STANDARD SHOULDER CT SCANS DO NOT PROVIDE ADEQUATE MEASUREMENT OF GLENOID VERSION

Introduction: Glenoid version seems to play an important role in the loading and stability of the glenohumeral joint. Measurement of Glenoid version on standard x-rays has been shown to be inaccurate. The purpose of this study was to assess the accuracy of the glenoid version measured on standard CT scans. Material and Methods: The version of the glenoid was assessed using a multislice CT. We analysed 60 scapulae in 47 Patients (32 male; 18 to 83 years; 17 osteoarthritis and 29 instability). The retroversion of the glenoid was measured in 2 planes. First on the standard axial plane and second in a corrected axial plane (multiplanar reconstruction of scapula in a “true” axial plane with respect to the three-dimensional adjustment of the scapula). Results: In the standard axial plane the mean retroversion was 8° (range, −5° to 22°). In the correct axial plane the difference of the retroversion was averages 6° compared to the standard axial plane. The range of the error was form 0° to 15°. Conclusion: Measurement of glenoid retroversion on standard axial ct scans was unreliable. The clinical relevance: The standard shoulder CT is not suited for the preoperative planning of the glenoid correction. Therefore we would advocate the assessing of the glenoid version a defined “true” axial plane obtainable trough multiplanar reconstruction.