Functional reconstruction of acutely burnt achilles tendon with composite anterolateral thigh flap with fascia lata: a case report

Summary

Soft tissue defects in the postero-inferior aspect of the leg are still challenging, especially when they affect the Achilles tendon due to its important functional involvement in the normal movement of the ankle. Dorsiflexion and flexion may be affected if proper reconstruction is not achieved, thus limiting daily activities such as walking, climbing stairs or running. Several techniques, including local or regional flaps, combinations of tendon substitutes with free muscular or fasciocutaneous flaps, and free composite flaps with tendon have been described for the reconstruction of complex defects caused by burn sequelae, tumors, trauma, chronic ulcers, etc. The gold standard treatment for moderate to large defects is the anterolateral thigh (ALT) flap with vascularized fascia lata. The ALT flap is reliable because of a long vascular pedicle and a large donor area. Moreover, the fascia lata mimics the Achilles tendon perfectly when rolled on itself. The aim of this article is to present the application of this technique for the first time in a case of an acute burn. The timing of reconstruction with free flaps is critical in acute burns. In our case, it was performed on the 24th day post-burn and no microsurgical complications appeared. More than six months after surgery, the patient showed a normal gait, was able to lift his own weight against gravity and no complications were detected in the donor area.

Introduction

The combined loss of the Achilles tendon and overlying soft tissue represents a reconstructive challenge.^1-5 On the one hand, cutaneous defects on the distal third of the leg require some of the most complex procedures in plastic surgery, such as microsurgical techniques, which are required in many cases.

On the other hand, the damaged Achilles tendon reconstruction is a procedure of great importance because of its functional implications. The surgical challenge is even greater when Achilles tendon and overlying soft tissue defects coexist.^2,5 Optimal reconstruction of the Achilles tendon should ensure not only stable cover able to resist friction while walking, but also adequate ankle contour to allow for the use of normal footwear, as well as the appropriate strength, durability and tension to achieve active plantar flexion.^1-3

The purpose of this paper is to present a case report of functional reconstruction of a segmentary defect of the Achilles tendon and the overlying skin produced by acute thermal burns using a free composite anterolateral thigh (ALT) flap with fascia lata.

Case report

In February 2017, a 24-year-old male with no medical history was admitted to our hospital with deep second and third degree burns in the postero-lateral aspect of the distal third of his right leg, caused by a domestic accident with the flames from a fireplace two weeks before (Fig. 1).

Fig. 1.

Debridement of the burns was performed in a first surgical attempt 20 days after the accident. Achilles tendon exposure, a devitalized appearance and purulent exudates were observed. For this reason, definitive cover and reconstruction of the defect was rejected in favour of a temporary cover made with partial thickness skin grafts obtained from the right thigh. Wound cultures were obtained in which a Cloxacillin sensible Staphylococcus aureus was grown, whereby antibiotic treatment with Cloxacillin was initiated for 7 days. The resulting defect was approximately 15x5 cm and it showed 5 cm of direct exposure of the Achilles tendon in the lower half (Fig. 2).

Fig. 2.

In a second attempt, 24 days after the burn and having optimized the wound with antibiotic therapy, definitive coverage was performed with a free fasciocutaneous anterolateral left thigh (ALT) flap, measuring 17x7.5 cm (Fig. 3), anastomosed end-to-side to the posterior tibial artery and end-to-end to the two posterior tibial veins (Fig. 4). All recipient vessels were identified and dissected within the tissues proximal to the upper edge of the wound, at an approximate distance of 3 cm. The flap included a lateral extension to incorporate 8 cm of the left thigh fascia lata, which was rolled and sutured on itself and, after flap transposition, it was anchored with anchors to the calcaneus bone on the one side and to the healthy proximal remnant of Achilles tendon with a non-absorbable suture on the other (Fig. 5).

Fig. 3.

Fig. 4.

Fig. 5.

The postoperative course was uneventful. Two weeks after surgery, the patient progressively restarted his workload. Six months after surgery and after a process of motor rehabilitation, the patient presented a normal gait and he was able to lift his own weight against gravity (Fig. 6). No complications had been reported in the donor area: the knee extension was complete, the gait was normal and the patient had not reported any hypoesthesias in the thigh. The aesthetic result of both the donor and recipient areas was optimal and he was not expected to require secondary procedures.

Fig. 6.

Discussion

While the simple rupture of the Achilles tendon can be managed only with sutures or tendon grafts, the management of segmental defects combined with soft tissue involvement remains a complex reconstructive challenge owing to the lack of suitable tissue on site.¹ The Achilles tendon is essential for normal ankle joint movement. For this reason, loss of its function seriously affects dorsiflexion and flexion of the joint, therefore affecting daily activities such as walking, climbing stairs, standing for long periods of time or running.^2,3,5,6 In the treatment of complex defects in the postero-inferior aspect of the leg, local or regional flaps can jeopardize the survival of the previously injured leg. In addition, lesions that cause the defect may also affect the vascularization of the region because the zone of injury is usually larger than it appears on simple clinical examination. Given the fact that local flaps are not available to provide structures similar to a tendon, the best solution to functional and cover problems are free flaps.⁵ Regarding this, it is vitally important to perform the reconstruction with a flap able to bring both the vascularized tendon and the skin coverage together.⁵ 5A vascularized tendinous substitute may have the advantages of increased resistance to infection, faster healing, less adhesion to surrounding tissue and greater sliding capacity.^1-4 Reconstruction options that combine isolated components, such as tendon allografts, with muscular (latissimus dorsi, gracilis, tensor fasciae latae) or fasciocutaneous free flaps (radial forearm) have become outdated.⁵ Otherwise, free flaps from the upper limb, such as radial forearm flaps with the palmaris longus tendon, brachioradialis flaps with the flexor carpi radialis tendon, and lateral arm flaps with the triceps tendon, as well as some flaps from the lower limb, like the dorsalis pedis flap with the extensor digitorum longus tendon and the groin flap including the vascularized external oblique aponeurosis,^1,3-6 have been used for small-sized defects.⁵

Given the large size of our defect (15x5 cm) and the need to perform a fully functional reconstruction, we considered the anterolateral thigh (ALT) flap with fascia lata to be the best option. The free composite ALT flap provides all the components needed: vascularized fascia lata for tendon reconstruction and soft tissue cover. When the fascia lata strip is rolled on itself, it mimics a tendon that adequately replaces the Achilles tendon defect. The fascia lata receives sufficient blood supply via the prefascial and subfascial vascular plexus when it remains attached to the ALT flap.³ Furthermore, the ALT flap with vascularized fascia lata has been shown to achieve an acceptable ankle potency and an optimal range of motion in the composite reconstruction of the Achilles tendon, ² thus providing all the advantages required for tendinous reconstruction of this area. Donor area morbidity, despite objectively existing, is slight and does not interfere with daily activities.² The ALT flap has the advantage of having a long vascular pedicle, a great donor area, the quality of durable skin, freedom in design and tissue thinness. For this reason, the ALT flap with fascia lata is considered the gold standard in the functional reconstruction of Achilles tendon large defects.^1,5

The reconstruction of complex defects of the postero-inferior aspect of the leg with free ALT composite flap with fascia lata was first described by Lee and co. in 2000.³ Since then, it has been used by different groups for the treatment of defects of multiple etiologies, including burn sequelae, tumors, trauma produced by sport, work or traffic accidents, chronic ulcers, etc..^1-6 However, this technique has not been described for the treatment of acute burns as in our case. Kuo and co. demonstrated in their study that blood vessels 3 cm proximal to the skin defect produced by burns could be used for microsurgical anastomosis if their walls had normal elasticity, an intact endothelium not separated from the media and good arterial bleeding when sectioned.⁷ These 3 premises were fulfilled by the recipient vessels of our patient, so no microvascular complication appeared.

The timing of burn reconstruction with free flaps requires important planning. Compared to the use of free flaps for other indications (trauma, breast reconstruction, head and neck oncology, etc.), flap failure rate tends to be higher in burn reconstruction, especially for surgeries carried out during the 5th-21st day post-burn.^8-10 Infection, post-surgical inflammatory changes and vascular damage (most likely from inadequate debridement and wound cleaning) are etiological factors potentially causing the failure of microsurgical reconstruction at this early stage.¹¹ In our case, microsurgery was performed on the 24th day post-burn and, as already mentioned, no complications were detected.

Conclusion

The free ALT composite flap with vascularized fascia lata offers a reliable option for a single stage Achilles tendon reconstruction including the overlying soft tissue defects. The present case demonstrates that it is also useful for the correction of defects secondary to acute burns, and this was not found in the consulted bibliography. Adequate surgical timing (avoiding microsurgery in the early period) and the choice of receptor vessels (at least 3 cm away from the wound) will not ensure surgery success, but they may decrease the rate of complications in burn reconstruction with free flaps.