A fresh look at vascularized flexor tendon transfers

Journal of Plastic, Reconstructive & Aesthetic Surgery (2007) 60, 793e810

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 allee des tulipes, 33600 Bordeaux-Pessac, France

Received 20 October 2006; accepted 6 February 2007

KEYWORDSSliding systems;Secondary flexorreconstruction;Ulnar pedicle;Microvacuolarorganization;Allotransplantation

Summary The authors present the results of their surgical experience based on an originalapproach in secondary reconstructing 71 flexor tendons of the hand. For 20 years, they havebeen using vascularized tendon transfers either islanded or as free transfers. Their techniquesare 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 theirobservations 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 withthe tendon itself, thereby avoiding the two traditional stages of tendon reconstruction. Resultsare 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 oftransfers available offers possibilities for reconstruction that are better suited to the rangeof 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 byElsevier Ltd. All rights reserved.

From the outset, surgical principles concerning the re-construction of finger flexor tendons have centered on thetendon as a simple force transmission belt between themuscular structure, which is responsible for the creation ofthe force, and the mobile articulated structure, which is

* Corresponding author. Tel.: þ33 05 56 46 48 48; fax: þ33 05 5646 48 49.

E-mail address: [email protected] (J.C.Guimberteau).

a Tel.: þ33 05 56 46 48 48; fax: þ33 05 56 46 48 49.

1748-6815/$-seefrontmatterª2007BritishAssociationofPlastic,Reconstrudoi:10.1016/j.bjps.2007.02.021

bent by this force. Consequently, this very mechanicalconcept led to the development of techniques mainlyaiming at rebuilding this transmission belt as solidly aspossible. Until then, the nature of tendon biology had notbeen questioned because everyone was convinced of itsavascular nature and that its mechanical function simu-lated a transmission belt. From the 1940s onward, a signif-icant body of research has accumulated confirming thehealing difficulties of tendons, the major reason beinginsufficient collagen production. Instead, the notion de-veloped of so-called vascular survival connections through

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794 J.C. Guimberteau et al.

adhesion to the peripheral tissue. This was thought largelyto diminish the sliding capacity of the tendons as well astheir functional recovery.

Potenza introduced the essential notion of vascularadhesion.1 From then on, authors sought to adapt theirideas to this apparently unavoidable concept of tendon ad-hesion and to lessen its importance in order to optimize thesliding capacities of the structures. Nevertheless, the con-cept of tendon adhesion was not completely suppressed.Attempts to understand why tendons need vascular orpseudo-vascular connections were put in abeyance. Indeed,some research quite frankly tended to minimize the roleof vascularization. These discoveries practically froze re-search and techniques for several years because it seemedpointless to carry out any research if one took as a foundingprinciple that tendons are only very slightly vascularizedand 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 andthe receiver site. Catgut leaves, mersilene and silicon weregradually introduced and showed their efficacy but to thedetriment of tendon solidity as they suppressed theseadhering vascular connections. Rupture due to necrosisalso became a major complication. The fact that tendonsneed this adhesion in order to survive was acknowledged,as was its detrimental effect on sliding and functionaloutcome. For several decades, research was aimed atdecreasing the frequency of adhesion and optimizingfunctional results. Yet two antagonistic factors had to bereconciled: healing without sliding and sliding with the riskof rupture.

From the outset, these techniques have required avas-cular tendon grafts using different types of tendon such asthe palmaris longus, the plantaris and others.3 Numeroussuggestions were made but little by little, the two-stagetechniques became popular. Termed two-stage tenoplastyby James Hunter and Paneva Olevitch, it required a two-stage operational sequence 4,5 Firstly, a silicon cord capableof recreating the conditions of a synovial sheath is inserted.A tendon transfer is then carried out either by grafting or bytransferring a superficial flexor previously stitched to the re-maining flexor profundus in the first stage and thus ensuringthe 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 onlyapproached 50% . The daily practice of every surgeon dem-onstrates that the two-stage technique necessitates at leastsix months, thus discouraging numerous patients and sur-geons owing to the time factor and to the poor quality ofthe functional result. Moreover in the mid to long term,the outcome becomes less satisfactory with the fingers oftenretracting in flexion.

However, these techniques obey a certain mechanicallogic. In fact, the transmission cord principle persists byoptimizing the solidity of the stitching in the first stage ofthe operation. An attempt is made to solve the biologicalproblem by trying to create sliding conditions with a syno-vial pseudo-sheath. This surgical approach aims at adaptingto the problem of adhesion formation by doing everythingpossible to obtain the rather strange concept of ‘suppleadhesion’ Although this principle may represent enormous

progress compared to the past, it has no real futurebecause the biological realities and imperatives are notrespected. The poor results achieved and the difficultiesencountered, as well as surgical observations during otherprocedures, led some surgeons to question the veryfoundations of what others had believed for years abouttendons, their supposed avascular nature and mechanicalrole like a transmission belt.

In all the above-mentioned techniques, the tendon wasalways non-vascularized and placed in a more or lesssclerotic receiver site with the impossible mission of bothhealing and sliding at the same time. Other research byPeacock, Smith and Bellinger, and others demonstrated thatthe tendon is a perfectly vascularized organ with a vasculardistribution that is both intrinsic and extrinsic, as well ashaving a very specific lymphatic drainage system6e9 Further-more, no physiological or microanatomical explanationshave been proposed to date for the concept of virtual spacebetween the tendon and the sheath in zones III, IV and V.Present-day techniques remain completely alien to thesenew biological realities and continue either to ignore themor, at least, to exclude them from surgical applications.

Not only is better knowledge of the intimate physiologyof the tendon vital, but also the conditions favoringoptimum function must be understood. First we exploredthe organic and physiological pathway at a fundamentallevel.

For many decades, terms such as elasticity, mobility,hierarchical tissue distribution, stratification and virtualspace between organs have been taken for granted, yet thereal basis for them needs to be questioned. Their scientificunderpinnings were limited to the notion of virtual space orthe existence of loose connective tissue, but the bio-mechanical foundations for these theories were morethan vague. In the last 50 years, research has focused onthe microscopic level while the global concept of meso-sphericity has been abandoned. As time has gone by, and asresearchers have examined these tissues more closely, newhypotheses have emerged concerning the organization ofthe subcutaneous tissues and led to a new concept, thecreation of a model and to new surgical procedures.10

Material and method

Microvideo-observations and analysis inzones 3, 4 and 5.

We have performed 95 video observations in vivo withfunctional analysis, either directly under the skin or closeto tendons, muscle and nerve sheaths during human surgicaldissection using light microscopy (magnification �25).

This gliding or sliding of tissue, which is traditionallycalled ‘connective’, ‘areolar’ or ‘loose tissue and para-tenon around the tendons,’ has for long been considered tobe ‘packing tissue’ that fills spaces between and withinorgans. In fact, this tissue plays a mechanical role, allowingmovements between the structures it connects, preservingmobility and independence between organs and, in partic-ular, between tendons and skin. This tissue is important forthe nutrition of the structures embedded in it and acts asa frame for blood and lymph vessels Fig. 1.

A look at vascularized flexor tendon transfers 795

Figure 1 (a) Traction on the paratendon during surgery. (b) Searching for an epitendinous plane. (c) Network between the tendonand the peripheral system: the M.V.C.A.S. (d) Epitendinous dissection exposes the sliding system M.V.C.A.S.

However, itsmechanical significance ismajor; itdiminishesfriction while facilitating deformability and adaptability.

This collagenous system, traditionally known as theparatendon, can be seen surrounding the tendon. It iscomposed of multidirectional filaments, intertwining andcreating partitions which enclose microvacuolar shapesFig. 2. We term this the Multimicrovacuolar Collagenous Dy-namic Absorbing System (M.V.C.A.S.) in order to emphasizeits functional involvement. This system is situated betweenthe tendon and its neighboring tissue and seems to promoteoptimal sliding. The tendon is able to travel far and fastwithout any hindrance, and without inducing movementin any other neighboring tissue, thus accounting for theabsence of any dynamic repercussions of movement onthe skin surface. When the flexor tendon moves, its move-ment is barely discernible in the palm. In the light of newinformation obtained from dissections of fresh or forma-lin-treated cadavers, the time has come to confirm someanatomical truths about this tissue and to definitively dis-card certain preconceived ideas.

Traditional concepts are at variance with anatomicalreality. The notion of multilayered sliding between com-pletely anatomically separate tissues d sliding thanks towhat many believe to be an elastic process d has to berevised in the light of all these observations. The theory ofdiscontinuity in separate layers should now be abandonedin favor of the noting of continuous matter and micro-vacuolar framework.11,12 Electron microscope scanning de-molished the existence of different superimposed layersbecause they were never observed. Furthermore, the ele-mentary laws of mechanics and rheology presented theproblem in terms of global dynamics where continuous

matter composed of millions of vacuoles, each measuringa few microns to a few millimeters in size, is organized indispersed branching fractal patterns Fig. 3. The sides ofthe 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 wayof perceiving the problem of reconstruction. These obser-vations demonstrating the real histological continuity be-tween the paratenon, the common carpal sheath and theflexor tendons illustrate the perfect vascularization ofthis functional ensemble. They are innovative in that theyintroduce a new concept: the SLIDING UNIT, composed ofthe tendon and its surrounding sheaths.

From now on, Potenza’s principle, involving tendonadhesions and reconstruction of the digital sheath using asilicon rod, should be set aside in favor of other principles.

/ A tendon only has optimal functional value when it issurrounded by its original sliding sheath and its vascularheritage.

/ A tendon is adherent only when it is artificially separatedfrom 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 thetransmission of force through the sliding unit.

For zones III, IV, and V, the authors set out to definea different role for the tendon in the production andtransmission of a force. The tendon is not a transmissionbelt acting in the carpal sheath surrounded by a virtualspace; nor is it an organ that is avascular or only veryslightly vascularized. The tendon is not nourished by the


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.

synovial fluid, but by its own vascular system like everyorgan. It is one of the main constituent elements butthanks to the M.V.C.A.S can no longer be dissociated fromits sheath. It subtends the tendon-sheath couple and themajor role of the vascularization with peripheral collagenorganization. Moreover it has a fundamental biologicalconsequences.

The basic principles for a new method ofreconstruction

The idea is to transfer en bloc a digital flexion unit composedof the flexor tendon with the sliding sheaths from zones 3, 4and 5 to zones 1 and 2 in a single step. The strategy forsecondary reconstruction is therefore totally changed. Thisnew technique is now used for the reconstruction of fingerflexor 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 forminga sliding unit Fig. 4.

In order to conform to these two basic principles, theproposed new technique must satisfactorily answer threebasic questions.

(1) Which sliding zone should be used to replace zones Iand II, which are subject to so many problems and com-plications? The mesotendon and its vascular branchesprovide good vascularization of the flexor tendon andthe sliding carpal sheath both extrinsically and intrinsi-cally. The structure thus transferred is a real slidingstructure which already exists naturally in zones III, IVand V.

(2) How will the replacement flexion structure bevascularized?

Vascularization is ensured by a pre-retinacular meso-tendon with branches arising from the ulnar artery. Atthe inferior third of the wrist, just before the flexorretinaculum carpi or the annular ligament, the latter hastwo or three branches of around 1 mm in diameter. Thesebranches pass through the common carpal sheath towardsthe superficial flexor tendons, especially those of themiddle finger, the ring finger and the little finger, byway of a fine transparent mesotendon acting as a mesen-tery. This vascular approach to the flexor system and thecommon carpal sheath is made distal to the tendon-muscle junction, thus allowing the concept of retrogradeisland transfers to be adapted to purely tendinousstructures.

(3) How is the sliding unit positioned in No Man’s Land?Fig. 5.


Figure 3 (a) Microvacuola inside the MCVAS. (b) Magnification M.V.C.A.S. under the electron microscope. (c) A microvacuola witha hexagonal shape. (d) Microvacuola is filled with GAG and the frame contains collagen type I, III and IV.

Nowadays, the technique of island retrograde forearmtransfer is used to transfer a forearm or wrist structurepedicled on an arterial axis. For retrograde vascularizedtendon transfer, only the ulnar-based pedicle is suitableowing to its distally based palmar point of rotation and toits branch transmission at the level of the tendon. Sincethere are many clinical circumstances and forms of tissuedestruction, this surgical technique has been developedover time to include a wide range of variants.

A safe and generous anatomy

Arteries

The ulnar artery runs parallel to the nerve in a valleysurrounded laterally by the flexor carpi ulnaris and mediallyby 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 isrelatively superficial in the lower and middle compart-ments. However, in the upper compartment, the cutaneo-vascular relationships are less clear and the raising ofa reverse island flap is thus more problematic. Cutaneousvascularization is ensured by a series of two to four smallpedicles linked to the main pedicle through the fascia. Thevessels are about 1 cm long and 1 to 3 mm in diameter.Since the small pedicles lie 15 to 25 mm apart, each flapusually contains at least two pedicles of good quality. Inall 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 twovenous systems, the venae comitantes of the ulnar arteryand the superficial system, whose veins are of largerdiameter. Both systems have abundant anastomotic net-works, which make it easy to raise both free and pedicledflaps.

Technical aspects: the various basicprocedures

� Basic procedure for the transfer of the flexorsuperficialis of the ring finger

TechniqueThe basic procedure consists of the transfer of the flexorsuperficialis tendon of the ring finger to repair any type oftendon defect. Preoperative evaluation includes Allen andDoppler tests to ascertain that the radial artery providesadequate blood supply to the hand. Angiography of the armis also advisable. A bayonet-shaped incision is first tracedand then made on the medial side of the forearm, the axisof the incision overlying the lateral border of the flexorcarpi ulnaris. The ulnar pedicle is dissected and all its


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.

branches are carefully separated and divided. First thecutaneous branches between the ulnar artery and the skinare then carefully isolated. These emerge from the volaraspect of the pedicle and are the principal components ofthe ulnar forearm flap. These branches should be dividedonly when skin transfer is not required. The ulnar pedicle isthen separated from the ulnar nerve on its dorsal aspectalong its whole length from the lower third of the forearmto Guyon’s canal. On the posterior wall of the pedicle, thebranches for the ulnar bone and ulnar styloid are thenidentified. The branches on the anterolateral side emergingjust before Guyon’s canal are those supplying the commoncarpal sheath and the flexor sliding system. These smallbranches are orientated forward and arborize into thecommon carpal sheath, the multimicrovacuolar absorbingsystem, the epitendon and the endotenon. They emergefrom 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 sheathand its vascular connections from the ulnar pedicle Fig. 7.These connections, usually comprising two or three smallbranches on the anterolateral side and measuring on aver-age 0.2 to 0.5 mm in diameter, are found just before theproximal edge of the flexor retinaculum. At the level ofthe A1 pulley, strong traction on the tendon makes possiblethe section just at the beginning of the decussation, therebyavoiding dilaceration of the vinculum longum of the flexorprofundus.

Then the myo or musculo-tendinous junction of the FS issectioned. All the MVCAS comprising the common carpalsheath surrounding the tendon transfer is kept in place, thusensuring a real vascular connective link defining the conceptof mesotendon. After proximal ligation of the ulnar pedicle,dissection and ligature of all the other branches of the ulnarpedicle to the deep arch division are performed to obtaina rotation point at the level of the deep branch. A compositemesotendinous island transfer 20 cm long is then raised, aswith any reversed forearm flap.

Like any reversed forearm flap, the sliding unit, which ispliable and plastic, is transferred to the distal part of thehand in order to provide a complete flexor tendon unit forany finger from the pulp to the wrist. The naturalcollagenous organization of the tendon is preserved andthe distal extremity remains distal. The whole proceduretakes 3 hours: 1 hour for finger dissection and preparation,1 hour for raising the transfer and 1 hour for insertion andclosure. The rest of the operation follows conventionalprinciples of tendon surgery. The tendon area wrapped inthe common carpal sheath is laid into the ‘no man’s land’beneath the A2 and A3 pulleys, which must be carefullypreserved or solidly reconstructed, since the tendon trans-fer exposes them to much greater strain than a simpletendon graft. The pulley system is not a very easy problemto solve. From the beginning of dissection, we prefer toreuse the remaining sclerotic components of the tendon orpulley, and to tunnelize and preserve the strong attach-ments. Sometimes, pulleys previously preserved are toonarrow and require careful dilatation.


Figure 5 Transfer of a sliding flexion unit composed of a flexor tendon and its surrounding sheaths in a reverse island pedicledmanner. Stage 1: Mesotendon identification. Insert: the mesotendon. Stage 2: Section of FS IVth and ulnar pedicle. Island ulnartendon transfer isolated. Stage 3: Insertion of the island transfer into digital zone. Stage 4: Tendon sutures outside of the no man’sland and pulley reconstruction.

It is better to rebuild a pulley in good condition than tokeep one where the transfer and its blood supply arestretched. The transfer is first inserted into the distalphalanx by means of a ‘barbed wire’ suture. The proximalsuture with the distal extremity of the relevant flexorprofundus is performed using Pulvertaft’s method. Thetension on the suture is easy to assess and should beslightly overcorrected in comparison with the other fingers.On completion of the procedure, a dynamic Kleinert-typesplint 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 ringfinger for flexor profundus reconstruction withflexor superficialis in place

TechniqueThis procedure was first attempted after much reflexionand with good experience of the basic procedure obtainedin 30 cases of flexor transplants. There is no fundamentaldifference in the dissection and the transplant elevation.The most difficult thing is to respect the flexor superficialisand the chiasma. Because the thickness of the two tendonstogether is narrowed, the A1 and A2 pulleys sometimesmake the procedure difficult. The delay seems to influencethe narrowing of the pulleys. The pulleys may be widened

by mechanical manipulations, thus avoiding rupture, butthis procedure is not easy. Otherwise, strong pulley re-construction is mandatory. Our functional results obtainedto date have been surprisingly good and very oftenexcellent. In good practical conditions, the results aremuch better than with a tenodesis or an arthrodesis.

� Combined island flexor superficialis tendon andpalmaris brevis transfer for flexor and pulleyreconstruction

TechniqueFor a long time we used the Welby procedure for pulleyreconstruction. However, the idea arose of using thePalmaris Longus as another vascularized island tendon onthe same mesotendon as the Flexor superficialis. It istransferred at the same time as the flexor superficialis.Like the Welby procedure, we use it with a periosteumwedge suture as cross lacing from A1 to A4.

Before suturing, the sliding of the implanted tendon hasto be checked.

� Composite flexor tendon and skin flap transfer

This constitutes the main advantage of this group ofprocedures, and allows the skin problem and tendonreconstruction to be solved at the same time. Fig. 8.


Figure 6 (a) Various vascular branches emerging from the ulnar artery in front of entrance to Guyon’s canal. Bone, skin, flexortendons. (b) Because of the very distal rotation point of the ulnar pedicle compared to radial pedicle, placement can be performedwithout technical difficulty. (c) Vascular branches running from the anterolateral side of the ulnar pedicle to the flexor superficialisof the fourth finger. (d) Mesotendon and its vascular connections from the ulnar pedicle is acting as a true mesentery.

TechniqueIn the lower third of the forearm, the ulnar pedicle not onlysends branches to the flexor superficialis tendons but alsoto the skin. These branches are easily identified, beingclose to the mesotendon branches and constantly ofexcellent caliber, allowing simultaneous composite transferof the skin and tendon.15 Slight upwards traction on the in-ternal edge of the flap reveals the small vertical pediclesarising from the ulnar artery that vascularize the skin. Afteridentifying the skin flap pedicle, complete flap dissection isperformed. 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 ofthese cutaneous branches, the skin transfer can be rotatedand positioned on the digital surface without changing thephysiologic direction of the tendon fibers.

The proximal extremity of the flap is placed distallyafter 180� rotation. The skin is closed tension-free, pro-viding good healing without skin disunion or necrosis. This isof fundamental importance for achieving a good functionalresult.

AdvantagesThe operation is very reliable, with almost completeabsence of sequelae. The anatomic presentation is con-stant, since at least one good-sized artery could be found inall patients. The flap has 360� mobility around a rotation

point in the palm, which makes the entire skin surface ofthe hand and digits accessible. This is not the case with theradial flap. Tissue quality is excellent, being fine, fat-freeand virtually hairless. There are no sequelae at the donorsite, since the scar on the forearm is usually very fine andnot hypertrophic. The technique allows for further de-velopments such as sensory innervation (by means of themedial cutaneous branches of the ulnar nerve).

IndicationsIn cases with huge skin palmar digital retraction after manyprevious procedures, the main problem is skin repair. Aplain skin graft can never solve this difficulty. In some caseswhere the overlying skin is extremely scarred and of poorquality, particularly at the base of P1 or P2, it would beimpossible to replace the flexor tendon and achieve earlymotion. Skin of this sort inevitably breaks down or necro-ses, compromising the functional result, so it should bereplaced. Fig. 10. The solution is to perform a safe skin flapat the same time as tendon reconstruction, thereby makingearly motion possible.

� Ulnar trail

The wide variety of composite flaps made possible by theulnar pedicle at the inferior third of the forearm offersmany solutions to a large number of clinical presentationsand surgical reconstructive requirements. For example, it ispossible to perform a double skin flap with one or two flexor


Figure 7 (a) The mesotendon and ulnar artery branches. Flexor superficialis transfer after section at the level of chiasma andbefore section at the tendineomuscular junction. (b) After tendinomuscular section and before ulnar artery section. (c,d) Slidingsystem 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.

tendon transfers, or a skin flap with a flexor tendon forreconstruction and a palmaris longus as an islanded transferfor pulley repair. It is also possible to add a bone transfer atthe same time16 Fig. 11.

Discussion

This new technique using a mesovascular tendon island,which is now our standard procedure for Boyes grade III orIV cases, is likely to set the trend for future flexor tendonsurgery because the requisite tendon reconstruction can becarried out in one operation. Compared with all othertendon graft techniques, the advantages of this techniqueare as follows. It makes use of a living tendon islanded on athin mesotendon with vascular branches, providing a per-fect blood supply to all areas both extrinsic and intrinsic. Itthus avoids adhesions and improves the vascularity of thesurrounding tissues. Since the transfer is a real vascularizedflexor tendon and not a simple avascular graft, it retains itsflexibility, pliability and resistance and allows the correcttension to be achieved. Because the vascular network isspared, all the sheaths are also spared. The MVCAS and inparticular the carpal sheath (which is transposed into a ‘noman’s land’) retain the unrestricted gliding movementof the tendon. The length of the tendon transfer is

approximately 18 to 20 cm. This allows easy reconstructionof any type of flexor tendon defect from the pulp to thecarpal area. Thus the tendon repairs are not under tensionand lie outside ‘no man’s land.’ Because of the very distalrotation point and the plasticity and versatility of the mes-otendon, the placement and anchoring procedures needcareful 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 anatomicallyconstant and dissection takes approximately the sameamount of time as a reversed-flow forearm skin flap (approx-imately 90 minutes). This is a ONE-STAGE PROCEDURE sparingall the gliding surfaces, which means that recipient bedpreparation by a pseudo-synovial sheath using a silicone rodis unnecessary. However, all the pulleys have to be repairedcarefully because the traction exerted by this type of tendonhas been found to be greater because the tissue resistance islesser. The radial forearm flap does not allow transfer of thecommon carpal sheath and the flexor tendon because theradial pedicle supplies them only at the myotendinous leveland its point of rotation is tooproximal. Thenewtechniqueofcomposite transfer described in this paper is specificallyconfined to the ulnar vascular system and may be conve-niently termed the ulnar trail system.


Figure 8 Diagramm of a transfer of a sliding flexion unit composed of a flexor tendon andþ skin island flap. Stage 1: Mesotendonand skin branches identification. Stage 2: Section of FS IVth and ulnar pedicle. Island ulnar tendonþ 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.

The main disadvantage of our technique is the need totransect the ulnar pedicle. However, in our experience of539 cases of all varieties of ulnar transfers, no undesirablelong-term effects such as paresthesia or functional deficitshave been encountered 1 year after surgery. It is neverthe-less preferable to restore arterial continuity either bya venous graft or a vascular prosthesis 2 mm in diameter.

Assessment of results

It is almost impossible to evaluate the results of tendonreconstruction operations by any statistical method. Thereare so many variables; e.g. the type and extent of theinjury, the age of the patient, the accompanying injuries ofnerves and vascular structures and the procedures used ethat only general conceptions, based on experience, can beused.

‘‘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-economicstatus and desire for future employability have an impacton functional outcome. All of these factors must be takeninto consideration in determining the aim of reconstruc-tion, in choosing the type of procedure to be done andevaluating the results.

Many systems of evaluation have been proposed. We usethe TAM with Strickland’s modifications18,19 system becauseit is based on an international methodology. Nevertheless,the arithmetical addition of degrees between extensionand flexion compared with the hypothetical maximum

amplitude, while not distinguishing between metacarpo-phalangeal joint and proximal interphalangeal or distalinterphalangeal joints, would seem debatable for thissort of salvage situation. A significant alteration of meta-carpophalangeal joint movement only rarely occurs. Clearlyin such cases, the principal aim is to restore effective anduseful function, including grip, and especially to achieverecovery of good proximal interphalangeal joint movement.For heavily damaged fingers, too many unfavorable factorsare present to be able to achieve a 100 percent result, andthe patient should be informed of this. More importanceshould 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 asfollows:

Class III: Patients in whom the range of passive motion inthe proximal interphalangeal or distal interphalangealjoints was restricted even after a period of elastic traction.

Class IV: Patients with all possible complicating factorssuch 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 thesecircumstances, we use a composite skin and flexor tendontransfer.

Our study was divided into 3 groups:

Group A: 16 patients, including 11 grade III and 5 grade IVpatients in whom flexor superficialis transfers were used;Group A’: 12 patients in whom only the flexor profunduswas ruptured were repaired by islanded flexor superficialis;


Figure 9 Raising of the composite flexor tendonþ 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 mesocutaneousand 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 inthe same time as tendon system reconstruction.

Group B: 35 grade IV patients needing skin transfers andhaving either major skin retraction due to a skin gap orskin stiffness accompanied by either vascular or nerve prob-lems with fragile skin where composite skin and flexorsuperficialis 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 healingproblems during early mobilization inducing pain and in-flammation and requiring dressing. We now prefer to adda skin flap in order to reinforce cicatrization, even if slightremodeling under local anesthesia may be required severalmonths 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 poorresults so a tenodesis or arthrodesis is usually performedinstead. However, in our opinion and with the experiencegained, we felt that the technique was indicated in youngsubjects such as rugby players. The results were beyond


Figure 10 Various cases of palmar skin retraction needing a flexor system restoration and skin resurfacing with a compositeflexor 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 flexorsuperficialis tendon and palmaris longus transfer for pulley reconstruction. (i) Composite skinþ flexor tendonþ bone transfer.


Figure 12 Functional results of the flexion system transfers: group A.

anything we expected since performing range of motionwas obtained in 75% of cases. Nevertheless, the techniqueis extremely intricate and is indicated only in youngsubjects capable of following stringent rehabilitation.

To date, there have been 12 cases: 4 excellent, 5 goodand 3 poor, including 2 who preferred not to have jointarthrodesis after intervention. Four cases (30%) requiredtenolysis, which revealed the excellent state of the trans-ferred tendon. Any adherences found were always locatedaround the tendinous anastomoses. Tenolysis performedobtained 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 skinbecomes more supple and sensitive, joints are less stiff andare mechanically active, and flexion is improved.

Overall, 42 patients (66.6%) achieved an excellent, orgood result compared to an average of 55% in series wheresimilar cases are operated using the two-staged procedurewith or without a silicone rod. However, in this particular

field, precise evaluation of results is a real challenge, andin many previous publications results have been evaluatedby different methods, rendering true comparison difficult,if not misleading. What is sure is this new technique seemsto give better functional performance and reduces time lostfrom work.

Twenty years on

These procedures have now become routine practice. Theyare safe, technically easy to perform and above all providesolutions to problems which often led to amputations orarthrodesis in the past. Only one patient requested anamputation since he was unable to carry plasterboardpanels owing to a problem with his index finger.

Nevertheless, the functional outcome of patients has notimproved in the last 15 years. The percentages are still asthey were originally since factors influencing the quality ofoutcome go far beyond the purely technical or surgical. Theway the patient evolves is of paramount importance andis of course unpredictable. There is his tissue quality,whether pain or edema is present, and the duration ofthe post-operative phase. Other factors to be taken intoconsideration are the patient’s own will to get better andthe skill of his physiotherapist. Smoking and the relative


Figure 13 Functional results of the flexion system transfers for cases of rupture of the flexor profundus with flexor superficialisintact: group A’.

proximity of a specialized rehabilitation team are alsomajor factors.

Regrettably, some flexor tendon island transfers werenot performed when, during a tenolysis, the tendons werecontinuous but of poor quality. The outcome one day laterwas a ruptured tendon. The functional outcome in suchcases was very poor. As regrettable are the cases in whichskin transfers were not performed in patients in whom post-operative difficulties occurred owing to dehiscence. From1996, we changed our approach and now perform moreoften composite skin and tendon transfers. In complextendon reconstruction, the approach must be sound, well-founded, offering totally manageable post-operative solu-tions. . Sometimes a tenolysis may be required. It leads tovery good results because it is performed on a living tendonand not just on a collagenic graft. The combined skin flapreshaping allows second-look surgery to be done in goodconditions of cicatrisation and facilitates immediate re-habilitation, which is a major advantage. About 539 ulnarflaps of all type have been performed over 20 years and nocomplication has ever occurred with sectioning of the ulnarpedicle.The psychological impact for patients is verypositive because they do not feel they are being abandonedfor a few months. Rehabilitation can be begun straightawaysince all the technical issues are now resolved. This is alsotechnically satisfying for the surgeon.

Other experience using vascularized flexortendon autotransplants and homotransplants

These types of ulnar vascularized tendons or tendon andskin transfers with multiple applications and good func-tional results could set a trend in tendon reconstructivesurgery, even though these techniques cannot be used in allindications. Other kinds of vascularized tendons transferscan be used for different indications.

Toe-to-finger free flexor tendon transfer fordigital flexion reconstruction

In view of the concept of pedicled tendon transfer, which isnot necessarily the first line in cases where the entireflexion mechanism is damaged, we transferred the flexormechanism of the second toe as a free composite flap andrepaired the flexor tendons, digital sheath and palmarplates of a long finger en bloc and in a single operation.

Operative technique

On the donor site, the tendon is approached througha plantar incision from the medial side of the second toeto the mid plantar area. The plantar fat is retracted and the


Figure 14 Functional results of the flexion system transfers with a combined skin flap: group B.

plantar aponeurosis is transected, exposing the second toeflexor 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 sheathby 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 isharvested from distal to proximal. Concerning the vascularsupply of the toe flexor system, it depends on the medialcollateral digital artery which is a terminal branch of thefirst common plantar digital artery, a branch itself of themedial plantar artery. Venous drainage is carried out bythe constant comitantes veins.

There are two different anatomic types. In type I, whichis present in 50% of the cases, the second toe medialcollateral artery arises directly from the first commonplantar digital artery, giving a long vascular pedicle. Intype II, i.e. the other 50% of cases, the second toe medialcollateral artery arises from the medial branch of the medialplantar artery beneath the big toe flexor tendon and hasa short vascular pedicle. Dissection is performed on the

phalangeal sub-periosteal plan elevating the whole flexortoe system with the two tendons, the eight flexor pulleysand the three plantar plates with their vascular supply.The flexor tendons are transected as far as the flexor digitdefect requires and the vascular pedicle is freed as far aspossible depending on the anatomical type. Finally, thedonor site is closed, primarily with skin adjustment. Neithera tenotomy on the extensor system nor a bone fixation isnecessary.

The free tendon transfer is then deployed over therecipient digit. Some surgical adjustments may be requiredto adapt the flap to its recipient site. For example, lateralresection of the metatarso-phalangeal plate may beneeded to narrow it, or full circumferential incision ofthe flexor tube on the cruciform pulleys to lengthen it andto fix the A2 and A4 annular pulleys exactly in their mostfunctional positions. The digital sheath is secured laterallyto the fibrous bundles by two continuous non-resorbablesutures. The annular pulleys should be fixed in theiranatomical position. The distal stump of the FDP tendonis secured with a Kleinert suture and protected witha barbed wire for 4 weeks. Meanwhile, the proximal FDSand FDP tendon stumps are repaired with the Pulvertafttechnique. The tendons are sutured with adequate tension,the digits in a cascade position.

The second toe free flexor tendon auto-transfer is theonly one-step procedure for reconstructing complex flexortendon digit defects anatomically, dynamically andfunctionally.


Figure 15 Free vascularized flexion auto transfer from the 1st toe. Right: Motion performances before. Middle: Transfer. Left:After 1 year postoperative.

Results

Our clinical experience comprises six free tendon transfers.All the patients started physiotherapy the day after theoperation according to the Duran protocol. The results areas 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 patientsand none complained about the foot scar. Fig. 15.

Human allotransplant of a digital flexionsystem 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 maintenancedoses for these relatively weak antigenic response organs.Ideas regarding tissue compatibility have evolved towardmore simplified techniques over the last few years. Thespecific characteristics of the anatomic structure of theulnar vascular network, previous experience in homotendongrafts,20 the use of low-dose cyclosporine, and the need toimprove functional results have all combined to producesuccessful human vascularized allotransplants of a completedigital system by microsurgery.21

Transplantation technique on a brain-deadcadaver

The original procedure is described, based on our knowledgeof the ulnar blood supply of the flexor superficialis, especiallyof the ring finger. The arm is placed in hyperabductionto facilitate cooperation with the other surgical teams.

Figure 16 Free vascularized flexor tendon unit allotransplantation program. Right: motion performances before. Middle: A biflexor superficialis and profundus allotransplant after milking and washing, to be placed in a sterile refrigerated container. Layoutof the allotransplant before insertion. Left: After 1 year postoperative.


A tourniquet is applied just before aorta clamping. First, theheart and liver are removed. Then nephrectomy can beaccomplished, a period during which the hand surgeon canperform the procedure. These procedures take at least 2 h.

The various branches of the ulnar pedicle in the forearmare identified. The flexor digitorum sublimis of the ringfinger is separated from the flexor digitorum sublimis of themiddle and small fingers and is dissected at the tendon-muscle junction. All the tendon-nourishing pedicles comingfrom the ulnar pedicle as well as all adjacent mesotendonsare carefuIly preserved.

The superficial palmar arcade is then clamped andtransected distally to the third common palmar digitalartery, conserving the two collateral pedicles inside thetransplant. The functional unit composed of the profundusand superficialis tendon flexors and the entire pulleysystem is then separated from the digital bone skeletonusing a medial-side access. Dissection is performed in thesubperiosteal plane along the skeleton of Pl, P2, and P3,but the digital tendon sheath is not opened. On the radialside of the ring finger, the procedure is the same. The onlyremaining link between the structure to be transplantedand 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 hasbeen abandoned, and the veins of the forearm superficialnetwork, which are more suitable for microsurgery, arepreferred.

The ulnar pedicle is then ligated above the branchsupplying the skin, and the transplant is placed in a sterileplastic container containing refrigerated serum at 4 �C.

Insertion of the transplant. Insertion is performed bymeans of barbed wires integrating the lateral structures ofthe transplant into the periosteal edge of the recipient bedon both sides at the base of Pl, the head of Pl, the base ofP2, 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 avoidvascular compression before being sutured to the distalend of the recipient flexor digitorum profundus in themanner of Pulvertaft. Extremities of the ulnar artery areend-to-side anastomosed. The dorsal ulnar veins are alsoanastomosed with recipient anterior forearm veins. Totalischemia 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 thepatient had no active motion preoperatively, the functionalresult was considered as very good with a range of motion inflexion of 80� in the proximal interphalangeaI joint and noextension defect and a range of motion in flexion of 55degrees in the distal interphalangeal joint with an exten-sion defect of 35�. Fig. 16.

The average total active flexion almost equaled therange of passive motion available. This finger is now veryfunctional and fully adapted.

Both of these techniques are to be used when all othershave failed. The interest of the procedures is to be able to

reconstruct all the pulleys, to keep the digital canal intactand to avoid adherence. This is a highly challengingapproach technically speaking.

We present a completely new approach to flexor tendonreconstruction for major salvage surgery. The use of anislanded tendon vascularized by the mesotendon, with allits gliding surfaces intact, is a major step forward in dealingwith adhesions and has the added merit of being a one-stage procedure. These types of vascularized tendons ortendon and skin transfers with multiple applications andgood functional results could set a trend in tendon re-constructive surgery. We believe that the superior resultsachieved to date suggest that this should be the goldstandard for such cases.

References

1. Potenza AD. Critical evaluation of flexor-tendon healing andadhesion formation within artificial digital sheath. J. BoneJoint Surg 1963;45A:1217.

2. Lundborg G, Holm S, Myrhage R. The role of the synovial fluidand tendon sheath for flexor tendon nutrition. Scand J PlastReconstr Surg 1980;14:99.

3. Littler JW. Free tendon grafts in secondary flexor tendon re-pair. Am J Surg 1947;74:315.

4. Hunter JM. Artificial tendons. Their early development and ap-plication. In: Proceedings of the American Society for Surgeryof the Hand. J Bone Joint Surg 1965;47A:631e2.

5. Paneva Holevitch E. Resultats du traitement des lesions multi-ples des tendons flechisseurs des doigts par greffe effectuee endeux temps. Rev Chir Orthop Repar 1972;58:481.

6. Verdan CE. The decades of tendon surgery. In: American Acad-emy of Orthopedic Surgeons Symposium on Tendon Surgery. St.Louis: Mosby; 1975.

7. Smith JW, Bellinger CG. La vascularisation des tendons. In:Tubiana R, editor. Traite de la Chirurgie de la Main, vol. 1.Paris: Masson; 1986. p. 375e80.

8. Zbrodowski A, Gajisin S, Grodecki J. Mesotendons of digitalflexor muscles and their vasculature. Hand 1981;13:231.

9. Schatzker J, Branemark PI. Intravital observation on the micro-vascular anatomy and microcirculation of the tendon. ActaOrthop Scand Suppl 1969;126:23.

10. Guimberteau JC, Kleinert H, Verdan Cl. New ideas in handsurgery; island vascularized flexor tendon transfers, the slid-ing system Aquitaine Domaine Forestier. 56 allee desTulipes. Pessac 33600: Institut Aquitain de la Main, ISBN 2-84023-268-5, http://www.livres-medicaux.com; 2001. 210 p.

11. Guimberteau JC, Bakhach J. Subcutaneous tissue function:the multimicrovacuolar absorbing sliding system in handand plastic surgery. In: Siemonov Maria Z, editor. Tissue Sur-gery. New Techniques in Surgery. Springer; 2006. p. 41e54[Chapter 4].

12. Guimberteau JC, Sentucq-Rigall J, Panconi B, et al. Introduc-tion to the knowledge of subcutaneous sliding system inhumans. Ann Chir Plast Esthet February 2005;50(1):19e34[Microchirurgie].

13. Guimberteau JC, Panconi B, Boileau R. Mesovascularized islandflexor tendon: new concepts and techniques for flexor tendonsalvage surgery. Plast Reconstr Surg 1993;92(5):888e903.

14. Guimberteau JC, Goin JL, Panconi B, et al. Tendon ulnar arteryand island flap in hand surgery: technique, indications. Eur JPlast Surg 1989;12:12.

15. Guimberteau JC, Goin JL, Panconi B, et al. The reverse ulnarartery forearm island flap in hand surgery: about 54 cases.Plast Reconstr Surg 1988;81:925.

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16. Guimberteau JC, Panconi B. Recalcitrant nonunion of thescaphoid treated with a vascularized bone graft on the ulnarartery. J Bone Joint Surg 1990;72:88.

17. Boyes JH. Flexor tendon grafts in the fingers and thumb: anevaluation of end results. J Bone Joint Surg 1950;32A:489.

18. Strickland JW, Glogovac SV. Digital function following flexortendon repair in zone II: A comparaison of immobilization andcontrolled passive motion techniques. J Hand Surg 1980;5(6):537e43.

19. Strickland JW. Results of flexor tendon surgery in zone II inflexor tendon surgery. Hand Clin 1985;1:167e79.

20. Peacock Jr EE. Homologous composite tissues grafts of the dig-ital flexor mechanism in human beings. Transplant Bull 1960;7:418.

21. Guimberteau JC, Baudet J, Panconi B, et al. Human allotrans-plant of a digital flexion system vascularized on the ulnar ped-icle: a preliminary report and 1-year follow-up of two cases.Plast Reconstr Surg 1992;89:11, 35, 1.

Science

A fresh look at vascularized flexor tendon transfers