"Prosthetics and Rehabilitation"

The person who has an amputation is called an amputee. The part that is left after the amputation is called a stump.
Levels of amputation in the lower-extremity are;
® Partial foot
® Syme
® Transtibial (below-knee)
® Knee disarticuiation (through knee)
® Supracondylar (Gritti Stockes)
® Transfemoral (above knee)
® Hip disarticulation
® Transpelvic (hemipelvectomy)
® Translumbar (hemicorporektomy)

Reasons for amputation

1. Peripheral vascular diseases
• Arterioscierosis
• Diabetes mellitus
• Buerger's disease

2. Tumors
Amputees with malign tumors may be receiving chemotherapy. Chemotherapy will cause changes in limb volume. Socket fit and gait training should be done when the patient is feeling well. The permanent prosthesis should not be given until 6 weeks after chemotherapy is finished.

3. Trauma
This is important in underdeveloped countries. The main causes are accidents in the workplace; car and train accidents, burns and firearm wounds (landmine, bullet etc)

4. Chronic Infections
Osteomyelit is the most important chronic infection.

5. Congenital Deformities
Decision to amputate a congenital deformity should be made very carefully. The patient may be functional in spite of the deformity and amputation may cause loss of function.

Amputation

If muscles do not have an insersion point they will retract. These retracted muscles will not be able to perform isometric contractions. In time atrophy will be seen. Atrophy and retracted muscles will not be able to control movements of the stump. The shape of the stump will be bulbous or conic.

To make a total contact socket we need a cylindrical stump. With a total contact socket some of the body weight will pass through the stump to the socket. This means that bones of the stump bear weight. We know that bone should be under intermittent pressure. If there is no pressure on bone we see osteoporosis.

In short, the operation technique should give muscles an insersio so that they can contract isometrically. If antagonist and agonist muscles are sutured together this is called myoplasty. If the muscles are fixed to bone this is called myodesis. Osteomyoplasty is myoplasty and myodesis and closing the bone with periosteum. Osteomyoplasty gives us a physiologic stump.

Prosthesis

Parts of a prosthesis include;
® Socket
® Prosthetic feet
® Shank
® Joint (knee or hip joint)
® Suspension device
For the patient who is using a prosthesis for the first time, a temporary or preparatory prosthesis may be used before the final (definite) prosthesis. The temporary prosthesis is usually not cosmetic. It is used during the period of limb shrinkage. The limb will not reach its final shape until 3-6 months after amputation. In the temporary prosthesis, as limb shrinkage takes place the patient will wear more and more socks. When the patient is wearing 10 to 15 ply socks the amputee should be given a new socket. If the definitive prosthesis is fitted too early, the limb continues to shrink and the prosthesis becomes too large.

All prosthesis consists of a suspension device, socket, shank (this may include artificial joints if the amputation level is above knee), terminal device (the foot).

Partial Foot Amputations

In amputation of a single toe or a single ray (toe + metatarsal) there is not much loss of function. If amputation is done on the first ray there will be a problem with push-off. For toe and ray amputations the space is filled with rubber or foam.

If the great toe and the first ray are amputated a long steel shank in the sole of the shoe, a metatarsal pad and rocker sole can be used to prove function. For the transmetatarsal amputation a cusrom molded insole (stiff insole) is required. This is a slipper type prosthesis. A slipper type prosthesis can also be used in a Lisfranc and Chopart-Boyd aputations. Slipper like prosthesis end at the ankle joint. Sometimes a laminated prosthesis is used for Chopart amputation. Muscular imbalance and deformity is common with a Chopart amputation.

Syme Amputation


A intact heel-pad is very important in a Syme amputation because weight is born on this heel pad. The Syme amputation prosthesis is not cosmetic but function is very good. The syme amputation prosthesis usually has a removable medial window.The window when replaced, provides suspension over the malleoli.

Advantages of Syme amputation

® Phantom pain is minimal
® Weight is born at the end of the stump (distal weight bearing)
® Epiphyseal plates at the lower end of the tibia are protected
® Energy expenditure is lower than a transtibial amputation
® The patient with a Syme amputation may walk for short distances at home without a prosthesis





Transtibial amputation (Below knee amputation)
It is usually done at the upper 1/3 of the tibia because vascularization is better. It is important to protect the knee joint for,
® Lower energy expenditure
® Save the epiphyseal growth plates at the upper end of the tibia. Even very short transtibial stumps (limbs) can be successfully fitted with a prosthesis.

Unlike Syme amputation, the end of the transtibial stump cannot bear total body weight. So body weight is taken from the patellar tendon or the whole surface of the stump by a PTB or, total surface weight bearing prosthesis.

To make a total surface weight bearing prosthesis we need a total contact socket. Even when weigt bearing is by the patellar tendon or the end of the stump (like in Ertl and Frank amputation) the socket should be total contact.

Prosthetic Feet

Prosthetic Feet are classified into five types.
® SACH Foot
® Single-axis Foot
® Multi-axis Foot
® Solid Ankle Flexible Keel Foot
® Energy Storing Foot

The SACH Foot (Solid Ankle Cushion Heel)
At heel strike the cushion heel is compressed, it simulates plantar flexion. The anterior keel is rigid. The SACH foot is light, durable and inexpensive. It is prescribed especially for children and geriatric patients and below knee amputations.

The single axis-foot has a single mechanic ankle joint for plantar and dorsi flexion. This motion is limited by anterior and posterior bumpers. Foot flat is quicker with the single-axis joint therefore the knee is more stable. The single axis foot is heavier, more expensive and less durable then the SACH foot. It is mostly used with transfemoral amputations where knee stability is very important.
Multi-axis feet such as Greissinger, has movement in all three planes i.e. dorsiflexion, plantarflexion, transvers rotation, abduction, adduction. These movements stimulate inversion and eversion. Shock absorption is better in multi-axis feet therefore they are good for walking on uneven ground and for scarred, sensitive stumps. Multi-axis feet are heavier, more expensive and less durable than SACH foot.




Solid ankle flexible keel foot such as the STEN and Otto-bock dynamic foot is like the SACH foot but it has a flexible anterior keel.Solid ankle flexible keel foot are lighter than multi-axis feet and allow a limited motion in inversion-eversion and transvers rotation. They absorb shock in late stance phase. Push off is easier with a flexible keel. They are preferred for moderately active and fat amputees.




Energy Storing Feet (Seattle Foot, Seattle Light, Carbon Copy II, III, Quantum Foot, Flex Foot, Springlife)

The amputee can walk faster with less energy with an energy storing foot, so they are indicated for active patients. They store energy with weight bearing and release energy when weight is taken off. They give a "springy" feeling. Energy storing feet are expensive and indicated for the active patient.
















Shanks in Below Knee Prosthesis

The shank can be exoskeletal with a hard plastic shell. It is very durable but does not allow alignment changes when the prosthesis is finished.

The endoskeletal shank has a pylon covered by soft foam. It is less durable but is lighter and more cosmetic and allows for alignment changes even after the prosthesis is finished.

Sockets In The Below Knee Prosthesis

Patellar Tendon Bearing Socket


The PTB is a total contact socket. It has a bar under the patella to apply pressure to the patellar tendon. The trimline extends anteriorly to the mid patellar region. The trimline extends posteriorly to the level of the patellar bar. In very short stumps the popliteal trimline is higher; in longer stumps it is below the patellar bar.

In PTB sockets some of the pressure is given to the patellar tendon and some to other pressure tolerant areas

The pressure sensitive areas are;
® Tibial crest (crista tibialis)
® Tibial tubercule
® Femoral condyles
® Fibular head
® Distal tibia
® Distal fibula
® Hamstring tendons

The pressure tolerant areas are;
® Patellar tendon
® Pretibial muscles
® Gastrocnemius
® Popliteal fossa
® Area below medial tibial condyle
® Lateral of fibula between fibular head and distal

If the plastic socket has an insert it is called a "soft socket". Soft inserts are given when;
® The patient has peripheral vascular disease
® There is extensive scarring
® If there is not enough subcutaneous tissue.

Total Surface Bearing Sockets

Pressure is distributed to all areas of the stump.



Knee Disarticulation (Through Knee Amputation)
Distal weight bearing is possible. It is much more functional than transfemoral amputations. The lower femoral epyphysial growth plates and thigh muscles are intact but like the Syme amputation knee disarticulation is not cosmetic and a special polycentric knee joint must be used.


Supracondylar Amputations

Partial end bearing is possible in a supracondylar amputation like Gritti Stockes. It is more cosmetic than a disarticulation but slipping and infection may be a problem.

Transfemoral Above Knee Amputation

In a transfemoral amputation if osteomyoplasty is performed hamstring muscles will assist in hip extension. They will help in stabilizing the knee joint.

The stump should be about 3-5cm from the trochanter minor or 8cm from the trochanter major. Soft tissue volume is also important. A flabby bulbous stump will not fit into a socket.

A single-axis foot is better for knee stability. If a SACH foot is used a softer heel is necessary for knee stability. Energy storing feet may be used if the amputee is active. An endoskeletal shank that allows alignment changes is preferred.

Knee Joints

Knee joints are single-axis or polycentric. They may have constant friction, or weight activated friction, or changing friction with the direction of movement. They are mechanical or fluid-controlled (hydrolic-pneumatic)

The “Safety Knee” locks itself with friction when weight is given to the extremity in stance phase.

Knee Control (Stability) is provided by:
1-Activation of hip extensors.
2-Using a manual locked knee
3-Mechanic alignment (The anterior posterior mid point of the socket passes 0-18 mm in front of the knee joint).
4-Extension aids in the joint
5-Friction mechanism of the knee joint.(Safety knee or constant friction)

Sockets Of Above Knee Prosthesis


The Quadrilateral Socket is wide medio-laterally and narrow anterio-posteriorly.It has a posterior shelf for the ischial tuberosity and gluteal muscles.There is inward pressure on the femoral(scarpa) triangle to keep the ischial tuberosity on the posterior shelf.In the socket there is a channel for the adductor longus, hamstring and rectus femoris tendons.





Ischial Containment Socket

he ischium is not on the ischiogluteal shelf.It is in the socket.The socket contains the ischium.


NSNA(normal shape – normal alignment) was developed by Long and Cat-Cam(contoured adducted trochanteric – controlled alignment method) was developed by Sabolich.Compared with the quadrilateral socket the ischial containment socket gives medio-lateral control or “bony lock”.

The ischial containment socket is wider in antero-posteriorly when compared with the quadrilateral socket.The ischial containment socket is helpful for short limbs and weak gluteus medius and vascular problems and energy expenditure is less.

Socket material can be rigid plastic laminate or flexible thermoplastic.The flexible socket ISNY(Icelandic-Swedish-New York) has two separate sockets.The inner flexible socket(soft-thin transparent) and the rigid outher supporting frame.



The flexible socket is more comfortablei it gives better total contact.It is better for stumps with scar tissue, it provides better suction suspension but it is expensive.




Suspension In The Above Knee (Transfemoral) Prosthesis
Suspension systems are;
→ Isometric contractions


Hip Disarticulation

The pelvis is intact and the femur is amputated. Weight is born through the ischial tuberosity and gluteal muscles.

Socket for Hip Disarticuiation

The socket extends to above the iliac crest (crista iliaca). Suspension is provided by inward pressure given just above to iliac crest. The socket is made of more elastic material on the posterior so that the patient can don and doff (put on - take off) the prosthesis easily. The socket should surround the contours of the body and have velcro closures to stop piston action.

Hemipelvectomy (transpelvic amputation)
The femur and the part of the pelvic bones are amputated. The transpelvic amputee bears weight on the soft tissue and lower rib cage, and the gluteal region on the contralateral (sound) side.

Socket for Hemipelvectomy Amputation

The lower lumbar tissues are in the socket and the proximal (border-trimline) of the socket extends to the second rib.





Shank Of Hip Disarticulation and Transpelvic Amputations

A lightweight endoskeletal prosthesis is used.(see picture)

Hip Joint Mechanism

They are similar for hip disarticulation and transpelvic amputations. The free hip Joint, has a posterior bumper extension stop and an anterior flexion stop. It does not allow abduction-adduction or rotation. The hip joint is made stable by placing it anteriorly to the anatomic hip joint (6-6.5cm). A hip extension assist may be used. The knee joint used for transfemoral amputations can be used for hip disarticulation and hemipelvectomy prostheses.Learning posterior pelvic tilt to advance the prosthesis is very important.

Vaulting (rising on the toe of the sound foot) is the most common gait deviation in high amputations. Vaulting should be avoided.

Energy requirements of hip disarticulation and transpelvic amputations ere high. Therefore motivation and cardiopulmonary status are important.

Translumbar Amputation (Hemicorporectomy)
The rectum, bladder and lower half of the body are lost. Translumbar amputation is done only to save lives. The patient should be prepared for the amputation psychologically. Prosthetic training begins with a sitting device to increase sitting tolerance. The socket should allow place and access to ostomy stomas. The amputee should learn stoma care and transfers in and out of the socket. Successful ambulation with prosthetic limbs is very difficult.

Bilateral Amputations
For the bilateral hip disarticulation amputee a molded jacket or bucket socket may be necessary for sitting. Because of high energy expenditure using a walkinq prosthesis may not be possible for the geriatric patient. A young traumatic amputee can ambulate with bilateral hip disarticulation prosthesis using assistive devices.

Bilateral transfemoral amputees can walk but if they are geriatric and have vascular problems they may not be able to ambulate with prosthesis.

Stubbies are short transfemoral prostheses without knee joint and with a rocker bottom. Stubbies are uncosmetic but energy expenditure is lower then normal prostheses.

Special wheelchairs with anti-trippers are required for bilateral proximal amputees.

Bilateral transtibial amputees are functional walkers but if they are old or have vascular problems they may need a cane.The transfemoral-transtibial amputee usually needs a cane for walking.