Vascular venous anatomy of the calcaneal fillet flap for tibial stump reconstruction: Anatomical study focused on reduction of vascular complications

Introduction Traumatic lower-limb amputations and severe leg injuries may necessitate below-knee amputation when replantation or reconstruction is not feasible. In these situations, tibial bone and soft tissue may be insufficient to preserve the knee. The use of tissue from the amputated part, particularly the foot fillet flap, can allow knee salvage with significant functional benefit. The foot fillet flap is a composite flap that can be designed as pedicled or free, depending on injury characteristics. However, venous insufficiency remains a potential complication. This study investigated the venous drainage of the flap using cadaveric specimens. Materials and methods Five fresh-frozen lower limbs were prepared and injected with colored latex into both the superficial and deep venous systems. Flaps were then dissected to analyze venous drainage pathways. Results Injection of the superficial system demonstrated that medial and lateral dorsal skin territories were not interconnected. Both territories showed perforating connections with the anterior tibial veins. Additional connections were identified between the deep system and the peroneal veins. These findings indicate that in large foot fillet flaps, approximately 230 cm2 in size, reliable venous drainage requires inclusion of both the medial system (great saphenous vein or tibial veins) and the small saphenous vein. Alternatively, the anterior tibial veins may provide sufficient outflow, as they appear capable of collecting venous blood from both systems. Conclusions For extensive foot fillet flaps, optimal venous drainage can be achieved either by combining medial and lateral systems or by utilizing the anterior tibial veins. From a practical perspective, extending the plantar and medial ankle skin—territories drained by the posterior tibial and great saphenous veins—may allow reliance on a single venous system, thereby reducing the risk of venous congestion.