These authors sought to assess the reliability of 4 different shoulder arthroplasty 3-dimensional preoperative planning programs in measuring glenoid retroversion and compared these to manual measurements conducted by 2 fellowship-trained musculoskeletal radiologists.
They conducted a retrospective review of computed tomography (CT) scans of 76 shoulders undergoing shoulder arthroplasty. 76 CTs were analyzed for glenoid inclination and version using 4 templating software systems (VIP, Blueprint, TrueSight, ExactechGPS).
Measurements of glenoid version and inclination differed between at least 2 programs by 5º-10º in 75% and 92% of glenoids respectively, and by >10º in 18% and 45% respectively.
The degree of agreement among observations was affected by the Walch class of the studied glenoids, with the highest inter-rater reliability among Walch A glenoids (i.e. those without glenoid deformity) and lower reliability among Walch B and Walch D glenoids.
It is apparent that a lot of time, energy and money can be directed at the measurement of glenoid version. At this point, one might ask, "how important precise version measurements are to the outcome of shoulder arthroplasty?". The final word is surely not it, but it is possible that precise measurement and "correction" of glenoid version may not be as critical to the outcome as once thought.
These authors studied a population of patients undergoing total shoulder arthroplasty (TSA) stratified into two groups: those with the glenoid implanted in ≥ 15 degrees of retroversion and those with the glenoid implanted in <15 degrees of retroversion.
The mean improvement in the SST (6.7) for the retroverted group was comparable to that for the nonretroverted group (5.8).
The percent of maximal possible improvement (%MPI) for the retroverted glenoids (70%) was comparable to that for the nonretroverted glenoids (67%).
The 2-year SST scores for the retroverted (9.3) and the nonretroverted glenoid groups (9.4) were similar
No patient in either group reported symptoms of subluxation or dislocation.
The radiographic results for the retroverted glenoid group were similar to those for the nonretroverted group with respect to
(a) central peg lucency (four of 21 retroverted [19%] versus six of 50 non-retroverted [12%]
(b) average Lazarus radiolucency scores (0.5 versus 0.7), and
(c) the mean percentage of postoperative posterior humeral head decentering (3.4% versus 1.6%).
The percentage of patients with retroverted glenoids undergoing revision (0 of 21 [0%]) was comparable to the percentage of revisions among the non-retroverted glenoids (three of 50; [6%]).
These authors concluded that postoperative glenoid retroversion was not associated with inferior clinical results at 2 years after surgery. This suggests that it may be possible to effectively manage arthritic glenohumeral joints without specific attempts to modify glenoid version.
Below is an example of a severely retroverted B2 glenoid managed with a ream and run procedure without attempting to change glenoid version. On the left is the preoperative axillary and the right the axillary at three months after surgery when the patient had 150 degrees of comfortable shoulder elevation. Note the lack of change of glenoid version and the use of an anteriorly eccentric humeral head component.
A second example is a man in his mid 70's presented with a stiff painful shoulder. These x-rays were obtained a the time of office evaluation, showing osteoarthritis
and a B2 glenoid.
His axillary view showed centering of an anteriorly eccentric humeral component on a secure glenoid component placed in retroversion with some penetration of the cortex of the glenoid neck.
He allowed us to take a short movie of his shoulder function two and one half years after surgery.
His axillary "truth" view, shows a retroverted type B2 glenoid
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Here are some videos that are of shoulder interest
