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Technical note
Acta chir belg, 2003, 103, 238-240
Introduction
HIPPOCRATE of COS (480-377 BC) described in the fifth
century B.C. amputation techniques for gangrene : “He
recommended amputation of the gangrenous extremity
at the joint below the boundaries of the blackening as
soon as it is fairly dead and has lost its sensitivity and he
advised that care must be taken not to wound the living
part. He recommends to wait for the demarcation line
and self amputation of the extremity” (1). CELSE (50 AC)
described in his “De Arte Medica” a flap operation
where the bone must be divided at a higher level.
There has been a big evolution since HIPPOCRATE, but the
basics in amputation techniques such as the indications
(all referring to gangrene), the aims of amputation i.e.
relief of pain and removal of diseased tissue and the
level of amputation above the demarcation line, all
remain.
The primary advantage of the below-knee amputation
is the maintenance of the patient knee-joint, at least if it
is still functional and shows less than 15 % flexion con-
tracture. This permits a better rehabilitation and ambula-
tion compared to the above-knee amputation (70% vs
10-30%).
A good psychological support is needed in all
patients. Active participation in decision making and
acceptance of the amputation as the only treatment
option is an essential criterium for a rapid revalidation
afterwards. A younger person can walk without help in
6 weeks with modern prostheses and rehabilitation tech-
niques. However, in older patients coexisting morbidity
is responsible for a mortality rate of up to 18%.
The indications and aims of amputation as mentioned
in Tables I and II are valid for all levels of amputations.
An arterial reconstruction can be combined with an
amputation to lower the level of an amputation. In case
of trauma complicated by infection or an infective gan-
grene, a two-stage operation is performed. The first
stage consists in an open supramalleolar guillotine
amputation, combined to appropriate antibiotic treat-
ment and irrigation with antiseptics, followed by a
below-knee amputation at a viable level 5 to 7 days later.
The most challenging part of the below-knee amputa-
tion is the determination of the level of amputation : it
must be the most distal site that can heal uncompro-
mised. However, “no objective test can predict the
amputation level” (2). Indeed, the experienced surgeon’s
How to Perform a Below-Knee Amputation
C. Randon, J. Deroose, F. Vermassen
Department of thoracic and vascular surgery, Ghent University Hospital, Belgium.
Key words. Below-knee amputation ; gangrene ; revalidation ; vascular.
Abstract. Eventhough modern techniques have improved patient survival and limb salvage rates in patients with criti-
cal limb ischaemia and end-stage vascular disease, amputation is sometimes the only possible treatment.
In younger patients with traumatic avulsion of a foot, infected gangrene of the foot or a peripheral tumour, amputation
is out of discussion and commonly accepted. In older vascular patients, amputation should rather be considered as the
starting point for revalidation and rehabilitation than as failure of a revascularization technique.
The evolution in prostheses permits a rapid revalidation in most patients. However, an accurate amputation technique is
still required to produce a good quality stump allowing early fitting of prosthetics.
—————
Presented at “the third Belgian week of surgery”, may 2
th
,
2002, casino Knokke.
Table I
Indications
– Failed arterial reconstruction or inoperable arterial disease with
end-stage ischaemia and non-reconstructable arterial disease
– Acute ischaemia (thrombosis or embolism) with failed revascu-
larization
– Extensive tissue necrosis
– Infected gangrene
– Trauma
Table II
Aims of amputation
– Removal of diseased tissue
– Relief of pain
– Primary healing of the amputation at the chosen level
– Construction of a stump and provision of a prosthesis that will
permit useful function
How to Perform a Below-knee Amputation 239
clinical judgment is the best predictor for a maximal
viable stump length. Other methods to establish the most
distal amputation level able to heal are mentioned in
Table III. Measurement of the segmental systolic pres-
sure in diabetic patients is unreliable due to calcifica-
tions in the distal vessels. Some additional tests are men-
tioned in literature but they have a low sensitivity and
specificity (Table IV).
Techniques
Various techniques for transtibial amputation are
described in literature (Table V).
The oldest method used for infective gangrene as
mentioned previously is “the circular method or guillo-
tine method“ ; the skin, the muscles and bones are cut
circular in the same plane. But due to the retraction of
the soft tissues, the bone projects outwards. This opera-
tion is always followed by a second operation to correct
these errors.
The best known and most used technique is the long
posterior myocutaneous flap based on the underlying
gastrocnemius muscle as proposed by Burgess. The
anterior and posterior flaps of equal length (known as
the fishmouth flaps) and the medial and lateral myocu-
taneous flaps of equal length created through sagittal
incisions are valuable alternatives. The applied method
relays on the remaining available skin.
In this article we describe the long posterior flap tech-
nique. Anatomically the blood supply to the posterior
flap through posterior calf collaterals in the gastrocne-
mius muscle with steal of blood from the other compart-
ments and the soleus muscle is usually better than the
blood supply to the anterior flap in an ischaemic leg
even if there is no recordable arterial pressure at the
ankle on doppler examination. However, in practice,
there are no more healing problems with the fishmouth
incision.
The skin incision is marked on the affected leg. The
level of transsection of the bone is located 10 to 12 cm
or approximately one hand breadth, including the
thumb, below the tibial tuberositas. This incision is
placed 1 cm distal to the planned level of transsection.
The anterior incision ends 2 cm medially from the tibial
border. To draw the flap, one can use the 1/3-2/3
method : 2/3 of the circumference of the leg is the hori-
zontal part of the amputation and the 1/3 of the circum-
ference is the length of the flap (Fig. 1). If any doubt,
generous flaps are cut and retrimmed at closure.
Electrocautery should be avoided to prevent damage
to the surrounding soft tissue . The large vessels should
be ligated. Never use a tourniquet because a residual
haematoma can end up in an infection.
Start on the anterior surface down to the tibia and pro-
long your incision medially and laterally before turning
distally on the drawings. The saphenous vein, if still pre-
sent, is ligated. The muscle of the anterior compartment
is sharply divided and the anterior neurovascular bundle
is ligated. The incision is prolonged through the lateral
compartment. The posterior and peroneal neurovascular
bundles are divided and ligated. The posterior flap
Table III
Critera to determine the level of amputation
– Clinical judgment (80% healing)
– Measurements of peripheral pulses at different levels (segmental
Doppler systemic pressure)
– Capillary refill time
– Rubor level
– Condition of the skin (e.g. trauma with skin laceration)
– Level of ischaemic atrophy (gangrene)
– Demarcation line
– Tumour level
– Angiography when a combined revascularization-amputation is
planned
Table IV
Other level predicting tests
– Fluorescein dye measurements
– Laser Doppler velocimetry
– Laser Doppler measurements of skin perfusion pressure
– Photoelectric skin perfusion pressures
– Isotope skin blood flow measurements (xenon 133)
– Skin temperature measurements
– Transcutaneous oxygen measurements (tcPO2)
– Transcutaneous carbon dioxide measurements (tcPCO2)
Table V
Amputation methods
– A long posterior myocutaneous flap (Burgess and Romano)
– The fishmouth flap (Persson)
– Skew flap (Roehampton)
– A medially based myocutaneous flap (developed in Dundee)
– The circular method
Fig. 1
skin incision for below-knee amputation
240 C. Randon et al.
which consists of the gastrocnemial and soleus muscle is
sharply and carefully freed from its tibial and fibular
attachments.
A periosteal elevator is used to mobilize the perio-
steum to a point just proximal to the site of bone divi-
sion. Resection of too much periosteum increases bone
overgrowth and sequester formation. The fibula is trans-
sected 3 to 4 cm proximal to the level of tibial transsec-
tion (Fig. 2). Before transsecting the tibia check if any
metallic prosthesis for fracture fixation is present. This
should be removed. The tibial bone is transsected at a
level above the flaps but is still longer than the fibular
stump. To avoid seeding of bone dust provoking neocal-
cifications or osteofits, a Findlay’s metal retractor or
even a cloth compress around the stump can be used.
The use of bone wax is discouraged as it acts like a for-
eign body. Smooth contours of the tibial bone are creat-
ed with a rasp, angulated bone remnants and bony
prominences are avoided as they cause functional inca-
pacity. The distal tibia is bevelled at the anterior cortex
at an angle of 45° to 60°.
Nerves must be divided without excessive traction at
a level above the bony division to avoid neuralgia and
stump pain due to neurinoma formation at a point of
pressure. The vasa vasorum of the sciatic nerve are lig-
ated to avoid bleeding before ligating the nerve itself.
The nerve can be cauterized or infiltrated with alcohol
90° (H
UBER and LEWIS) or chirocaine 2% to avoid neuri-
noma formation. If prosthetic material is present it
should be removed. The deep muscles are transsected
just distally to the level of the tibia. Remove enough
muscle so that the end of the stump is not bulbous, this
means in most cases resection of the soleus muscle only
leaving the gastrocnemial muscle for the myocutaneous
flap. The avascular plan between the soleus and gastroc-
nemius muscle is easily identified medially and devel-
oped by blunt dissection. The soleus muscle is trans-
sected at the level of the tibia with ligation of the poste-
rior tibial vessels. At that stage, the posterior flap is
retrimmed to avoid “dog ears”.
The stump is rinsed with saline before closure to
remove clots and debris. The use of local antibiotics
shows no better result in recent literature (3). A drain is
usually not needed in an ischaemic limb, but if required,
use a closed suction drain.
The muscle fascia or aponeurosis of the posterior flap
is sewn without any tension to the anterior fascia with
interrupted absorbable sutures to avoid retraction. The
skin is closed atraumatically and without traction, to
avoid dehiscence, with interrupted vertical mattress
sutures and sterile tapes in between. A stump dressing is
applied.
Mobilization of the knee joint from the first postoper-
ative day is required to avoid deep vein thrombosis
(12.5%). The first wound control is performed after
48 hours. After the operation, the stump skin retracts :
1/3 of the original size of the flap (4 cm retraction in a
flap of 12 cm).
References
1. VASCONSELOS E. Chapter I (1-20 ; 25-49) and Chapter V (174-181)
In : Modern methods of amputation. New York : Philosophical
library, Inc., 1945.
2. GREENALGH R. M., JAMIESON C. W., NICOLAIDES A. N. Part II,
Chapter 9 - Investigation of critical ischemia (75-84) and Part VI,
Chapters 33, 34, 35 - Major amputation for vascular disease (361-
389). In :GREENALGH R. M., JAMIESON C. W., NICOLAIDES A. N.
(eds.). Limb salvage and amputation for vascular disease.
Philadelphia : W.B. Saunders company, 1988.
3. ALLCOCK P. A., JAIN A. S. Revisiting transtibial amputation with the
long posterior flap. Br J Surg, 2001, 88 : 683-8.
C. Randon
Department of thoracic and vascular surgery
Ghent University Hospital
De Pintelaan 185
B-9000 Gent, Belgium
Fig. 2
the long posterior flap technique
