Objective To explore the perceptions of wearing an ankle-foot orthosis (AFO) in patients with peripheral artery disease (PAD) who did and did not adopt the AFO intervention. This follows a clinical trial of the effectiveness of an AFO in improving walking distances for patients with PAD-related claudication. Design A randomized crossover trial of standard of care and an AFO for 3 months. Semistructured interviews were conducted 1.5 months into the AFO intervention to understand acceptability, demand, implementation, and practicality. Data were analyzed using a summative content analysis approach. Setting Vascular surgery clinic and biomechanics research laboratory. Participants Patients (N=15; male, 100%; age, 71.9±.6.7y; body mass index [calculated as weight in kilograms divided by height in meters squared], 29.0±.5.5; ankle brachial index: AFO intervention withdrawal, 0.543; AFO intervention completion, 0.740) with claudication completed the study, and 6 withdrew prior to intervention completion. Interventions A certified orthotist fit participants with an AFO that was worn for 3 months. Main Outcome Measures Qualitative analysis of the semistructured interviews. Results Key differences were reported between AFO intervention completion and AFO intervention withdrawal. Six of 14 of AFO intervention completion participants described their initial reactions to the AFO as negative vs 3 of 6 AFO intervention withdrawal participants. Only 5 of 15 AFO intervention completion participants reported minimal use of the AFO compared with 5 of 6 AFO intervention withdrawal participants. The AFO intervention withdrawal group reported higher levels of physical discomfort with the use of the AFO (4/6 vs 7/15) and preexisting health issues becoming a barrier to the use of the AFO (3/6 vs 5/15). Positive aspects reported included ease in standing and walking for AFO intervention withdrawal (4/6) and AFO intervention completion groups (13/15) as well as walking straighter and longer with less pain for AFO intervention withdrawal (3/6) and AFO intervention completion groups (9/15). Conclusions Patients withdrawing prior to completion of AFO intervention tended to have more negative perceptions, more comorbidities, and more physical discomfort than those completing the intervention. Both groups reported positive aspects of the AFO. Implementation studies are needed to address barriers to AFO adoption.

A Knee-Ankle-Foot orthosis (KAFO) is used as a supportive device by individuals with lower limb disability. A type of KAFO that allows knee flexion-extension is prescribed for people who need knee stability in the transverse and frontal planes. In such an orthosis, mimicking the human knee motion is vital to avoid relative motion (called pistoning) between the limb and the orthosis. A four-bar mechanism, owing to its polycentric nature, simplicity and ease of fabrication can provide a customizable, biomimetic solution. This paper presents an improved and robust optimization approach to synthesize a four-bar mechanism to closely mimic the anatomical knee motion. The reference human knee centrode is obtained from literature. A genetic algorithm is used for optimal synthesis of the fourbar mechanism. Results show that the average error between the reference centrode and the centrode of the synthesized four-bar mechanism is very small (0.2 mm). Thus, the synthesized crossed four-bar linkage can reproduce better anthropomorphic characteristics of the knee joint. The methodology can be used for the design of customized orthotic knee joints for KAFOs and knee braces.

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The outcomes of this survey can motivate and guide researchers to design improved orthotic solutions to meet the needs of lower limb orthosis users all over the world. Implications for Rehabilitation  • This is a first of its kind survey that brings forth the needs of lower limb orthosis users in India, and is an important step towards rehabilitation and empowerment of people with lower limb disability.  • The pilot survey helps to identify critical areas for design improvements in a knee-ankle-foot orthosis.  • The outcomes of this survey can help researchers to design functionally improved assistive devices that better meet the needs of users than currently available technology in developing countries such as India.

Introduction Pistoning is relative sliding motion between an affected limb and its corresponding externally fit assistive device (like an orthosis). Pistoning causes skin problems, pain, and discomfort to the orthosis user. Misalignment of an orthotic joint with respect to the anatomical joint is one of the causes of pistoning motion, and the current knowledge pertaining to the effects of orthotic knee center (OKC) misalignments in lower-limb orthoses is limited. This work quantifies the effects of OKC misalignment in terms of relative motion between the limb and the orthosis and predicts locations of resultant pressure point on the limb. Method A two-dimensional link segment model that simulates relative motion between the limb and orthosis was developed. The OKC was systematically misaligned in the anterior-posterior (A-P), proximal-distal (P-D) directions, and their combination to simulate orthosis/thigh strap sliding and identify pressure points on the thigh. Simulations were performed for stand-to-sit activity and walking with a knee-ankle-foot orthosis. Results It was found that OKC misalignment causes increased A-P and P-D relative motions with an increase in misalignment distance for the stand-to-sit activity. The A-P and P-D relative motions are of greater concern for activities involving increased knee flexion such as sitting, squatting, and kneeling as compared with walking with an orthosis. Although the A-P and P-D relative motions during walking are of small magnitude, they occur with reversals in the direction and are repetitive in nature, which may cause skin problems and discomfort due to recurring pressure points. Conclusions The model provides a means to study the consequences of misalignment and insights for orthosis modification for improved comfort. A software simulation tool based on the presented model can serve as an educational and training tool in prosthetics and orthotics courses for creating awareness about the importance of proper alignment of orthotic knee joints. Study of misalignments of this nature will also guide fabrication and fitting of lower-limb orthoses/exoskeletons.