A Mile in Their Shoes

The Motion Analysis Center at Shriners Hospital utilizes three-dimensional gait analysis to guide patient treatment

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LEXINGTON It sounds like the beginning of a riddle: What do you call a physical therapist who doesn’t treat patients? Hank White, PT, PhD, has the answer, and it’s no laughing matter.

White is a physical therapist who works in the Motion Analysis Center (MAC) at Shriners Hospital for Children Medical Center (SHCMC) in Lexington.

“I often tell people I am not a normal physical therapist because I do not treat patients,” says White, who has worked at Shriners Hospital for Children (SHCMC) for the past 25 years. “Instead, I perform biomechanical and physical therapy evaluations with patients as part of their care at SHCMC.”

It’s safe to say this career wasn’t in White’s plans when he completed his undergraduate work with a bachelor’s degree in agriculture from the University of Kentucky. His area of study was horse husbandry. His altered his course after that, earning an entry-level master’s degree in physical therapy from Washington University in St. Louis and a PhD in rehabilitation sciences from the University of Kentucky.

At SHCMC, White is part of an interdisciplinary team consisting of three physicians, an engineer, a kinesiologist, a physical therapist, and a coordinator. Within the MAC, all of these team members work together to generate a single report for the patient.

“Each of us has a different role and, because we all have different backgrounds, it provides an environment for interdisciplinary interaction and discussion,” White says. “We each initially have our own potential answer to a question but work together to form a single answer. It requires numerous people to make a MAC work effectively and efficiently.”

Henry J. Iwinski, MD, pediatric orthopaedic surgeon and chief of staff at Shriners Hospitals for Children Medical Center – Lexington concurs. “With the data we obtain from a gait study in our Motion Analysis Center, we can better tailor the treatment required to the functional status and needs of the patient. We can also evaluate the results of our interventions in a very precise manner. The research we do assists us in finding new and better ways to treat patients.”

Technology Assists Diagnosis

The Motion Analysis Center requires an array of technology, including a motion-capture system involving numerous digital cameras linked together via computer, simultaneously measuring the movement of reflective markers attached to the patient’s skin. White compares this to the green screen technology used in making movies and video games.

The reflective markers are placed on specific bony landmarks on the patient’s trunk, arms, pelvis, legs, and feet. If at least two cameras track each marker, the motion capture system is able to recreate a three-dimensional representation of the patient walking. This is then processed to develop a graph of each joint motion.

Additional technologies include force plates which measure the total force and center of pressure applied by the foot to the ground. Surface electromyography measures muscle activity. A metabolic cart measures the oxygen consumed and carbon dioxide produced by a patient while wearing a mask to measure how much energy the patient uses to walk. Dynamic pedobarography is another force plate which measures forces and pressures acting on the foot when it is on the floor.

“All of these technologies can be used in isolation or simultaneously depending on what clinical question we’re trying to answer,” White says. “We use them when performing a whole-body, three-dimensional gait analysis to develop a treatment plan to improve walking for children diagnosed with cerebral palsy.”

Patient Population and Presentations

The majority of the patients seen in the MAC have a primary diagnosis of clubfoot deformity or cerebral palsy. Cerebral palsy affects approximately two to three children per 1,000 births. Patients diagnosed with CP often demonstrate muscle weakness, muscle spasticity, joint and muscle contractures, and bone deformities. These impairments can result in impaired walking or reaching abilities. Three-dimensional analysis of walking and reaching tasks can be performed to document changes in these abilities over time and after therapeutic and surgical interventions.

Approximately one to four children per 1,000 births have a clubfoot deformity. Initially, the deformity is treated with casting soon after birth, followed by 3–4 years of wearing a brace. If the child experiences a reoccurrence of the deformity, the dynamic pedobarograph can be used to monitor changes in the patient’s footprint when walking.

“Shriners Hospitals for Children is unique because we use the technology to perform clinical assessment of children to provide objective documentation of care we provide,” White says. “Most clinicians do not routinely use this technology because of the initial cost of the equipment and low reimbursement rates from insurance companies. Almost 20 years ago, SHC decided to begin investing in this technology. Therefore, we’re able to provide a service that most other children’s hospitals cannot provide.”

White adds that cost is often seen as a hurdle to using the MAC, but he says the benefits far outweigh the costs.

Cost vs. Benefit

“The cost of performing a whole-body three-dimensional gait analysis is similar to the cost of magnetic resonance imaging,” White says. “Cost is not a good enough reason to not perform an assessment, which may prevent an incorrect or incomplete surgical plan of care for a child and their family. The additional cost to perform a gait analysis typically results in an overall decrease in the cost of care because fewer surgical admissions and rehabilitations are required.”

While the MAC has demonstrated benefits, not all patients are good candidates for the MAC and its many tools. For instance, a child must be able to walk 30 feet (with or without an assistive device) independently, meaning without assistance from another person.

It does not matter how slowly a patient walks, but they must demonstrate the ability to take repeated steps without pausing or stopping.

The patient must also be able to follow simple commands and cannot have tactile defensiveness. “A child with such sensitivity will continually take off the markers/electrodes or will be unable to demonstrate a typical walk with marker/electrodes placed on the skin,” White explains.

White also explains that the MAC staff must be aware of the Hawthorne effect, a principle describing how people tend to behave differently when they know they are being observed. A patient not being watched may walk on differently than when they are being observed by medical personnel. MAC staff ask the patient’s family to help assess the patient and confirm their movements are representative of their typical gait.

“The data obtained by the MAC are utilized by orthopedic surgeons to document current status, to develop a surgical treatment plan, and to document change after surgery,” White says. “Physical therapists can also use the data to document changes over time for their patients.”

White says SHCMC often receives referrals from orthopedists from other parts of Kentucky and surrounding states asking for whole body gait analysis. The Lexington SHCMC provides care for children and adolescents from Kentucky and the surrounding states of Ohio, West Virginia, Indiana, and Tennessee. Patients of Lexington Shriners Medical Center receive an initial evaluation by a pediatric orthopedic surgeon. If the surgeon believes it will be beneficial to the patient’s plan of care, a three-dimensional gait analysis may be ordered.

“Cost is not a good enough reason to not perform an assessment, which may prevent incorrect or incomplete surgical plan of care for a child and their family.”— Hank White, PT, PhD, Shriners Hospital for Children Medical Center

White might not treat patients himself, but it is clear that the work of him and his team at the MAC is helping make great strides in patient care.