We evaluated the shoulder function according to the degree of protrusion or sinking of proximal ends of humeral interlocking nails.

On 12 patients who were treated using humeral antegrade intramedullary nailing, the shoulder function has been evaluated with the Constant's shoulder function score and the shoulder score index of the research of American Shoulder and Elbow Surgeons, before removal of nails and one year after that. The degree of protrusion or sinking of the proximal ends of nails was measured on shoulder AP X-ray films. Patients with shoulder dysfunction or neurovascular injuries were excluded from this study.

Protrusion of the proximal end of the nail caused rotator cuff irritation and impingement and shoulder dysfunction. In the case of sinking of the proximal end of the nail, the shoulder function status was decreased with the sinking degree of the proximal end of it after nail removal.

We thought that an accurate preoperative measurement of the nail length is needed and sinking the proximal end of nail minimally, simultaneously avoiding the protrusion, is important for the restoration of shoulder function after nail removal.