Walter Reed’s State-of-the-Art Biomechanics Lab

This past September, the Military Advanced Training Center (MATC) opened its doors at Walter Reed Army Medical Center in Washington, D.C. Geared toward rehabilitating wounded soldiers and helping them return to duty, the MATC is a 31,000-square foot, $10 million state-of-the art facility that boasts cutting edge technology and equipment.

The MATC uses a multidisciplinary approach to provide medical care and rehabilitative services for Warriors in Transition. Funding for the MATC was allocated by Congress after the war in Iraq began. Construction of the facility began in November 2006 and was fast-tracked, enabling the MATC to be finished several months ahead of schedule. Featuring “one-stop shopping” that stresses a multidisciplinary team approach to care, the facility’s services range from physical therapy and postoperative care to counseling. The building also provides offices for more than 15 specialties, including physicians, nurse case managers, psychologists, social workers, benefits counselors and Veterans Affairs representatives.

Biomechanics lab

Biomechanics labHoused within the MATC is the Center for Performance and Clinical Research, which is the facility’s biomechanics lab. The size of the new biomechanics lab, 50 feet by 35 feet, easily doubled the size of the previous lab, and the lab features the latest in technological advances and equipment for analyzing gait and helping patients recover to their fullest potential.

Used for both clinical as well as research purposes, the lab features a 23 camera system and six calibrated force plates for collecting gait data. The biomechanics lab also has an instrumented treadmill as well as the ability to collect metabolic data for analysis.

Collecting data

To collect gait data, reflective markers are strategically placed all over a patient’s body and the patient begins moving. The cameras, which are specialized high-speed, high-resolution digital video cameras, emit infrared light that hits the markers and then bounces back to the cameras. As the patient walks, a three-dimensional rendition is created and numbers are assigned to represent how the patient is moving, said Brian S. Baum, MS, a biomedical engineer at the Center for Performance and Clinical Research Biomechanics Lab, MATC, Walter Reed Army Medical Center.

“As the body moves, the markers move, and we can run that through the computer and tell exactly how each of the joints is moving,” Baum said. “We can tell how hard somebody is stepping on their limbs. We can calculate the forces and the torques and the powers that are being generated at each of the joints.”

A preliminary report is generated using the objective gait data, and a treatment plan outlining recommendations and goals then is devised using input from all members of the multidisciplinary team. Although the biomechanics lab itself is staffed by physical therapists and engineers, as many primary care providers as possible are incorporated in the analysis process; this usually includes at a minimum a prosthetist, physical therapist and physician, said Barri L. Schnall, MPT, a gait specialist at the Center for Performance and Clinical Research, MATC, Walter Reed Army Medical Center.

In addition, data collected during the gait analysis can be used to provide immediate feedback to prosthetists, who can then use the data to make dynamic rather than bench adjustments to prostheses.

“We are using this as somewhat of a dynamic alignment tool in getting feedback to the prosthetist. If we see something during the gait collection, we can call the prosthetist and say ‘maybe if you adjust the foot, maybe plantar flex the foot or toe out the foot, that will change the kinetic pattern,’” Schnall said. “We can have them evaluate the patient while they are still there and eliminate a lot of the guesswork that is involved in prosthetic alignment.”

Running studies

Another unique capability of the biomechanics lab is that its large size can accommodate running studies. Two of the six force plates are larger to allow for the collection of running data, and the lab’s size can be increased even further by opening the doors to the lab to create additional lead-in space for running.

“The nice thing about this lab is the size, that is the key figure,” Schnall said. “There are not many clinical or medical research labs that have the type of space that we have currently, and the purpose for having this additional space was to be able to accommodate running studies.”

Being able to accommodate running studies at the facility is important for several reasons. Schnall noted there is not much research on high-impact activities in young amputees, and because most of the patients treated at the MATC are young otherwise healthy adults who want to return to their active lifestyle, running often is one of their goals.

“We are focused on returning to duty requirements and optimizing amputee rehab to either return these guys to active duty or to return them to the highest level of functioning,” Schnall said.

Research studies

 
The biomechanics lab features a 23 camera system and six calibrated force plates for collecting gait data
Used for both clinical as well as research purposes, the biomechanics lab features a 23 camera system and six calibrated force plates for collecting gait data. The biomechanics lab also has an instrumented treadmill as well as the ability to collect metabolic data for analysis.
All images reprinted with the permission of Walter Reed Army Medical Center.

Although the primary focus of the biomechanics lab is clinical, a number of ongoing research protocols also are being conducted. Some of the lab’s current research studies include hill assessment indices as well as stair assessment indices, which are correlated with patients’ objective gait and metabolic analyses to help formulate rehabilitation plans.

In addition, the lab also assesses different types of knee units to provide objective information about how patients function with their prosthesis. One of the lab’s ongoing studies is looking at transtibial amputees who walk at various speeds while wearing rucksacks of varying weight to determine how they compare to an uninjured control population, Schnall said.

Although the patient population at the MATC is primarily a younger population, the staff at the facility see an entire range of functional abilities and a range of comorbidities. Some patients’ goals are simply to stand up and walk whereas other patients’ goals are to become a Paralympian, Baum said.

“We see the entire range, which gives us a unique opportunity to perform research on that entire range of those functional abilities so we can design some protocols specifically for the more elite, higher functioning people,” Baum said. “In the same right, we can identify and perform research protocols that are based primarily on the functional abilities of balance and just working on improving gait function in general.”

As a result, Baum noted all of the areas being researched are applicable not only to the facility’s military population but also to the general amputee population.

“Really, just from looking at the various functional abilities, we are performing research looking at the whole range, and that all applies to the world outside of our population as well,” Baum said.

Military amputee population

The types of lower extremity injuries seen at the MATC include from Symes amputations, transtibial, transfemoral, and knee and hip disarticulations. Often, multiple limbs, including upper extremities, are involved. Some patients who return to active duty choose redeployment to active in the field, while others may return to alternative jobs or duties rather than to their prior job before being injured. Schnall noted that the highest percentage of patients who do return to active duty and deployment are transtibial amputees.

According to one report on the Internet, the number of amputees who return to active military duty has increased significantly in the past 10 years. In 1998, approximately 4% of amputees remained on active military duty. Today, this number is estimated at 20%.

Since the war in Iraq began, 6,310 soldiers wounded in Iraq and 635 wounded in Afghanistan have been treated at Walter Reed Army Medical Center. The total number of patients from both Iraq and Afghanistan who required amputation is 725; of these, 533 were treated at Walter Reed and the remainder were treated at Brook Army Medical Center in Texas, said Donald H. Vandry with Walter Reed Army Medical Center Public Affairs.

Besides the MATC’s biomechanics lab, the only other biomechanics lab at a military facility is at Brook Army Medical Center. At the MATC biomechanics lab, the primary focus is on the amputee population, which is where most of the facility’s funding is directed, Schnall said. However, the lab also evaluates some clinical and research spine patients as well as some Wounded Warriors with brain injuries.

Reimbursement issues

 
The CAREN system provides motion analysis using a video capture system similar to the camera system used for gait analysis
The CAREN system provides motion analysis using a video capture system similar to the camera system used for gait analysis.

In the civilian sector, clinical biomechanics labs on the magnitude of the MATC’s lab are virtually nonexistent. One of the primary reasons for this is the current lack of reimbursement for gait analysis. Most civilian clinical gait analysis labs are geared toward pediatrics “because that is what is reimbursable,” Schnall said. She noted there also are some university-affiliated biomechanics labs that are geared primarily toward education and research.

For the amputee population, determining those patients who would benefit from gait analysis is fairly intuitive.

“Obviously, patients who have more involvement, for example, patients with hip disarticulations or transfemoral amputees with contralateral injuries – those would be people who would probably benefit more from computerized biomechanical analysis as opposed to patients with transtibial amputations, which is a little more straightforward with less compounding variables to look at,” Schnall said.

Improving treatment

Within the biomechanics community, which uses gait analysis for clinical and research evaluation in rehabilitation, one of the charges is to identify ways the technology can be used to improve the treatment and rehabilitation process for a range of afflictions, Baum said.

“Right now, the insurance reimbursement issue is probably the biggest thing that the biomechanics community is trying to work with to show that it is valuable information and needed,” Baum said. “Insurance is really only reimbursing for cerebral palsy preoperative and postoperative surgery evaluations, so outside of the cerebral palsy population, there is not much getting reimbursed.”

Valuable technology

Baum noted the level of reimbursement can be expected to change in the civilian sector in the future as the technology continues to be proven to be not only valuable but also imperative. In addition, baum noted that as the technology improves and “you can do more and more faster and faster and cheaper and cheaper, these systems are going to also continue to develop and evolve and be seen in more places.”

Virtual environment lab

 
Specialized high-speed, high-resolution digital video cameras emit infrared light that hits reflective markers and then bounces back to the cameras
To collect gait data, reflective markers are strategically placed all over a patient’s body and the patient begins moving. The cameras, which are specialized high-speed, high-resolution digital video cameras, emit infrared light that hits the markers and then bounces back to the cameras. As the patient walks, a three-dimensional rendition is created and numbers are assigned to represent how the patient is moving.

One additional cutting edge feature at the MATC is a high-tech virtual environment laboratory, known as the Computer-Assisted Rehab Environment or CAREN. The CAREN system, which is one of only eight in the world with only 2 having treadmills embedded in the platform, builds a virtual environment around patients as they perform various activities on a platform. The CAREN system provides motion analysis using a video capture system similar to the camera system used for gait analysis.

Despite the high-tech, cutting edge technology used at the MATC and the gait lab, the most important aspect of treatment focuses on the human aspect. The team approach to treatment with input from all team members is crucial.

“We try and have the clinicians, the primary care providers, participate in the analysis portion or the assessment portion of the gait analysis, and we really consider their input in terms of how we make our recommendations,” Schnall said.

Staff on hand

In addition, having a mix of physical therapists and engineers on staff allows the clinical and engineering aspects to be melded together. However, the most important member of the team is the patient. Schnall noted that although there is a heavy focus on return to duty, if a patient’s goal is “just to be able to get up and walk and go to the restroom, if that is their goal, then that is what we respect, and we try and make recommendations for the optimal prosthesis for them or the optimal alignment for them to be able to achieve that goal.”

She noted that for patients with the same injury and the same type of data but with different goals for themselves, the assessment and treatment plans can be totally different.

“We really listen to the patients’ goals. We need to consider what their goals are,” Schnall said. “They are certainly an integral part of the team.”

Mary L. Jerrell, ELS, is a correspondent for O&P Business News.

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