A fresh look at vascularized flexor tendon transfers

A fresh look at vascularized flexor tendon transfers:
concept, technical aspects and results
J.C. Guimberteau*,a
, J. Bakhach a
, B. Panconi a
, S. Rouzaud a
Institut aquitain de la main-56 alleé des tulipes, 33600 Bordeaux-Pessac, France
Received 20 October 2006; accepted 6 February 2007
KEYWORDS
Sliding systems;
Secondary flexor
reconstruction;
Ulnar pedicle;
Microvacuolar
organization;
Allotransplantation
Summary The authors present the results of their surgical experience based on an original
approach in secondary reconstructing 71 flexor tendons of the hand. For 20 years, they have
been using vascularized tendon transfers either islanded or as free transfers. Their techniques
are based on extensive knowledge of the sliding mechanisms involved around the flexor ten-
dons, for which the authors have developed new scientific explanations resulting from their
observations and the fine analysis of movements. This sliding system has a multimicrovacuolar,
multifibrillar architecture that is able to accommodate every request for movement. By per-
forming vascularized transfers, the authors also transfer the sliding capability together with
the tendon itself, thereby avoiding the two traditional stages of tendon reconstruction. Results
are better than with the traditional techniques and the gain in time is considerable. Moreover,
the biological and physical advantages of transferring living structures are such that the func-
tional outcome in secondary interventions is much better. Furthermore, the wide variety of
transfers available offers possibilities for reconstruction that are better suited to the range
of presentations encountered in this challenging area of surgery. This new approach to recon-
struction is reserved for complex clinical cases and experienced surgeons.
ª 2007 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by
Elsevier Ltd. All rights reserved.
From the outset, surgical principles concerning the re-
construction of finger flexor tendons have centered on the
tendon as a simple force transmission belt between the
muscular structure, which is responsible for the creation of
the force, and the mobile articulated structure, which is
bent by this force. Consequently, this very mechanical
concept led to the development of techniques mainly
aiming at rebuilding this transmission belt as solidly as
possible. Until then, the nature of tendon biology had not
been questioned because everyone was convinced of its
avascular nature and that its mechanical function simu-
lated a transmission belt. From the 1940s onward, a signif-
icant body of research has accumulated confirming the
healing difficulties of tendons, the major reason being
insufficient collagen production. Instead, the notion de-
veloped of so-called vascular survival connections through
* Corresponding author. Tel.: þ33 05 56 46 48 48; fax: þ33 05 56
46 48 49.
E-mail address: adf.guimberteau@wanadoo.fr (J.C.
Guimberteau).
a
Tel.: þ33 05 56 46 48 48; fax: þ33 05 56 46 48 49.
1748-6815/$-seefrontmatterª2007BritishAssociationofPlastic,ReconstructiveandAestheticSurgeons.PublishedbyElsevierLtd.Allrightsreserved.
doi:10.1016/j.bjps.2007.02.021
Journal of Plastic, Reconstructive & Aesthetic Surgery (2007) 60, 793e810

adhesion to the peripheral tissue. This was thought largely
to diminish the sliding capacity of the tendons as well as
their functional recovery.
Potenza introduced the essential notion of vascular
adhesion.1
From then on, authors sought to adapt their
ideas to this apparently unavoidable concept of tendon ad-
hesion and to lessen its importance in order to optimize the
sliding capacities of the structures. Nevertheless, the con-
cept of tendon adhesion was not completely suppressed.
Attempts to understand why tendons need vascular or
pseudo-vascular connections were put in abeyance. Indeed,
some research quite frankly tended to minimize the role
of vascularization. These discoveries practically froze re-
search and techniques for several years because it seemed
pointless to carry out any research if one took as a founding
principle that tendons are only very slightly vascularized
and receive sufficient nourishment from the synovial fluid.2
This was the mechanistic period.
Thus everything was done to diminish adhesion by
limiting the contact between the transferred tendon and
the receiver site. Catgut leaves, mersilene and silicon were
gradually introduced and showed their efficacy but to the
detriment of tendon solidity as they suppressed these
adhering vascular connections. Rupture due to necrosis
also became a major complication. The fact that tendons
need this adhesion in order to survive was acknowledged,
as was its detrimental effect on sliding and functional
outcome. For several decades, research was aimed at
decreasing the frequency of adhesion and optimizing
functional results. Yet two antagonistic factors had to be
reconciled: healing without sliding and sliding with the risk
of rupture.
From the outset, these techniques have required avas-
cular tendon grafts using different types of tendon such as
the palmaris longus, the plantaris and others.3
Numerous
suggestions were made but little by little, the two-stage
techniques became popular. Termed two-stage tenoplasty
by James Hunter and Paneva Olevitch, it required a two-
stage operational sequence 4,5
Firstly, a silicon cord capable
of recreating the conditions of a synovial sheath is inserted.
A tendon transfer is then carried out either by grafting or by
transferring a superficial flexor previously stitched to the re-
maining flexor profundus in the first stage and thus ensuring
the solidity of the suture. Despite all these precautions,
functional results were mediocre because apart from Hunt-
er’s series which found 80% good results, other teams only
approached 50% . The daily practice of every surgeon dem-
onstrates that the two-stage technique necessitates at least
six months, thus discouraging numerous patients and sur-
geons owing to the time factor and to the poor quality of
the functional result. Moreover in the mid to long term,
the outcome becomes less satisfactory with the fingers often
retracting in flexion.
However, these techniques obey a certain mechanical
logic. In fact, the transmission cord principle persists by
optimizing the solidity of the stitching in the first stage of
the operation. An attempt is made to solve the biological
problem by trying to create sliding conditions with a syno-
vial pseudo-sheath. This surgical approach aims at adapting
to the problem of adhesion formation by doing everything
possible to obtain the rather strange concept of ‘supple
adhesion’ Although this principle may represent enormous
progress compared to the past, it has no real future
because the biological realities and imperatives are not
respected. The poor results achieved and the difficulties
encountered, as well as surgical observations during other
procedures, led some surgeons to question the very
foundations of what others had believed for years about
tendons, their supposed avascular nature and mechanical
role like a transmission belt.
In all the above-mentioned techniques, the tendon was
always non-vascularized and placed in a more or less
sclerotic receiver site with the impossible mission of both
healing and sliding at the same time. Other research by
Peacock, Smith and Bellinger, and others demonstrated that
the tendon is a perfectly vascularized organ with a vascular
distribution that is both intrinsic and extrinsic, as well as
having a very specific lymphatic drainage system6e9
Further-
more, no physiological or microanatomical explanations
have been proposed to date for the concept of virtual space
between the tendon and the sheath in zones III, IV and V.
Present-day techniques remain completely alien to these
new biological realities and continue either to ignore them
or, at least, to exclude them from surgical applications.
Not only is better knowledge of the intimate physiology
of the tendon vital, but also the conditions favoring
optimum function must be understood. First we explored
the organic and physiological pathway at a fundamental
level.
For many decades, terms such as elasticity, mobility,
hierarchical tissue distribution, stratification and virtual
space between organs have been taken for granted, yet the
real basis for them needs to be questioned. Their scientific
underpinnings were limited to the notion of virtual space or
the existence of loose connective tissue, but the bio-
mechanical foundations for these theories were more
than vague. In the last 50 years, research has focused on
the microscopic level while the global concept of meso-
sphericity has been abandoned. As time has gone by, and as
researchers have examined these tissues more closely, new
hypotheses have emerged concerning the organization of
the subcutaneous tissues and led to a new concept, the
creation of a model and to new surgical procedures.10
Material and method
Microvideo-observations and analysis in
zones 3, 4 and 5.
We have performed 95 video observations in vivo with
functional analysis, either directly under the skin or close
to tendons, muscle and nerve sheaths during human surgical
dissection using light microscopy (magnification Â25).
This gliding or sliding of tissue, which is traditionally
called ‘connective’, ‘areolar’ or ‘loose tissue and para-
tenon around the tendons,’ has for long been considered to
be ‘packing tissue’ that fills spaces between and within
organs. In fact, this tissue plays a mechanical role, allowing
movements between the structures it connects, preserving
mobility and independence between organs and, in partic-
ular, between tendons and skin. This tissue is important for
the nutrition of the structures embedded in it and acts as
a frame for blood and lymph vessels Fig. 1.
794 J.C. Guimberteau et al.

However,itsmechanicalsignificanceismajor;itdiminishes
friction while facilitating deformability and adaptability.
This collagenous system, traditionally known as the
paratendon, can be seen surrounding the tendon. It is
composed of multidirectional filaments, intertwining and
creating partitions which enclose microvacuolar shapes
Fig. 2. We term this the Multimicrovacuolar Collagenous Dy-
namic Absorbing System (M.V.C.A.S.) in order to emphasize
its functional involvement. This system is situated between
the tendon and its neighboring tissue and seems to promote
optimal sliding. The tendon is able to travel far and fast
without any hindrance, and without inducing movement
in any other neighboring tissue, thus accounting for the
absence of any dynamic repercussions of movement on
the skin surface. When the flexor tendon moves, its move-
ment is barely discernible in the palm. In the light of new
information obtained from dissections of fresh or forma-
lin-treated cadavers, the time has come to confirm some
anatomical truths about this tissue and to definitively dis-
card certain preconceived ideas.
Traditional concepts are at variance with anatomical
reality. The notion of multilayered sliding between com-
pletely anatomically separate tissues d sliding thanks to
what many believe to be an elastic process d has to be
revised in the light of all these observations. The theory of
discontinuity in separate layers should now be abandoned
in favor of the noting of continuous matter and micro-
vacuolar framework.11,12
Electron microscope scanning de-
molished the existence of different superimposed layers
because they were never observed. Furthermore, the ele-
mentary laws of mechanics and rheology presented the
problem in terms of global dynamics where continuous
matter composed of millions of vacuoles, each measuring
a few microns to a few millimeters in size, is organized in
dispersed branching fractal patterns Fig. 3. The sides of
the vacuoles, which are intertwined, are composed of col-
lagen fibers, probably type 1,3,4,6. This approach to ten-
don physiology also supposes a completely different way
of perceiving the problem of reconstruction. These obser-
vations demonstrating the real histological continuity be-
tween the paratenon, the common carpal sheath and the
flexor tendons illustrate the perfect vascularization of
this functional ensemble. They are innovative in that they
introduce a new concept: the SLIDING UNIT, composed of
the tendon and its surrounding sheaths.
From now on, Potenza’s principle, involving tendon
adhesions and reconstruction of the digital sheath using a
silicon rod, should be set aside in favor of other principles.
/ A tendon only has optimal functional value when it is
surrounded by its original sliding sheath and its vascular
heritage.
/ A tendon is adherent only when it is artificially separated
from its own sliding sheath, or when the harmony be-
tween the tendon and the sheath has been interrupted.
/ A tendon is only one of the elements involved in the
transmission of force through the sliding unit.
For zones III, IV, and V, the authors set out to define
a different role for the tendon in the production and
transmission of a force. The tendon is not a transmission
belt acting in the carpal sheath surrounded by a virtual
space; nor is it an organ that is avascular or only very
slightly vascularized. The tendon is not nourished by the
Figure 1 (a) Traction on the paratendon during surgery. (b) Searching for an epitendinous plane. (c) Network between the tendon
and the peripheral system: the M.V.C.A.S. (d) Epitendinous dissection exposes the sliding system M.V.C.A.S.
A look at vascularized flexor tendon transfers 795

synovial fluid, but by its own vascular system like every
organ. It is one of the main constituent elements but
thanks to the M.V.C.A.S can no longer be dissociated from
its sheath. It subtends the tendon-sheath couple and the
major role of the vascularization with peripheral collagen
organization. Moreover it has a fundamental biological
consequences.
The basic principles for a new method of
reconstruction
The idea is to transfer en bloc a digital flexion unit composed
of the flexor tendon with the sliding sheaths from zones 3, 4
and 5 to zones 1 and 2 in a single step. The strategy for
secondary reconstruction is therefore totally changed. This
new technique is now used for the reconstruction of finger
flexor systems in Boyes grade III and IV presentations13,14
2 Basic principles
(1) The tendon can only be conceived as vascularized.
(2) The tendon can only be conceived as an element in as-
sociation with its surrounding sheaths and forming
a sliding unit Fig. 4.
In order to conform to these two basic principles, the
proposed new technique must satisfactorily answer three
basic questions.
(1) Which sliding zone should be used to replace zones I
and II, which are subject to so many problems and com-
plications? The mesotendon and its vascular branches
provide good vascularization of the flexor tendon and
the sliding carpal sheath both extrinsically and intrinsi-
cally. The structure thus transferred is a real sliding
structure which already exists naturally in zones III, IV
and V.
(2) How will the replacement flexion structure be
vascularized?
Vascularization is ensured by a pre-retinacular meso-
tendon with branches arising from the ulnar artery. At
the inferior third of the wrist, just before the flexor
retinaculum carpi or the annular ligament, the latter has
two or three branches of around 1 mm in diameter. These
branches pass through the common carpal sheath towards
the superficial flexor tendons, especially those of the
middle finger, the ring finger and the little finger, by
way of a fine transparent mesotendon acting as a mesen-
tery. This vascular approach to the flexor system and the
common carpal sheath is made distal to the tendon-
muscle junction, thus allowing the concept of retrograde
island transfers to be adapted to purely tendinous
structures.
(3) How is the sliding unit positioned in No Man’s Land?
Fig. 5.
Figure 2 (a) Peritendinous sliding system. (b) Histological and collagenous continuity between the epitendon and M.V.C.A.S. (c)
3D Microvacuola. (d) Sketch of this organization in microvacuoles.

Nowadays, the technique of island retrograde forearm
transfer is used to transfer a forearm or wrist structure
pedicled on an arterial axis. For retrograde vascularized
tendon transfer, only the ulnar-based pedicle is suitable
owing to its distally based palmar point of rotation and to
its branch transmission at the level of the tendon. Since
there are many clinical circumstances and forms of tissue
destruction, this surgical technique has been developed
over time to include a wide range of variants.
A safe and generous anatomy
Arteries
The ulnar artery runs parallel to the nerve in a valley
surrounded laterally by the flexor carpi ulnaris and medially
by the muscle and tendons of the flexor digitorum super-
ficialis of the fourth and fifth fingers. Covered only by skin,
subcutaneous fat and the superficial fascia, this artery is
relatively superficial in the lower and middle compart-
ments. However, in the upper compartment, the cutaneo-
vascular relationships are less clear and the raising of
a reverse island flap is thus more problematic. Cutaneous
vascularization is ensured by a series of two to four small
pedicles linked to the main pedicle through the fascia. The
vessels are about 1 cm long and 1 to 3 mm in diameter.
Since the small pedicles lie 15 to 25 mm apart, each flap
usually contains at least two pedicles of good quality. In
all our patients, the anatomic representation was constant,
both topographically and with regard to vascular distribu-
tion Fig. 6.
Veins
The anterior compartment of the forearm is drained by two
venous systems, the venae comitantes of the ulnar artery
and the superficial system, whose veins are of larger
diameter. Both systems have abundant anastomotic net-
works, which make it easy to raise both free and pedicled
flaps.
Technical aspects: the various basic
procedures
Basic procedure for the transfer of the flexor
superficialis of the ring finger
Technique
The basic procedure consists of the transfer of the flexor
superficialis tendon of the ring finger to repair any type of
tendon defect. Preoperative evaluation includes Allen and
Doppler tests to ascertain that the radial artery provides
adequate blood supply to the hand. Angiography of the arm
is also advisable. A bayonet-shaped incision is first traced
and then made on the medial side of the forearm, the axis
of the incision overlying the lateral border of the flexor
carpi ulnaris. The ulnar pedicle is dissected and all its
Figure 3 (a) Microvacuola inside the MCVAS. (b) Magnification M.V.C.A.S. under the electron microscope. (c) A microvacuola with
a hexagonal shape. (d) Microvacuola is filled with GAG and the frame contains collagen type I, III and IV.

branches are carefully separated and divided. First the
cutaneous branches between the ulnar artery and the skin
are then carefully isolated. These emerge from the volar
aspect of the pedicle and are the principal components of
the ulnar forearm flap. These branches should be divided
only when skin transfer is not required. The ulnar pedicle is
then separated from the ulnar nerve on its dorsal aspect
along its whole length from the lower third of the forearm
to Guyon’s canal. On the posterior wall of the pedicle, the
branches for the ulnar bone and ulnar styloid are then
identified. The branches on the anterolateral side emerging
just before Guyon’s canal are those supplying the common
carpal sheath and the flexor sliding system. These small
branches are orientated forward and arborize into the
common carpal sheath, the multimicrovacuolar absorbing
system, the epitendon and the endotenon. They emerge
from the ulnar pedicle and form part of the sliding system.
They act as a mesentery and are called the mesotendon,
a mobile structure 2 cm long.
A mesotendinous structure composed of the flexor super-
ficialis of the ring finger is raised with the carpal sheath
and its vascular connections from the ulnar pedicle Fig. 7.
These connections, usually comprising two or three small
branches on the anterolateral side and measuring on aver-
age 0.2 to 0.5 mm in diameter, are found just before the
proximal edge of the flexor retinaculum. At the level of
the A1 pulley, strong traction on the tendon makes possible
the section just at the beginning of the decussation, thereby
avoiding dilaceration of the vinculum longum of the flexor
profundus.
Then the myo or musculo-tendinous junction of the FS is
sectioned. All the MVCAS comprising the common carpal
sheath surrounding the tendon transfer is kept in place, thus
ensuring a real vascular connective link defining the concept
of mesotendon. After proximal ligation of the ulnar pedicle,
dissection and ligature of all the other branches of the ulnar
pedicle to the deep arch division are performed to obtain
a rotation point at the level of the deep branch. A composite
mesotendinous island transfer 20 cm long is then raised, as
with any reversed forearm flap.
Like any reversed forearm flap, the sliding unit, which is
pliable and plastic, is transferred to the distal part of the
hand in order to provide a complete flexor tendon unit for
any finger from the pulp to the wrist. The natural
collagenous organization of the tendon is preserved and
the distal extremity remains distal. The whole procedure
takes 3 hours: 1 hour for finger dissection and preparation,
1 hour for raising the transfer and 1 hour for insertion and
closure. The rest of the operation follows conventional
principles of tendon surgery. The tendon area wrapped in
the common carpal sheath is laid into the ‘no man’s land’
beneath the A2 and A3 pulleys, which must be carefully
preserved or solidly reconstructed, since the tendon trans-
fer exposes them to much greater strain than a simple
tendon graft. The pulley system is not a very easy problem
to solve. From the beginning of dissection, we prefer to
reuse the remaining sclerotic components of the tendon or
pulley, and to tunnelize and preserve the strong attach-
ments. Sometimes, pulleys previously preserved are too
narrow and require careful dilatation.
Figure 4 (Above) Sliding unit composed of flexor tendon, common carpal sheath (zone 3) and mesotendon containing ulnar ped-
icle branches. Flexion-Extension. (Below) Diagram of the MCVAS sliding system.

It is better to rebuild a pulley in good condition than to
keep one where the transfer and its blood supply are
stretched. The transfer is first inserted into the distal
phalanx by means of a ‘barbed wire’ suture. The proximal
suture with the distal extremity of the relevant flexor
profundus is performed using Pulvertaft’s method. The
tension on the suture is easy to assess and should be
slightly overcorrected in comparison with the other fingers.
On completion of the procedure, a dynamic Kleinert-type
splint is applied to allow early movement.
INDICATION: Cases with flexor tendons or pulleys re-
construction but without skin problems and where mobili-
zation can intervene early.
Transfer of the flexor superficialis of the ring
finger for flexor profundus reconstruction with
flexor superficialis in place
Technique
This procedure was first attempted after much reflexion
and with good experience of the basic procedure obtained
in 30 cases of flexor transplants. There is no fundamental
difference in the dissection and the transplant elevation.
The most difficult thing is to respect the flexor superficialis
and the chiasma. Because the thickness of the two tendons
together is narrowed, the A1 and A2 pulleys sometimes
make the procedure difficult. The delay seems to influence
the narrowing of the pulleys. The pulleys may be widened
by mechanical manipulations, thus avoiding rupture, but
this procedure is not easy. Otherwise, strong pulley re-
construction is mandatory. Our functional results obtained
to date have been surprisingly good and very often
excellent. In good practical conditions, the results are
much better than with a tenodesis or an arthrodesis.
Combined island flexor superficialis tendon and
palmaris brevis transfer for flexor and pulley
reconstruction
Technique
For a long time we used the Welby procedure for pulley
reconstruction. However, the idea arose of using the
Palmaris Longus as another vascularized island tendon on
the same mesotendon as the Flexor superficialis. It is
transferred at the same time as the flexor superficialis.
Like the Welby procedure, we use it with a periosteum
wedge suture as cross lacing from A1 to A4.
Before suturing, the sliding of the implanted tendon has
to be checked.
Composite flexor tendon and skin flap transfer
This constitutes the main advantage of this group of
procedures, and allows the skin problem and tendon
reconstruction to be solved at the same time. Fig. 8.
Figure 5 Transfer of a sliding flexion unit composed of a flexor tendon and its surrounding sheaths in a reverse island pedicled
manner. Stage 1: Mesotendon identification. Insert: the mesotendon. Stage 2: Section of FS IVth and ulnar pedicle. Island ulnar
tendon transfer isolated. Stage 3: Insertion of the island transfer into digital zone. Stage 4: Tendon sutures outside of the no man’s
land and pulley reconstruction.

Technique
In the lower third of the forearm, the ulnar pedicle not only
sends branches to the flexor superficialis tendons but also
to the skin. These branches are easily identified, being
close to the mesotendon branches and constantly of
excellent caliber, allowing simultaneous composite transfer
of the skin and tendon.15
Slight upwards traction on the in-
ternal edge of the flap reveals the small vertical pedicles
arising from the ulnar artery that vascularize the skin. After
identifying the skin flap pedicle, complete flap dissection is
performed. Fig. 9.
The second step is ulnar pedicle dissection and identi-
fying the mesotendon branches.
Generally, the skin island lies proximal to the mesoten-
don. However, thanks to the pliability and flexibility of
these cutaneous branches, the skin transfer can be rotated
and positioned on the digital surface without changing the
physiologic direction of the tendon fibers.
The proximal extremity of the flap is placed distally
after 180
rotation. The skin is closed tension-free, pro-
viding good healing without skin disunion or necrosis. This is
of fundamental importance for achieving a good functional
result.
Advantages
The operation is very reliable, with almost complete
absence of sequelae. The anatomic presentation is con-
stant, since at least one good-sized artery could be found in
all patients. The flap has 360
mobility around a rotation
point in the palm, which makes the entire skin surface of
the hand and digits accessible. This is not the case with the
radial flap. Tissue quality is excellent, being fine, fat-free
and virtually hairless. There are no sequelae at the donor
site, since the scar on the forearm is usually very fine and
not hypertrophic. The technique allows for further de-
velopments such as sensory innervation (by means of the
medial cutaneous branches of the ulnar nerve).
Indications
In cases with huge skin palmar digital retraction after many
previous procedures, the main problem is skin repair. A
plain skin graft can never solve this difficulty. In some cases
where the overlying skin is extremely scarred and of poor
quality, particularly at the base of P1 or P2, it would be
impossible to replace the flexor tendon and achieve early
motion. Skin of this sort inevitably breaks down or necro-
ses, compromising the functional result, so it should be
replaced. Fig. 10. The solution is to perform a safe skin flap
at the same time as tendon reconstruction, thereby making
early motion possible.
Ulnar trail
The wide variety of composite flaps made possible by the
ulnar pedicle at the inferior third of the forearm offers
many solutions to a large number of clinical presentations
and surgical reconstructive requirements. For example, it is
possible to perform a double skin flap with one or two flexor
Figure 6 (a) Various vascular branches emerging from the ulnar artery in front of entrance to Guyon’s canal. Bone, skin, flexor
tendons. (b) Because of the very distal rotation point of the ulnar pedicle compared to radial pedicle, placement can be performed
without technical difficulty. (c) Vascular branches running from the anterolateral side of the ulnar pedicle to the flexor superficialis
of the fourth finger. (d) Mesotendon and its vascular connections from the ulnar pedicle is acting as a true mesentery.

tendon transfers, or a skin flap with a flexor tendon for
reconstruction and a palmaris longus as an islanded transfer
for pulley repair. It is also possible to add a bone transfer at
the same time16
Fig. 11.
Discussion
This new technique using a mesovascular tendon island,
which is now our standard procedure for Boyes grade III or
IV cases, is likely to set the trend for future flexor tendon
surgery because the requisite tendon reconstruction can be
carried out in one operation. Compared with all other
tendon graft techniques, the advantages of this technique
are as follows. It makes use of a living tendon islanded on a
thin mesotendon with vascular branches, providing a per-
fect blood supply to all areas both extrinsic and intrinsic. It
thus avoids adhesions and improves the vascularity of the
surrounding tissues. Since the transfer is a real vascularized
flexor tendon and not a simple avascular graft, it retains its
flexibility, pliability and resistance and allows the correct
tension to be achieved. Because the vascular network is
spared, all the sheaths are also spared. The MVCAS and in
particular the carpal sheath (which is transposed into a ‘no
man’s land’) retain the unrestricted gliding movement
of the tendon. The length of the tendon transfer is
approximately 18 to 20 cm. This allows easy reconstruction
of any type of flexor tendon defect from the pulp to the
carpal area. Thus the tendon repairs are not under tension
and lie outside ‘no man’s land.’ Because of the very distal
rotation point and the plasticity and versatility of the mes-
otendon, the placement and anchoring procedures need
careful attention but can be performed without difficulty.
The operation is performed in the same way as a classic re-
versed-flow radial or ulnar forearm flap.
The mesotendinous vascular branches are anatomically
constant and dissection takes approximately the same
amount of time as a reversed-flow forearm skin flap (approx-
imately 90 minutes). This is a ONE-STAGE PROCEDURE sparing
all the gliding surfaces, which means that recipient bed
preparation by a pseudo-synovial sheath using a silicone rod
is unnecessary. However, all the pulleys have to be repaired
carefully because the traction exerted by this type of tendon
has been found to be greater because the tissue resistance is
lesser. The radial forearm flap does not allow transfer of the
common carpal sheath and the flexor tendon because the
radial pedicle supplies them only at the myotendinous level
and its point ofrotation is tooproximal. Thenew techniqueof
composite transfer described in this paper is specifically
confined to the ulnar vascular system and may be conve-
niently termed the ulnar trail system.
Figure 7 (a) The mesotendon and ulnar artery branches. Flexor superficialis transfer after section at the level of chiasma and
before section at the tendineomuscular junction. (b) After tendinomuscular section and before ulnar artery section. (c,d) Sliding
system of the Common Carpal sheath is transferred in the sliding unit. (e) The flexion sliding unit is islanded and after revascular-
ization. (f) Forward translation of the sliding unit transfer.

The main disadvantage of our technique is the need to
transect the ulnar pedicle. However, in our experience of
539 cases of all varieties of ulnar transfers, no undesirable
long-term effects such as paresthesia or functional deficits
have been encountered 1 year after surgery. It is neverthe-
less preferable to restore arterial continuity either by
a venous graft or a vascular prosthesis 2 mm in diameter.
Assessment of results
It is almost impossible to evaluate the results of tendon
reconstruction operations by any statistical method. There
are so many variables; e.g. the type and extent of the
injury, the age of the patient, the accompanying injuries of
nerves and vascular structures and the procedures used e
that only general conceptions, based on experience, can be
used.
‘‘Tendons in the fingers are the most difficult to repair.’’
e Joseph H. Boyes.17
This statement remains true.
The influences of aspects of the patient’s life such as
their psychological profile, smoking history, socio-economic
status and desire for future employability have an impact
on functional outcome. All of these factors must be taken
into consideration in determining the aim of reconstruc-
tion, in choosing the type of procedure to be done and
evaluating the results.
Many systems of evaluation have been proposed. We use
the TAM with Strickland’s modifications18,19
system because
it is based on an international methodology. Nevertheless,
the arithmetical addition of degrees between extension
and flexion compared with the hypothetical maximum
amplitude, while not distinguishing between metacarpo-
phalangeal joint and proximal interphalangeal or distal
interphalangeal joints, would seem debatable for this
sort of salvage situation. A significant alteration of meta-
carpophalangeal joint movement only rarely occurs. Clearly
in such cases, the principal aim is to restore effective and
useful function, including grip, and especially to achieve
recovery of good proximal interphalangeal joint movement.
For heavily damaged fingers, too many unfavorable factors
are present to be able to achieve a 100 percent result, and
the patient should be informed of this. More importance
should also be attached to preoperative skin condition.
Our study comprised 63 Boyes grade III and IV patients,
all previously operated on at least twice. Criteria were as
follows:
Class III: Patients in whom the range of passive motion in
the proximal interphalangeal or distal interphalangeal
joints was restricted even after a period of elastic traction.
Class IV: Patients with all possible complicating factors
such as major soft-tissue damage, joint stiffness, poor vas-
cularization and trophic changes.
Our strategy was determined by the skin quality.
Since mobilization is early (3 days postoperatively), it is
mandatory to avoid skin dehiscence or necrosis. In these
circumstances, we use a composite skin and flexor tendon
transfer.
Our study was divided into 3 groups:
Group A: 16 patients, including 11 grade III and 5 grade IV
patients in whom flexor superficialis transfers were used;
Group A’: 12 patients in whom only the flexor profundus
was ruptured were repaired by islanded flexor superficialis;
Figure 8 Diagramm of a transfer of a sliding flexion unit composed of a flexor tendon and þ skin island flap. Stage 1: Mesotendon
and skin branches identification. Stage 2: Section of FS IVth and ulnar pedicle. Island ulnar tendon þ skin transfer isolated. Stage 3:
Insertion of the island transfer into digital zone. Stage 4: Tendon sutures outside of the no man’s land and digital skin resurfacing.

Group B: 35 grade IV patients needing skin transfers and
having either major skin retraction due to a skin gap or
skin stiffness accompanied by either vascular or nerve prob-
lems with fragile skin where composite skin and flexor
superficialis transfers were preferred.
Results
Group A Fig. 12
16 patients were analyzed.
4 excellent (3 grade III, 1grade IV,) 25%
7 good (6 grade III, 1 grade IV) 43.75%
3 medium (1 grade III, 2 grade IV,) 18.75%
2 poor (1 grade III, 1 grade IV) 12.5%
Great improvement was achieved in 68.75% of patients.
The fair and poor results were mainly due to healing
problems during early mobilization inducing pain and in-
flammation and requiring dressing. We now prefer to add
a skin flap in order to reinforce cicatrization, even if slight
remodeling under local anesthesia may be required several
months later.
Group A’ Fig. 13
Group A’ began somewhat later after 10 years of experi-
ence. Reconstruction of deep flexor function while con-
serving the superficial flexor is known to produce poor
results so a tenodesis or arthrodesis is usually performed
instead. However, in our opinion and with the experience
gained, we felt that the technique was indicated in young
subjects such as rugby players. The results were beyond
Figure 9 Raising of the composite flexor tendon þ skin flap island transfer for tendon repair and digital palmar resurfacing. (a)
Outline of the skin flap incision based on the lateral edge of the flexor carpi ulnaris. (b) After identification of the mesocutaneous
and mesotendinous branches and before ulnar pedicle transsection. (c,d) Forward translation of the composite transfer. (e,f)
Thanks to ulnar pedicle plasticity and distal rotation point, placement is easy and a complete skin resurfacing is performed in
the same time as tendon system reconstruction.

Figure 10 Various cases of palmar skin retraction needing a flexor system restoration and skin resurfacing with a composite
flexor transfer and skin flap.
Figure 11 The Ulnar Trail. Other multiple combinations: (a,b,c) One or multiple flexor transfers. (d) Skin flap. (e) Combined is-
land flexor superficialis tendon and skin flap. (f) Double flexor tendons and double skin flap transfer. (g,h) Combined island flexor
superficialis tendon and palmaris longus transfer for pulley reconstruction. (i) Composite skin þ flexor tendon þ bone transfer.

anything we expected since performing range of motion
was obtained in 75% of cases. Nevertheless, the technique
is extremely intricate and is indicated only in young
subjects capable of following stringent rehabilitation.
To date, there have been 12 cases: 4 excellent, 5 good
and 3 poor, including 2 who preferred not to have joint
arthrodesis after intervention. Four cases (30%) required
tenolysis, which revealed the excellent state of the trans-
ferred tendon. Any adherences found were always located
around the tendinous anastomoses. Tenolysis performed
obtained 2 excellent and 2 very good results.
Group B Fig. 14
35 patients were analyzed. There were 22 good (63%)
5 medium (14%) and 8 poor (23%).
The results show that 63% of these extreme salvage
flexor tendon situations were greatly improved. The tech-
nique also produces favorable trophic changes. Finger skin
becomes more supple and sensitive, joints are less stiff and
are mechanically active, and flexion is improved.
Overall, 42 patients (66.6%) achieved an excellent, or
good result compared to an average of 55% in series where
similar cases are operated using the two-staged procedure
with or without a silicone rod. However, in this particular
field, precise evaluation of results is a real challenge, and
in many previous publications results have been evaluated
by different methods, rendering true comparison difficult,
if not misleading. What is sure is this new technique seems
to give better functional performance and reduces time lost
from work.
Twenty years on
These procedures have now become routine practice. They
are safe, technically easy to perform and above all provide
solutions to problems which often led to amputations or
arthrodesis in the past. Only one patient requested an
amputation since he was unable to carry plasterboard
panels owing to a problem with his index finger.
Nevertheless, the functional outcome of patients has not
improved in the last 15 years. The percentages are still as
they were originally since factors influencing the quality of
outcome go far beyond the purely technical or surgical. The
way the patient evolves is of paramount importance and
is of course unpredictable. There is his tissue quality,
whether pain or edema is present, and the duration of
the post-operative phase. Other factors to be taken into
consideration are the patient’s own will to get better and
the skill of his physiotherapist. Smoking and the relative
Figure 12 Functional results of the flexion system transfers: group A.

proximity of a specialized rehabilitation team are also
major factors.
Regrettably, some flexor tendon island transfers were
not performed when, during a tenolysis, the tendons were
continuous but of poor quality. The outcome one day later
was a ruptured tendon. The functional outcome in such
cases was very poor. As regrettable are the cases in which
skin transfers were not performed in patients in whom post-
operative difficulties occurred owing to dehiscence. From
1996, we changed our approach and now perform more
often composite skin and tendon transfers. In complex
tendon reconstruction, the approach must be sound, well-
founded, offering totally manageable post-operative solu-
tions. . Sometimes a tenolysis may be required. It leads to
very good results because it is performed on a living tendon
and not just on a collagenic graft. The combined skin flap
reshaping allows second-look surgery to be done in good
conditions of cicatrisation and facilitates immediate re-
habilitation, which is a major advantage. About 539 ulnar
flaps of all type have been performed over 20 years and no
complication has ever occurred with sectioning of the ulnar
pedicle.The psychological impact for patients is very
positive because they do not feel they are being abandoned
for a few months. Rehabilitation can be begun straightaway
since all the technical issues are now resolved. This is also
technically satisfying for the surgeon.
Other experience using vascularized flexor
tendon autotransplants and homotransplants
These types of ulnar vascularized tendons or tendon and
skin transfers with multiple applications and good func-
tional results could set a trend in tendon reconstructive
surgery, even though these techniques cannot be used in all
indications. Other kinds of vascularized tendons transfers
can be used for different indications.
Toe-to-finger free flexor tendon transfer for
digital flexion reconstruction
In view of the concept of pedicled tendon transfer, which is
not necessarily the first line in cases where the entire
flexion mechanism is damaged, we transferred the flexor
mechanism of the second toe as a free composite flap and
repaired the flexor tendons, digital sheath and palmar
plates of a long finger en bloc and in a single operation.
Operative technique
On the donor site, the tendon is approached through
a plantar incision from the medial side of the second toe
to the mid plantar area. The plantar fat is retracted and the
Figure 13 Functional results of the flexion system transfers for cases of rupture of the flexor profundus with flexor superficialis
intact: group A’.

plantar aponeurosis is transected, exposing the second toe
flexor system and its vascular network.
Attention should be paid to several anatomical particu-
larities here:
The second toe flexor sheath is shorter than the second,
third and fourth digital flexor sheaths by 15% on aver-
age, while it is longer than the fifth digital flexor sheath
by 5% on average;
The metatarso-phalangeal plate is wider and thicker
than the metacarpo-phalangeal plate;
The third annular pulley is more developed in the toe
flexor sheath.
The vascular type is identified and the tendon flap is
harvested from distal to proximal. Concerning the vascular
supply of the toe flexor system, it depends on the medial
collateral digital artery which is a terminal branch of the
first common plantar digital artery, a branch itself of the
medial plantar artery. Venous drainage is carried out by
the constant comitantes veins.
There are two different anatomic types. In type I, which
is present in 50% of the cases, the second toe medial
collateral artery arises directly from the first common
plantar digital artery, giving a long vascular pedicle. In
type II, i.e. the other 50% of cases, the second toe medial
collateral artery arises from the medial branch of the medial
plantar artery beneath the big toe flexor tendon and has
a short vascular pedicle. Dissection is performed on the
phalangeal sub-periosteal plan elevating the whole flexor
toe system with the two tendons, the eight flexor pulleys
and the three plantar plates with their vascular supply.
The flexor tendons are transected as far as the flexor digit
defect requires and the vascular pedicle is freed as far as
possible depending on the anatomical type. Finally, the
donor site is closed, primarily with skin adjustment. Neither
a tenotomy on the extensor system nor a bone fixation is
necessary.
The free tendon transfer is then deployed over the
recipient digit. Some surgical adjustments may be required
to adapt the flap to its recipient site. For example, lateral
resection of the metatarso-phalangeal plate may be
needed to narrow it, or full circumferential incision of
the flexor tube on the cruciform pulleys to lengthen it and
to fix the A2 and A4 annular pulleys exactly in their most
functional positions. The digital sheath is secured laterally
to the fibrous bundles by two continuous non-resorbable
sutures. The annular pulleys should be fixed in their
anatomical position. The distal stump of the FDP tendon
is secured with a Kleinert suture and protected with
a barbed wire for 4 weeks. Meanwhile, the proximal FDS
and FDP tendon stumps are repaired with the Pulvertaft
technique. The tendons are sutured with adequate tension,
the digits in a cascade position.
The second toe free flexor tendon auto-transfer is the
only one-step procedure for reconstructing complex flexor
tendon digit defects anatomically, dynamically and
functionally.
Figure 14 Functional results of the flexion system transfers with a combined skin flap: group B.

Results
Our clinical experience comprises six free tendon transfers.
All the patients started physiotherapy the day after the
operation according to the Duran protocol. The results are
as follwos: 4 good (2 grade III, 2 grade IV) 66.6%.
1 medium (1grade IV) 16.6%
1 poor (1 grade IV) 16.6%
Great improvement was achieved in 66,6% of patients
and none complained about the foot scar. Fig. 15.
Human allotransplant of a digital flexion
system vascularized on the ulnar pedicle
Introduction of cyclosporine in 1980 changed the indica-
tions and improved success rates in allovascularized
transplantations with the use of low, nontoxic maintenance
doses for these relatively weak antigenic response organs.
Ideas regarding tissue compatibility have evolved toward
more simplified techniques over the last few years. The
specific characteristics of the anatomic structure of the
ulnar vascular network, previous experience in homotendon
grafts,20
the use of low-dose cyclosporine, and the need to
improve functional results have all combined to produce
successful human vascularized allotransplants of a complete
digital system by microsurgery.21
Transplantation technique on a brain-dead
cadaver
The original procedure is described, based on our knowledge
of the ulnar blood supply of the flexor superficialis, especially
of the ring finger. The arm is placed in hyperabduction
to facilitate cooperation with the other surgical teams.
Figure 15 Free vascularized flexion auto transfer from the 1st toe. Right: Motion performances before. Middle: Transfer. Left:
After 1 year postoperative.
Figure 16 Free vascularized flexor tendon unit allotransplantation program. Right: motion performances before. Middle: A bi
flexor superficialis and profundus allotransplant after milking and washing, to be placed in a sterile refrigerated container. Layout
of the allotransplant before insertion. Left: After 1 year postoperative.

A tourniquet is applied just before aorta clamping. First, the
heart and liver are removed. Then nephrectomy can be
accomplished, a period during which the hand surgeon can
perform the procedure. These procedures take at least 2 h.
The various branches of the ulnar pedicle in the forearm
are identified. The flexor digitorum sublimis of the ring
finger is separated from the flexor digitorum sublimis of the
middle and small fingers and is dissected at the tendon-
muscle junction. All the tendon-nourishing pedicles coming
from the ulnar pedicle as well as all adjacent mesotendons
are carefuIly preserved.
The superficial palmar arcade is then clamped and
transected distally to the third common palmar digital
artery, conserving the two collateral pedicles inside the
transplant. The functional unit composed of the profundus
and superficialis tendon flexors and the entire pulley
system is then separated from the digital bone skeleton
using a medial-side access. Dissection is performed in the
subperiosteal plane along the skeleton of Pl, P2, and P3,
but the digital tendon sheath is not opened. On the radial
side of the ring finger, the procedure is the same. The only
remaining link between the structure to be transplanted
and the donor’s hand is now the ulnar pedicle itself.
The tourniquet is released, and vascularization is imme-
diate .The use of ulnar veins to ensure venous return has
been abandoned, and the veins of the forearm superficial
network, which are more suitable for microsurgery, are
preferred.
The ulnar pedicle is then ligated above the branch
supplying the skin, and the transplant is placed in a sterile
plastic container containing refrigerated serum at 4
C.
Insertion of the transplant. Insertion is performed by
means of barbed wires integrating the lateral structures of
the transplant into the periosteal edge of the recipient bed
on both sides at the base of Pl, the head of Pl, the base of
P2, and the head of P2. At P3, the anchorage is transbone.
Anastomoses. The proximal extremity of the flexor digi-
torum sublimis and profundus is passed under the superfi-
cial palmar arch of the recipient hand in order to avoid
vascular compression before being sutured to the distal
end of the recipient flexor digitorum profundus in the
manner of Pulvertaft. Extremities of the ulnar artery are
end-to-side anastomosed. The dorsal ulnar veins are also
anastomosed with recipient anterior forearm veins. Total
ischemia time is 3 h.
Functional results
A very good functional result was obtained 4 months later.
The wrist swelling had abated little by little, and since the
patient had no active motion preoperatively, the functional
result was considered as very good with a range of motion in
flexion of 80
in the proximal interphalangeaI joint and no
extension defect and a range of motion in flexion of 55
degrees in the distal interphalangeal joint with an exten-
sion defect of 35
. Fig. 16.
The average total active flexion almost equaled the
range of passive motion available. This finger is now very
functional and fully adapted.
Both of these techniques are to be used when all others
have failed. The interest of the procedures is to be able to
reconstruct all the pulleys, to keep the digital canal intact
and to avoid adherence. This is a highly challenging
approach technically speaking.
We present a completely new approach to flexor tendon
reconstruction for major salvage surgery. The use of an
islanded tendon vascularized by the mesotendon, with all
its gliding surfaces intact, is a major step forward in dealing
with adhesions and has the added merit of being a one-
stage procedure. These types of vascularized tendons or
tendon and skin transfers with multiple applications and
good functional results could set a trend in tendon re-
constructive surgery. We believe that the superior results
achieved to date suggest that this should be the gold
standard for such cases.
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