While trying to climb aboard a train that was pulling out of a station, Kurt Muller fell under the train and caught his left leg in its wheels. He was then fl own to a nearby hospital where they had to amputate his badly mangled left leg below the knee. After two and a half months of recovery and rehabilitation, however, Muller was back at work using a prosthetic leg. “I'm still able to drive my stick-shift car and even ski on two legs, thanks to the DeRoyal below-knee brace,” he says.
Muller, like many other athletes with disabilities, has come a long way from despair and immobility to being recognized as one of the world's fittest and most courageous athletes. With the Paralympics in Athens, Greece, soon approaching, both the athletes and the equipment they will wear are being carefully tested.
The Paralympics is now held for both summer and winter sports. This year in Athens, the world's elite athletes with disabilities will assemble from many parts of the globe to show off their running, lifting, jumping, swimming and shooting skills in 21 sports events. As courageous and determined as they are, however, these athletes cannot do it alone. They must depend on the special equipment and prosthetic devices created by the orthotics and prosthetics (O&P) industry, and they know that without the industry's dedication and progress, success would not be possible.
Because of the diversity of the 21 different sports categories under the Paralympics banner, the equipment range required for the participating athletes can be demanding. Within some sports, such as track and field, there are specific classifications for different levels of amputation. Other sports, such as tennis and basketball, have just two categories: one for wheelchair athletes and one for amputees. Some athletes, such as swimmers and soccer players, will compete without the use of a prosthetic device; however, most athletes will use a modified prosthesis or orthopedic device to improve their performance.
Paralympians rarely suffer from self-pity; in fact, they seem to be a feisty lot. Upper-limb amputees still cycle, swim, and play tennis and hockey. To hold a hockey stick or balance themselves correctly, however, many upper-limb amputees will wear hand, lower-arm or full-arm prostheses. Three types of upper-limb prosthesis have been developed for arm and hand amputees:
- Passive function
The passive function hand or arm is the most popular for active athletes because it is the most adaptable and rugged. Hybrid upper-limb prostheses, such as the mechanical type made by Otto Bock, use cables and pulleys and can be battery-operated.
The myoelectric Utah Arm made by Motion Control, which translates EMG muscle signals from the residual limb to the inside of the prosthesis, is state-of-the-art for everyday use and “light duty” sports, but may be too fragile to use in highly physical contact sports. Several companies offer upper-limb replacements, however, for the active, even rugged, athlete. TRS, Inc., based in Boulder, Colorado, is a leading innovator of body-powered upper-limb prosthetic devices. TRS was formed in 1979 by upper-limb amputee Bob Radocy, who was frustrated by the limited performance of commercially available prosthetic devices. Radocy lost his left hand about four inches below the elbow in an auto accident in 1971 and started experimenting with all types of prosthetic devices while in graduate school. Using his engineering and biological sciences education and design experience, he applied this knowledge to create a high-performance prehensor (gripping device), which allowed him to be competitive with two-handed peers in any activity he chose.
Today, TRS makes a wide range of specialized hand prostheses for the following sports: aerobics/dance, archery, baseball/softball, basketball, bicycling, canoeing/kayaking, fishing, football, volleyball, golf, hockey, pool/billiards, snow skiing, swimming, weightlifting and windsurfing. The hands for the various sports are unique. For basketball, for example, TRS has produced a prosthetic basketball hand that enables the wearer to display safe, quick-action control of the ball during any dribbling, shooting or passing situation. The Re- Bound Pro is strong but flexible, and it provides a unique, resilient wrist/ hand and finger-like type of ball control. In addition, it fits all standard body-powered mechanical prosthetic wrists.
For swimming, the TRS prosthesis design, which mimics a folding wing, reduces resistance during the power stroke. The device can be rotated for various swimming strokes and styles or for aerobic exercise.
For sports in which a grip/release mechanism is required, TRS prehensors can be modified to accept a special “locking pin” accessory, which provides a reliable means of handling a piece of equipment, such as a bow, a golf club or barbells.
A chance water-skiing accident in 1976 turned out to be the catalyst for a revolution in the field of lower-limb prosthetics – a field that badly needed innovation. The loss of his leg just above the ankle transformed an active young American sportsman, Van Phillips, then a 21-year-old student in Arizona, into a frustrated amputee. Quickly determining that the existing prosthetic feet offered in the '70s were inadequate, young Van Phillips teamed up with Dale Abildskov, an aerospace composite engineer, while working at the University of Utah in 1982. According to their plan, a carbon fiber material well-known in the aerospace industry for its superior strength and flexible properties was cut into an L-shaped foot and attached to a sole below and a prosthetic socket above. When weight was applied by landing on the heel, it was converted into energy that literally put spring into the step, simulating the spring action of the normal foot and allowing the wearer to run and jump. The Flex-Foot® concept was born in 1984, and demand for the new foot soared as active amputees across America became aware of its incredible spring and energy-return features. Today, more than 90 percent of amputee athletes worldwide wear some model of the basic Flex-Foot®, and its widespread availability has given amputees the opportunity to run, jump and compete at a new level in the Paralympics.
Ossur, an Icelandic company, manufactures the Flex-Foot® line of prostheses. All premium Ossur Flex-Foot® products are made from 100% carbon fiber, a material used extensively in the aerospace industry for it's superior strength and flexibility. Amputees can benefit from the Flex-Foot® full-length toe lever, simulated ankle motion, proportional response and shock absorption.
It's no wonder that Shea Cowart, Paralympic champion sprinter at 100 and 200 meters, can cover the distance at a remarkable 13.68 seconds for 100 meters and 29.64 seconds for 200 meters (T-43 double below-knee amputee classification). Leading amputee runners like Cowart attach spikes directly to a Flex-Foot® or other carbon fiber custom feet rather than wear a mechanical prosthetic foot inside a shoe. Ossur makes three types of custom Flex-Foot® designs for running: the Cheetah™, a custom foot for track and field sports, the Flex-Sprint™, recommended for transfemoral amputees, and the C-Sprint™ for distance running.
Otto Bock®, another progressive company with offices in Germany, the U.S. and Canada, also has a carbon fiber foot called the Sprinter, which is custom-made for the serious track athlete. It is extremely lightweight with a double-contoured toe for high propulsion and decreased drag.
The company also offers the Gold Medal foot, which is designed for amputees with higher body weights to perform at high-activity levels with more stability. It comes with three removable plugs to provide different stiffness adjustments. The Gold Medal can be used either with a silicone prosthetic cover inside a sport shoe, as in basketball or tennis, or it can be used directly in a sports boot, such as inside a hockey boot for skating.
Ron Mann, a mixed martial arts champion, uses the Venture™ foot made by College Park Industries in Fraser, Michigan, on the regular kickboxing circuit. The Renegade prosthetic foot from Freedom Innovations features an industry-first all-carbon- fiber shock pylon. This unique feature allows maximum shock absorption during vertical loading with an ultra-light design.
Additionally, Freedom Innovations has launched the Ski Foot, which facilitates direct linkage to a ski binding, eliminating the need for a ski boot. This can be considered an advantage for the amputee, considering the additional weight the ski boot represents and the significant limitations on movement it imposes.
The Comfort Factor
The aim of a prosthetic device is to imitate the function of the human body as closely as possible, but unless it is comfortable to wear, it loses much of its intended effect. The interface material used between the residual limb and the prosthetic device is therefore crucial for fitting and as a comfort component to enable the athlete, especially at the Paralympic level, to perform at his or her optimal level.
Fortunately, there is a vast array of socks, sleeves and interface materials from which to choose. Hole-In-One prosthetic socks produced by Knit-Rite offer amputees thicknesses ranging from sheath to six-ply and are made with a distal hole especially for use with pin suspension mechanisms. The knit construction eliminates the need for cutting the sock, helps prevent raveling, and adds little or no additional distal thickness.
Another manufacturer, Royal Knit in Lees Summit, Missouri, makes seamless prosthetic socks in a variety of materials and designs. Royal Knit's socks contain CoolMax® to help with moisture management and Lycra® stretch for conformity.
Silipos®, the leader in gel technologies in the medical field, has introduced a new reinforced version of its popular Explorer™ Suspension Sleeve that offers enhanced flexibility and freedom of movement. Fabricated from the Silipos® proprietary medical-grade Tri-Block Polymer Mineral Oil Gel, the Explorer™ Reinforced Suspension Sleeve incorporates an inner flexible band of fabric for additional durability and is resistant to shear forces and abrasion. The reinforced sleeves are recommended for all activity levels and are designed to easily flex at the knee joint without constriction and without impeding the range of motion.
After three years of research and development, Ohio Willow Wood has introduced the Alpha® AK Liner for above-knee amputee comfort.
This completely new concept offers the following:
- A customized gel pattern for added comfort, eliminating the need to build padding into the socket. The gel pattern protects the often-tender lateral side near the femur and at the distal end, while thinning dramatically proximally.
- A unique Alpha® AK Liner fabric, which provides flexibility, allows easier donning and doffing of the liner, and offers enhanced comfort. • A selection of sizes especially designed with the variety of above-knee shapes in mind.
There are several other companies offering complete ranges of prosthetic liners and sleeves for amputees. Alps Products in St. Petersburg, Florida, lists an impressive chronological string of industry firsts in gel valve-integrated sleeves and liners.
Iceross® silicone liners from Ossur mean you don't have to compromise. These liners stabilize soft tissues, minimize stretching, improve circulation, add comfort, and offer durability and intimacy of fit for amputees at all activity levels.
Whether it's a mechanical foot, prosthetic arm or sports-specific hand attachment, there seems to be something unique available for athletes with disabilities in every sport. Moreover, if it's not available today, the dynamic O&P industry's enthusiasm, drive and innovation will make it a reality for the Paralympic athlete of tomorrow. When it comes to sports equipment for the world's leading disabled athletes, one can honestly say that they are not at a disadvantage.