Abstract
Background
India has a large number of above-knee amputation patients who require a prosthetic leg that is affordable, conformal, functional, and durable. Available low-cost solutions, such as Jaipur foot, employ gypsum plaster in the process of fabricating a fitting socket. This has four shortcomings: (1) requirement of trained technicians, (2) high possibility of manual errors leading to rework, (3) long production time of several hours, and (4) difficulty in scaling up for widespread application.
Materials and Methods
An improved approach is presented here, which combines computer-aided parametric design and numerically controlled machining with manual thermoforming to overcome the above issues. The socket is semi-automatically designed based on 60 parameters, derived from 23 measurements obtained on the natural stump of a patient. The three-dimensional (3D) computer-aided design model of the socket can be used for additive manufacturing (3D printing), which was found to be accurate, but time-consuming and expensive. Hence, a hybrid process was evolved with the following three steps: computer numeric control machining of the stump and shank replica in polyurethane (PU) foam, followed by coating with suitable epoxy, and finally high-density polyethylene pipe thermoforming over the PU foam replicas.
Results
Three prostheses were fabricated using both conventional and hybrid processes and provided to volunteer patients. The hybrid process resulted in 28% reduction in overall fabrication time and improved satisfaction of patients due to better fit and comfort.
Conclusion
The proposed approach can be adapted for mass customization, required to meet the large gap in demand and supply, especially in resource-constrained settings.
Keywords: Computer numerical control machining, Computer-aided parametric design, Jaipur foot prosthesis
Introduction
An estimated 5.4 million Indians are reported to be affected by movement disability [1] caused by various diseases or amputation. Amputation of lower limbs is known to far exceed those of the upper limbs [2, 3]. The majority of lower-limb amputations are classified as transtibial (below knee), transfemoral (above knee [AK]), and knee disarticulation (through knee), for which the corresponding prostheses are recommended [4]. Most of the patients are close to the poverty line and require an affordable solution [5]. One of the first, and still the most popular, low-cost innovations developed in India for rural amputees was Jaipur foot prosthesis developed at Sawai Man Singh Medical College, Jaipur, by Dr. P. K. Sethi and Mr. Ram Chandra Sharma [6]. This prosthesis has been distributed free of cost by Bhagwan Mahaveer Viklang Sahayata Samiti to over 500,000 patients from Asia, Africa, and Latin America [7]. Several other nongovernmental organizations (NGOs), such as Ratna Nidhi Charitable Trust (RNCT) based in Mumbai, have replicated the fabrication process to cater to patients in their areas of operation. Such NGOs regularly conduct rural camps for patients who cannot afford a visit to metro cities such as Mumbai to receive the prosthesis. Such camps are required to be organized twice, once for taking measurements and a second time for the distribution of prosthesis; this adds to cost overheads [8].
A typical AK prosthesis comprises four components: (a) socket, which encloses the natural stump or residual limb of the patient; (b) shank, along the length of the leg; (c) foot, connected to the lower end of shank; and (d) single-axis locked knee joint, between the socket and shank, as shown in Fig. 1. The Jaipur Foot prosthesis costs < Rs. 3000 ($40) [9]. The knee joint stays locked during walking and needs to be manually unlocked for sitting position (Fig. 1).
Fig. 1.
Conventional Jaipur foot prosthesis (original image)
Fabrication of patient-specific socket is the most time-consuming step in the entire process and requires considerable manual skills. First, gypsum plaster bandages are placed around a patient’s natural stump until the hip region. A prosthetist then marks pressure-tolerant and pressure-sensitive areas on the plaster (Fig. 2a). The gypsum plaster cast is removed after drying to obtain a negative replica (mold) of the residual limb. The mold is filled with plaster paste and is extended to the knee line to get a positive replica of the stump (Fig. 2b). The plaster is scraped at pressure-tolerant areas and added at pressure-sensitive areas in consultation with the prosthetist. A technician then achieves the smooth surface finish of the plaster stump using a manual sanding tool such as a grater, taking into account the desired tolerances (Fig. 2c). This ensures better fitment and optimal pressure distribution, thereby improving patient comfort. A high-density polyethylene (HDPE) pipe, which will serve as a socket material, is heated to 210–220 °C in a furnace, removed, and manually draped around the plaster stump to fabricate the socket (Fig. 2d). A matching shank part is also obtained in a similar manner. Prefabricated knee joint and foot are then assembled with the socket and shank to obtain the complete prosthesis [10].
Fig. 2.
Conventional fabrication process for prosthesis socket (original image). a Gypsum plastering around stump to create mold. b Mold removal to obtain stump replica. c Rectification of stump replica using a sanding tool. d High-density polyethylene thermoforming to obtain socket part
In the last few years, several groups have worked on the design, materials, and fabrication process of sockets for AK prostheses. The relevant work is briefly discussed next.
Previous Work
Several designs for the socket have been proposed in the literature, of which quadrilateral and ischial containment are the most common [11]. The quadrilateral design, first introduced in the 1950s, has a cross-section with rounded edges, narrower in the anteroposterior (AP) dimensions. Significant weight-bearing occurs at the line contact between the ischial tuberosity (IT) and the horizontal posterior wall of the socket [12]. On the other hand, ischial containment sockets provide an oblique and sloping contour by complete containment of the IT and ramus areas, increasing the supportive forces. Other prominent designs include Marlo Anatomical Socket (MAS) and subischial socket. The MAS design features an improved containment at the medial ischial ramus. In subischial socket design, the posterior wall does not directly interact with the IT [13]. Both these designs provide better stability for prosthetic users with less pistoning effect (frictional movement) between the natural stump and socket part [13]. However, they have higher process complexity and costs (compared to quadrilateral or ischial containment designs), making them less suitable for resource-constrained settings [14].
Patient-specific sockets can be fabricated in different ways. Thermoforming of sockets (mentioned earlier) is a well-established process [15]. Other techniques include vacuum forming and digital fabrication. Vacuum forming requires two additional stages to cut and weld the socket for easy removal of stump replica [16]. Digital technologies, including three-dimensional (3D) scanning and computer-aided design/computer-aided manufacturing (CAD/CAM), have also been explored for prosthesis socket design and fabrication. The cloud of surface points generated from 3D scanning of patient’s stump can be virtually stitched in a CAD program to reconstruct the 3D model of the stump [17, 18]. Alternately, the stump model can be semi-automatically generated from a set of parameters measured on the patient’s residual limb [19]. This parameter-based model can be easily modified by material removal at pressure-tolerant areas and material addition at pressure-sensitive areas. Then, the 3D model can be utilized for fabricating the stump replica using machining (material removal using a cutting tool) or 3D printing (material addition layer by layer, also known as additive manufacturing) [20]. In general, CAD/CAM technologies require a high level of technical skills, especially when complex geometries are involved, as in prosthetic limbs. In particular, additive manufacturing processes have been reported to have clinical, technological, and financial barriers for delivering custom prostheses [21].
Problem and Approach
The conventional process of socket fabrication followed by most NGO prosthetic centers across India has a few limitations. The sculpting of the plaster stump to meet anatomical and functional requirements requires the knowledge of socket design principles and appropriate fabrication skills. The technicians have diverse educational backgrounds, and most of them have acquired relevant expertise through observation or personal experience. Their nonuniform and arbitrary approaches make it challenging to standardize prosthesis fabrication. Second, the process takes up to 3 h (Fig. 2) even more so during wet seasons because plaster paste takes more time to dry. This reduces productivity. It is difficult for patients from distant villages to travel twice to prosthetic center—once for the measurements and a second time for prosthesis fitment. These factors make it difficult to scale up the process. With a requirement of more than 5 million prostheses and < 100 prosthesis distribution centers in the country [22, 23], there is a large gap between demand and supply. Hence, there is a dire need to find an alternative approach that is easily scalable to rapidly produce high-quality prosthetic sockets at affordable costs.
A related issue is with gypsum plaster, which has conventionally been used to fabricate stump replica [13]. Although this material is easily available, sculptable, and stable, the daily exposure levels for the technicians exceed the limits (maximum 5 mg/m3 respiratory exposure over 8-h workday) prescribed by the Occupational Safety and Health Administration [24]. This necessitates finding an alternative approach for creating stump replicas. One way is 3D scanning, followed by 3D printing of the residual limb [16]. Initial experiments were conducted using a handheld scanner called “structure sensor” (Occipital, Inc.). This was found to be more appropriate and comfortable for scanning patient stumps, although it has less accuracy than stationary or mounted systems. However, the large amount of data (cloud of points) generated in the scans were found to be difficult to store and transmit over conventional networks, especially in remote areas. The CAD model reconstructed from the scan data was 3D printed using “Fortus 900mc” (Stratasys, Inc.). However, an average-sized socket (Fig. 3) took about 8 h to print and cost over Rs. 10,000, making this approach unsuitable for the rapid and cost-effective socket fabrication.
Fig. 3.
Patient-specific three-dimensional printed above-knee socket (original image)
The quadrilateral socket design does not have negative slopes or grooves, which allows easy separation of the stump replica from the socket during the thermoforming process. The MAS and subischial designs have more intricate shapes, which require more complicated processes and increase fabrication time and cost. Therefore, the quadrilateral design was selected. To overcome various limitations associated with the conventional process, an improved approach was evolved. This involves semi-automatic generation of the 3D CAD model of the stump replica with a quadrilateral design, based on selected parameters measured on the patient’s residual limb. The stump replica is fabricated by machining of polyurethane (PU) foam, thus avoiding gypsum plaster casting. The replica is then used in the conventional thermoforming process to fabricate the socket in HDPE; the shank is also fabricated in a similar manner. The proposed design and fabrication approach are described in detail in the following section.
Methodology
The steps involved in the proposed approach starting from the measurement of the patient’s natural stump, followed by generation of parametric CAD models of the stump and shank, machining of their replicas, and finally thermoforming of socket and shank part are described in the following sections.
Stump Measurements
Suitable standard anatomical measures were established based on easily identifiable marker points. The goal is to facilitate quick, complete, and accurate measurement of the patient’s residual limb, which is critical for a comfortable fit of the custom-designed socket. Through discussions with prosthetists and technicians, 23 key measurements were identified to capture the stump geometry, while minimizing time and effort. These measurements can be taken using a measuring tape and a mediolateral (ML) caliper, familiar to NGO technicians. A bilingual chart (English and Hindi) for recording these measurements was also developed (Fig. 4).
Fig. 4.
a Length and anteroposterior measurement sheet (original image). b Mediolateral and perimeter measurement sheet (original image)
The measurements were taken on two reference planes: AP (Fig. 4a) and ML (Fig. 4b). Tables a–d (inset in Fig. 4) give a detailed description of these parameters. The reference ML length for the patient hip region (#14 and #15 in Fig. 4b) is later divided into two to obtain the individual limb dimensions because, for this location, an individual limb cannot be measured. For a quadrilateral socket, weight-bearing is achieved primarily through the ischium and the gluteal musculature [10]. Hence, the quadrilateral type of socket was designed to maintain high conformity at greater trochanter (GT) on the femur, IT on the hip, and ischiopubic ramus (IPR) near the groin. The anatomical location of these points is shown in Fig. 5. The contour shapes of the stump model can be further customized for individual patients in consultation with the prosthetist.
Fig. 5.
Lower-limb anatomy (modified image)
Socket Design
Based on the 23 input measurements, six planes were identified. Going from knee to hip region, these planes are (1) socket end plane (at the knee line if the conventional knee joint is used), (2) stump end plane, (3) midplane (MP, 50 mm distal to IPR plane), (4) IPR plane, (5) IT plane, and (6) GT-IPR inclined plane. Figure 6a shows the anterior view of the stump model with the six planes.
Fig. 6.
Patient-specific computer-aided design model of stump replica: a anterior view, b medial view (original image)
The measured parameters were used for generating a 3D model of the stump using CAD software (SolidWorks). First, a circular contour was drawn at the stump end plane with sufficient clearance for the distal end of the patients’ natural stump. Further, a rounded quadrilateral contour was drawn at MP, IPR, IT, and GT-IPR inclined planes for the proximal part of the stump, increasing the overall conformity in this region. The contour at IT level was modified to project outward by 15 mm from the constructed edge of a rounded quadrilateral on the posterior side, forming the predominant weight-bearing region to accommodate line contact with the IT. Further, the radius of the anteromedial corner of the quadrilateral on the IPR plane was reduced by 2 mm for achieving pressure tolerance at adductor tendon region. A rounded quadrilateral contour on GT-IPR inclined plane was created to mark a preliminary trim line during socket fabrication, giving unconstrained access to the residual limb during prosthetic wearing. These contours were connected using a 3D loft surface using relevant functions in the CAD program (SolidWorks). Between the stump end and the socket end planes, a smooth surface of revolution, tangential to the loft surface, is created to close the model from the bottom. An additional extrusion was added at the top of the model to ease handling during fabrication, completing the 3D CAD model generation of the stump replica. Because this is an open type of quadrilateral design, conformity was strictly ensured for the region between the IPR and GT. The remaining areas of the stump replica were given appropriate overall allowances in the CAD model, achieving the required material addition and hence the off-loading at the pressure-sensitive areas. Figure 6a, b shows the anterior and medial views of the stump model. A 3D CAD model for the shank replica was generated with the help of two circular contours, at the knee line plane and at the ankle plane, joining them through a smooth loft surface. Figure 7 shows the finished shank model.
Fig. 7.
The computer-aided design model of the shank (original image)
The 3D models as developed above are defined by sixty unique parameters, derived from the 23 measurements taken on the patient stump (Fig. 4). These derived parameters enable the semi-automatic generation of patient-specific CAD models of stump and shank. The CAD models can be saved in suitable formats for 3D printing or machining.
Socket Fabrication
The 3D CAD models of the stump and shank were cut into two halves, in either AP or ML plane, using suitable software (Meshmixer from Autodesk, Inc.) to facilitate machining. Each half was saved as a separate CAD model, and its cutting tool path was generated (using Fusion 360 CAM software from Autodesk, Inc.). The tool path file was sent to a computer-controlled machine to machine the stump from PU blocks (Fig. 8). These were inspected in terms of perimeter, AP and ML dimensions, and IT and IPR plane heights.
Fig. 8.
Computer numeric control machining of polyurethane foam stump (original image)
The PU foam was found to have strong adhesion to hot HDPE pipe. To avoid direct contact between them, different surface coating options such as epoxy, putty, primer, and clear coat were explored. “M-Seal epoxy” was found to have the required stability at the thermoforming temperature range (210–220 °C) and also required less time for its application compared to other materials. The coating thickness was accounted for by incorporating a design tolerance of 2 mm in the stump CAD model.
The epoxy-coated PU foam stump was then used for manual thermoforming of HDPE pipe. For this, the HDPE pipe was first heated to 210–220 °C and held for about 15 min at this temperature to allow the desired plasticity to be attained. The heated HDPE pipe was taken out of the furnace, held in a cloth, and manually draped over the epoxy-coated PU foam stump to form the socket. Further cutting and grinding operations along the trim line were carried out for profiling the socket. The HDPE shrinkage during thermoforming is accounted by separate tolerance in the CAD model. The single-axis locked knee joint, Jaipur foot, and the leather belt type of suspension were further assembled with the socket and shank part to obtain the complete prosthesis.
As mentioned earlier, the thermoforming technique using HDPE pipe is similar to that in a conventional method, except that gypsum plaster stump is replaced by PU foam stump. This allows easier adaption of the proposed process in NGOs, resulting in better conformance (fit between the socket and residual limb) along with higher productivity (shorted lead time for fabrication). Figure 9 compares the flowcharts for the conventional (Fig. 9a) and proposed approaches (Fig. 9b) of socket fabrication.
Fig. 9.
Comparison of flowcharts for the conventional and the proposed process (original image). a Flowchart for conventional process. b Flowchart for proposed process
Results and Discussion
The proposed approach is illustrated and compared with the conventional fabrication process by taking up a pilot study involving three cases of prosthesis fabrication in association with an NGO called RNCT based in Mumbai. Technicians of this NGO fabricated three prostheses using the proposed approach and allowed the project team to observe the conventional process as well as to measure the time for various steps, enabling comparison of both approaches.
Lead Time Comparison
The conventional process for prosthesis fabrication at RNCT requires two technicians. One technician (A) carries out gypsum plaster filling, extension, and stump modification while the second technician (B) carries out prosthesis alignment. The patient’s residual limb measurement and HDPE thermoforming involve both technicians. The steps and the time taken are listed in Table 1. It is to be noticed that these steps are performed sequentially in the conventional process, whereas the proposed process enables parallel processing by the technicians, except while thermoforming.
Table 1.
Fabrication steps and resources required
| Step of the fabrication process | Time duration (min) | Working technician |
|---|---|---|
| Conventional fabrication process | ||
| Measurement taking | 15 | A and B |
| Gypsum plaster filling and extension for socket part | 30 | A |
| Gypsum plaster filling and extension for shank part | 15 | A |
| Gypsum plaster drying | 150 | – |
| Plaster replica modification for socket and shank part | 15 | A |
| HDPE thermoforming for the socket | 15 | A and B |
| HDPE thermoforming for the shank | 15 | A and B |
| Alignment and distribution | 45 | B |
| Total time required for conventional fabrication | 300 | – |
| Proposed fabrication process | ||
| Measurement taking and CAD model generation | 15 | A |
| Machining of PU foam stump and shank part | 75 | B |
| Epoxy coating and drying | 30 | A |
| HDPE thermoforming for the socket | 15 | A and B |
| HDPE thermoforming for the shank | 15 | A and B |
| Alignment and distribution | 45 | B |
| Total time required for proposed fabrication | 195 | – |
HDPE high-density polyethylene, CAD computer-aided design, PU polyurethane
The total lead time to fabricate three prostheses, using the two approaches, is depicted in Fig. 10. It can be observed that the conventional process allows fabricating three prostheses in a typical shift of 8 h. On the other hand, the lead time with the proposed hybrid process (for three prostheses) is only 5 h and 45 min, thereby saving 28% time. Indeed, it is possible to fabricate five prostheses in the same 8-h shift using the hybrid process.
Fig. 10.
Prosthesis fabrication lead time by conventional and proposed process (original image)
Preliminary Feedback
Detailed gait analysis of unilateral AK amputation patients receiving leg prosthesis fabricated using the conventional approach as well those fabricated using the proposed approach has been initiated after obtaining the approval of the Institutional Ethics Committee of MGM Institute of Health Sciences, Navi Mumbai. The initial study to establish the overall protocol is briefly described here.
The prosthetist of RNCT carried out static and dynamic alignment and observed the gait before handing over the prostheses to the volunteer patients. He also collected weekly feedback from all patients for 3 weeks after prosthesis delivery. Patient confidentiality was maintained by masking personal information. Table 2 summarizes their feedback in terms of the daily commute, the average use of the prosthesis, comfort level, and willingness to recommend the prosthesis to other users. Comfort rating and willingness to recommend were based on the visual analog scale (number on a pictorial scale).
Table 2.
Summary of feedback from three volunteer patients (original table)
| Questions | Patient number | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | |||||||
| Feedback week | |||||||||
| 1 | 2 | 3 | 1 | 2 | 3 | 1 | 2 | 3 | |
| Average daily usage of AK prosthesis (h) | 2 | 4 | 4 | 1 | 1 | 2 | 4 | 3 | 4 |
| Average weekly usage of AK prosthesis (days) | 5 | 5 | 4 | 4 | 5 | 6 | 5 | 3 | 4 |
| Comfort rating of AK prosthesis usage to walk 2 km in one go (out of 10) | 7 | 7 | 7 | – | – | – | – | – | 7 |
| Comfort rating of AK prosthesis usage for daily commute (out of 10) | 7 | 7 | 8 | 6 | 7 | 8 | 8 | 8 | 9 |
| Number of days, in a month, AK prosthesis causes distractions (days) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| How likely to recommend AK prosthesis to colleagues? (out of 10) | 8 | 8 | 9 | 8 | 7 | 8 | 8 | 8 | 9 |
AK above knee
Patient 1 was a 57-year-old male who had been using an old prosthesis for 8 years. Discomfort in wearing the prosthesis had resulted in an abnormal gait with hip abduction. His feedback revealed the use of the new prosthesis for a greater number of hours in a day and to perform daily commute more conveniently compared to the old prosthesis. Patient 2 was a 55-year-old male with controlled diabetes who had an amputation 4 years earlier. His requirement was a light-weight prosthesis to reduce the effort in climbing stairs. He reported that the prosthesis fabricated using the new approach was more comfortable, and he was able to climb stairs with less effort by the end of the 3rd week. Patient 3 was a 52-year-old male who had a traumatic amputation 3 years earlier. With the new prosthesis, his average prosthetic use increased, reducing dependency on family members, which was otherwise required during the non-prosthetic wearing period.
For all the three patients, the comfort rating for daily commute with new prosthesis increased with usage from the 1st week to the 3rd week. The rating of comfort at the end of the 3rd week for all the three patients was 8 or 9 on a scale of 0–10. All of them were happy to recommend the prosthesis to other colleagues. These are, however, the preliminary results, and a more detailed study is underway.
Conclusion
The proposed approach for fabricating AK prostheses overcomes the limitations of the conventional process. In particular, the use of gypsum plaster to fabricate patient-specific replicas of stump and shank (as in the conventional approach) has been eliminated by the hybrid method combining: (a) generation of 3D model of stump from parameters measured on patient’s residual limb, (b) fabrication of physical replica of stump by machining PU foam, (c) epoxy coating of the stump to prevent adhesion with HDPE pipe, and (d) conventional thermoforming of HDPE pipe over the stump replica. This approach is less dependent on the skill level of technicians and minimizes related errors (as in the conventional process). The hybrid method also reduced the lead time for fabricating three prostheses by two technicians to < 6 h, representing a saving of 28% in an 8-h workday. This allows two more prostheses to be fabricated on the same day. Feedback of three volunteer patients showed that the prosthesis fabricated using the proposed approach is more comfortable than that fabricated using the conventional approach. The standardization of the entire process allows its adaptation for mass customization with high productivity while ensuring high quality (comfortable fit for patients). A more detailed study involving a larger number of volunteer patients is underway to further establish the efficacy of the proposed approach.
The proposed approach is based on the open type of quadrilateral socket design, to optimize the resources currently available at NGO prosthetic centers. The ischial containment type of socket design is more common, but its intricate oblique geometry at the IT makes it difficult to separate the stump and socket part using the proposed approach. There is a need to include the design of separable stump part to allow ischial containment type of socket design. Another limitation of the proposed approach is that the NGO technicians need to be trained in the new measurement process, 3D model generation using CAD software, and machining and coating of the stump. For this purpose, the project team is developing suitable training material.
The project team at IIT Bombay is working closely with the NGO (RNCT) to upgrade the current facility and fully establish the new process in their premises. They are also working with the researchers of R2D2 Lab in IIT Madras, to incorporate a knee joint in the conventional AK prosthesis. The new design of prosthesis along with the new process for its fabrication is expected to significantly improve the product quality while keeping it nearly as affordable as the conventional prosthetic leg and increase the productivity to cater to a larger number of needy patients.
Acknowledgements
This project was carried out at Biomedical Engineering and Technology (incubation) Centre (BETiC) at IIT Bombay, funded by Rajiv Gandhi Science and Technology Commission, Government of Maharashtra, Mumbai, and Department of Science and Technology, Ministry of Science and Technology, New Delhi. The support provided by Mr. Rajiv Mehta, Trustee of RNCT, and his team including Ms. Nandini Thakkar, Mr. Salodkar (prosthetist), Mr. Buddha, Mr. Mane, Mr. Manoj, and Mr. Sawant is deeply acknowledged. Valuable insights about prosthesis design and patient rehabilitation were provided by Dr. Rajani Mullerpatan and her team at the Centre for Human Movement Science, MGM Institute of Health Sciences, Navi Mumbai, as well as Mr. Soikat Ghosh Moulic and Mr. Sanjoy Singh Oinam from Mobility India. Prof. Muhammad Salman, Civil Engineering Department, and Mr. Pratap Shingade at Structural Evaluation and Materials Testing Lab at IIT Bombay allowed access to their experimental facilities. Mr. Ashok Mawade, Industrial Design Centre, IIT Bombay, helped in evolving the coating process. BETiC researchers Mr. Shrishail Hamine and Dr. Trimbak Kawadikar helped in exploring 3D parametric modeling. The measurement templates were developed by two summer interns Arvind and Viren from Symbiosis Institute of Technology, Pune. Dr. Aayush Kant, IIT Bombay, helped in drafting and improving the paper. The project team is especially grateful to the three volunteer patients who tried out the prostheses and provided regular feedback. The project received the Google Impact Challenge for Disabilities Award, which is supporting the implementation of technologies described in this paper.
Funding
This project was carried out at Biomedical Engineering and Technology (Incubation) Centre at IIT Bombay, funded by Rajiv Gandhi Science and Technology Commission, Government of Maharashtra, Mumbai, and Department of Science and Technology, Ministry of Science and Technology, New Delhi. The support provided by Mr. Rajiv Mehta, Trustee of RNCT, and his team including Ms. Nandini Thakkar, Mr. Salodkar (prosthetist), Mr. Buddha, Mr. Mane, Mr. Manoj, and Mr. Sawant is deeply acknowledged.
Compliance with Ethical Standards
Conflict of interest
The authors declare that they have no competing interests.
Ethical standard statement
Detailed gait analysis of unilateral AK amputation patients receiving leg prosthesis fabricated using the conventional approach as well those fabricated using the proposed approach has been initiated after obtaining the approval of the Institutional Ethics Committee of MGM Institute of Health Sciences, Navi Mumbai. The initial study to establish the overall protocol is briefly described in this paper.
Informed consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published, and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Footnotes
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