Three-dimensional printed upper-limb prostheses lack randomised controlled trials

Diment, Laura; Thompson, Mark S.; Bergmann, Jeroen

doi:10.1177/0309364617704803

Cited by 38 publications

(51 citation statements)

References 14 publications

(16 reference statements)

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“…3D printing technology has been identified as having the potential to benefit the production of prosthetic sockets. 3,4,10,11 For example, in the current study, the 3D printed sockets took 9 hours and 9 minutes to print but required much less active time from a technician than traditional manufacturing methods. While 3D printing allows for rapid prototyping of custom designs, decreased manufacturing times and increased opportunities for collaboration, the main limitation continues to be the lack of standardization and regulation which may place patients at risk of receiving unsafe devices.…”

Section: D Printed Socketsmentioning

confidence: 72%

“…1 Over the past three decades, several groups have begun to create prosthetic sockets using rapid prototyping techniques. 2,3,4 The Prosthetist is responsible for choosing fabrication techniques that provide adequate strength and safety to their patients while maximizing function. 5 Currently, their decisions are not grounded on an evidence-based foundation as minimal evidence is available.…”

Section: Introductionmentioning

confidence: 99%

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An Investigation of the Structural Strength of Transtibial Sockets Fabricated Using Conventional Methods and Rapid Prototyping Techniques

Pousett¹,

Lizcano

Raschke³

2019

Can. Prosthet. Orthot. J.

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BACKGROUND: Rapid Prototyping is becoming an accessible manufacturing method but before clinical adoption can occur, the safety of treatments needs to be established. Previous studies have evaluated the static strength of traditional sockets using ultimate strength testing protocols outlined by the International Organization for Standardization (ISO). OBJECTIVE: To carry out a pilot test in which 3D printed sockets will be compared to traditionally fabricated sockets, by applying a static ultimate strength test. METHODOLOGY: 36 sockets were made from a mold of a transtibial socket shape,18 for cushion liners with a distal socket attachment block and 18 for locking liners with a distal 4-hole pattern. Of the 18 sockets, 6 were thermoplastic, 6 laminated composites & 6 3D printed Polylactic Acid. Sockets were aligned in standard bench alignment and placed in a testing jig that applied forces simulating individuals of different weight putting force through the socket both early and late in the stance phase. Ultimate strength tests were conducted in these conditions. If a setup passed the ultimate strength test, load was applied until failure. FINDINGS: All sockets made for cushion liners passed the strength tests, however failure levels and methods varied. For early stance, thermoplastic sockets yielded, laminated sockets cracked posteriorly, and 3D printed socket broke circumferen-tially. For late stance, 2/3 of the sockets failed at the pylon. Sockets made for locking liners passed the ultimate strength tests early in stance phase, however, none of the sockets passed for forces late in stance phase, all broke around the lock mechanism. CONCLUSION: Thermoplastic, laminated and 3D printed sockets made for cushion liners passed the ultimate strength test protocol outlined by the ISO for forces applied statically in gait. This provides initial evidence that 3D printed sockets are statically safe to use on patients and quantifies the static strength of laminated and thermoplastic sockets. However, all set-ups of sockets made for locking liners failed at terminal stance. While further work is needed, this suggests that the distal reinforcement for thermoplastic, laminated and 3D printed sockets with distal cylindrical locks may need to be reconsidered. LAYMAN’S ABSTRACT 3D printing is a new manufacturing method that could be used to make prosthetic sockets (the part of the prosthesis connected to the individual). However, very little is known about the strength of 3D printed sockets and if they are safe to use. As Prosthetists are responsible for providing patients with safe treatments, the strength of 3D printed sockets needs to be established before they can be used in clinical practice. The strength of sockets made using current manufacturing methods was compared to those made using 3D printing. Strength was tested using the static portion of the ISO standard most applicable for this situation which outlines the forces a socket must take at 2 points in walking–when the foot is placed on the ground (early stance) and when the foot pushed off the ground (late stance). Sockets made for two prosthetic designs (cushion and locking) were tested to determine if one is safer than the other. All sockets made for cushion liners passed the standard for forces applied statically. However, different materials failed in different ways. At early stance, thermoplastic sockets yielded, laminated composite sockets cracked and 3D printed sockets broke circumferentially. At late stance other components failed 2/3 of the time before the sockets were affected. This provides initial evidence that sockets made for cushion liners are statically safe to use on patients. Sockets made for locking liners failed around the end, showing that 3D printing should not be used to create sockets with the design tested in this study. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/31008/24937 How to Cite: Pousett B, Lizcano A, Raschke S.U. An investigation of the structural strength of transtibial sockets fabricated using conventional methods and rapid prototyping techniques. Canadian Prosthetics & Orthotics Journal. 2019; Volume2, Issue1, No.2. DOI: https://doi.org/10.33137/cpoj.v2i1.31008 CORRESPONDING AUTHORBrittany Pousett, BSc, MSc, Certified Prosthetist,Head of Research at Barber Prosthetics Clinic,540 SE Marine Dr, Vancouver, British Colombia V5X 2T4, Canada.Email: brittany@barberprosthetics.com

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Section: D Printed Socketsmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 99%

An Investigation of the Structural Strength of Transtibial Sockets Fabricated Using Conventional Methods and Rapid Prototyping Techniques

Pousett¹,

Lizcano

Raschke³

2019

Can. Prosthet. Orthot. J.

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“…To safely use these sockets in either a diagnostic or a definitive phase, the efficacy and effectiveness of these devices must be clearly shown. 9 3D-printed sockets should satisfy the same requirements as lower limb conventional prostheses as stated in ISO Standards 10328. Based on the results, the sockets in this study exceeded the threshold of 4480 N. However, it is important to note that the sockets were evaluated with a specific set of criteria.…”

Section: Discussionmentioning

confidence: 99%

How Infill Percentage Affects the Ultimate Strength of 3d-Printed Transtibial Sockets During Initial Contact

Campbell

Lau

Pousett³

et al. 2018

Can. Prosthet. Orthot. J.

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BACKGROUND: 3D printing is becoming more popular across many industries. The first step to safely introducing 3D printed sockets in to prosthetics is to conduct strength testing on these sockets. PURPOSE: This study tests how changing the infill percentage (the percentage of material between the internal and external socket wall) affects the strength of 3D-printed transtibial sockets. METHODS: A Fused Deposition Modelling (FDM) printer was used to print a total of nine transtibial (TT) sockets (three sockets at 30% infill, three sockets at 40% infill, and three sockets at 50%) using polylactic acid (PLA). A strength-testing apparatus measured, in Newtons (N), the maximum load the 3D-printed transtibial sockets could withstand at initial contact of the gait cycle. RESULTS: Based on the specific criteria outlined in this research project, all nine sockets exceeded the 4480N threshold set by ISO Standard 10328. Eight out of nine sockets failed at approximately double the force required with one socket (socket #2) failing at 5360N. Seven out of nine sockets failed at the medial popliteal region and two out of nine sockets failed at lateral mid socket region. Differences in infill percentage from 30%, 40%, 50% did not appear to influence strength of sockets. CONCLUSION: Strength of 3D-printed TT sockets needs rigorous testing to be deemed safe for patient use. More definitive research and a higher number of samples are required to investigate how a larger range of infill percentage can affect strength. Until all the requirements of ISO Standard 10328 are satisfied, the safety of using 3D-printed TT sockets in clinical practice are uncertain. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/30843/23262 LAYMAN’S ABSTRACT 3D printing is beginning to be used in prosthetics because it has the potential to be less expensive and more customizable to individual needs and styles. Unfortunately, there are companies using this technology to print prosthetic sockets for people without the proper education and training. Before people can start using this new technology safely, testing needs to be done to determine the strength of these 3D printed prosthetic sockets. Our project investigates how strong a 3D printed prosthetic socket is for an amputee below the knee. This is challenging because the entire weight will be put through the socket and it needs to be strong enough that it will not break. There is an international standard that gives instructions and information on testing the strength of a prosthetic socket. Our project will follow a part of these instructions and see how much weight can be put through a socket before it breaks. Our project printed nine identical prosthetic sockets, but the infill percentage of each socket was different. The infill percentage is the amount of material between the walls of an object. We put each socket in a machine and applied a compressive force until it broke and measured that force. Our tests showed the infill percentage did not change the strength of the sockets. They all passed the force measurement given by the international standard. Because our project only tested a part of the standard, there are many more tests that need to be done before the public can start using 3D-printed prosthetic sockets safely. How to Cite: Campbell L, Lau A, Pousett B, Janzen E, Raschke S.U. How infill percentage affects the ultimate strength of 3D-printed transtibial sockets during initial contact. Canadian Prosthetics & Orthotics Journal, Volume 1, Issue 2, No 2, 2018. https://doi.org/10.33137/cpoj.v1i2.30843

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“…Charles W. Hull in 1986 was the first to report stereolithography [ 1 ] as a tool to fabricate 3D structures. Since then, 3D printing has evolved into a multifunctional fabrication tool that offers unique advantages for biomedical applications including diagnostics [ 2 ], scaffolds for 3D implants [ 3 ], prosthesis [ 4 ] and tissue engineering [ 5 ]. In recent years, the ability to convert computer-assisted design (CAD) files into 3D-printed pieces, also known as additive manufacturing, has sparked significant progress in the field of diagnostics [ 6 ].…”

Section: Introductionmentioning

confidence: 99%

3D-Printed Biosensor Arrays for Medical Diagnostics

2018

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While the technology is relatively new, low-cost 3D printing has impacted many aspects of human life. 3D printers are being used as manufacturing tools for a wide variety of devices in a spectrum of applications ranging from diagnosis to implants to external prostheses. The ease of use, availability of 3D-design software and low cost has made 3D printing an accessible manufacturing and fabrication tool in many bioanalytical research laboratories. 3D printers can print materials with varying density, optical character, strength and chemical properties that provide the user with a vast array of strategic options. In this review, we focus on applications in biomedical diagnostics and how this revolutionary technique is facilitating the development of low-cost, sensitive, and often geometrically complex tools. 3D printing in the fabrication of microfluidics, supporting equipment, and optical and electronic components of diagnostic devices is presented. Emerging diagnostics systems using 3D bioprinting as a tool to incorporate living cells or biomaterials into 3D printing is also reviewed.

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Three-dimensional printed upper-limb prostheses lack randomised controlled trials

Cited by 38 publications

References 14 publications

An Investigation of the Structural Strength of Transtibial Sockets Fabricated Using Conventional Methods and Rapid Prototyping Techniques

An Investigation of the Structural Strength of Transtibial Sockets Fabricated Using Conventional Methods and Rapid Prototyping Techniques

How Infill Percentage Affects the Ultimate Strength of 3d-Printed Transtibial Sockets During Initial Contact

3D-Printed Biosensor Arrays for Medical Diagnostics

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