Resection of the radial head frequently causes instability of the proximal end of the radius. To prevent this instability, we performed a stabilization technique using an anconeus muscle flap. Since 2003, six patients with radiocapitellar joint dysfunction have been treated with radial head resection combined with stabilizing its proximal end using an anconeus muscle flap. At a mean follow-up of 51 months, all patients were free from elbow pain and the mean Mayo Elbow Performance Score and the Disabilities of the Arm, Shoulder and Hand score significantly improved. Radiographic findings showed no apparent instability of the proximal radius. The anconeus is useful as a reliable muscle flap for preventing instability of the proximal radius after a radial head resection. This procedure does not require any microvascular techniques and makes it possible to apply a pedicled muscle flap using a relatively simple technique without any considerable risks of elbow dysfunction.