Does "correction" of glenoid retroversion improve glenohumeral stability?

Long-term results after posterior open glenoid wedge osteotomy for posterior shoulder instability associated with excessive glenoid retroversion

These authors reviewed 6 consecutive patients (7 shoulders) having a posterior open wedge glenoid osteotomy to correct posterior shoulder instability associated with excessive glenoid retroversion.

Mean glenoid retroversion of all 7 shoulders was corrected from 20 degrees to 3 degrees.

They found recurrent, symptomatic posterior shoulder instability in 6 of 7 shoulders (86%). 

In the 5 shoulders with preoperative static posterior subluxation of the humeral head, the humeral head was not recentered. 

Figure: Preoperative and follow-up CT (17 years postoperative) after posterior open wedge glenoid osteotomy for glenoid dysplasia for posterior glenohumeral instability. 

(A) Preoperative CT scan shows pathologic glenoid retroversion of 25 degrees. 

(B) Postoperative CT scan shows correction of glenoid retroversion to 8 degrees.

Note the posterior subluxation of the humeral head postoperatively with development of severe osteoarthritis despite the "correction" of retroversion. 

All 7 shoulders showed progression of glenoid arthritic changes.

The authors concluded that changing glenoid version using a posterior open wedge glenoid osteotomy for posterior shoulder instability associated with excessive glenoid retroversion neither reliably restored

shoulder stability nor recentered the joint.

Comment: This study suggests that glenoid version is not the primary determinant of glenohumeral instability. In fact in the figure above, one can see that on the preoperative CT scan, the humeral head is relatively well centered on the retroverted glenoid articular surface, whereas on the postoperative view, the humeral articular surface is posteriorly decentered on the glenoid with "corrected" version.

In a prior publication Static posterior humeral head subluxation and total shoulder arthroplasty, these authors found that the subluxation index defined as a/b x 100% in the figure below (centered head (35-65%); posterior subluxation (>65%); anterior subluxation (<35%))

did not correlate with glenoid retroversion prior to arthroplasty 

or after total shoulder replacement.

Recent publications indicate that in arthritic shoulders with preoperative retroversion, the humeral head can be reliably recentered without changing glenoid version:

Does Postoperative Glenoid Retroversion Affect the 2-Year Clinical and Radiographic Outcomes for Total Shoulder Arthroplasty?

Anatomic Total Shoulder Arthroplasty with All-Polyethylene Glenoid Component for Primary Osteoarthritis with Glenoid Deficiencies

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The total shoulder arthroplasty (see this link).

The ream and run technique is shown in this link.

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Shoulder rehabilitation exercises (see this link).

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Note that author has no financial relationships with any orthopaedic companies.