"Posterior humeral subluxation" is a result of glenoid retroversion; is it a clinical problem?

A recent article, Total Shoulder Arthroplasty for Primary Glenohumeral Osteoarthritis: does the posterior humeral subluxation persist after correction of the glenoid version at 5 years minimum?, used the term "posterior humeral subluxation" to refer to the percentage (a/D (%)) of the humeral head posterior to the scapular axis. 

362. The authors observed that "posterior humeral subluxation" was highly correlated (p<0.0001) with glenoid version both preoperatively 

     

     and postoperatively

     
     

     
     
     

     This result was noted in a prior post Arthritic subluxation of the shoulder - what does it mean?.

     
     

     
     In this diagram from that post, the percentage of posterior displacement of the humeral head relative to the scapular axis (blue symbols) was strongly correlated with the glenoid retroversion, irrespective of Walch glenoid type. By contrast, the percentage of posterior displacement (decentering) of the humeral head relative to the glenoid face (red symbols) was not strongly related to glenoid retroversion, but was strongly related to Walch glenoid type (note differences between type A1 and A2 glenoids in comparison to types B1, B2, B3 and C).
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The reason for the strong relationship between glenoid retroversion and the posterior displacement of the humeral head relative to the scapular axis can be seen by comparing the two diagrams below; in each the humeral head is centered in the glenoid fossa. 

The first shows that 5 degrees of retroversion results in 6% posterior displacement of the humeral head in relation to the scapular axis (equivalent to 56% "posterior humeral subluxation").
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     The second shows that 25 degrees of retroversion results in 38% posterior displacement of the humeral head in relation to the scapular axis (equivalent to 88% "posterior humeral subluxation").
     
     Note that the values obtained from these simple diagrams (green dots) are highly consistent with actual clinical values reported above.

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     Other studies have also pointed out that posterior displacement of the humeral head in relation to the plane of the scapula is determined primarily by the degree of glenoid retroversion.  Importance of a three-dimensional measure of humeral head subluxation in osteoarthritic shoulders found that the correlation between retroversion and posterior displacement of the humeral head relative to the body of the scapula had an R²  of 0.8634. A similar relationship can be seen in the data for 707 shoulders from Identification of threshold pathoanatomic metrics in primary glenohumeral osteoarthritis. Qualitative and quantitative analysis of glenoid bone stock and glenoid version: inter-reader analysis and correlation with rotator cuff tendinopathy and atrophy in patients with shoulder osteoarthritis found that the correlation between retroversion and posterior displacement of the humeral head relative to the plane of the scapula had an R²of 0.8161. CT assessment of the relationship between humeral head alignment and glenoid retroversion in glenohumeral osteoarthritis found “a nearly perfect linear relationship between glenoid retroversion and humeral-scapular alignment, with a Pearson correlation coefficient of 0.90 (R² = 0.81, p < 0.001).” 
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364. From all these studies we can conclude that >80% of the variance in the alignment of the humeral head to the plane of the scapula is determined by glenoid retroversion.
     
     
     Two prior posts discuss whether or not it is important to "correct" glenoid retroversion when the humeral head is centered in the glenoid socket. "Subluxation of the shoulder", why does it matter? and Does glenoid version need to be corrected in anatomic shoulder arthroplasty? Interestingly, Static posterior humeral head subluxation and total shoulder arthroplasty found that re-centering of the humeral head on the glenoid was not correlated with glenoid version or its correction.
     
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Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link).
The total shoulder arthroplasty (see this link).
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link).
Shoulder rehabilitation exercises (see this link).