title: Reliability of measurements performed on two dimensional and three dimensional computed tomography in glenoid assessment for instability.
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 one week 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.
authors: Department of Human Evolutionary Biology, Adam Mickiewicz University in Poznań, Umultowska 89, PL-61-614, Poznań, Poland. akubicka@amu.edu.pl.
authors: Anna Maria
authors: 0000-0002-7844-9225
authors: AM
authors: Kubicka
authors: Department of Traumatology, Orthopaedics and Hand Surgery, University of Medical Sciences in Poznań, Poznań, Poland.|Rehasport Clinic, Poznań, Poland.
authors: Jakub
authors: J
authors: Stefaniak
authors: Department of Traumatology, Orthopaedics and Hand Surgery, University of Medical Sciences in Poznań, Poznań, Poland.|Rehasport Clinic, Poznań, Poland.
authors: Przemysław
authors: P
authors: Lubiatowski
authors: Rehasport Clinic, Poznań, Poland.
authors: Jan
authors: J
authors: Długosz
authors: Rehasport Clinic, Poznań, Poland.
authors: Marcin
authors: M
authors: Dzianach
authors: Department of Traumatology, Orthopaedics and Hand Surgery, University of Medical Sciences in Poznań, Poznań, Poland.
authors: Marcin
authors: M
authors: Redman
authors: Department of Human Evolutionary Biology, Adam Mickiewicz University in Poznań, Umultowska 89, PL-61-614, Poznań, Poland.
authors: Janusz
authors: J
authors: Piontek
authors: Department of Traumatology, Orthopaedics and Hand Surgery, University of Medical Sciences in Poznań, Poznań, Poland.
authors: Leszek
authors: L
authors: Romanowski
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007593:Joint Instability / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012540:Scapula / Q000000981:diagnostic imaging*; D012785:Shoulder Joint / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
keywords: Glenoid defect; Scapula; Shoulder; Shoulder instability; Three-dimensional measurement; Three-dimensional reconstruction