Reliability of measurements performed on two dimensional and three dimensional computed tomography in glenoid assessment for instability

Abstract

Purpose The main purpose of this study is to establish which of two methods is more reliable in glenoid assessment for instability in pre-operative planning. Accordingly, we have studied the intra-and inter-observer reliability of glenoid parameters with the use of two-dimensional (2D) and three-dimensional (3D) reconstructed computed tomography (CT) images. Methods One hundred glenoids were measured with the use of 2D-CT and 3D-CT (in 3D orientation) by two independent observers (one experienced and one inexperienced). Measurements were repeated after one week for 30 randomly selected glenoids. Results The intra-class correlation coefficient (ICC) for interobserver reliability was significantly greater for 3D-CT (0.811 to 0.915) than for 2D-CT (0.523 to 0.925). All intra-observer reliability values for 3D-CT were near perfect (0.835 to 0.997), while those for 2D-CT were less reliable (0.704 to 0.960). A dependent t-test showed that, for both observers, almost all glenoid parameters (except R and d) differed significantly (p < 0.05) between 2D and 3D measurement methods. Conclusions Therefore, it can be concluded that 3D glenoid reconstructions are more reliable for glenoid bone loss assessment than 2D-CT. The results suggest that quantifying a glenoid defect with the use of 2D image only-even if performed by an experienced orthopaedic surgeon-is prone to errors. Differences in measurements between and within observers can be explained by plane setting and identifying glenoid rim in 2D -C T. Accordingly, we recommend that glenoid measurements should be performed in 3D orientation using 3D reconstruction obtained from CT images for pre-operative assessments, which are crucial for surgical planning.

Reliability of humeral head measurements performed using two- and three-dimensional computed tomography in patients with shoulder instability

“…We have been able to show in our previous study that 3D glenoid reconstruction is more reliable for glenoid bone loss assessment than 2D [14]. Therefore, we have focused on the measurement of humeral head defects in shoulder instability.…”

Does Bone Loss Imaging Modality, Measurement Methodology, and Interobserver Reliability Alter Treatment in Glenohumeral Instability?

“…Bishop et al 44 demonstrated MRI to be less reliable than CT. 44 Bois et al 28 demonstrated poor reliability for 2-dimensional CT measurements. Kubicka et al 29 determined 2-dimensional CT to be less reliable than 3-dimensional CT, which they attributed to differences in plane of cut that are overcome by our study design. Markenstein et al 35 demonstrated MRI to be reliable for the assessment of glenoid bone loss.…”

“…[25][26][27] In addition, they can be performed on both 2-dimensional CT slices and 3-dimensional osseous scapular reconstructions with subtraction of the humeral head to allow an en face view. [28][29][30][31] As CT involves radiation and additional cost, there has been significant interest in determining whether these measurements could be made accurately and reliably using magnetic resonance imaging (MRI) alone. 29,[31][32][33][34][35][36][37][38] Driven by this interest, 3dimensional MRI reconstructions also have become available.…”

“…[28][29][30][31] As CT involves radiation and additional cost, there has been significant interest in determining whether these measurements could be made accurately and reliably using magnetic resonance imaging (MRI) alone. 29,[31][32][33][34][35][36][37][38] Driven by this interest, 3dimensional MRI reconstructions also have become available. 30,34,38 Despite these numerous previous studies, it remains unclear whether the method of measurement is clinically relevant.…”

“…30,34,38 Third, many studies have examined 3-dimensional reconstructions, which may not be available depending on the facility in which the CT is performed. 28,29,31,[34][35][36] The frequent lack of availability of 3D reconstructions limits the applicability of these previous studies to general orthopaedic practice. Fourth, few published articles examined the reliability of combined humeral and glenoid bone loss measurements.…”