Background: Postburn dorsal and palmar interdigital commissural contracture is one of the most common complications of hand burns which restricts finger motion and presents a serious cosmetic defect. Many techniques and flaps have been suggested, and research continues for more effective techniques as the problem has not been solved. Methods: Anatomy of scar interdigital commissural contractures was studied in 760 operated patients aiming to develop a new, more effective surgical technique. Results: There are two anatomic types of scar commissural contractures: edge and total. Dorsal and palmar commissural contractures are identified as the edge type and are caused by the fold located along interdigital fossa’s edge. In the fold, the lateral sheet is scars, and the medial sheet and adjacent interdigital fossa are healthy skin. Total commissural contracture is characterized by interdigital fossa obliteration and phalanges’ fusion. Scar sheets have a trapeze-shaped surface deficiency (contracture cause), which spreads from the fold’s crest to metacarpophalangeal joints. The surgical technique consists of scar surface deficiency compensation and commissural groove and slant restoration which can be optimally achieved with the trapezoid adipose-cutaneous flap. The best donor site is interdigital fossa. The small skin grafts on the lateral surface of proximal phalanges did not present a cosmetic defect. Conclusion: Dorsal and palmar interdigital commissural contractures are of an edge type and can be successfully reconstructed with trapeze-flap plasty.