Hip–knee–ankle–foot prostheses (HKAF) are full lower-limb devices for people with hip amputations that enable individuals to regain their mobility and move freely within their chosen environment. HKAFs typically have high rejection rates among users, as well as gait asymmetry, increased trunk anterior–posterior lean, and increased pelvic tilt. A novel integrated hip–knee (IHK) unit was designed and evaluated to address the limitations of existing solutions. This IHK combines powered hip and microprocessor-controlled knee joints into one structure, with shared electronics, sensors, and batteries. The unit is also adjustable to user leg length and alignment. ISO-10328:2016 standard mechanical proof load testing demonstrated acceptable structural safety and rigidity. Successful functional testing involved three able-bodied participants walking with the IHK in a hip prosthesis simulator. Hip, knee, and pelvic tilt angles were recorded and stride parameters were analyzed from video recordings. Participants were able to walk independently using the IHK and data showed that participants used different walking strategies. Future development of the thigh unit should include completion of a synergistic gait control system, improved battery-holding mechanism, and amputee user testing.

Powered ankle-foot prostheses offer the potential to emulate natural locomotion dynamics, thereby addressing the issues related to uneven gait and insufficient propulsion typically experienced by individuals with lower-limb amputation wearing a passive prosthetic device. Despite significant progress, existing powered prostheses are often hindered by their substantial build height, bulky design, excessive weight, and noise level, limiting their widespread adoption. This work presents ELSA (Efficient and Lightweight Spring Ankle), a lightweight (1.15 kg) and compact (11 cm high) powered ankle-foot prosthesis fitting within the volume of a shoe and capable of providing a net positive mechanical energy over the gait cycle. This level of integration is achieved through an innovative arrangement of a spring and actuator mechanisms operating in synergy. This hybrid architecture offers users the choice to (i) walk actively, with propulsive energy assistance; (ii) regeneratively, potentially allowing for energy harvesting to recharge the device battery; or (iii) completely turned off (passive). This prototype has been validated during benchtop experiments and through trials involving four amputated participants. These tests encompassed various scenarios, including treadmill walking and everyday ambulation tasks. Additionally, a sensitivity analysis was conducted to assess how different control parameters impacted the provided mechanical energy and resulting gait performance.

BACKGROUND: Prosthetic solutions for individuals with hip disarticulation and hemipelvectomy amputations currently rely exclusively on passive hip joint mechanisms. Although powered knee and ankle joint prostheses have improved gait in people with amputation, no powered hip joint options are commercially available. OBJECTIVE: To develop and validate the mechanism, structural integrity, and design of an anteriorly mounted powered hip joint prosthesis. METHODOLOGY: A microprocessor-controlled powered hip joint prosthesis (PHP) was developed, incorporating a cable-and-pulley transmission system. Stress calculations and Finite Element Analysis (FEA) were performed to ensure that the device can withstand the forces from daily activities. The prototype underwent mechanical strength testing in accordance with International Organization for Standardization (ISO) 15032:2000 standards, ensuring suitability for user loads of up to 100 kg. For functional testing, three able-bodied individuals were video recorded while walking with the power hip in a prosthesis simulator. For each participant, hip angles and stride parameters during level walking were assessed by analyzing five gait cycles. FINDINGS: The novel PHP met most of the design criteria; however, it protruded 56 mm anteriorly from the lamination plate, exceeding the specified criterion of 20 mm. The joint's range of motion included 22° of extension and 145° of flexion. The joint prototype's height was 347 mm, and it weighed 3.9 kg. Furthermore, it passed ISO 15032:2000 strength tests, withstanding a 3360 Newton (N) load without failure. The device successfully enabled able-bodied individuals to walk using a hip disarticulation simulator and supported a 98 kg user during level walking. CONCLUSION: The microprocessor-controlled PHP exhibited successful performance in both mechanical strength and functional testing. Future work is needed to optimize and assess the design, which could reduce the device's weight and size. A complex control system to adjust gait based on pelvic motion is currently under development. Layman's Abstract Currently, prosthetic solutions for people with hip disarticulation and hemipelvectomy amputation rely solely on passive prosthetic hip joints. While powered knee and ankle joints prostheses can improve gait, there are no powered hip joints prostheses available on the market. This study introduced and evaluated a powered hip joint prosthesis with a cable-and-pulley transmission system. The powered hip joint prosthesis met most of the design criteria and has range of motion of 22° of extension and 145° of flexion. The heigh of the joint was 347 mm, and it weighed 3.9 kg. Furthermore, it passed the strength tests, withstanding a 3360 Newton (N) load without failure. To evaluate the joint's performance, testing was conducted with three able-bodied individuals using a prosthesis simulator during level walking. This joint successfully enabled able-bodied individuals to walk and supported a 98 kg user during level walking. Future work is needed to optimize and assess the design, to reduce the device's weight and size. Furthermore, a control system to improve movement and function is needed and is currently under development. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/44494/33657 How To Cite: Brannen K, Baddour N, Cho L, Langlois D, Dumond P, Lemaire E.D. Development and evaluation of an anteriorly mounted microprocessor-controlled powered hip joint prosthesis. Canadian Prosthetics & Orthotics Journal. 2024; Volume 7, Issue 2, No. 7. https://doi.org/10.33137/cpoj.v7i1.44494 Corresponding Author: Professor Edward Lemaire, PhDAffiliation: Department of Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Canada.E-Mail: elemaire@uottawa.caORCID ID: https://orcid.org/0000-0003-4693-2623

Background/Objectives: Hip-level amputees face ambulatory challenges due to the lack of a lower limb and prosthetic hip power. Some hip-level amputees restore mobility by using a prosthesis with hip, knee, and ankle joints. Powered prosthetic joints contain an actuator that provides external flexion-extension moments to assist with movement. Powered knee and powered ankle-foot units are on the market, but no viable powered hip unit is commercially available. This research details the development of a novel powered four-bar prosthetic hip joint that can be integrated into a full-leg prosthesis. Methods: The hip joint design consisted of a four-bar linkage with a harmonic drive DC motor placed in the inferior link and an additional linkage to transfer torque from the motor to the hip center of rotation. Link lengths were determined through engineering optimization. Device strength was demonstrated with force and finite element analysis and with ISO 15032:2000 A100 static compression tests. Walking tests with a wearable hip-knee-ankle-foot prosthesis simulator, containing the novel powered hip, were conducted with three able-bodied participants. Each participant walked back and forth on a level 10 m walkway. Custom hardware and software captured joint angles. Spatiotemporal parameters were determined from video clips processed in the Kinovea software (ver. 0.9.5). Results: The powered hip passed all force and finite element checks and ISO 15032:2000 A100 static compression tests. The participants, weighing 96 ± 2 kg, achieved steady gait at 0.45 ± 0.11 m/s with the powered hip. Participant kinematic gait profiles resembled those seen in transfemoral amputee gait. Some gait asymmetries occurred between the sound and prosthetic legs. No signs of mechanical failure were seen. Most design requirements were met. Areas for powered hip improvement include hip flexion range, mechanical advantage at high hip flexion, and device mass. Conclusions: The novel powered four-bar hip provides safe level-ground walking with a full-leg prosthesis simulator and is viable for future testing with hip-level amputees.

Deploying machine vision for wearable robot control faces challenges in terms of usability, reliability, privacy, and costs.