Standard total shoulder arthroplasty for arthritis with glenoid bone deficiency

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

Currently many surgeons are using augmented glenoid components or reverse total shoulder arthroplasty to manage arthritic shoulders with type B2 and B3 glenoid pathoanatomy.

These authors sought to evaluate the ability of shoulder arthroplasty using a standard glenoid component to improve patient self-assessed comfort and function and to correct preoperative humeral-head decentering on the face of the glenoid in patients with primary glenohumeral arthritis and type-B2 or B3 glenoids. They identified 66 shoulders with type-B2 glenoids (n = 40) or type-B3 glenoids (n = 26) undergoing total shoulder arthroplasties with a non-augmented glenoid component inserted without attempting to normalize glenoid version and with clinical and radiographic follow-up at a minimum of 2 years. 

Shoulder pathoanatomy was characterized on the axillary "truth" view in terms of glenoid version (angle between lines G and S) and humeral head decentering on the face of the glenoid (distance between line  P - the perpendicular bisector of line segment G - and the center of the humeral head, C). Preoperative CT scans and computer planning software were not used in this case series.

This method allowed direct comparison of glenoid version and humeral decentering before and after the arthroplasty

The Simple Shoulder Test (SST) score improved from 3.2 ± 2.1 points preoperatively to 9.9 ± 2.4 points postoperatively (p < 0.001) at a mean time of 2.8 ± 1.2 years for type-B2 glenoids and from 3.0 ± 2.5 points preoperatively to 9.4 ± 2.1 points postoperatively (p < 0.001) at a mean time of 2.9 ± 1.5 years for type-B3 glenoids. These patient reported outcomes were as good as those achieved with other glenoid types.

These outcomes were achieved without changing glenoid version: postoperative glenoid version was not significantly different from preoperative glenoid version. 

The humeral head centering on the glenoid was restored: the mean humeral-head decentering on the glenoid face was reduced for type-B2 glenoids from 214% ± 7% preoperatively to 21% ± 2% postoperatively (p < 0.001) and for type-B3 glenoids from 24% ± 6% preoperatively to 21% ± 3% postoperatively (p = 0.027). 

The rates of bone integration into the central peg for type-B2 glenoids (83%) and type-B3 glenoids (81%) were not inferior to those for other glenoid types (A1 67%, A2 85%, B1 74%, D 75%).

Anterior penetration of the glenoid neck by the central peg of the glenoid component was observed in 2 (11%) of 19 of the type-B1 glenoids, in 6 (15%) of 40 of the type-B2 glenoids, and in 6 (23%) of 26 of the type-B3 glenoids. Perforation of the glenoid by the central peg was not associated with inferior clinical or radiographic outcomes. Twelve of the 14 shoulders with glenoid neck penetration had ingrowth of bone between the flanges of the central peg with no radiographic evidence of component loosening. The final mean SST score for the 14 shoulders with central peg penetration was 9.4 ± 2.3 points, a value not significantly different (p = 0.649) from that for all of the type-B2 and B3 glenoids (9.7 ± 2.2 points).

Comment: These minimum 2-year outcomes for 40 shoulders with type-B2 glenoids and 26 shoulders with type-B3 glenoids do not appear to be inferior to the minimum 2-year results reported recently for a combined group of 71 shoulders with type-B2 or B3 glenoid anatomy treated with posteriorly augmented glenoids inserted using preoperative CT scans and 3-dimensional planning  software (see this link). 

This study demonstrates that good two year clinical outcomes can be achieved for B2 and B3 glenoid components using a standard (non-augmented) glenoid component inserted without changing glenoid version. Further glenoid research with longer followup will be required to compare these outcomes to those achieved using other techniques.  

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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).