Anconeus interpositional arthroplasty has been used in the treatment of radiocapitellar and radioulnar joint problems occurring after trauma. We performed anconeus interposition arthroplasty in a 31-year-old male patient who developed heterotopic ossification (HTO) in the elbow following surgical treatment of an isolated radial neck fracture. Treatment with implant removal and excision of the radial head resulted in recurrent HTO and a stiff elbow. The patient underwent excision of the heterotrophic new bone and mobilization of the proximal radius. The anconeus muscle was mobilized and interposed between the proximal radius and ulna. Sixteen months after the operation, forearm rotation, elbow flexion and extension increased by 80 degrees, 45 degrees, and 60 degrees, respectively. Control X-rays showed maintenance of the radiohumeral gap without any signs of HTO.