Since the beginning of the Overseas Contingency Operation, nearly three fourths of all service members seeking care for amputated limbs have been treated at Walter Reed National Military Medical Center (WRNMMC), which has made the hospital world renowned for prosthetic device implementation, especially with prosthetic legs.
Unrestrained by the politics and financial burdens of a civilian health care system, WRNMMC is able to provide an unchallenged level of amputee care and “bring back normalcy,” said David Laufer, the director of Orthotic and Prosthetic Services at WRNMMC. “We try to return Soldiers, Sailors, Airmen and Marines to the level of activity that they enjoyed prior to their injury as quickly as possible.”
For amputees, time is of the essence. When a person is confined to a wheel chair or bedside due to loss of limb, it becomes impossible without a prosthetic device, to exercise certain muscle groups. This can cause muscular atrophy which can greatly increase recovery periods and make muscle growth far more difficult to achieve, said Laufer.
“We tend to get [patients] as soon as their sutures are taken out and their surgeon allows them to take weight, which is typically 4-6 weeks after a patient has left the battlefield,” said Certified Prosthetist and Orthotist, Mike Corcoran. “In the civilian sector, you’d be looking at about two weeks before the first piece of prosthetic equipment is fitted and ready to go. Whereas here, if we start [our first session with] them in the morning by 7 o’clock we can have them take their first steps by one in the afternoon”
Regardless of the speed at which prosthetics are delivered, each device is unique and tailored to the specific amputee. Expert care and precision are required through constant sessions of fittings and repair.
Of the many parts that make up a prosthetic limb, the socket is the first the piece to be made. This component remains in direct contact with the patient via suction over the residual appendage and holds the prosthetic in place. In order to maintain a cohesive bond between the patient and the prosthetic, the cast must be formed to create a tight seal.
A variety of socks and silicone liners can be used to make up for slight change in its size, because each amputee’s limb is different depending upon the person and site of severance. Anything less than a perfect fit can cause the socket to be loose and make walking impossible or cause serious pain to the wearer. As time goes on, swelling from surgeries will decrease the size and continued use of muscles will tone and shape them, necessitating totally new sockets.
New amputees will start with hard plastic sockets and these can be adjusted and molded with a blow torch. The sockets still require replacement every six weeks and are generally considered too weak for long term use. “A patient will go through about six plastic sockets,” said Corcoran.
After about 6 months the residual limb will begin to stabilize in size and a carbon fiber socket can be made. Carbon fiber sockets are much lighter than plastic and are 10 times stronger than steel. However, they are inflexible, which means when a limb changes size, a new cast will have to be made. It is for this reason that Walter Reed Bethesda also continues to provide care for veteran amputees long after they have left the service.
Just beneath the cast sits the attachment plate, connecting the prosthetic user to the moving joints of the device. While it seems to be a simple device, “the plate isn’t attached in any old fashion,” said Corcoran. “When [a patient] is standing on the prosthetic, you want the weight positioned directly in the middle of the plate.” This placement requires prosthetist to understand the shape of the limb, it’s center of gravity and the natural gait of the patient. If the plate is off center, it will cause the downward force to be uneven, hindering a service member’s ability to walk and causing serious pain, said Corcoran.
The moving joints are the most complex portion of any prosthesis and can vary depending upon the patient’s level of amputation. No single device can replace all the functionality of a naturally operating leg. A variety of components are required in order to replicate the performance from different actions covering every part of the leg including the foot, knee and hip.
In a normally functioning leg, calf muscles and ankles are what propel us forward as we walk, so prosthetic feet must fulfill much the same function. While there are over 90 different kinds of feet, most are made of carbon fiber frames, curved in the shape of the letter “J.”
According to Corcoran, “when the person [steps forward] and their body weight compresses that prosthetic foot, as soon as they finish the end of the step, the energy that’s stored up in that carbon spring is released and that’s what propels them forward.”
Carbon fiber feet are known as passive feet, due to the fact that these carbon fiber springs do not produce any force greater than the weight placed upon them, meaning that amputees must actually expel 50 percent more energy than a person with legs in order to walk. However, “we now have powered feet which use batteries to propel the user forward,” said Corcoran. “These normalize effort and allow below the knee amputees to expel no more energy than a normal intact human.”
Patients, whose leg no longer contains an operational knee joint, are known as above the knee amputees. These patients lack the ability in at least one leg to cushion the fall from each step and require prosthetic knees.
There are currently three different types of knees used for these amputees and can be found in patients at Naval Support Activity Bethesda: mechanical knees, microprocessor knees and powered knees. A mechanical knee, much like a passive foot, must be swung into position, requiring a great deal of effort and energy expenditure by the patient. However, powered and microprocessor knees both contain computers which monitor gyroscopes to place the leg in the correct position for constant forward momentum.
In the past, patients would begin working with mechanical knees in order to become familiar with the available devices. However, today, those with at least one naturally functioning knee joint benefit from WRNMMC’s unique approach to prosthetic training. From their very first day in prosthetic rehabilitation, they are given powered legs. These legs are motorized and propel the prosthetic forward naturally, with little to no instruction.
“When we get someone in powered legs for the first time, we just tell them to stand up and start walking like they did before their injury,” said Corcoran. “The knee is that intuitive. You don’t have to learn how to use it.”
The practice has greatly advanced recovery times. Many patients are now able to skip an interim period of four to six weeks walking with cane assistance and begin walking using prosthetics independently in half the time. “We’ve fit around 15 patients this way and the results have been just tremendous,” said Corcoran.
If both of a patient’s legs have been amputated above the knee, they have far less contact with the ground and receive more specialized care as a result. These patients are placed first in ‘Shorties,’ or legs with no prosthetic knees. The casts are connected directly to prosthetic feet which allow amputees time to work on their core strength and balance, until they are ready to utilize full prosthetic knees.
In addition to supplying these devices, Walter Reed Bethesda has adapted a wide range of prosthetics to suit the needs of wounded warriors. “We have, in conjunction with several companies, to develop several devices for specific applications,” saic Corcoran. “Recently, we adapted a knee that was made for skiing so that it could by used for bicylcing. Our staff worked together and changed the hinge and the pneumatics so that when you were riding a bike the leg constantly pushes down allowing them to pedal.”
These prosthetics allow service members opportunities never before thought possible. Many are using their prosthetics to return to an independent lifestyle, like Capt. Edward Klein, who took pride in standing at his best friend’s wedding. Others are using their prosthetics to lead more active lives than they had before, like professional runner Spec. Luis Puertas, who was able to compete in the 2013 Paralympics World Championships in Lyon, France.
“I have a couple of legs for different things, that pretty much let me do whatever I want,” said Staff Sgt. Nicholas Lavery. “I’ve got one for cycling, boxing and jujitsu. I do a lot of mixed martial arts. I just use different knees and feet for different activities.”
“This stuff is really amazing, but we know it doesn’t replace what was lost,” said Corcoran. “We’re trying to partner with prosthetic manufactures to get as close as we can to the real thing, and we’re doing a whole lot better than we were 5 years ago.”