Aims. The aim of this study was to analyse the effect of altered viewing
perspectives on the measurement of the glenopolar angle (GPA) and
the differences between these measurements made on 3D CT reconstructions
and anteroposterior (AP) scapular view radiographs. . Materials and Methods. The influence of the viewing perspective on the GPA was assessed,
as were the differences in the measurements of the GPA between 3D
CT reconstructions and AP scapular view radiographs in 68 cadaveric
scapulae. Results. The median GPA in 3D reconstructions and AP scapular views were
42.7° (95% confidence intervals (CI), 42.0° to 43.5°) and 41.3°
(95% CI 40.4° to 42.0°) respectively (p <
0.001). All but five
of 20 malpositions demonstrated a significant difference in GPA
compared with the respective AP scapular view (p ≤ 0.005). The GPA
was most susceptible to malposition in retroversion/
The liner design is a key determinant of the constraint of a reverse total shoulder arthroplasty (rTSA). The aim of this study was to compare the degree of constraint of rTSA liners between different implant systems. An implant company’s independent 3D shoulder arthroplasty planning software (mediCAD 3D shoulder v. 7.0, module v. 2.1.84.173.43) was used to determine the jump height of standard and constrained liners of different sizes (radius of curvature) of all available companies. The obtained parameters were used to calculate the stability ratio (degree of constraint) and angle of coverage (degree of glenosphere coverage by liner) of the different systems. Measurements were independently performed by two raters, and intraclass correlation coefficients were calculated to perform a reliability analysis. Additionally, measurements were compared with parameters provided by the companies themselves, when available, to ensure validity of the software-derived measurements.Aims
Methods
Accurate measurement of the glenoid version is important in performing total shoulder arthroplasty (TSA). Our aim was to evaluate the Ellipse method, which involves formally defining the vertical mid-point of the glenoid prior to measuring the glenoid version and comparing it with the ‘classic’ Friedman method. This was a retrospective study which evaluated 100 CT scans for patients who underwent a primary TSA. The glenoid version was measured using the Friedman and Ellipse methods by two senior observers. Statistical analyses were performed using the paired Aims
Methods
Aims
Materials and Methods
The glenopolar angle assesses the rotational
alignment of the glenoid and may provide prognostic information
and aid the management of scapula fractures. We have analysed the
effect of the anteroposterior (AP) shoulder radiograph rotational
offset on the glenopolar angle in a laboratory setting and used
this to assess the accuracy of shoulder imaging employed in routine
clinical practice. Fluoroscopic imaging was performed on 25 non-paired scapulae
tagged with 2 mm steel spheres to determine the orientation of true
AP views. The glenopolar angle was measured on all the bony specimens
rotated at 10° increments. The mean glenopolar angle measured on
the bone specimens in rotations between 0° and 20° and thereafter
was found to be significantly different (p <
0.001). We also obtained
the AP radiographs of the uninjured shoulder of 30 patients treated
for fractures at our centre and found that none fitted the criteria
of a true AP shoulder radiograph. The mean angular offset from the
true AP view was 38° (10° to 65°) for this cohort. Radiological
AP shoulder views may not fully project the normal anatomy of the scapular
body and the measured glenopolar angle. The absence of a true AP
view may compromise the clinical management of a scapular fracture. Cite this article:
