Collaborators and Investigators

• Sponsor: Istituto Nazionale Assicurazione contro gli Infortuni sul Lavoro
• Collaborators: Istituto per i Polimeri Compositi e Biomateriali (CNR-IPCB); Istituto di Chimica della Materia Condensata e di Tecnologie per l'Energia (CNR-ICMATE)

Publications and helpful links

General Publications

• Versluys R, Beyl P, Van Damme M, Desomer A, Van Ham R, Lefeber D. Prosthetic feet: state-of-the-art review and the importance of mimicking human ankle-foot biomechanics. Disabil Rehabil Assist Technol. 2009 Mar;4(2):65-75. doi: 10.1080/17483100802715092.
• Manero A, Smith P, Sparkman J, Dombrowski M, Courbin D, Kester A, Womack I, Chi A. Implementation of 3D Printing Technology in the Field of Prosthetics: Past, Present, and Future. Int J Environ Res Public Health. 2019 May 10;16(9):1641. doi: 10.3390/ijerph16091641.
• South BJ, Fey NP, Bosker G, Neptune RR. Manufacture of energy storage and return prosthetic feet using selective laser sintering. J Biomech Eng. 2010 Jan;132(1):015001. doi: 10.1115/1.4000166.
• Klute GK, Berge JS, Orendurff MS, Williams RM, Czerniecki JM. Prosthetic intervention effects on activity of lower-extremity amputees. Arch Phys Med Rehabil. 2006 May;87(5):717-22. doi: 10.1016/j.apmr.2006.02.007.
• Hafner BJ, Sanders JE, Czerniecki J, Fergason J. Energy storage and return prostheses: does patient perception correlate with biomechanical analysis? Clin Biomech (Bristol). 2002 Jun;17(5):325-44. doi: 10.1016/s0268-0033(02)00020-7.

Study record dates

Study Major Dates

• Study Start (Actual): May 5, 2025
• Primary Completion (Actual): June 7, 2025
• Study Completion (Actual): June 7, 2025

Study Registration Dates

• First Submitted: April 7, 2025
• First Submitted That Met QC Criteria: April 14, 2025
• First Posted (Actual): April 22, 2025

Study Record Updates

• Last Update Posted (Actual): February 27, 2026
• Last Update Submitted That Met QC Criteria: February 9, 2026
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Safety; Lower limb amputation; Additive manufacturing; Prosthesis foot; Performances
• Other Study ID Numbers: CP-PAI-01-23

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Anthropometric characteristics Kinematics data measured via IMUs, optoelectronic system and force plates Scores of PROMs
• IPD Sharing Time Frame: IPD will be availabale within 6 months after study completion. Study completion is expected to occur by April 17th 2025
• IPD Sharing Access Criteria: IPD will be shared with Istituto per i Polimeri Compositi e Biomateriali (CNR-IPCB) and Istituto di Chimica della Materia Condensata e di Tecnologie per l'Energia (CNR-ICMATE), both located in Lecco (Italy). Both the Institutions contributed to the development and manufacturing of the 3D printed prosthesis foot under evaluation.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No