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

Anna Maria Kubicka,Janusz Piontek,Marcin Dzianach,Leszek Romanowski,Marcin Redman,Przemysław Lubiatowski,Jan Długosz,Jakub Stefaniak

doi:10.1007/s00264-016-3253-9

Abstract

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. 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 oneweek for 30 randomly selected glenoids. The intra-class correlation coefficient (ICC) for inter-observer 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. 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-CT. 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.

Highlights

Accurate assessment of glenoid bone loss is important in preoperative decision making and planning
The intra-class correlation coefficient (ICC) for interobserver reliability was significantly greater for 3D-computed tomography (CT) (0.811 to 0.915) than for 2D-CT (0.523 to 0.925)
Conclusions it can be concluded that 3D glenoid reconstructions are more reliable for glenoid bone loss assessment than 2D-CT

Summary

Introduction

Accurate assessment of glenoid bone loss is important in preoperative decision making and planning. The choice of operative procedure for shoulder instability is predominantly based on the calculation of glenoid bone loss [3,4,5]. Accurate measurement of glenoid parameters is challenging, and of great interest in clinical research [7]. Radiographic imaging is still widely used in shoulder instability to assess the presence or absence of bony abnormalities, fractures, Hill-Sachs lesion or any other pathologic changes in the joint [13,14,15,16]. Roentgenographic examination is used in the following: post-operative assessment of changes in the implant position after total shoulder arthroplasty (TSA) [7, 17, 18], measuring glenoid version [19], detection of scapular fractures [20], or evaluation of reverse shoulder arthroplasty (RSA) [21]. Due to certain limitations of this method several research projects focus on comparing the reliability of radiographic imaging, two-dimensional (2D) and three-dimensional (3D) computed tomography (CT)

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