The Keystone Flap in Greater Trochanter Pressure Sore

The keystone flap is a fascia-based island flap with two conjoined V-Y flaps. Here, we report a case of successful treatment of a trochanter pressure sore patient with the traditional keystone flap. A 50-year-old male patient visited our department with a $3{\times}5cm$ pressure sore (grade III) to the left of the greater trochanter that was covered with eschar. Debridement was done and the defect size increased to $5{\times}8cm$ in an elliptical shape. Doppler ultrasound was then used to locate the inferior gluteal artery perforator near the wound. The keystone flap was designed to the medial side. The perforator based keystone island flap covered the defect without resistance. The site remained clean, and no dehiscence, infection, hematoma, or seroma developed. In general, greater trochanter pressure sores are covered with a perforator based propeller flap or fascia lata flap. However, these flaps have the risk of pedicle kinking and require a large operation site. For the first time, we successfully applied the keystone flap to treat a greater trochanter pressure sore patient. Our design was also favorable with the relaxation skin tension lines. We conclude that the keystone flap including a perforator is a reliable option to reconstruct trochanteric pressure sores.