Ankle Reconstruction

Clinical Presentation

A 68-year-old Asian male sustained left ankle open fracture and dislocation as a result of a motorcycle collision. He had a complex open wound over the medial malleolus with an exposed flexor digitorum longus tendon. He was managed initially by the orthopedic trauma service for wound debridement and placement of an external fixator. The critical part of the wound measured 7 × 4 cm and the rest of the wound measured 5 × 6 cm ( Fig. 48.1 ). The plastic surgery service was consulted to provide soft tissue coverage for this complex ankle wound. No further orthopedic procedures were needed after soft tissue reconstruction.

Operative Plan and Special Considerations for Reconstruction

The distally based sural artery flap can also be used to cover a complex wound in the ankle if the flap donor site is available and the pedicle of the flap in the territory of the lesser saphenous vein is not involved with previous trauma or surgery. The flap can provide good skin coverage to a wound in both the medial and lateral aspects of the ankle. The donor site of a distally based sural artery flap is centrally located in the posterior calf over the medial and lateral gastrocnemius muscles. The skin island can be harvested from the proximal two-thirds of the posterior leg with a skin paddle up to 12 × 8 cm. The flap receives blood supply primarily from three to six septocutaneous perforators arising from the peroneal artery in a retrograde fashion. The most proximal end of those perforators is located about 6 cm proximal to the lateral malleolus. Therefore, preoperative evaluation to determine the patency of the peroneal artery is critical. The flap also receives a blood supply, again in a retrograde fashion, from the fasciocutaneous perforators from the posterior tibial artery, venocutaneous perforators from the lesser saphenous vein, and neurocutaneous perforators from the sural nerve. Thus, the blood supplies to the flap through both the lesser saphenous vein and sural nerve systems should all be included within the adipofascial pedicle to ensure adequate blood supply when the flap is used to cover an ankle wound (see Chapter 45 , Case 2; Fig. 45.9 ). In addition, a venous supercharge should also be prepared if the flap becomes congested after its inset.

Operative Procedures

Under general anesthesia with the patient in the prone position, the medial ankle wound, measuring 7 × 4 cm with the exposed underlying tendon and joint capsule, was debrided. All unhealthy-looking skin edges and colonized tissues were sharply debrided and the wound was then irrigated with Pulsavac. The wound appeared to be fresh and clean after a definitive debridement performed by the plastic surgery service.

The whole course of the lesser saphenous vein was mapped with a handheld Doppler between the Achilles tendon and the lateral malleolus. Although the scar presented in the lateral aspect of the distal leg, the pedicle of the less saphenous vein appeared to be intact and could be used for the flap. The pivot point of the flap turnover was marked about 6 cm above the lateral malleolus. A 7 × 4 cm of the flap’s skin island was designed based on the size of soft tissue wound and two triangular extensions were also included because they acted as a dog ear for each end and would normally be excised during the closure of the flap’s donor site ( Fig. 48.2 ).

Under tourniquet control, the proximal incision of the flap was made to explore the lesser saphenous vein and its accompanying vessels distal to the flap. The lesser saphenous vein and its accompanying vessels were then divided with hemoclips. The sural nerve and its accompanying vessels were exposed and then divided again with hemoclips after incising the fascia. The skin island was elevated along the subfascial plane and it was then completely elevated as a fasciocutaneous island flap. The adipofascial pedicle of the flap, about 2 cm wide, was dissected free after multiple zigzag skin incisions proximal to the skin paddle. After releasing the tourniquet, the flap was turned over and tunneled under the skin bridge to place over the medial aspect of the ankle wound. The flap was then inset into the medial ankle wound to cover the exposed tendon with interrupted 3-0 Monocryl sutures in a half-buried horizontal mattress fashion. One drain was placed under the flap ( Fig. 48.3 ).

The flap donor site in the middle of the leg was closed primarily with a split-thickness skin graft after undermining the adjacent skin edge to reduce the size of the needed skin graft. The split-thickness skin graft was harvested with a dermatome from the left lateral thigh and meshed to 1:1.5 ratio. The skin graft was approximated to the adjacent skin edges with interrupted chromic sutures. The less critical part of the wound was also covered by a skin graft. The rest of the skin incision for the flap dissection was closed in two layers with interrupted sutures ( Fig. 48.4 ).

Follow-Up Results

The patient did well postoperatively without any issues related to the distally based sural artery flap for soft tissue coverage of the medial ankle wound. He was discharged from the hospital on postoperative day 5. His left medial ankle wound healed uneventfully. He was followed by the plastic surgery service for routine postoperative care and by the orthopedic trauma service for left ankle fracture and dislocation.

Final Outcome

During further follow-up, the complex left anterior ankle wound after the distally based reverse sural artery flap reconstruction had healed well with excellent contour and minimal scarring. The rest of the wound after skin grafting also healed well with no wound breakdown, recurrent infection, or contour issues related to the soft tissue flap reconstruction ( Fig. 48.5 ). The flap donor site after skin grafting and primary closure also healed well ( Fig. 48.6 ). The patient has resumed his weight-bearing status and returned to his normal activities as instructed.

Pearls for Success

An ankle complex soft tissue wound can also be reconstructed with a distally based sural artery flap if only skin coverage is needed. The skin island is elevated as a fasciocutaneous island flap with dual blood supplies: one is based on the lesser saphenous vein system and the other is based on the sural artery system. The adipofascial pedicle of the flap can be designed as narrow as 2 cm wide as long as both the lesser saphenous vein and the sural nerve systems are included and can be visualized. The pedicle is dissected free and can be tunneled under the skin bridge if there is no significant compression to the pedicle of the flap. The donor site can be closed primarily after undermining if it is less than 5 cm wide or closed with a skin graft. Early venous congestion after a distally based sural artery flap is relatively common because the flap has been turned over. In case of prolonged postoperative venous congestion, application of topical nitroglycerin paste or medicinal leech therapy may be used. Inspection of the flap pedicle is required to ensure there is no direct compression. If venous congestion persists or worsens, the flap can be placed back to the donor site or a supercharge can be performed with microsurgical technique to augment venous drainage between the proximal lesser saphenous vein and an adjacent vein in the foot.