1-Amputation Levels

Amputation levels above the knee are shown in Figure 1. These

levels include the following:

Hemipelvectomy is the loss of any part of the ilium, ischium, and

pubis.

Hip disarticulation is the loss of all of the femur. The

hemipelvectomy and hip disarticulation procedures are usually

done in cases of malignant tumors, extensive gangrene, massive

trauma, or advanced infection.

Short transfemoral amputations occur when lessthan 35% of

femoral length is present. A larger weight bearing surface can be

created if femoral transaction can be done at the level of the lesser

trochanter. This level retains the femoral head and neck and the

greater trochanter, resulting in improved prosthetic fit. The number

of transfemoral amputations has declined since the 1980s. This

decline is due to improved surgical techniques and better

preoperative assessment of vascular status.

Medium tansfemoral amputations occur when between 35 and

60% of femoral length is present. Ideally, tansfemoral limbs should

be at least 4 inches or 10 cm above the lower end of the femur to

allow room for the prosthetic knee. In a transfemoral amputation,

both anterior and posterior muscular surfaces are well vascularized;

therefore, equal flaps are fashioned.

A rotationplasty is applicable to patients who have a malignant

tumor in the middle or distal femur. It is also done in cases of

PFFD. A rotationsplasty involves an osteotomy in the proximal

third of the femur, distal to the lesser trochanter, and in the

proximal part of the tibia, distal to the tibial tuberosity. The foot is

rotated 180° and the tibia reattached to the remaining femur. The

foot is fit into the prosthesis and acts as a knee joint. Prosthetically,

this amputation has the advantage of preserving the anatomic ankle

joint, which acts as a knee joint, and a long lever arm for better

prosthesis control. The rotationsplasty procedure is illustrated in

Figure 2.

Long transfemoral amputations occur when more than 60% of

femoral length is present but not capable of end bearing. A

transfemoral amputation is depicted in Figure 1-14.

In a supracondylar amputation, the patella may be left for better

end bearing. However, the area created between the end of the

femur and the patella may delay healing.

A knee disarticulation amputation offers good weight distribution

and retains a long, powerful, muscle – stabilized femoral lever arm.

In addition, the thigh muscles are completely preservfed, thereby

ensuring good muscular balance. This amputation maintains the

femoral length in growing children by preserving the growth

potential of the distal femoral epiphysis. However, the knee

disarticulation amputation yields a noncosmetic socket because of

the need for an external joint mechanism and resulting difficulty

with swing-phase control. Knee disarticulation amputation is often

performed on the patient who will not become a prosthetic walker.

This amputation avoids the possibility of knee flexion contractures

and provides an excellent platform for sitting and transfers.

Transtibial amputation levels are depicted in Figure 3. These

include the flowing:

A very short transtibial amputation occurs when less than 20% of

tibial length is present. This amputation may result from trauma

and is usually not done as an elective procedure. A very short

transtibial amputation results in a small-moment arm, making knee

extension difficult. Moment arms are further described in Chapter

5, "Biomechanics Implications of Prosthetic and Orthosis".

A standard transtibial amputation occurs when between 20 and

50% of tibial length is present. An elective amputation in the

middle third of the tibia, regardless of measured length, provides a

well-padded and biomechanically sufficient lever arm. At least 8

cm of tibia is required below the knee joint for optimal fitting of a

prosthesis.

A long transtibial amputation occurs when more than 50% of

tibital length is present. This amputation is not advised because of

poor blood supply in the distal leg.

The level of tibial transaction should be as long as possible

between the tibial tubercle and the junction of the middle and distal thirds

of the tibia. A long posterior flap for transtibial amputations is

advantageous because it is well vascularized and provides an excellent

weight-bearing surface. In addition, the scar is on the anterior border, an

area that is subject to less weight bearing. The deep calf musculature is

often thinned to reduce the bulk of the posterior flap.

In a transtibial amputation, the fibula is transected 1 to 2 cm shorter

than the tibia to avoid distal fibula pain. If the fibula is transected at the

same length as the tibia, the patient senses that the fibula is too long,

which may cause pain over the distal fibula. If the fibula is cut too short,

a more conical shape, rather than the desired cylindrical – shape residual

limb results. The cylindrical shape is better suited for total contact

prosthetic fitting techniques. A bevel is placed on the anterior distal tibia

to minimize tibial pain on weight bearing. To avoid a painful neuroma, a

collection of axons and fibrous tissue, nerves should be identified, drawn

down, severed, and allowed to retract at least 3 to 5 cm away from the

areas of weight-bearing pressure.

A Syme amputation was named for James syme, a noted University of

Edinburg surgeon, in the mid-1800s. This amputation is an ankle

disarticulation in which the heel pad is kept for good weight bearing. The

Syme amputation results in a residual limb that possesses good function

due to the long lever arm to control the prosthesis and the ability to

ambulate without the prosthesis.

Associated problems with the Syme amputation include an

unstable heel flap, development of neuromas of the posterior tibial nerve,

and poor cosmesis. Performed properly, the residual limb is ideally suited

for weight bearing and lasts virtually the life of the patient.

The bulky residual limb that results from a Syme amputation may

be streamlined by trimming the remaining metaphyseal flares of the tibia

and fibula

Foot amputations levels are depicted in Figure 4. These include

the following:

A transmetatarsal amputation (TMA) may be performed for

deformities resulting from trauma to the toes, infection or gangrene

due to frostbite, diabetes, arteriosclerosis, or autoimmune

circulatory connective tissue disorders. There are approximately

10,000 TMAs a year in the United States, with a failure rate of

about 30%. Of all the amputations done in the United Kingdom,

this amputation has the highest failure rate. This high failure rate is

due to a combination of substantial loss of weight-bearing areas on

the neuropathic foot and the decreased foot length available to

generate a plantarflexor moment. As a result, the remaining tissues

bear an increased load. This amputation should b elimited to

patients with an intact posterior tibial pulse, a warm foot, and

localization of osteomyelitis or gangrene to the phalanges. A dorsal

incision is made through the mid-to proximal metatarsal shafts. A

long, thick, myocutaneous plantar flap including the flexor tendons

is used, with closure of this flap onto the dorsum of the foot. The

transmetatarsal procedure is depicted in Figure. 1-20.

The Lisfranc amputation is done at the tarsometatarsal joint and

involves a disarticulation of all five metatatarsal and digitis.

The Chopart amputation, at the talonavicular and clacaneocuboid

joints, involves a disarticulation through the midtarsal joint leaving

only the clacaneus and talus. Both the Lisfranc and Chopart

amputations were introduced before blood transfusions and

antibiotics were available. They were planned as diarticulations to

be performed as rapidly as possible. These amputations often result

in an equines and varus deformity due to the pull of the

plantarflexors and loss of dorsiflexor and peroneal muscles. In

addition, a distal sensitive end often leads to skin breakdown.

There is much less indication for their use today.

A trransphalangeal (toe disarticulation) amputation is done at the

metatarsophalangeal joint. Toe disarticulations result in

biomechnical deficiencies. Amputation of the great toe affects

push-off during fast walking and running; as a result, patients with

PVD often have a nonpropulsive gait pattern. If the base of the

proximal phalanx with the insertion of the flexor hallucis brevis

issaved, stability is enhanced. Second-digit amputation results in

severe hallux valgus.

Phalangeal or partial toe amputation involves excision of any part

of one or more toes. The lesser toes serve little function in patients

with ischemic PVD. As a result, gait is not markedly affected with

amputation of the lessor toes. Prosthesis is usually not necessary

for teo amputations.

In general, as much viable tissue as possible shouldbe preserved

after hand injury and partial amputation. This view must, however, be

tempered with an appreciation of what will remain functional. The

retention of a finger or part of one which is anaesthetic, cold and stiff

dose no service to the patient and will actively discourage use of the hand

and ability to work and, even after amputation, pain and a lack of desire

to return to normal function will persist.

2-Upper limb levels of amputation

Amputation of Digits

Generally the level will be determined by the degree of injury fig.5.

If the injury is solely to the index or little finger, useful function is

unlikely unless one and a half phalanges are still present. Even at this

level initial acceptance of this limited loss by the patient is often

transmuted into a desire for cosmesis and later amputation is requested.

The best cosmesis is achieved by amputation through the metacarpal shaft

with suitable beveling.This, however, reduces the span of the hand and

power of the grip and it may be better in largey manual workers to

amputate through the metacarpophalangeal joint.

The long and ring fingers are best amputated through whatever

level will leave a mobile and comfortable stump. Even a very short

stump, for example the proximal phalanx, may have some definite

functional value and in the half-closed position be at least cosmetically

acceptable. Amputations of either of these fingers in which the metatarsal

ray is excised for cosmetic reasons may seriously disturb function and are

seldom desirable.

As much of the thumb as can be must be preserved for as long as

possible. Any stump covered with sensititive skin may be of great value.

Wrist disarticulation

Indications for wrist disarticulation are rare but usually related to severe

trauma to the hand with considerable loss of tissue and loss of sensation.

Any tissue with sensation should be preserved. Even carpal bones and

remnants of metacarpals, providing they are covered by viable skin, may

be useful as the wrist extensors and flexor may be preserved as well.

The Forearm

The usual indications for amputation through the forearm are for

severe trauma affecting the wrist and hand and occasionally it is used as

treatment for chronic sepsis or tumour of the hand.

Ideally as with other amputations, the stump should be as long as

possible. A too distal amputation, however, whilst having the advantage

of a long lever and ease of fitting, often suffers from cold and cyanotic

skin with little subcutaneous and muscular tissue covering the bone ends.

Therefore the ideal distance is 17cm measured from the olecranon in the

average adult and this roughly corresponds to the junction of the proximal

two-thirds and the distal one-third of the forearm.

Occasionally the extent of the trauma or disease affecting the hand

and forearm may be too great to allow a useful below-elbow stump to be

fashioned. In the past conventional treatment would have been to

amputate at the level of the distal humerus but as a result of the recent

improvements in prosthetic design, disarticulation at the elbow is

preferable. It looks as though it will be possible, by retaining the bulbous

stump, to have a self-retaining socket and a better joint in the future.

Technique. The skin flaps will often be determined by whatever

skin is available but where possible qual anterior and posterior flaps

should be made the incisions beginning at the level of the humeral

epicondyles and extending distally 4 cm beyond the point of the

olecranon posteriorly and to point just distal to the insertion of the biceps

anteriorly.

Amputation through the Humerus

The commonest indication is severe truma of the forearm.

Occasionally this amputation may be used for sepsis or malignant

tumours. As elsewhere in the upper limb the level may be determined by

factors beyond the surgeon's control. The ideal is 10cm above the elbow

joint, which leaves room for the elbow mechanism in the prosthesis and

provides the best length of stump for fitting. Above this level as long a

stump as possible should be retained.

Amputation through the Neck of the Humerus

This operation does not leave the patient with any functional stump

and should not be performed when it is possible to leave a humeral stump

extending to three finger breadths below the anterior axillary fold. This is

the critical minimal length to which an upper limb.

Prosthesis can be fitted. It the amputation is being performed for

malignant tumour at the lower end of the humerus there is no alternative

but diarticulation at the shoulder joint. To leave the humeral head in situ

when it is permitted on pathological grounds, however, produces a better

cosmetic appearance, particularly when wearing clothes, by preserving

the rounded contour of the shoulder.

Shoulder disarticulation

The arm completely lost

Forequarter Amputation

Clavicle, scapula, and arm are excised. This amputation is rarely

performed and is indicated only for malignant tumours around the

shoulder joint, particularly where the tumour has spread into the

surrounding muscles so that the less mutilating procedures of

disarticulation of the shoulder or amputation through the neck of the

humerus are no longer practicable.

Fig .1 above knee levels of amputation

Fig. 2 Rotationplasty

Fig.3 transtibial (below knee) amputation

Fig.4 foot amputation levels

Fig.5 upper limb amputation levels