Amputation Levels
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 amputationAmputation
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 levelsFig.5 upper limb amputation
levels
