These authors used three-dimensional reconstructions of computed tomography scans to evaluate the 3-dimensional relationship of the humeral head to the plane of the scapula in 151 nonpathologic shoulders (control group) and 110 shoulders with primary glenohumeral arthritis (OA group).
Subjects were positioned in the CT gantry in a supine position; both arms were adducted to the trunk, the elbows were at right angles, and the forearms were positioned in the anterior direction with neutral rotation.
The scapulohumeral relationship could be determined reliably: the intraclass correlation coefficient ranged between 0.780 and 0.978; the typical error of measurement ranged between 2.4% and 5.0%. Both type A and type B shoulders showed significant posterior displacement of the humeral head in relation to the scapular plane (P <.001). Type B shoulders had significantly more posterior displacement of the humeral head in relation to the scapular plane than type A shoulders (P <.001). A tendency of inferior displacement was noted, although with only marginal statistical significance (P = .051). For each glenoid type, a medial deviation of the humeral head, representing a reduced glenohumeral distance, was measured (P <.001).
The main characteristics of primary glenohumeral osteoarthritis were posterior humeral head displacement in relation to the plane of the scapula and reduced glenohumeral distance in both type A and type B shoulders.
Shoulders were classified as centered (type A) or posteriorly displaced (type B) according to the Walch classification.
The scapulohumeral relationship could be determined reliably: the intraclass correlation coefficient ranged between 0.780 and 0.978; the typical error of measurement ranged between 2.4% and 5.0%. Both type A and type B shoulders showed significant posterior displacement of the humeral head in relation to the scapular plane (P <.001). Type B shoulders had significantly more posterior displacement of the humeral head in relation to the scapular plane than type A shoulders (P <.001). A tendency of inferior displacement was noted, although with only marginal statistical significance (P = .051). For each glenoid type, a medial deviation of the humeral head, representing a reduced glenohumeral distance, was measured (P <.001).
The main characteristics of primary glenohumeral osteoarthritis were posterior humeral head displacement in relation to the plane of the scapula and reduced glenohumeral distance in both type A and type B shoulders.
Comment: This study is focused on the relationship of the humeral head of the adducted arm to the plane of the scapula. The figures above show the posterior displacement of the humeral head with the arm at the side in type A glenoids (left), type B glenoids (center) and normal glenoids (right).
It is important to recognize that this analysis does not include the relationship of the humeral head center to the face of the glenoid, i.e. whether or not the humeral head is centered on the glenoid or not.
It is also important to note that these images were obtained with the arm at the side, rather than in the functional position of elevation in the plane of the scapula, so that functional decentering could not be assessed.
Our approach to imaging the arthritic shoulder is shown in this link. We emphasize the importance of the axillary view obtained with the arm in a functional position of elevation, which we refer to as the 'truth' view, as shown in this link and again here..
===
Consultation for those who live a distance away from Seattle.
Click here to see the new Shoulder Arthritis Book.
Click here to see the new Rotator Cuff Book
Click here to see the new Shoulder Arthritis Book.
Click here to see the new Rotator Cuff Book
Use the "Search" box to the right to find other topics of interest to you.
You may be interested in some of our most visited web pages including:shoulder arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'
See from which cities our patients come.
See the countries from which our readers come on this post.
You may be interested in some of our most visited web pages including:shoulder arthritis, total shoulder, ream and run, reverse total shoulder, CTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'
See from which cities our patients come.
See the countries from which our readers come on this post.
