BACKGROUND:
Primary glenohumeral osteoarthritis with posterior wear of the glenoid and posterior subluxation of the humerus (Walch type B) presents a challenge to the treating surgeon. Our hypothesis was that glenoids with biconcavity (B2) would be associated with worse outcomes (functional scores and complications) than B1 glenoids.

MATERIALS AND METHODS:
We retrospectively analyzed prospectively collected data on 112 anatomic total shoulder arthroplasties (104 patients) with B glenoids. Preoperative computed tomography identified 64 B1 glenoids and 48 B2 glenoids (50 and 37 available for follow-up).

RESULTS:
A significant difference between B1 and B2 glenoids was noted in average retroversion (11° vs. 16°; P < .001) and average posterior humeral subluxation (65% vs. 75%; P < .001). No significant difference was seen in mean age (69.5 vs. 69.2 years) or body mass index (28.5 vs. 27.4) at time of surgery. At average follow-up of 60 months (range, 23-120 months), glenoid component radiolucencies (51.6%, B1; 47.9%, B2), range of motion, preoperative and postoperative scores of the shortened Disabilities of the Arm, Shoulder, and Hand questionnaire, and patient satisfaction were not significantly different between the 2 groups. Four revisions (4.6%) were documented for acute postoperative infection (2.3%), subscapularis failure (1.1%), and glenoid loosening (1.1%).

CONCLUSIONS:
Although biconcave glenoids commonly have more severe retroversion and posterior subluxation of the humerus, we were unable to find a clinical or radiographic difference in outcome of patients with B1 or B2 glenoids treated with anatomic total shoulder arthroplasty at intermediate-term follow-up. Continued clinical and radiographic follow-up of these cohorts will be necessary to assess any future divergence in outcome.





Polls results
1

On a scale of 1 to 10, rate how much this article will change your clinical practice?

NO change
BIG change
50% Article relates to my practice (1/2)
50% Article does not relate to my practice (1/2)
0% Undecided (0/2)
2

Will this article lead to more cost-effective healthcare?

0% Yes (0/2)
50% No (1/2)
50% Undecided (1/2)
3

Was this article biased? (commercial or personal)

0% Yes (0/2)
50% No (1/2)
50% Undecided (1/2)
4

What level of evidence do you think this article is?

50% Level 1 (1/2)
0% Level 2 (0/2)
50% Level 3 (1/2)
0% Level 4 (0/2)
0% Level 5 (0/2)