Distal bipedicled "supra cross leg" flap: a salvage option for complex lower limb defects

Open leg fractures are severe and common injuries. When a free flap and/or a local pedicled flap is not feasible or has failed, the cross-leg flap remains a last-resort option to avoid amputation. The aim of this study is to explain the technical aspects and clinical advantages of the distal bipedicled "supra cross-leg" flap, based on a series of four cases.

Four patients underwent reconstruction using a distal bipedicled "supra cross-leg" flap between 2016 and 2026 at HIA Percy, a Level I trauma center and burn treatment center (Clamart, France). Demographic, trauma-related, and surgical data were collected.

All patients were male, with a mean age of 35 years (± 7.9). The distal bipedicled "supra cross-leg" flap was performed at a mean of 59 days (± 15.9) after injury. The mean flap size was 408 cm² (± 99.3). Three patients required early surgical revision due to infection. Flap division was performed at a mean of 34 days (± 4.1). No flap failure was observed. The reconstructed soft tissue coverage subsequently allowed secondary bone reconstruction through partial elevation of the flap.

The distal bipedicled "supra cross-leg" flap is a reliable and reproducible technique that allows extensive cutaneous coverage. This flap, combining a distal sural flap and a distal great saphenous flap of the leg, enables coverage of large soft-tissue defects thanks to a wide usable flap surface and a rich, mixed vascular supply dependent on the posterior tibial and fibular vascular networks. The timing of flap division should be delayed when premature flap elevation is required for septic reasons. The length of the pedicle facilitates positioning of the flap on the recipient site. The use of external fixation to temporarily stabilize the two lower limbs provides a stable construct that facilitates nursing care and patient mobilization.

IV.