A standardized fluoroscopic method for profiling humeral rotational alignment during intramedullary nailing.
BACKGROUND: To date, limited methods exist for intraoperative assessment of humeral rotation during intramedullary nailing. Here, we propose a standardized fluoroscopic sequence that relies on humeral bony anatomy and known retroversion between the proximal humerus, relative to the transepicondylar axis of the elbow. METHODS: Eight paired cadaveric specimens (4/4 M/F, N = 16) were mounted to simulate intraoperative positioning. Fluoroscopic images were acquired using a standardized sequence that includes a Grashey view of the proximal humerus and a lateral of the elbow. Rolling angles for each view were recorded and a corrective index was computed by calculating the difference in angulation between the Grashey view and lateral of the elbow. To test the proposed method, a transverse fracture of the proximal humerus was induced, and rotation was set during intramedullary fixation using the proposed sequence. RESULTS: Paired T-test comparing contralateral corrective indices showed no statistical difference across the paired sides (P = .190). Moreover, Pearson correlation among sides showed contralateral agreement (rho = 0.957, P = .0002) with absolute differences ranging from 1° to 8° suggesting that contralateral extremity can serve as a template for rotational profiling using this method. CONCLUSION: The proposed fluoroscopic sequence provides a standardized method to restore native rotation of the humerus during intramedullary fixation, whereby the contralateral extremity can be used as a reference.
