Improved accuracy of K-wire positioning into the glenoid vault by intraoperative 3D image intensifier-based navigation for the glenoid component in shoulder arthroplasty.

INTRODUCTION: This article aimed to show that navigation, based on an intraoperative mobile 3D image intensifier, can improve the accuracy of central K-wire placement into the glenoid vault for glenoid component. HYPOTHESIS: The navigated k-wire placement is more accurate and shows a smaller deviation angle to the standard centerline compared to the classical "free hand technic". METHODS: In 34 fresh frozen sheep scapulae, 17 K-wire placements using the navigation (group 1) were compared with 17 using standard "face plane technique" (group 2). The relation to glenoid standard and alternative centerlines (CL) and the position within the glenoid vault were analyzed. RESULTS: In groups 1 and 2 the angle between the K-wire and standard CL was 2.2° and 4.7°, respectively (P=0.01). The angle between the K-wire and alternative CL was 14.4° for group 1 and 17.2° for group 2 (P=0.02). More navigated K-wire positions were identified within a 5mm corridor along the glenoid vault CL (52 vs. 39; P=0.004). DISCUSSION: Intraoperative 3D image intensifier-based navigation was more accurate and precise than standard K-wire placement. TYPE OF STUDY AND LEVEL OF PROOF: Basic science study, evidence level III.