The successful management of low supracondylar fractures of the adult humerus is difficult. In the elderly, where osteoporosis complicates surgical treatment, non-union is not uncommon and can occur after surgical or non-operative methods of treatment. Significant disability may result from a painful flail arm, and ulnar neuropathy may complicate the picture.Complex and demanding methods of internal fixation of the initial injury, and of the non-union, have been described. In the treatment of non-union, some have found it necessary to resort to total elbow replacement.A new method of surgical treatment of these fractures and non-unions has been developed. This is based on a novel internal fixation device which obtains its hold in the small distal fragment, or fragments, by means of a transcondylar rod, passed from medial to lateral. This interlocks near its ends with a number of stiff wires which are passed proximally to obtain a hold in the proximal fragment. Secure fixation is achieved allowing early mobilization, even in the osteoporotic patient.This device was conceived with the elderly osteoporotic patient in mind. It was developed in response to the problem of non-union in such a patient. It has also been used in young patients with high-energy injuries. It has been used in 12 patients to date.One patient died of complications of his multiple injuries. All the other fractures united including one non-union. Overall there were three excellent, six good and two fair results (modified Jupiter scoring). In eight elderly osteoporotic patients, all women, six obtained 100° or more of elbow flexion and all obtained 90°.