Lower Limb Amputation

Are there any mobility exercises that should be performed for the lower limb amputee shortly after surgery?

Mobility for a lower limb amputee is an important issue. Shortly after surgery is completed and as long as the person is medically stable, both physical and occupational therapists can begin giving the new amputee techniques that will help improve mobility. One of the first skills taught to the amputee is how to move around in bed. A new above- or below-knee amputee may find it difficult to move in bed, particularly if surgery caused them to become weak and deconditioned. Even though the patient may not want to move because of pain and fatigue, bed mobility is extremely important since it prevents the development of pressure sores that can lead to secondary problems like infection, further surgery and limb loss. One way a new amputee can move in bed is with the use of a trapeze. A trapeze is an apparatus that may be attached to the person’s bed and hangs over his head. This trapeze gives the new amputee the ability to grab onto something and if he is strong enough to move his body in bed, thereby relieving skin pressure.

Another important mobility technique taught by the rehabilitation team is the single leg pivot shift transfer. A transfer simply means that the individual is moving from one place to another, such as from a bed to a wheelchair or toilet. A single-leg pivot shift transfer involves having the new amputee stand on the sound limb and turn his body in order to comfortably sit onto a new surface. Often, especially if the individual is weak or unsteady, this type of transfer needs to be done with the assistance of a therapist or nurse (Figure 23). If the person has both lower limbs amputated or is too weak to use a single-leg pivot transfer, then an alternative method of transfer can be tried using a sliding board.

With this technique, a sturdy board is placed between one surface, such as a wheelchair or bed, and another surface, such as a shower chair or toilet. It is important that the two surfaces be relatively level so that the individual can slide himself across the board to the other surface. In this way, the amputee does not require lower limbs or a prosthesis to move from one surface to another.

Additional techniques can be taught for activities of daily living which consist of dressing, bathing, toileting and eating. Typically, an occupational therapist proves to be a vital component of the rehabilitation team and can show the new amputee how to perform these ADLs. Occasionally, especially if the individual has a concomitant medical problem such as a previous stroke or arthritis, then adaptive equipment such as a sock donner, reacher or shower chair may be necessary. Certain body positions such as the bridge maneuver described above can be an ideal position in which an amputee will be able to pull up underwear or pants. It should be noted that if an amputee is unable to put on pants by himself then it is unlikely that he will be able to put on a lower limb prosthesis independently.

What are common parts of a lower limb prosthesis?   

One of the first prosthesis used may be an IPOP which is discussed above. After a few weeks though, the individual may be ready for his initial prosthesis. Various components make up a prosthesis. In general, most lower limb prostheses consist of the socket, suspension system, skeleton or frame, joints (hip, knee, ankle) and foot. The type, durability and expense of these components vary depending on the type of residual limb as well as the age, related medical problems and activity level of the amputee. For example, some types of sockets incorporate a brace also known as an orthosis into the socket. This is done so that contact is maintained between the prosthesis and the residual limb. This type of socket-suspension system is sometimes used in adults with unusual residual limbs or who require added support or stability.

In individuals with transfemoral amputations, a quadrilateral or an ischial containment socket is often used. The ischium is another term for the bones of the pelvis that we sit on. In an ischial containment socket, there is better contact between the residual limb and the prosthesis because the ischium is held within the socket together with the residual limb. This allows a better distribution of the weight from the body onto the lower limb as well as providing better stability and muscle function. The quadrilateral socket is named because it has four sides making up its walls. Each wall has certain advantages that enable a transfemoral amputee to walk more effectively and comfortably. It is variable which type of individual with an above-knee amputation uses which type of socket.

Various suspension systems that keep the prosthesis held onto the residual limb are available. One type of suspension system uses one of two types of belts either known as a Silesian belt or Total Elastic Suspension (TES) belt. The Silesian belt anchors to the socket on its outer aspect and then wraps around the person’s pelvis, opposite hip and then reattaches back to the anterior socket. The TES belt is different than the Silesian belt. It is made from elastic neoprene and is worn around the waist. Because of its ability to retain body heat, it can be quite warm in hotter climates or during the summer months. Fortunately, both of these suspension devices can be adjusted in size for comfort.

A different type of suspension is referred to as a suction suspension system. There are basically two types of these suction devices, the first being the traditional suction suspension. With this type of suspension the residual limb is pulled into the socket using a donning sock. The donning sock is then pulled out through a valve hole leaving the residual limb snugly in the socket. After the valve hole is sealed, a negative pressure system is created and the limb is held into the prosthesis via a vacuum phenomena. With this system, there is better contact with the prosthesis and less motion that occurs while the limb is in the socket. Excessive motion can be uncomfortable and lead to skin breakdown and blisters, which are obviously not good things particularly if the individual has PVD.

If the person does not have the strength or dexterity to pull the sock through the valve hole, another type of suction device known as roll-on silicon suction suspension can be tried. This type of suction system uses a silicon sleeve rolled onto the residual limb. The outer portion of the silicon sleeve is lubricated and placed into the socket. Once all of the air is displaced out of the socket, the valve hole is then covered, maintaining suspension via a vacuum system. The disadvantage of this system is that the silicon can be hot and the residual limb can become sweaty. Additionally, the residual limb must be of a consistent size and not be swollen. This can be a problem in people who have heart failure or who have kidney failure and require dialysis as these medical problems cause the limbs to fluctuate in size. These suction systems can also be used in conjunction with some of the belt systems described above for added security.

If an individual does have fluctuations in the size of their residual limb, there may be times when the limb may not fit adequately into the socket and the prosthesis will need to be replaced. However, one way to prolong the fit of the socket on a changing limb is to use a flexible socket made of plastic material that can be heated and remolded so as to improve fit. Additionally, slip sockets may be used. A slip socket has one or more thin inner layers or liners that can be peeled out of the socket to accommodate the expanding limb. An individual may also use socks to help improve the fit and longevity of a socket. These socks are made of a thin cloth material that can come in different plies (thicknesses) and when the residual limb changes, the sock ply can be adjusted allowing better fit of the residual limb in the socket.

What are some important things lower limb amputees should know about wheelchairs?

Reliance on a wheelchair varies; some people use one immediately after surgery in the hospital while others continue to rely on one after they return home. Some people may only really need to use a wheelchair for long distances, such as for shopping or for getting around the neighborhood. Although some may equate the use of a wheelchair with disability, it is important to stress that its use right after surgery can serve multiple purposes. First, it provides a means for the patient to get around the hospital either by having someone push them or by propelling their own chair. A person must realize, though, that using his arms to propel the chair puts more stress on the cardiac system than normal walking and he probably needs to go at a slower pace to avoid that stress. The other added advantage of using a wheelchair is that it will help strengthen the arms. Having strong arms helps support the patient when he first attempts to walk with a prosthesis.

A wheelchair that has a large wheel axle set behind the seat is very helpful for an above- knee amputee. Some wheelchairs will even come with anti-tipping bars extending out from the back of the wheelchair. These two features are needed because the amputee no longer has legs to counterbalance the weight of the torso. When all of the weight of the torso is towards the back of the chair, it can cause the chair to tip backwards leading to injury. One shouldn’t forget though that if they spend significant amounts of time sitting, they may be at risk for developing a contracture at the hip which may prevent one from wearing a prosthesis. Below-knee amputees should remember to keep the knee straight while sitting in a wheelchair to prevent contractures.

Another important safety measure is always to lock the wheelchair when getting in or out of it to prevent the chair from rolling away.

How does a lower limb amputee get up off the floor after a fall?

A fall for a lower limb amputee can be a very scary experience. The reason is that it may be difficult for many people to get back up on their feet once they fall down. In addition, the fall may cause an injury that may even make it harder to get up when using prosthetic limbs. For this reason, one of the goals of therapy should be to teach amputees techniques on how to get up after a fall. Various ways to do this exist.

Which are more common, lower limb or upper limb amputations?

In the United States and most industrialized countries, lower limb amputees tend to be more common than upper limb amputees.

Why do patients with cardiac disease have a difficult time using a lower limb prosthesis?

Studies have shown that when someone walks with a lower limb prosthesis, it takes a higher amount of energy as compared to normal individuals who walk at the same speed. This energy expenditure translates into greater stress on the heart. For example, when a below-knee amputee walks with a prosthesis at a certain rate of speed, it puts more stress on the heart than compared to a person with two normal limbs. Additionally, an above-knee amputee walking at that same speed has an even higher rate of cardiac stress. Bilateral above-knee amputees create even higher demands of stress on the cardiac system. Because of this increased demand, it is easy to see why some amputees, especially if they are older or have heart disease, will have a difficult time walking with a prosthesis. Lower limb amputees, especially if they have severe cardiac disease, should discuss the ramifications of trying to walk with a prosthesis with their physicians.

If an amputee decides not to walk, that inactivity may create a vicious cycle. He may end up without any form of physical activity or exercise, leading to further deconditioning and worsening of the heart disease. It is important, therefore, that all amputees seek some form of aerobic exercise in order to stay fit and reduce the risk of cardiac disease.