ENDOLITE
Prosthetics

Rehabiltation

The Clinic

The members of the rehabilitation team are professionals in their specific area and you will find that they are happy to answer questions regarding your treatment and to provide you with information including details of support groups and special interest topics. A valuable part of the rehabilitation process is the interaction with other amputees and their families. The firsthand experiences of established amputees can provide not only understanding and support, but a wealth of tips on living with your prosthesis. This is also a good time for your family or carer to talk through some of the issues of concern to them.

Doctor

You will be assessed first by a doctor, specialised in rehabilitation, who will note details of your medical history, current medical needs and impairment status: i.e. position of amputation and condition of the stump (residual limb). The doctor will also be interested in your lifestyle and expectations so that the choice of prosthetic treatment and rehabilitation can be assessed accordingly.

Prosthetist

The prosthetist is trained in the design, fabrication and fitting of artificial limbs (prostheses). He/she will be interested in the condition of your stump, your general fitness and your prosthetic requirements so that preparation of your first prosthesis can begin. The working relationship and communication between you and your prosthetist is important as you will be involved with them on a long term basis for prosthetic care and maintenance, necessary adjustments and future prostheses as required.

Physiotherapist

The physiotherapist will co-ordinate your early limb care and mobility programme and will teach you how to walk on your new prosthesis (gait training). You will probably have started treatment with a physiotherapist very soon after surgery when you will have been instructed in suitable joint and body positioning so as to maintain good range of limb movement.

Occupational Therapist

The role of the occupational therapist is to ensure that you are suitably prepared for your home and, if applicable, work environment. This may entail visits to your home for assessment purposes as you may need some additional equipment to assist you with mobility and safety around the house. If you will be using an upper limb prosthesis then the occupational therapist will train you in efficient use of the prosthesis.

Nurse

The nurse will check your personal details including blood pressure and weight and will ensure that any limb dressings you may be using are satisfactory. If you have a medical condition which requires regular treatment such as diabetes, then be sure to tell the nurse so that treatment is not forgotten whilst at the clinic.

Amputation Level

The position on a limb at which an amputation is carried out depends on a number of factors:

· the reason for which amputation is required

· the condition of the bone and tissue above the problem area

· the amount of tissue required to provide a ‘flap’ to cover the end of the amputation site

In all cases the surgeon will try to limit the number of joints which are removed since these play a major role in mobility and limb function. Because of the importance of joints to limb function, amputation sites were traditionally referred to in terms of their position relative to a joint: hence names like Above Knee and Below Knee Amputation. It is current thinking that the names given to impairment levels should more accurately describe the position on the body. Some of the most common are listed below:

Assessment

You will attend for your first assessment with your Rehabilitation Doctor. The doctor will provide you with some introductory information on suitable prostheses. He/she may check your stump to see how the healing process is progressing and to assess dimensions which will affect prosthetic choice. Your lifestyle, medical history and general health will be discussed and some other members of the clinic team may come in to discuss your initial rehabilitation and choice of prosthesis with which to begin your gait training. This is a good time to bring up some of the queries you may have; it is normal for people to have lots of questions at this stage. If you have very personal or sensitive questions, which you find difficult to ask right now, there will be plenty of opportunities later on when you are more accustomed to the staff and the clinic environment.

Residual Limb Care

In the early stages after amputation there is a considerable amount of tissue swelling in the residual limb as a result of the surgical procedure. This is not a good time to fit a permanent prosthesis as it would become loose in a matter of days. It is usual to employ a shrinkage device to speed up the reduction of swelling, these devices include rigid dressings, shrinker socks, controlled environment therapy, preparatory prostheses and pneumatic pylon devices. The choice of shrinkage device will depend on impairment level, general health and treatment environment but some form of shrinker must be worn when not in bed.

• The rigid dressing is a plaster cast which is applied to the residual limb over some socks which maintain both comfort and compression. It provides a means of assisting shrinkage whilst providing protection and allowing some weight bearing on the limb.
  
• Shrinker socks are elasticated socks, which come in a variety of sizes to suit most trans tibial and trans-femoral limbs. The size of the shrinker sock should be reduced according to the rate of shrinkage so that adequate compression is maintained.
  
• Controlled Environment Therapy entails encasing the stump in a sterile air bag with a control unit, which maintains a pattern of predetermined air pressure and temperature settings around the healing limb. The system permits even compression loading over the skin and the transparent pressure bag allows observation.
  
• A preparatory prosthesis is a basic limb which allows early mobility and training to begin. It will usually have a foot and pylon attached to a socket. Socks provide a comfortable interface between the skin and the socket and extra socks can be worn as shrinkage occurs. Though this limb may not be particularly cosmetic it does play a valuable part in enabling a new amputee to resume walking.
  
• The pneumatic pylon device is a basic limb pylon which has an inflatable tube into which the stump can be fitted. Once in position the device is inflated to a level at which adequate weight can be transferred to the impaired limb for mobility. The device is usually used in the physiotherapy department since the amount of pneumatic pressure on the limb tissue must be carefully monitored.

Skin Care

Good skin integrity is most important for successful use of a prosthesis and an individual programme of skin care should begin once the initial dressings and sutures have been removed. Getting used to seeing, touching and caring for your residual limb is an important part of the healing process. It is important to maintain good hygiene and washing the limb daily in mild cleanser and water will help to ensure that the scar tissue is kept clean. The skin should be dried carefully before putting on any shrinkage device or prosthesis. If you notice any broken skin or areas of redness be sure to notify a member of the medical staff. A daily routine of limb massage will help make the stump feel less sensitive. The medical staff can advise you on a suitable lotion which will reduce friction and this will help your hands to move across the tissues smoothly and deeply so that you can gradually begin to tolerate more pressure on the limb, particularly on the scar area. The aim is to keep the tissues mobile since adherent tissue may cause problems later with the prosthesis.

Exercises

The maintenance and improvement of muscle strength and joint mobility are essential for successful rehabilitation. After amputation the remaining limbs may be required to work harder so care should be taken to look after your body and ensure a healthy diet and good general fitness. Your physiotherapist will provide you with a varied programme of exercises, designed to increase muscle strength and encourage joint usage and which will prepare you for the next stage of rehabilitation: prosthetic training.

Limb Positioning

Keeping the joints near the amputation site mobile is of utmost importance during the early days of rehabilitation. Our natural instinct is to curl up and protect ourselves when we feel pain. After amputation, however, the joints need to move so as to retain a good range of motion.

:) Things to do!

Lying frequently on your tummy will help straighten the hips and is beneficial for lower limb amputees.

Trans-tibial amputees should use a limb board on which to rest the stump whilst sitting in a wheelchair, this will help keep the knee joint straight.

:( Things to avoid!

Do not lie with a pillow under the stump or lower back as this will encourage a reduction in hip joint motion.

Avoid lying or sitting with the knee bent.

Don’t place a pillow between the legs as this causes tightening of the muscles on the outside of the limb.

Prosthetic Programme

Prosthetic limb design will vary from person to person depending on activity needs, general health and physical ability, impairment level and the length and condition of the stump. The number of component parts will usually increase with higher levels of amputation so that levels above trans-tibial will require a prosthetic knee joint and levels above trans-femoral will require both prosthetic knee and hip joints.

The Socket

The part of the prosthesis which usually interfaces with the body is called the socket. Since the other components of the prosthesis are attached to the socket it needs to be made from light, strong, formable materials such as thermo plastics, polymer laminates and metal alloys.

Sockets are designed so that weight bearing is proportionally distributed over a large area of skin tissue which is pressure tolerant. Obviously one would not want to take much weight at the cut end of bone as the skin cover would quickly become damaged and painful. Many socket designs include a soft liner material which improves comfort and may also be used to maintain the prosthesis on the body.

PTB Socket

In the trans-tibial socket a commonly utilised weight bearing area is the tendon just below the knee cap. This results in a Patellar- Tendon-Bearing (PTB ) socket which has a distinctive triangular shape. The socket is fitted with a soft light foam liner and is worn over a sock. Suspension may be provided by:

• extending the socket to hold on over the knee joint (supracondylar PTB)
• attaching a cuff strap, which will tighten above the knee to hold the limb on securely
• adding a thigh corset and external knee joints that suspend the limb, help to stabilise the knee and may relieve socket weight bearing

Trans-tibial Socket with Polymer Liner

In order to improve interface comfort between the skin and the socket much recent development has been carried out on producing socket liners from various polymer formulations. These liners not only cushion the loading on tissue but their airtight structure and surface tackiness provide good suspension properties.

The method of donning this type of liner usually requires that it is rolled up onto the residual limb and a lubricant may be necessary to ease the process.

• Silicone sleeves are rolled directly onto the skin and have a lock on the end to attach into the socket. The air lock and surface friction created between the skin and the sleeve prevent the limb from slipping off.
• Gel liners have a soft elastic surface and improved tear strength to that of silicone sleeves whilst suspending the limb in a similar fashion.
• Urethane liners have the best flow characteristics and are therefore very comfortable but may require an additional device for limb suspension.

The positive properties of these liners are counterbalanced somewhat by issues of weight, tear strength, price and donning process and prescription choice will vary accordingly.

Trans-femoral Sockets

In the trans-femoral socket weight is usually distributed over the whole surface of the stump but with particular emphasis on the pelvic seat (ischium). The top of the socket is formed in a snug fitting shape around the hip, gluteal and groin area to ensure comfortable weight bearing and to prevent rotation of the socket on the residual limb. There is a variety of ways in which to maintain the socket in position:

• Suction suspension: the socket is designed to be an intimate fit so that an air lock is created between the skin and the socket which maintains the socket in position. This type of socket requires that the residual limb be pulled in using a bandage or sock, which feeds through a valve hole at the end of the socket. The hole is then plugged with a one way valve.

• Polymer liner suspension: an intimately fitting liner maintains a suction fit with the residual limb whilst a lock pin on the end of the liner locks into the socket and suspends the prosthesis.

• Belt suspension: there are various belts such as the TES belt and the Silesian belt which go around the pelvis and maintain the prosthesis in position.
• Hip joint and pelvic band: if there is some instability present then an external hip joint and belt is utilised to provide both suspension and a hip stabilising function.

Walking

Gait is the term used to describe the process of walking. It comprises two basic phases:

Stance Phase

The period from heel strike to mid stance and through to toe off, when the body weight is supported on the leg. In stance phase the prosthesis will be expected to support the entire body weight and if one is walking quickly, momentum will increase these forces to well above body weight. As an example if the user weighs 65kg (~143 lb) then, as the speed of walking and therefore momentum increases, the weight going through the prosthesis could be as much as 104kg (~229 lb).

The components which make up a prosthesis must be strong enough to withstand the frequent application of very high loads which one would expect to occur in normal walking, and yet have the ability to cushion impact so as to reduce jarring.

Component weight is an important factor in the design of a prosthesis since the use of lighter components will normally require less energy expenditure for mobility. Modern prosthetic components take advantage of a number of materials developed for the space industry such as: carbon fibre, which has a high strength to weight ratio, and polymers, which can be manipulated to give a variety of properties from cushioning to flexibility in structures.

Where possible, components which go into building a prosthesis will be designed to function without expending excess user energy and to return energy when required, such as an element of push off as the prosthetic toe leaves the ground.

To maintain the knee joint in a stable position during weight bearing, prostheses for trans-femoral level and higher may contain a braking device which provides some stabilisation to prevent the knee flexing whilst body weight is being supported during early stance. These units are weight activated and will allow the knee to bend when the weight is off the limb.

Swing Phase

The period from toe-off, when the knee flexes to allow the foot to clear the ground and accelerate forward, to when the heel strikes the ground for the next step. The muscles that mobilise the knee normally assist this function. The time for the swing phase should ideally speed up as walking speed increases otherwise the limb swings in slow arcs like a pendulum and results in an uneven cadence. Prosthetic knee units often contain a device which controls the swing phase period so that the prosthesis will respond to different walking or running speeds. These units may be electronically controlled pneumatic or hydraulic devices that are programmed optimally for each individual.

Limb Systems

See the products section for a full selection of the limb systems available from Blatchford.

Trans-tibial limbs are selected by first choosing a foot, trans-femoral limbs are chosen by first selecting a knee unit.

Text: Ben Blease
Editing & additional photographs: John Ross and Alan Tanner

Return to Top of Page