Congenital radioulnar synostosis treated using a microvascular free fasio-fat flap.

Congenital radioulnar synostosis, which is caused by fusion between the proximal end of the radius and ulna, is an uncommon deformity of the upper extremity. It is characterized by the forearm being fixed in some degree of pronation and patients present with a variety of functional limitations of the involved limb. This condition may lead to difficulties in daily activities, such as writing, eating, and accepting objects in an open palm. Many operative procedures have been developed to mobilize the fixed forearm but the long-term results are disappointing. Herein, we reported a 12-year-old female patient with congenital radioulnar synostosis of the bilateral forearm who was treated with separation of the bony bridge between the left radius and ulna combined with a free groin flap transfer into the separated space. The functional results are good and no recurrent ankylosis occurred during a period of 28 months postoperatively. The flap size and volume of the subcutaneous fat are the key factors for satisfactory results.