Rotational alignment of humerus after closed locked nailing

Objective: Rotational malalignment that may happen during closed nailing of humeral fractures is, to date, an unexplored area of investigation, The pu rpose of this study was to examine the effect of arm position during surger y on humeral rotational alignment and the effect of this alignment on shoul der motion and function. Methods: Thirty patients with eventual fracture healing after closed humera l locked nailing were retrospectively studied: 15 had retrograde nailing; 1 5, antegrade. Retrograde nailing was performed with the patient in a decubi tus position and with the upper arm anteriorly flexed and the forearm perpe ndicular to the operating table. Antegrade nailing was performed with the p atient in a semisitting position and with the upper arm in the so-called re sting position. The humeral retroversion angle as measured by computed tomo graphic scan, range of shoulder rotation, and Neer score of the shoulder fo r the fractured and the intact humeri were determined, and the discrepancy (i.e., value for the intact subtracted from that for the fractured) between the two was noted. To test the effect on alignment of positioning during r etrograde nailing, we similarly determined retroversion angles for another 15 patients treated in a supine resting position. Result: Between antegrade nailing and retrograde nailing in decubitus posit ion, there was a significant difference in the mean discrepancies for the r etroversion angles and the range of external rotation of the shoulder in th e neutral and abduction positions, but no significant difference for intern al rotation of the shoulder and Neer score. Between antegrade nailing and r etrograde nailing in supine resting position, there was no significant diff erence in the mean discrepancy for the retroversion angle, Conclusions: Positioning of the arm may significantly affect humeral rotati onal alignment and range of motion during closed nailing. Until a reliable method for intraoperative measurement of humeral rotation is devised, we re commend that closed nailing of humeral shaft fractures be performed with th e patient's upper arm in the resting position shown in this study.