Sarah R. Chang, PhD

Offering Evidence to Support Clinical Decision-Making

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AOPA/COPL grant recipient shares her research into socket suspension and other O&P technologies

O&P Almanac introduces individuals who have undertaken O&P-focused research projects. Here, you will get to know colleagues and healthcare professionals who have carried out studies and gathered quantitative and/ or qualitative data related to orthotics and prosthetics, and find out what it takes to become an O&P researcher.

SARAH R. CHANG, PhD, embraced a career in O&P research with the goal of making a positive impact on people’s lives. “Learning about the international O&P needs in low- and middle-income countries when I was younger was one of the initial starting points for my interest in this field,” says Chang, director of research and development (R&D) at Orthocare Innovations. That interest developed over time throughout college and graduate school as she became more exposed to the opportunities and needs in O&P.

Chang—one of the recipients of a 2020-2021 grant from AOPA and the Center for Orthotic and Prosthetic Learning (COPL)—was awarded funds to develop evidence-based clinical practice guidelines for vacuum-assisted socket suspension systems (VASS) based on the best available evidence evaluated in a systematic review. “We’ve completed a systematic review to gather all of the available published evidence on VASS,” she explains, “drawn from more than 60 peer-reviewed articles.”

Chang and her team at Orthocare are currently evaluating the data, evidence, and clinical applications to provide guidelines for clinicians who may be deciding whether elevated vacuum is the appropriate technology for a patient. The work will support prosthetists in their clinical care, says Chang, as well as offer the necessary evidence to support decisions on the best possible technology for each prosthesis user’s needs.

Overseeing R&D

Chang earned a bachelor’s degree in biomedical engineering from California Polytechnic State University in 2011, followed by a doctorate in biomedical engineering from Case Western Reserve University in 2017. She served as a postdoctoral fellow at Northwestern University Prosthetics-Orthotics Center in 2017, then took a job with Orthocare—an R&D company. “We develop prosthetic, orthotic, assistive, and rehabilitation devices as well as tools and approaches to assist O&P clinicians,” Chang explains.

In her current position at Orthocare, Chang is responsible for leading and collaborating with the multidisciplinary R&D team, which includes a mix of engineers and clinicians. She also initiates and oversees areas of R&D— both new and ongoing projects—which can include acquiring grant funding

or developing external collaborations. In addition, she performs engineering as needed; conducts experiments and clinical trials to evaluate the technologies; and collaborates with researchers and other professionals in the O&P and rehabilitation fields.

“My focuses are helping people lead healthy lives by being or staying mobile and positively impacting the lives of individuals with disabilities,” Chang adds. “Advancing medical technology and care through engineering and research is one way to provide the means for individuals to have improved or higher quality of life.”

In addition to their current work related to prosthetic socket suspension, Chang and the Orthocare team are involved in a project related to the “Assist-Knee” that is partially funded by the National Institutes of Health, National Center for Medical Rehabilitation Research. “We are developing a prosthetic knee to help geriatric or new transfemoral Sarah Chang, PhD, was assisted by Natalie Harold, MSPO, CPO, in taking physical measurements that are used in motion analysis calculations.

PHOTO: Sarah Chang, PhD FOLLOW US @AmericanOandP

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Chang presented a poster describing the multidomain approach to outcomes at the 2019 Military Health System Research Symposium. prosthesis users retain independence and mobility for high quality of life and better health,” she says. The prosthesis will assist with stand-to-sit and sitto-stand transitions by using energy storage and release technology.

She also is developing a smart ankle-foot orthosis (AFO), with funding from the National Institute on Disability, Independent Living, and Rehabilitation Research. “Our team previously conducted research that established relationships between gait characteristics of post-stroke AFO users and sagittal AFO stiffness and range of motion, and established how to improve the gait of persons after stroke,” she explains. “These scientific findings provide the foundation upon which we are developing an integrated system design that evaluates AFO user gait data to provide orthotists with AFO adjustment guidance.”

Other recent studies include an investigation into technology to assist with remote prosthetic alignment by providing a system of sensors and software to diagnose and guide the correction of very subtle and difficult-to-see imbalances in prosthesis user dynamic gait. “The system enables controlled alignment changes by the prosthetist,” she says. Chang also recently studied evidence related to the effects of hydraulic ankle-foot prostheses on transtibial prosthesis users’ gait biomechanics and patient-reported outcomes. “Improved walking speed was consistently reported when using a hydraulic ankle-foot prosthesis as compared to a nonhydraulic ankle-foot prosthesis in transtibial prosthesis users,” she explains.

Measuring Outcomes

Some of Chang’s research is directly related to patient outcomes and outcome measurements. “We are working on implementing digital mobile app versions of validated outcome measures, such as the Prosthesis Evaluation Questionnaire (PEQ),” she says. The PEQ was originally designed in paper format and can be labor-intensive for clinicians to score and calculate the results, so Chang and her colleagues have converted the PEQ to a mobile app that automates scoring. The digital version should help clinicians save time and allow them to focus on explaining to patients their results “and what it means for their clinical care,” she explains. “PEQ Mobile also gives clinicians the ability to export the patient’s results in a report to include in the medical record.”

Chang says she emphasizes a “multidomain approach” to outcomes. As more O&P facilities collect outcome measures and implement evidence-based practice, “it is important that we combine multiple domains of information to create a holistic view of patient performance and well-being, rather than looking at a single domain, which can be limited in scope and not necessarily be a complete picture of a patient,” she says.

For example, Chang points to a patient who performs the two-minute walk test well but is dissatisfied with the function of their O&P device. “If we only evaluated the walk test, we would only be looking at one dimension or one outcome, but not truly understanding the patient’s outcomes as a whole,” she explains. “This multidomain approach to outcomes that I’ve been working on provides a clinically useful scientific methodology that integrates a wide range of outcome measures and automates data processing to inform clinicians about patients’ function to support clinical decisions, evidence, and reimbursement.”

Different domains could include patient-reported outcomes, clinical tests, biomechanics, real-world activity, and clinician expertise, according to Chang. Data for those domains can come from a variety of sources, such as validated questionnaires, wireless wearable sensors, validated clinical tests, and clinician input. “We are currently developing and validating this approach, and working to automate it so it aligns with workflows in the clinic,” she says, to support clinical decision-making, comprehensively measure patient performance, engage patients in their rehabilitation, and provide the evidence that may be needed to adequately justify prescription in the eyes of the payors.

Eyeing the Future

As she plans for new investigations and considers what will be important to future O&P patients, Chang believes O&P projects will need to support clinicians in their clinical care and provide evidence or tools that the clinicians

need to serve their patients. “We need to continue including stakeholders, such as patients and providers, as active participants in the device research and development,” she says. “Future O&P projects will continue to provide individuals with the technology they need to maintain independence and the needed functionality to remain mobile.”

Chang has been “doing a lot of thinking lately” about the importance of real-world data—not just information collected in a study setting. “We need to collect more real-world evidence in O&P, in outcomes areas that are important to the users,” she says. “The means to collect, analyze, synthesize, report, and share the real-world evidence may need further development and exploration.”

Of course, researchers should continue to discuss what equates to “appropriate outcomes” for O&P patients. “There are several outcomes areas and outcome measurements that we can look at for our patients. Which ones should we be evaluating, and are there easy ways to implement the data collection and analyses within the patients’ lives and clinicians’ work?” she asks. “How do cultural, societal, or economic environments factor into these outcomes areas and outcome measurements?” Chang plans to stay focused on these questions as she continues her studies and plays a pivotal role in improving the quality of life for people with disabilities.

Notable Works

Sarah R. Chang, PhD, has been involved in dozens of important published studies, including the following: • Boone, D.A., Chang, S.R. “Enabling Technology for Remote Prosthetic

Alignment Tuning.” Military Medicine. 2021; 186(Suppl 1): 659-664. • Chang, S.R., Miller, C.H., Kaluf, B. “Effects of Hydraulic Ankle-Foot

Prostheses on Gait in Individuals With Transtibial Limb Loss: A Scoping

Review.” Journal of Prosthetics and Orthotics, 2021; 33(2): 101-109. • Chang, S.R., Boone, D.A. “A Conceptual Framework for Multi-

Domain Clinical Decision Support in Orthotics and Prosthetics.”

Submitted in 2021.

Ferrier Coupler Options! Interchange or Disconnect

The Ferrier Coupler provides you with options never before possible:

Enables a complete disconnect immediately below the socket in seconds without the removal of garments. Can be used where only the upper (above the Coupler) or lower (below the Coupler) portion of limb needs to be changed. Also allows for temporary limb replacement. All aluminum couplers are hard coated for enhanced durability. All models are interchangeable.

Model A5

The A5 Standard Coupler is for use in all lower limb prostheses. The male and female portions of the coupler bolt to any standard 4-bolt pattern component.

The F5 Coupler with female pyramid receiver is for use in all lower limb prostheses. Male portion of the coupler features a built-in female pyramid receiver. Female portion bolts to any standard 4-bolt pattern component.

The Ferrier Coupler with an inverted pyramid built in. The male portion of the pyramid is built into the male portion of the coupler. Female portion bolts to any 4-bolt pattern component. NEW! The FA5 coupler with 4-bolt and female pyramid is for use in all lower limb prostheses. Male portion of coupler is standard 4-bolt pattern. Female portion of coupler accepts a pyramid.

NEW! The FF5 has a female pyramid receiver on both male and female portions of the coupler for easy connection to male pyramids.

NEW! The FP5 Coupler is for use in all lower limb prostheses. Male portion of coupler has a pyramid. The Female portion of coupler accepts a pyramid. The Trowbridge Terra-Round foot mounts directly inside a standard 30mm pylon. The center stem exes in any direction allowing the unit to conform to uneven terrain. It is also useful in the lab when tting the prototype limb. TheThe unitunit isis waterproof and has a traction base pad.

Model FA5

Model F5 Model FF5

Model P5 Model FP5 Model T5