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Introduction

Conservative management of deep partial- or full-thick-ness burns, as also the development of complications likeinfection in the burn wound, can lead to the developmentof post-burn contractures. This is ascribed to healing bysecondary intention whereby the myofibroblasts contract inan attempt to close the relative tissue deficiency that ispresent.1 This is most prominent over a joint like the kneeand there is no strong evidence that static splinting pre-vents these contractures in the post-burn period2 even thoughsplinting has been advocated to prevent contractures. Ad-vances in burn management have led to a decreased inci-dence of post-burn contractures although patients still pres-ent with them, the knee joint being involved in approxi-mately 22% of all large joint contractures.3 In the earlystages of knee contractures, the skin and the joint capsule,with its associated ligaments, and the tendons and neu-rovascular structures are involved. Later on, there can bean associated subluxation or dislocation of the articulatingbones, which greatly compounds the management.

Management of flexion contractures of the knee canbe problematic. Physiotherapy may help in the early stageswhen the scar is soft and pliable, but with established con-tractures, the management is essentially surgical. This con-sists in releasing the contracture and covering the result-ant defect with a skin graft or a local or free flap. Othersupplementary procedures assuming importance in the man-agement of these contractures include tendon lengtheningfor long-standing contractures and the application of ex-ternal distractors as well as a variety of osteotomies. Flapcoverage is the best option following release of post-burncontractures since to a large extent it prevents recurrenceand has a much better aesthetic outcome.4,5 Flaps can beof various types, random pattern, musculocutaneous andfasciocutaneous flaps. Diverse locoregional fasciocuta-neous flaps can be harvested based on the local perfora-tor anatomy of a particular region. Perforator flaps are ro-bust and can be applied in either pedicled or free fashion.6

They have an important role in the reconstructive processsince the sacrifice of functioning muscle or other neu-rovascular structures is avoided.

ANTERIOR TIBIAL ARTERY PERFORATOR PLUS FLAPS FORRECONSTRUCTION OF POST-BURN FLEXION CONTRACTURESOF THE KNEE JOINT

Adhikari S.,* Bandyopadhyay T., Saha J.K.

Department of Plastic & Reconstructive Surgery, Institute of Postgraduate Medical Education & Research, Kolkata, India

SUMMArY. Background. Post-burn flexion contractures of the knee may arise even with adequate treatment of the burn injury.After release of the contracture, most of these defects require flap coverage. Here we describe the application of the perforator plusflap concept in the management of these contractures. Method. Between December 2010 and December 2011 five female and twomale patients with knee contractures were operated on using a perforator plus flap from the anterior tibia artery perforator. In onepatient both sides were operated on and the rest had unilateral surgeries. All patients had mature scars and the aetiology was ther-mal burn injury. All these contractures were categorized as Category 4 and Level 3 by the ICIDH guidelines with an average con-tracture angle of 87.5 degrees. The flap was raised after release of the defect and a Doppler study located the perforator below thefibular head. The base of the flap was kept intact at all times. The flap was then transposed towards the defect and inset in a ten-sionless manner. Results. All flaps survived well with marginal necrosis in only one flap, providing stable coverage to the kneejoint. The average residual contracture was around 10 degrees and the average range of flexion was 10-120 degrees. Conclusion.The perforator plus flap can be an excellent choice in defects over the posterior aspect of the knee where important neurovascularstructures and tendons are exposed. Level of evidence: Level IV.

Keywords: perforator plus flaps, post-burn contracture, knee

* Corresponding author: Souvik Adhikari, Department of Plastic & Reconstructive Surgery, Institute of Post-graduate Medical Education & Research, 244 A. J.C. Bose Road, Kolkata 700020, WB, India. E-mail: souvikadhikari@yahoo.com

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The failure rates of pedicled perforator flaps can bedrastically curtailed with the use of the “perforator plus”concept in which the blood supply to a flap from a per-forator is augmented by blood supply from the flap base.7

In our case series, the “perforator flap” concept wasapplied to reconstruct post-burn contractures of the kneejoints after adequate release of the scar.

Patients and methods

Between December 2010 and December 2011, sevenpatients with post-burn contractures of the knee had themreleased and reconstructed with a perforator plus flap cov-erage based on the anterior tibial artery perforator at thelateral aspect of the knee joint. The patients were five fe-males and two males suffering from thermal burn seque-lae. All of them had inadequate splinting in the post-burnperiod contributing to the formation of contractures. Theage range was from 28 to 45 yr, with a mean age of 34yr. Of these patients, two females presented bilateral low-er limb involvement. The patients presented to us 10-12months after their initial burn injury and none of them hadany surgical procedure for management of their contrac-tures (Table I).

The contractures were initially assessed for function-al deficit. The average contracture angle was 87.5 degrees(range, 60-100 degrees). As per the International Classifi-cation of Impairments, Disabilities and Handicaps (ICIDH),all patients8 were assigned to Category 4 for the first qual-ifier rating and Level 3 for the second qualifier rating(Table II). Indications for the perforator flap coverage were:

1. severe limitation of ambulatory function2. exposure of hamstring tendons and neurovascular

structures following release of the contracture3. aesthetic considerations

Surgical techniqueAll the patients were operated on under spinal anes-

thesia. A rough assessment was initially made of the ex-pected deficit of skin cover following contracture release

based on the dimensions of the extended lower limb onthe normal side or on the dimensions of a person with asimilar stature and sex when both lower limbs were in-volved. The perforator was next located on the lateral as-pect of the leg using a hand-held Doppler and the outlineof the flap to be elevated was marked over the lateral legand drawn slightly larger than the expected defect to al-low for primary contraction of skin after incision. Thetransverse length of the expected defect was marked in avertical direction along the length of the flap using the lo-

Patient No. Age Sex Etiology Time since burn Side Scar type Size of flap (cm) Perforator distance from(months) fibular head (cm)

1 29 M Thermal 10 Left Mature 6 x 14 2.1 2 34 F Thermal 9 Right Mature 7 x 18 1.5 3 28 F Thermal 10 Left Mature 8 x 18 2.2 4 32 F Thermal 12 Left Mature 6 x 16 3.5 5 35 F Thermal 9 Right Mature 7 x 15 3.2 6 45 M Thermal 12 Left Mature 7 x 18 2.3 7 35 F Thermal 10 Left Mature 8 x 18 1.8

11 Right Mature 7 x 17 2.1

Table I - Patient Demographics

For most people the ability to carry out an activity is not an‘all or nothing’ phenomenon. Activities may be carried out withvarying degrees of ease or difficulty, or as components ofdifferent types of behaviour. Activities may also be carried outusing technical or other aids, or with the help of another person.This classification is therefore designed to be used in conjunctionwith two qualifiers that indicate the manner of accomplishmentof the activity.

The first qualifier rates degree of difficulty of accomplishmentof the activity and is rated as follows:0 no difficulty1 slight difficulty2 moderate difficulty3 severe difficulty4 unable to carry out the activity9 level of difficulty unknown

The second qualifier is optional and describes any personal ornon-personal assistance used in accomplishment of the task.Assistance is rated as follows:0 no assistance needed1 non-personal assistance (including the use of assistive devices,

technical aids, adaptations, prosthesis, wheelchair, cane andother material help)

2 personal assistance (where the task is carried out with the‘help’ of another person, where ‘help’ includes supervisionas well as cuing and/or physical help)

3 both non-personal and personal assistance9 level of assistance unknown

Table II - Qualifiers of Activity limitations (International Classificationof Impairments, Disabilities and Handicaps - ICIDH, WHO)

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cation of the perforator as a fulcrum for flap transposition.A tourniquet was next applied without exsanguination ofthe limb. All the patients had a thick scar over the poste-rior aspect of the knee joint. Upon contracture release, thesciatic nerve and the biceps femoris tendon became ex-posed in most cases. Adequate straightening of the kneejoint was then accomplished by stretching supplementedwith Z-plasty of the contracted hamstring tendons. Thetourniquet was next released and confirmation of the vas-cularity of the limb was ensured followed by adequatehaemostasis. The fasciocutaneous flap was then raised fromdistal to proximal until the selected perforator was reachedusing loupe magnification. Additional perforators encoun-tered during elevation of the flap were ligated. The dis-section plane was just below the deep fascia and adequatecare was taken to ensure that there was no damage to thesuperficial peroneal nerve, which lay at close proximity.The base of the flap was retained in every case and the

flap was then transposed and inset in a tensionless man-ner using 3-0 vicryl sutures. The donor site was coveredwith a split-thickness skin graft. The dimensions of the elevated flap varied from 14 to 18 cm in length and from6 to 8 cm in width. Post-operatively, the flaps were notsubjected to any form of special monitoring and no anti-coagulant pharmacological agents like aspirin or clopido-grel were used. Parenteral prophylactic antibiotics wereused for a total of 3 days. After complete healing, the pa-tients were subjected to a standard physiotherapy program.

case report

A 35-yr-old female patient presented to us with bilater-al flexion contracture of the knees following a 42% TBSAburn injury sustained 10 months earlier. As per the med-ical records, she had burn wound sepsis, which led to de-layed healing and the development of contractures over the

Fig. 1 - Pre-operative picture of post-burn contracture over posteri-or aspect of right knee joint.

Fig. 2 - Flap marked over the lateral aspect of the leg. Doppleredperforator below fibular head marked in red.

Fig. 3 - Release of contracture and stretching: the hamstring tendonsand neurovascular structures are exposed.

Fig. 4 - Flap elevation in the subfascial plane is done up to the lev-el of the perforator which is shown. This point is used as a fulcrum.

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posterior aspect of the knee joints. The knee contractureswere surgically released at one-month intervals. At the sec-ond surgical operation the patient had a mature scar overthe posterior aspect of her right knee with a range of move-ment of only 50 degrees (Fig. 1). She was operated on un-der spinal anaesthesia and the flap markings were madeoutlining a flap of 7 x 17 cm over her lateral leg. The per-forator was located using a hand-held Doppler at a dis-tance of 2.1 cm from the fibular head (Fig. 2). The con-tracture was released next and passive stretching broughtthe knee back into a completely extended position (Fig.3). Tendon lengthening was not required in this particularinstance. The flap was next raised until the perforator wasreached (Fig. 4). Using this point as a fulcrum, the flapwas transposed to the defect covering all the neurovascu-lar structures and hamstring tendons which became ex-posed following release of the contracture (Fig. 5). Thedonor site was covered with a split-thickness skin graft(Fig. 6). The post-operative range of motion was 5-125degrees at the end of one month’s follow-up and the kneepresented pliable and stable coverage (Fig. 7).

results

At the time of writing this manuscript, the follow-upwas six months for five patients, three months for two,and one month for one side in one patient out of two withbilateral involvement. Of the two bilaterally affected pa-tients, one was operated on both sides using the perfora-tor plus flap technique while the other had this techniqueemployed on one side and split-thickness skin grafting onthe other, followed by post-operative splinting. The per-forator was located on average 2.3 cm from the fibularhead overlying the septum (range, 1.5-3.5 cm). Addition-al perforators were located distally to the first perforatorbut these were not maintained while elevating the flap.Raising did not entail sacrifice of any major nerve andsensation was preserved in the flap as also distally to it.Distal limb oedema was not encountered in our patientsfollowing flap harvest. One patient presented wounds overthe region of the flap harvest which did not prevent flapelevation or compromise its survival. No infection devel-oped in the post-operative period in any of the patients.The average operative time was 90 min (range, 70-110min). The average hospital stay was 10 days. Post-opera-tively, the average residual flexion contracture was 10 de-grees (range, 5-20 degrees). The average range of motionof the knee joint was 10-120 degrees (range, 0-130 de-grees) (Table III).

Discussion

The aims of operating on a patient with post-burn con-tracture of the knee are multifold. A flexion contracture of

Fig. 5 - Perforator plus flap is inset into the defect.

Fig. 6 - Donor site grafted with split-thickness skin graft.

Fig. 7 – Post-operative day 10: Stable coverage of the knee with fullextension achieved.

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the knee is a considerable functional problem to the pa-tient and is better prevented than treated. Splinting of theknee joint in extension in the immediate post-burn periodcan prevent the formation of these contractures, which canbe quite resistant to treatment even though a recent studyhas questioned the value of splinting in prevention of flex-ion contractures.2 Associated procedures commonly usedinclude the use of bandages, elastic garments, and intrale-sional steroid injections. In the early stages, the scar overthe posterior aspect of the knee joint is soft and early phys-iotherapy can improve the range of motion of a contract-ed joint which is obviously not possible in the later stages.9

Soft tissue contractures may result in joint subluxations ina few patients. The aims of treatment are to minimize scartissue over the flexor surface of the joint, restore the nor-mal position of the joint, reinstate total range of motionof the affected joint, and prevent recurrent contractureswith their attendant morbidity.10 Following scar release orexcision, defects can be covered using skin grafts, fascio-cutaneous and muscle flaps, and free flaps.6,11,12 Skin graftsare not usually advocated for coverage because adequatecontracture release may entail exposure of neurovascularbundles and hamstring tendons; moreover, a long periodof splinting may be required in the post-operative periodto prevent recurrence.13 In addition, when skin grafts areused in the popliteal fossa they prevent early ambulation.An additional factor in severe contractures is that the con-tracted tendons may need surgery for lengthening like Z-plasty, which necessitates a well-vascularized flap coverover the tendons.

Flap coverage of the posterior aspect of the knee jointis particularly useful since it brings vascularized tissue in-to the defect, thereby improving healing. It also preventsthe formation of re-contractures and allows ambulation veryearly in the post-operative period. For this purpose, bothmusculocutaneous and fasciocutaneous flaps can be used.A particularly useful flap is the gastrocnemius musculo-cutaneous flap for knee coverage.14 Fasciocutaneous flapsare considered more advantageous since no muscle is sac-

rificed and the long-term results are equivalent to muscu-locutaneous flap coverage. Free flaps as well as pedicledflaps all produce excellent results but most tend to sacri-fice a major vessel. Locoregional flaps may however mayhave a limited arc of rotation and free flaps are labour in-tensive and time consuming, and microvascular failureleads to total flap loss.

The perforator plus flap concept improves flap vascu-larity and particularly venous return by maintaining the cu-taneous pedicle. This can be especially of value becausethe located perforator may not be accompanied by a veinin all cases.15 Dissection up to the level of the perforatorensures a wide reach of the flap. It has been shown thatin the leg, the muscles of its anterior compartment are sup-plied from one angiosome whereas the skin of the leg tendsto get its supply from two or more angiosomes.16 The areain the upper lateral part of the leg is supplied by the an-terior tibial artery and its recurrent branch whereas the per-oneal artery takes over as it goes down the leg.17 This con-cept was used in flap elevation in which a perforator fromthe anterior tibial recurrent artery just below the fibularhead was used as the primary supply to our flaps.

The advantages of using this flap include the provi-sion of tissue possessing a perfect colour and texture match,which allows for optimal contouring of the posterior as-pect of the knee joint and causes minimal donor site mor-bidity. The defect created by raising the flap entailed cov-erage with a split-thickness skin graft only over a well-vascularized bed of muscles. The pliability and thinnessof the flap ensured excellent mobility of the knee joint fol-lowing post-operative rehabilitation. There was minimalchance of recurrence since the popliteal fossa was coveredin all cases. We have even succeeded in utilizing this flap,with no complications, in patients with previous superfi-cial second-degree burns of the donor site when an ade-quate Doppler signal was obtained. Operating times arenot much increased and no specialized instruments areneeded. Furthermore, this flap is easy to teach and hasvery low morbidity. Close attention should be paid to the

Patient No. Age Sex Side operated Duration of Preoperative Residual Postoperative Follow upon surgery (min) contracture contracture range of flexion (months)

angle (degrees) (degrees) (degrees)1 29 M Left 110 100 5 5-130 122 34 F Right 100 90 0 0-125 123 28 F Left 90 75 10 10-130 104 32 F Left 95 95 15 15-120 65 35 F Right 80 80 20 20-110 66 45 M Left 70 100 10 10-125 37 35 F Left 80 100 20 20-110 3

Right 95 60 5 5-120 1

Table III - Results of Surgery

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superficial peroneal nerve which, because of its proximi-ty to the flap, may be injured during the dissection, al-though no such injury occurred in our series.

conclusion

The perforator plus flap based on the anterior tibial

rÉSUMÉ. Contexte général. Les contractures en flexion du genou causées par les brûlures peuvent survenir meme si le traitementa été correct. Après la libération de la contracture, la plupart de ces défauts t la couverture moyennant l’emploi d’un lambeau cu-tané. Nous décrivons l’application de la méthode «perforateur plus lambeau» de ce type de contracture. Méthode. Cinq femmes etdeux hommes atteints de contractures du genou ont été opérés utilisant un lambeau perforateur plus lambeau provenant de l’artè-re tibiale. Dans un seul cas le patient a été opéré aux deux côtés, tous les autres ont été traités unilatéralement. Tous les patientsprésentaient des cicatrices matures et l’étiologie pendant la période décembre 2010 jusqu’à décembre 2011 était de brûlure ther-mique. Toutes ces contractures ont été classifiées dans la catégorie 4, niveau 3 par les directives ICIDH avec un angle de contrac-ture moyenne de 87,5 degrés. Le lambeau a été soulevé après la libération du défaut et une étude Doppler du perforateur situé endessous de la tête du péroné. La base du lambeau a été constamment maintenue intact en tout temps. Le lambeau est ensuite trans-posée vers le défaut et encadré en manière sans tension. Résultats. Tous les lambeaux ont survécu bien avec nécrose marginaledans un seul lambeau et ils ont fourni une couverture stable à l’articulation du genou. La contracture résiduelle moyenne était d’en-viron 10 degrés et l’amplitude moyenne de flexion était de 10 à 120 degrés. Conclusion. La technique du perforateur plus lambeaus’est démontrée un excellent choix dans le cas de défauts sur la face postérieure du genou quand des structures neurovasculairesimportantes et les tendons sont exposés. Niveau de preuve: IV niveau.

Mots-clés: perforateur plus lambeau, contracture post-brûlure, genou

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artery perforator is a robust flap which can be used to ef-fectively cover defects of the posterior aspect of the kneejoint. We have used this flap in the reconstruction of post-burn contractures of the knee joint but it may have a widerclinical application with a role to play in defects causedby tumour extirpation or trauma where the neurovascularstructures are exposed along with the hamstring tendons.

This paper was accepted on 15 February 2012.