Saturday, December 29, 2012

The eroded glenoid in total shoulders

Total shoulder arthroplasty does not correct the orientation of the eroded glenoid

This article brings up the important topic of management of the glenoid with posterior erosion - a very common finding in glenohumeral arthritis. Here's an example showing glenoid retroversion, posterior glenoid erosion and posterior humeral subluxation.

The authors sought to determine the extent to which the glenoid component position was governed by the preoperative erosion of the glenoid and whether excessive erosion of the glenoid was associated with perforation of the glenoid vault on insertion of a glenoid component. Using preoperative and postoperative CT scans the authors asssessed version, inclination, rotation, and offset of the glenoid relative to the scapula plane.

The surgical technique sought to position the glenoid perpendicular to the plane of the scapula. Asymmetrical reaming was used to change the orientation of the glenoid. The authors reference a method we described in 1994 for identifying the glenoid centerline to guide their reaming. They found that their preparation of the glenoid did not substantially change the version of the glenoid and that the keel of their glenoid component perforated the glenoid vault in 5 of 29 cases - especially in cases of severe posterior erosion in which the anterior cortex was perforated.

The authors do a nice job of pointing out the competing priorities in achieving a durable, stable, functional arthroplasty:
(1) normalizing glenoid version
(2) avoiding glenoid vault perforation
(3) preserving glenoid bone stock
(4) achieving glenohumeral stability

While it has been stated that glenoid penetration is associated with early loosening, we have not seen documentation of this statement.

Our goal in arthroplasty prioritizes the last two of these:  preserving glenoid bone stock and achieving glenohumeral stability as shown in this post regarding the ream and run and in this post regarding the total shoulder. 

The patient whose preoperative x-ray is shown above elected to have a ream and run. His post operative films so the humeral prosthesis centered in a glenoid that was only reamed enough to create a single concentric concavity.

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You may be interested in some of our most visited web pages including:shoulder arthritis, total shoulder, ream and runreverse total shoulderCTA arthroplasty,  and rotator cuff surgery.