Precise reconstruction of soft tissue defects in the lower leg and ankle using a modified cross-leg anterolateral thigh flap based on CTA

Shi Yan; Xu Yongqing; Wang Teng; Yang Xi; Meng Yuanyuan; Xia Hao; Fu Qichen; He Xiaoqing

doi:10.3969/j.issn.1009-4237.2025.09.004

Abstract：Objective To investigate the clinical efficacy of a modified cross-leg anterolateral thigh flap based on computed tomography angiography(CTA)in reconstructing soft tissue defects in the lower leg and ankle.Methods A retrospective analysis was carried out on 18 patients presenting with soft tissue defects in the lower leg and ankle.These patients were admitted to the 920th Hospital of the PLA Joint Logistics Support Force between Jun.2018 and Mar.2024,including 12 males and 6 females aged 19-53 years,mean 29.2 years.The causes of de-fects included heavy object impact in 8 cases,road traffic accidents in 7 cases,and machine crushing in 3 cases.All cases involved simultaneous injuries to any two of the anterior/posterior tibial/peroneal arteries.CTA from the ab-dominal aorta to the foot was conducted for all of them before operation,based on which Mimics 20.0 was used for 3D modeling of bones,blood vessels,and skin,and the optimal perforators of femoral arteries were selected according to the diameter and length to design the cross-leg flap.During the operation,flaps were harvested and anastomosed with the contralateral posterior tibial arteries and accompanying veins.After the operation,the survival of the flaps was recorded,and the Maryland scoring system was used to evaluate the patient's ankle function.Results All the free anterolateral thigh flaps were designed and harvested successfully.The location,diameter,and length of the per-forators were basically consistent with the preoperative modeling.The flap sizes ranged from 12 cm×8 cm to 20 cm×11 cm,which can completely cover the exposed bones and tendons.Partial necrosis occurred in 2 flaps:one under-went debridement and the other healed after pressing and dressing change.The other 16 flaps survived uneventfully.All donor sites healed satisfactorily.Patients were followed up for 7-24 months,and all flaps survived.At the final follow-up,according to the Maryland scoring system,the ankle function was excellent in 13 cases,good in 4,and fair in 1.Conclusion Preoperative CTA is helpful for a comprehensive assessment of the donor and recipient sites.The modified cross-leg anterolateral thigh flap based on CTA can precisely reconstruct soft tissue defects in the lower leg and ankle.