Understanding Prosthetics

Prosthetic devices are an invaluable tool in an amputee’s path to recovery, allowing them to return to their daily habits. We utilize state-of-the-art technology to produce a vast array of the highest quality prosthetics and ensure that “Live Life Without Limitations” is a motto and a reality for all our patients.

People with limb loss are a small group statistically – just under one-half of one percent of the U.S. population. As a result, the world of prosthetics remains unknown to most people until they are confronted with it directly.

A prosthesis is an artificial device designed to replace a missing part of the human body. The prosthesis consists of three major items: (1) the interface – also called the socket — which fits over the residual limb; (2) the components including feet, knees, hands, and more; and (3) an optional cosmetic cover for the prosthesis. The interface is typically made of plastic and carbon-graphite to provide both comfort and durability, and is custom-designed and fitted to your unique anatomy by the prosthetist. Prosthetic components are then attached to the socket to create the full prosthesis.

Virtually all below-knee amputees and upper-extremity amputees and many above knee amputees wear a soft liner between their socket and their skin. The liner provides added cushion, helps prevent pull on the skin, may provide suspension to hold prosthesis on the residual limb and otherwise protects the residual limb. The liner may have a pin at one end that locks into the socket for a secure fit.

While one prosthesis will permit you to perform all of your normal activities of daily living, A Step Ahead Prosthetics also specializes in designing prosthetics for specialized activities like running, cycling, swimming, and skating. Whatever the activity you want to participate in, we can design a prosthesis for it.

If you are a new amputee, you may have been told by medical professionals or other amputees that you will initially get a “preparatory prosthesis” that will be followed by a “definitive prosthesis” within three to six months. At A Step Ahead Prosthetics, the only thing preparatory about your first prosthesis is the prosthetic socket. This initial socket must be replaced three to six months later because of significant maturational changes (e.g. reduction in post-surgical swelling, increase in muscle mass) that take place in your limb after you begin wearing your prosthesis.

At A Step Ahead, we see no advantage in providing a full preparatory prosthesis (i.e. temporary socket and temporary components) made of less-expensive, lower-quality components. This commonly-accepted practice forces you to learn how to use a prosthesis twice and is discouraging because the first prosthetic is low quality. In contrast, we give you the “definitive” components from Day 1 so that you can begin your rehabilitation with the best tools available.

If you are a new lower-extremity amputee, you will begin walking between parallel bars for maximum support and safety. From there, you will progress outside the bars with crutches, and subsequently, to a cane and/or independent walking based on your individual needs and skills.

While you are walking, the prosthetist will assess your gait and fit to adjust your prosthesis as needed. Potential adjustments include the height of the prosthesis, its alignment, and socket modifications. The prosthetist may make adjustments to all of these things multiple times throughout the day if necessary. Your progress, comfort, and physiological needs will determine the modifications needed.

Most lower-limb prosthetics are held in place either by a pin locking system or a suction system. Depending on how recent your amputation surgery was and the condition of your surgical site, the prosthetist may elect to use non-permanent devices as an auxiliary means of suspension to keep the prosthesis on your limb initially. These devices include a belt, strap, or sleeve. No two people are alike, so your needs and the treatment you receive will be unique.

The prosthetist and a physical therapist will train you over the course of several hours, taking frequent breaks either for adjustments and/or to give you a rest. As a new amputee, the act of learning how to walk again may be exhausting, so you will probably welcome the frequent rest periods.

At the end of the visit, the prosthetist will tighten all of the attachment points and components of the prosthesis and instruct you about what to do before your next visit. If necessary, your doctor will be contacted so that your care is coordinated effectively between medical disciplines. In addition, at the appropriate time, we will speak with your physical therapist as part of your rehabilitation regimen.

Even if you are not able to walk in the prosthesis a great deal while at home following delivery, it is important that you continue to wear it all day, even if you are only sitting. This will help shape your residual limb and get you acclimated to the socket, reducing your total rehabilitation time.

Upper extremity amputations include finger and partial hand amputations, wrist disarticulation, below elbow, elbow disarticulation, above elbow, shoulder disarticulation and forequarter amputation. Regardless of the level of amputation, your prosthetist will strive to supply you with a comfortable, functional, and cosmetically pleasing prosthesis.

Like a lower-extremity prosthesis, an upper-extremity prosthesis also comprises a socket and components. Before you are fitted for your prosthesis, your prosthetist will show you how to wrap your residual limb to decrease swelling just as is done for lower-extremity amputees.

The socket design depends on the type of suspension used: suction, bony lock, or harness. Full suction is more secure, reduces harnessing, and provides greater ability to sense the position of the prosthesis (proprioception). With full suction the prosthesis feels lighter. Bony lock suspension may be used for those with wrist disarticulation and below elbow amputees. It is easy to put on and remove but may feel less secure than a suction lock. Harness suspension can be used for any upper-extremity prosthesis. It is less expensive and very reliable, but is not as natural-looking.

The terminal device is the part of the prosthesis that acts as the missing hand. A passive device provides cosmesis only and is not functional. Hooks are light and provide a good line of sight, making it easy to see where the hand is and what it is doing; however, they do not look natural. A prosthetic hand is used with a body-powered or myoelectric prosthesis and incorporates cosmesis and function. Both a hook and hand may be power-assisted.

Upper extremity amputees have four options for upper extremity prosthesis; Passive prosthesis, body-powered, myoelectric, and hybrid systems:

A passive prosthesis can be used by individuals who want nearly life-like cosmesis or who have a high level amputation and want a lightweight prosthesis for cosmetic reasons. While they are lightweight, they are not functional.

In a body-powered prosthesis, the components are controlled by gross body movements through a system of straps and a harness. The harness doubles as a suspension aid.

Myoelectric prosthetic components are controlled by voluntary muscle action through an electronic signal. Electrodes built into the socket pick up electrical signals created when the muscles contract; those signals are then amplified and sent to a computer in the prosthesis to create a specific movement by the prosthesis. Myoelectric prostheses provide the greatest amount of control of the elbow, forearm, and hand and require the least amount of strength to use.

The hybrid system combines body-powered and myoelectric components, such as a body-powered elbow and a myoelectric hand. This combination reduces both the weight of the prosthesis and its expense.

Early fitting of an upper-extremity prosthesis and encouragement in using both the natural and prosthetic hands equally help increase the chances that a person will be comfortable and functional with the prosthesis. Children with upper-extremity limb deficiencies should be fitted as early as possible. Rehabilitation with a physical or occupational therapist with expertise in upper-extremity prosthetics should begin as soon as possible to prevent joint contractures, reduce surgical edema, and prepare the limb for the prosthesis. Strengthening exercises for the residual limb help increase ability to accurately control the hook or hand (counteract pendulum effect).

If this is your first prosthesis, the only constant is change. The socket that felt comfortable twenty-four hours earlier is likely to feel different. You are experiencing pressure in areas where there was none previously. Why does this happen? Because your residual limb changes as you use your new prosthesis.

Specifically, all of the post-surgical swelling in your limb will lessen as you continue to wear the prosthesis. At the same time, muscles that may have atrophied as a result of your relatively inactive post-surgical lifestyle will begin to grow again. These factors change the way your prosthesis fits from day to day, and in some instances, from hour to hour. You can expect these changes to lessen over time. Most patients’ residual limbs stabilize three to six months after receiving their first prosthesis. Once this happens, the prosthetist will begin fitting you with a new inner socket (commonly called a “permanent” socket) that better fits your changed limb.

Even if you have been wearing a prosthesis for years, delivery of a new device necessitated by normal maturational changes to your residual limb undergoes an adjustment period. While your limb does not change shape as dramatically as a new amputee’s, you still need time to acclimate to the new fit, which often shifts pressure to different parts of your anatomy.

An important part of successful post-delivery rehabilitation depends on your ability to effectively communicate what you are feeling while wearing the prosthesis. If you are experiencing poking, pinching, irritation, pressure, or skin breakdown, we need to know. We cannot help you if we are unaware that there is an issue!

This is not to say that wearing a prosthesis is always a comfortable, problem-free process. Especially as a new amputee, there is a certain degree of discomfort that you will experience as your body adapts to bearing weight on soft tissue and bony areas that never had to before. However, the more you wear your prosthesis, the shorter this transition period will be. In addition, close communication with the prosthetist can lead to suggestions and adjustments that help minimize both the duration and intensity of discomfort.

DO NOT EVER MAKE ANY ADJUSTMENTS TO YOUR PROSTHESIS YOURSELF! A prosthesis is a sophisticated device that requires professional training and extensive experience to safely modify. Acting as your own prosthetist places you at significant risk for serious bodily injury, voids applicable manufacturers’ warrantees, and potentially exposes you to significant out-of-pocket expenses for any repairs/replacements that need to be made as a result. If you are experiencing problems, make sure to contact your prosthetist for a safe and effective remedy.

Following the delivery of your prosthesis, subsequent visits will focus primarily on continued gait training, socket adjustments, and alignment adjustments. Intensive physical therapy with a qualified physical therapist may begin as early as the day of delivery of your prosthesis.

The importance of physical therapy cannot be overstated. A physical therapist will help you regain strength, improve balance, improve cardiovascular endurance, teach you how to use your prosthesis on steps, ramps, and uneven terrain, how get up and down from the floor, and teach you how to be safe in many different situations and physical environments. Research shows that amputees require dramatically more energy to walk at even half the speed of able-bodied individuals. Therefore, an aggressive gait training program as well as aggressive stretching, strengthening, and a cardiovascular program is an important part of your rehabilitation. These activities permit your heart and lungs to operate more efficiently, permitting you to wear and use your prosthesis longer without getting as tired as you otherwise would. If you have other medical issues that make this type of physical therapy regimen impractical, we will speak with your doctor to design a program that is appropriate for you.

At A Step Ahead, we know that successful outcomes require more than a good prosthesis and basic gait training. A comprehensive, multi-disciplinary approach to patient care that includes high quality physical therapy provides patients the best opportunity to achieve their functional goals.

Whether your goal is to be able to walk your dog down the block or complete a triathlon, your access to the experience and expertise both of our prosthetic staff and the referrals to the appropriate therapy will help you reach your goals.