Anatomical study and clinical applications of posterior supramalleolar flap

Abstract

Objective To probe the anatomical characteristics of posterior supramalleolar flap and summarize the clinical experience of application of posterior supramalleolar flaps to repair serious foot and ankle trauma complicated by soft tissue defects, and to provide the basis for the clinical application of posterior supramalleolar flaps. Methods From August 2012 to October 2012 in 8 lower limb specimens of adult human cadavers, the cutaneous branches of the posterior tibial artery in 1/3 lower segment of cnemis marked by means of red latex through femur artery and their blood nutrition to the sural nerve and the lateral sural nerve were observed anatomically. The location, course, distribution of the lateral popliteal cutaneous artery and the anastomosis with the supramalleolar cutaneous branches of the posterior tibial artery were also observed anatomically. The length and outer diameter of the lateral popliteal cutaneous artery were measured. From February 2007 to June 2012, the clinical data of 15 cases treated by posterior supramalleolar flaps in the Center of Orthopedic Surgery, General Hospital of Lanzhou Military Region were retrospectively analyzed. There were 11 males and 4 females, aged 18-49 years (mean, 33 years). The trauma locations were 1/3 lower segment of cnemis in 3 cases, ankle and foot in 7 cases, weight loading plantar region in 5 cases. All soft tissue defects of patients were repaired by posterior supramalleolar flap. The survival of the flaps were observed after operations. 1 month after the wounds healed completely or 3 months after the fractures healed clinically the postoperative function was evaluated according to the American Orthopedic Foot and Ankle Society(AOFAS) score. Results In 8 lower limb specimens, the posterior tibial artery gave off 2 to 4 septocutaneous branches at 1/3 lower segment of cnemis. The septocutaneous branches toward the proximal and lateral supplied blood nutrition to the sural nerve and the lateral sural nerve, and anastomosed definitely with the lateral popliteal cutaneous artery. Lateral popliteal cutaneous artery was found in all 8 lower limb specimens, originated from the place (1.8±0.47)cm above the femoral condyles connection. This cutaneous artery pierces through deep fascia at the place (1.1±0.14)cm lateral to the midline in the popliteal space and go down at the surface of the lateral head of the gastrocnemius muscle. All 8 cases of lateral popliteal cutaneous artery accompanied with lateral sural cutaneous nerve. Total lengths of lateral popliteal cutaneous artery were from 10.05 cm to 18.71 cm, and the average was (14.21±3.89)cm. Their diameters were from 0.95 mm to 1.51 mm, and the average was (1.23±0.24)mm. Thirteen flaps used in repairing serious foot and ankle trauma complicated by soft tissue defects survived well, and 2 flaps had partial necrosis. Twelve cases were followed up 6-18 months (mean 11 months). Flaps in patients have good textures and appearances. The postoperative function was evaluated according to the AOFAS score: 8 cases had excellent results, 4 good. Conclusions Posterior supramalleolar flap is relatively hidden, and is not easy to be damaged. The flap can be used to repair a large area soft tissue defect with high successful rate. It is an fine choice to repair serious foot and ankle trauma complicated by soft tissue defects. Key words: Surgical flaps; Posterior supramalleolar flap; Soft tissue injuries; Ankle