Reliability and validity of 3D limb scanning for ankle-foot orthosis fitting

Three-dimensional printing technology applied to the production of prosthesis: A systemic narrative review

The purpose of this scoping review was to investigate the effects of 3-dimensional (3D)-printed prostheses. Articles published up to August 19, 2023, were searched in the PubMed, Cochrane Library, Embase, and Scopus databases. The search terms used were "3D printed prosthesis," "3D printed prostheses," "3D printed prosthe*," "3D printed artificial arm," "3D printed artificial leg," "3D printing prosthesis," "3D printing prostheses," "3D printing prosthe*," "3D printing artificial arm," and "3D printing artificial leg." This review included studies that applied 3D-printed prostheses to upper- or lower-limb amputees. Case reports, conference abstracts, presentations, reviews, and unidentified articles were excluded from the analysis. A total of 937 articles were identified, 11 of which were included after confirming eligibility through the title, abstract, and full text. The results indicated that the 3D-printed prostheses demonstrated the ability to substitute for the functions of impaired limbs, similar to conventional prostheses. Notably, the production cost and weight were reduced compared with those of conventional prostheses, increasing patient satisfaction. The use of 3D-printed prostheses is expected to gain prominence in future clinical practice. However, concerns regarding the durability of 3D-printed prostheses have increased among users. Therefore, there is an ongoing need to explore highly durable materials that can withstand the weight of the user without breaking easily. In addition, advancements are required in technologies that enable the depiction of various skin tones and the production of smaller-sized prostheses suitable for clothing.

Effects of Neuromuscular Electrical Stimulation with Gastrocnemius Strengthening on Foot Morphology in Stroke Patients: A Randomized Controlled Trial

This study aimed to investigate the effects of neuromuscular electrical stimulation (NMES) with gastrocnemius (GCM) strength exercise on foot morphology in patients with stroke. Herein, 31 patients with chronic stroke meeting the study criteria were enrolled and divided into two groups; 16 patients were randomized to the gastrocnemius neuromuscular electrical stimulation (GCMNMES) group, and 15 patients to the conventional neuromuscular electrical stimulation (CNMES) group. The GCMNMES group conducted GCM-strengthening exercise with NMES. CNMES group conducted NMES at paretic tibialis anterior muscle with ankle dorsiflexion movement. These patients underwent therapeutic interventions lasting 30 min/session, five times a week for 4 weeks. To analyze changes in foot morphology, 3D foot scanning was used, while a foot-pressure measurement device was used to evaluate foot pressure and weight-bearing area. In an intra-group comparison of 3D-foot-scanning results, the experimental group showed significant changes in longitudinal arch angle (p < 0.05), medial longitudinal arch angle (MLAA) (p < 0.01), transverse arch angle (TAA) (p < 0.01), rearfoot angle (RA) (p < 0.05), foot length (FL) (p < 0.05), foot width (FW) (p < 0.05), and arch height index (AHI) (p < 0.01) of the paretic side and in TAA (p < 0.05) and AHI (p < 0.05) of the non-paretic side. The CNMES group showed significant changes in TAA (p < 0.05) and FW (p < 0.05) of the paretic side and TAA (p < 0.05) and AHI (p < 0.05) of the non-paretic side. An inter-group comparison showed significant differences in MLAA (p < 0.05) and RA (p < 0.05) of the paretic side. In an intra-group comparison of foot pressure assessment, the experimental group showed significant differences in footprint area (FPA) (p < 0.05) of the paretic side and FPA symmetry (p < 0.05). The CNMES group showed a significant difference in only FPA symmetry (p < 0.05). An inter-group comparison showed no significant difference between the two groups (p < 0.05). Thus, NMES with GCM-strengthening exercises yielded positive effects on foot morphology in patients with stroke.

Three-dimensional imaging of the forearm and hand: A comparison between two 3D imaging systems

The conventional treatment for distal radius fractures typically involves immobilization of the injured extremity using a conventional forearm cast. These casts do cause all sorts of discomfort during wear and impose life-style restrictions on the wearer. Personalized 3D printed splints, designed using three-dimensional (3D) imaging systems, might overcome these problems. To obtain a patient specific splint, commercially available 3D camera systems are utilized to capture patient extremities, generating 3D models for splint design. This study investigates the feasibility of utilizing a new camera system (SPENTYS) to capture 3D surface scans of the forearm for the design of 3D printed splints. In a prospective observational cohort study involving 17 healthy participants, we conducted repeated 3D imaging using both the new (SPENTYS) and a reference system (3dMD) to assess intersystem accuracy and repeatability. The intersystem accuracy of the SPENTYS system was determined by comparison of the 3D surface scans with the reference system (3dMD). Comparison of consecutive images acquired per device determined the repeatability. Feasibility was measured with system usability score questionnaires distributed among professionals. The mean absolute difference between the two systems was 0.44 mm (SD:0.25). The mean absolute difference of the repeatability of the reference -and the SPENTYS system was respectively 0.40 mm (SD: 0.30) and 0.53 mm (SD: 0.25). Both repeatability and intersystem differences were within the self-reported 1 mm. The workflow was considered easy and effective, emphasizing the potential of this approach within a workflow to obtain patient specific splint.

A Review on 3D Scanners Studies for Producing Customized Orthoses

When a limb suffers a fracture, rupture, or dislocation, it is traditionally immobilized with plaster. This may induce discomfort in the patient, as well as excessive itching and sweating, which creates the growth of bacteria, leading to an unhygienic environment and difficulty in keeping the injury clean during treatment. Furthermore, if the plaster remains for a long period, it may cause lesions in the joints and ligaments. To overcome all of these disadvantages, orthoses have emerged as important medical devices to help patients in rehabilitation, as well as for self-care of deficiencies in clinics and daily life. Traditionally, these devices are produced manually, which is a time-consuming and error-prone method. From another point of view, it is possible to use imageology (X-ray or computed tomography) to scan the human body; a process that may help orthoses manufacturing but which induces radiation to the patient. To overcome this great disadvantage, several types of 3D scanners, without any kind of radiation, have emerged. This article describes the use of various types of scanners capable of digitizing the human body to produce custom orthoses. Studies have shown that photogrammetry is the most used and most suitable 3D scanner for the acquisition of the human body in 3D. With this evolution of technology, it is possible to decrease the scanning time and it will be possible to introduce this technology into clinical environment.

Leveraging Digital Workflows to Transition the Orthotics and Prosthetics Profession Toward a Client-Centric and Values-Based Care Model

The orthotics and prosthetics (O&P) profession has a history of responding to market demands in a reactive rather than proactive manner. This has created significant impacts including shrinkage in scope of practice and constraint in remuneration for professional services due to a fee-for-device third party payer system. Rapid changes in technology and healthcare combined with an outdated device-centric reimbursement system are creating unprecedented challenges that threaten sustainability of the O&P profession. Hence, a reassessment of the value of O&P care, and the O&P workflow process is necessary to inform an update to the value proposition and practice model for sustainability. This article reviews key factors contributing to the current state of O&P, and potential solutions involving an update in practitioner competencies, and the care delivery model (from device-centric to client-centric and values-based). Updates could be achieved by leveraging the use of digital workflows that increase efficiencies and enhance the value of clinical outcomes. Eventually, these updates could enable the O&P profession to elevate the value proposition that aligns with its most important stakeholders: client-patients and third-party reimbursement agencies in a rapidly changing technology and healthcare landscape.

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.

Personalized Offloading Treatments for Healing Plantar Diabetic Foot Ulcers

BACKGROUND

Non-removable knee-high devices are the gold-standard offloading treatments to heal plantar diabetic foot ulcers (DFUs). These devices are underused in practice for a variety of reasons. Recommending these devices for all patients, regardless of their circumstances and preferences influencing their ability to tolerate the devices, does not seem a fruitful approach.

PURPOSE

The aim of this article is to explore the potential implications of a more personalized approach to offloading DFUs and suggest avenues for future research and development.

METHODS

Non-removable knee-high devices effectively heal plantar DFUs by reducing plantar pressure and shear at the DFU, reducing weight-bearing activity and enforcing high adherence. We propose that future offloading devices should be developed that aim to optimize these mechanisms according to each individual's needs. We suggest three different approaches may be developed to achieve such personalized offloading treatment. First, we suggest modular devices, where different mechanical features (rocker-bottom sole, knee-high cast walls/struts, etc.) can be added or removed from the device to accommodate different patients' needs and the evolving needs of the patient throughout the treatment period. Second, advanced manufacturing techniques and novel materials could be used to personalize the design of their devices, thereby improving common hindrances to their use, such as devices being heavy, bulky, and hot. Third, sensors could be used to provide real-time feedback to patients and clinicians on plantar pressures, shear, weight-bearing activity, and adherence.

CONCLUSIONS

By the use of these approaches, we could provide patients with personalized devices to optimize plantar tissue stress, thereby improving clinical outcomes.