High correlation between inner and outer glenoid circle diameters and its clinical relevance

Abstract

PurposeThe majority of methods for measuring glenoid bone loss in shoulder instability use the best‐fit circle following the inferior glenoid rim. However, there is no precise method on how to draw this circle, particularly in case of a missing rim segment. Defining the radius is a source of substantial error. It was hypothesized that there is a relationship between the best‐fit inferior circle (inner circle), defined by Sugaya, and the circle tangent to the supra‐ and infra‐glenoid tubercles (outer circle), defined by Itoi, thus allowing a more consistent appreciation of the paleo‐glenoid. MethodsNinety‐five normal dry scapulae were examined. The specimens were digitally photographed obtaining perpendicular images of the glenoid cavity. Using HOROS® imaging software, a best‐fit inferior circle (inner circle) and a second circle fitting the most inferior and superior points of the glenoid (outer circle) were drawn by two investigators. The diameters and areas of the circles were recorded. Two‐way random‐effects intra‐class correlation coefficients (ICC) were used to measure intra‐ and inter‐observer agreement. A Bayesian measurement‐error regression model was used to determine the relationship between outer and inner circle measurements. ResultsThe mean glenoid height was 35.1 mm and the glenoid width 25.6 mm.The mean diameter of the outer circle was 35.7 ± 4.2 mm and the mean diameter of the inner circle was 26.8 ± 3.2 mm. ICC showed excellent inter‐ and intra‐observer agreement for both the outer circle diameter (ICC ≥ 0.95) and inner circle diameter (ICC ≥ 0.93). The two diameters demonstrated a very strong significant Pearson correlation (0.92, p < 0.001) and the regression showed excellent model fit R2 = 0.87. The areas of the two circles were also highly and significantly correlated (r = 0.94; p < 0.001). The ratio of inner circle to outer diameters was 0.74. ConclusionThere is a strong correlation between the inner and outer glenoid circle diameters. This study sets the base for the use the combined outer and inner circle and its ratio to better appreciate the paleo‐glenoid morphology and thus obtain a more reliable bone loss estimation. Application of this method aids in a more reliable estimation bone loss with potential benefit in surgical decision‐making.

Comparison of the Scapula in Human and Laboratory Rat Species from the Perspective of Translational Medicine

“…Digital calipers were used to measure parameters for rat scapula. Literature searches were carried out for the measurements of the human scapula, and the obtained literature data was evaluated [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] .…”

The arthroscopic treatment of anterior shoulder instability with glenoid bone loss shows similar clinical results after Latarjet procedure and iliac crest autograft transfer

“…These were: Age between 18 and 60 years, anterior type B2 and B3 instabilities according to the Gerber‐classification [15] and a glenoid deficit of at least 10%. The latter one was measured on parasagittal CT scans in a standardized fashion using the surface area method [3, 18]. Exclusion criteria were posterior and multidirectional instabilities, patients with nerve or vessel damage, radiologic signs of osteoarthritis, acute bony bankart lesions, instabilities accompanied by rotator cuff lesions, as well as pregnant and epileptic patients.…”

Bipolar bone loss and distance to dislocation

“…While the inner, or inferior, circle is more commonly used, in the setting of glenoid bone loss the outer circle method may be technically easier and more reproducible. A recent study noted a high correlation between the inner and outer circle measurements, with a ratio of 0.74 ( 26 ). Although future studies are needed to confirm the validity of this ratio, it may serve as a useful technique to mitigate variations in measurement attributable to the presence of bone loss.…”