Introduction

Vascularized flaps, pedicled or free, have a prominent place in the arsenal of post-traumatic locomotor system repair techniques [1]. They represent a relatively reliable surgical technique [2], notably thanks to advances made in microsurgical techniques since the 1960s.

Today, reconstruction in children aims to obtain full functionality and an aesthetic aspect close to what it was prior to the trauma by using autologous bone grafts, including an epiphyseal plate which brings the potential of growth to the graft, synchronous with the child’s growth.

Clinical case

A 3-year-old patient, with no particular history, presented bilateral multi-tissue damage of the feet following a lawn mower accident in April 2004.
The left foot lesions included tearing of the skin of the entire arch of the foot, amputation of the first phalanx of the hallux and a massive loss of substance of 4/5ths of the calcaneus, chiefly the greater tuberosity and its growth zone, associated with an avulsion of the soft tissues of the hindfoot up to the lateral malleolus. The talocrural joint was preserved (Fig. 1).

Surgical treatment

Initially, multiple successive cleanings and debridement were carried out. Reconstruction of the heel cup, from the foot’s sole to the metatarsophalangeal joint of the hallux started a month after the accident. The first step was to cover the heel cup with a free vascularized myocutaneous flap from the latissimus dorsi, collected in its entirety, including a skin paddle. It allowed the coverage of the foot’s sole up to the heel. Micro-surgical vascular connections were made on the posterior tibial arteriovenous pedicle. During that same step, an external fixator was placed to maintain the foot at a 90° angle and a cement spacer with antibiotics, deliberately oversized, was moulded to create ulterior reconstruction space for the calcaneus, placed under the latissimus dorsi muscle flap, and held to the remaining bone by K wires (Fig. 2).

The favourable evolution of that first coverage step enabled the reconstruction of the calcaneus 6 months after the accident. This bone reconstruction consisted of a vascularized free anterior iliac-crest flap, including the whole physis to bring back growth potential (Fig. 3).

Upon the cemented spacer removal and the opening up of the talus’ nucleus above, the great saphenous vein as well as the anterior tibial artery were individualized in preparation for the upcoming microsurgical connection.

The bone graft collected from the left anterior iliac crest was 6 cm by 3 cm (including the iliac crest’s physis), coupled with a thin muscular layer, all pedicled to the superficial circumflex iliac pedicle, dissected along its length down to the deep circumflex pedicle.

The bone flap was set by placing the osseous osteotomy zone against the plantar face of the talus, the physis finding itself in the plantar region and the anterior superior iliac spine in the position of the greater tuberosity of the calcaneus (Fig. 4). Osteosynthesis was ensured by K wires, the external fixator maintaining the foot at a right angle.
Vascular microsurgical connections were done on the anterior tibial artery from a termino-lateral point, as well as on the great saphenous vein for the venous return.
The external fixator was removed 10 months after the bone graft’s implantation, the patient was given silicone soles and followed-up until 2019, at the end of his growth.

Results

The patient is now aged 20 (1.69 m, 59 kg). He does not practice regular physical activity. This is 17 years after the trauma.

Clinical analysis: the patient has been wearing town footwear, size 36, on both feet, without orthopaedic insoles for the last 4 years. He describes some episodes of dermabrasion of the left foot’s dorsal face, which resolve spontaneously, without any other problems (Fig. 5,6 and 7).

He walks using small steps, without limping; the left hindfoot being in the axis, in varus of approximately 10° to the right. Plantar flexion of the left ankle is at 15°, dorsal flexion is at about 20°, i.e., ranges close to the norm.

The podoscope exam objectifies a bilateral plantigrade support, with a flat right foot and normal support of the left foot. He displays a plantar callus of the left heel and a bilateral callus of the plantar faces of the heads of the first two metatarsus (Fig. 8).

Radiological analysis: The comparison between X-rays made at the time of reconstruction and 17 years later objectifies a homogeneous growth of the vascularized graft of almost 1 cm along the whole length of the collected growth plate, as well as complete ossification of the plate. The measurements were made step by step and repetitively on multiple follow-up radiographies. Measure of the graft’s width growth was done along its entire length (at 25, 50 and 75% of the graft’s length from the proximal part to the distal part), showing a growth of 41.1%, 43.5% and 57.9% (so 8.77 mm, 8.58 mm and 8.27 mm), in comparison to the graft’s initial measurements at the time of its implantation (Fig. 9).

Discussion

Cases of paediatric heel reconstruction are rare in literature.

The vascularized free composite iliac-crest flap offers the possibility of a quality multi-tissular reconstruction for post-traumatic surgery of the lower limb, or mandibular reconstruction, because it contains an osseous part and a cutaneous covering. The advantages of this flap are many when there is proper indication (4). Feasible in one step, it is reliable, its pedicle is constant and of good microsurgical quality (diameter approximately 2 mm, length from 4 to 5 cm). When needed, this flap offers a skin reconstruction over a large surface. The flap’s osseous part’s dimensions can range from 5 to 10 cm in length, depending on the age of harvesting, and 3.5 cm in height [3].

The main vascularized osseous flaps in children, which provide a growth area, are the fibula’s proximal part, including its epiphysis, the scapula’s lateral flap and the iliac-crest flap [4]. The iliac-crest flap was the most appropriate choice for our case due to its shape, the best match for the defect requiring reconstruction (5). The use of a bone flap, including a growth plate, was indispensable in view of the child’s very young age, considering the objective growth of the heel.

Donor site morbidity remains moderate in children [6], while the change to walking patterns was described in adults in comparison with the fibula flap [7].
Thus, the use of this flap seems to provide the best compromise between filling an osseous defect of curvilinear shape combined with skin coverage, effective growth potential, and low morbidity [8].

Regarding initial cutaneous coverage, prior to bone reconstruction, the other flaps described for heel reconstruction were the following: the perforating flap type SCIP (Superficial Circumflex Iliac Artery Perforator flap) offers the advantage of being able to be collected thin, thus avoiding additional degreasing procedures (9). However, it was only described in 2004, namely subsequently to our case. Masquelet described the lateral supramalleolar flap as a locoregional solution for coverage of loss of substance of the distal end of the lower limb in 1988 [10]. However, this flap was too small to cover the initial loss of substance. The sural flap with a distal pedicle is a technique of choice for the coverage of acute traumatic loss of substance, exposing a noble structure in paediatrics [11]. For secondary indications of resurfacing, the indication must be weighed more prudently because of belated complications, in particular in the donor site, and was not chosen for this reason. Accordingly, the choice was made to use the free latissimus dorsi flap, despite the use of the two tibial pedicles, anterior and posterior, necessary for the vascular anastomosis of the two free flaps.

Long-term hindsight available to us allowed us to demonstrate an objective growth of the graft. It was significative enough to allow the patient to comfortably use footwear, without specific equipment. Clinical and radiographic analyses proves the soundness of these reconstruction methods in children, admittedly technically demanding, but relatively reliable due to the absence of associated pathology in children, making the vascular anastomosis reliable [8].

Conclusions

Traumatic lesions of the child’s foot, by lawn mower, in particular when they reach the heel, represent a challenge for reconstruction. Indeed, a triple objective must be achieved: filling the bone loss, ensuring good skin coverage quality, and providing enough growth for the future. The composite iliac-crest flap meets these criteria, with low morbidity and very satisfactory functional results. The technical requirement inherent to these free flaps is offset by their vascular reliability, particularly in children due to the absence of associated pathology.

References

1. Masquelet A : Techniques Chirurgicales Orthopédie-Traumatologie. Lambeaux pédiculés des membres. 10.1016/S0246-0467(20)66174-8.

2. Duteille F, Velik M, Nguyen JM, Merle M, Dautel G: “Free flap for soft tissue loss of the limbs in trauma victims”. Rev Chir Orthop Reparatrice Appar Mot. 2003;89:574-579.

3. Legré R, Samson P, Tomei F, Jouve JL: Treatment of substance loss of the bones of the leg in traumatology by transfer of the free vascularized iliac crest. A propos of 13 cases. Rev Chir Orthop Reparatrice Appar Mot 1998;84:264-71.

4. Gilbert A Mathoulin C: Vascularized bone grafts in children. Specifics and indications. Ann Chir Plast Esthet 2000;45:309-22.

5. Taylor GI, Corlett RJ, Mark W Ashton MW: The Evolution of Free Vascularized Bone Transfer: A 40-Year Experience. Plast Reconstr Surg 2016;137:1292-1305.

6. Tonoli C, Bechara A, Rossanez R, Belangero WD, Livani B: Use of the vascularized iliac-crest flap in musculoskeletal lesions. Biomed Res Int ; 2013;2013:237146.

7. Syczewska M, Krajewski R, Kirwil M, Szczerbik E, Kalinowska M: Gait changes in patients after reconstruction of facial bones with fibula and iliac crest free vascularized flaps. Acta Bioeng Biomech 2018;20:185-190.

8. Organek AJ, Klebuc MJ, Zuker RM: Indications and outcomes of free tissue transfer to the lower extremity in children: review. J Reconstr Microsurg 2006;22:173-81.

9. Tawa P, Lévy J, Brault N, Madar Y, Qassemyar Q: Superficial circumflex iliac artery perforator free flap in pediatric reconstruction: A case report. Ann Chir Plast Esthet, 2020 ; 65, 338-342.

10. Masquelet AC, Beveridge J, Romana C, Gerber C: The lateral supramalleolar flap. Plast Reconstr Surg 1988 ; 81 : 74-84.

11. Grandjean A, Romana C, Fitoussi F: Distally based sural flap for ankle and foot coverage in children. Orthop Traumatol Surg Res 2016;102:111-6.