Three-Dimensional Quantification of Glenoid Bone Loss in Anterior Shoulder Instability: The Anatomic Concave Surface Area Method

Abstract

Background: Recurrent shoulder instability may be associated with glenoid erosion and bone loss. Accurate quantification of bone loss significantly influences the contemplation of surgical procedure. In addition, assessment of bone loss is crucial for surgical planning and accurate graft placement during surgery. Purpose: To quantify the concave surface area of glenoid bone loss by using 3-dimensional (3D) segmented models of the scapula and to compare this method with the best-fit circle and glenoid height/width methods, which use the glenoid rim for bone loss estimations. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: A total of 36 consecutive preoperative bilateral computed tomography scans of patients eligible for a primary Latarjet procedure were selected from our institutional surgical database (mean patient age, 29 ± 9 years; 31 men and 5 women). The 3D models of both scapulae were generated using medical segmentation software and were used to map the anatomic concave surface area (ACSA) of the inferior glenoid using the diameter of the best-fit circle of the healthy glenoid. Bone loss was calculated as a ratio of the difference between surface areas of both glenoids (healthy and pathological) against the anatomic circular surface area of the healthy glenoid (the ACSA method). These results were compared with bone loss calculations using the best-fit circle and glenoid height/width methods. Inter- and intraobserver reliability were also calculated. Results: The mean (± SD) bone loss calculated using the ACSA, the best-fit circle, and glenoid height/width methods was 9.4% ± 6.7%, 14.3% ± 6.8%, and 17.6% ± 7.3%, respectively. The ACSA method showed excellent interobserver reliability, with an intraclass correlation coefficient (ICC) of 0.95 versus those for the best-fit circle (ICC, 0.71) and glenoid height/width (ICC, 0.79) methods. Conclusion: Quantification of instability-related glenoid bone loss is reliable using the 3D ACSA method.

Restoration of glenoid joint line: a three-dimensional analysis of scapular landmarks

“…Kwon et al 24 and Launay et al 26 have quantified the error produced when measuring scapular anatomical measurements directly on 2D medical images. 22 , 24 Due to the variation between patient position and gantry angle, this method of measurement is not recommended; however, if 3D visualization software is unavailable, TS, SN, and AL can be estimated in 2D.…”

Correlation of Glenoid Concavity With Surgical Failure After Arthroscopic Stabilization for Recurrent Anterior Shoulder Instability

“…The 2-dimensional measurement obtained in this fashion uses only the articular surface of the glenoid to calculate glenoid bone defect size, and the glenoid concavity is not considered. 8,11 Glenoid concavity compression by rotator cuff muscle contraction is a key contributor to the stability of the glenohumeral joint. 11,13,24 Various parameters, including glenoid retroversion, glenoid depth, glenoid diameter, and degree of glenoid concavity, have been revealed to be related to glenoid concavity compression and shoulder instability.…”

“…The 2-dimensional measurement obtained in this fashion uses only the articular surface of the glenoid to calculate glenoid bone defect size, and the glenoid concavity is not considered. 8,11…”