Treatment of B2 type glenoids with anatomic vs. reverse total shoulder arthroplasty: a retrospective review.

BACKGROUND

Patients with glenohumeral arthritis with Walch B2 glenoid morphology present a challenge for shoulder surgeons. Poor outcomes have been demonstrated in patients with anatomic total shoulder arthroplasty (aTSA) left in retroversion. Reverse total shoulder arthroplasty (rTSA) yields good midterm results. There is a paucity of studies comparing aTSA to rTSA in patients with glenohumeral arthritis and B2 glenoids. The purpose of this study was to compare the results of aTSA vs. rTSA in patients with glenohumeral arthritis with B2 glenoid morphology.

METHODS

We performed a retrospective review of patients who underwent total shoulder arthroplasty by a single surgeon. Preoperative computed tomography was used to determine glenoid type based on the modified Walch classification. Patients with B2 glenoid morphology were included in the study. Patients who had evidence of a rotator cuff tear or less than two years of follow-up were excluded. Patients were categorized by procedure type (aTSA vs. rTSA). Preoperative glenoid version, glenoid inclination, and posterior humeral head subluxation were measured using computed tomography. Patient reported outcome measures, active range of motion, and complications requiring revision (instability, rotator cuff insufficiency, infection, component loosening) were recorded. Postoperative glenoid version, glenoid inclination, and evidence of humeral head decentering were evaluated on standard shoulder radiographs. Statistical analysis was performed and results are presented as mean ± standard deviation.

RESULTS

A total of 224 patients were included. One hundred sixty-two patients underwent aTSA and 62 underwent rTSA. The mean length of follow-up was 25.6 ± 1.95 months for the rTSA group and 32.8 ± 2.27 for the aTSA group ( = .002). Patients who underwent rTSA were significantly older ( < .001) and had a significantly higher proportion of females ( = .019). Postoperatively patients in the aTSA group had significantly better external rotation ( < .001) and internal rotation (IR) compared to the rTSA group ( < .001). There were no differences in patient reported outcome measures between the two groups. No patients in the aTSA group had recurrent posterior humeral head subluxation. Eight complications requiring revision occurred, 4 in each group. One patient who underwent aTSA had evidence of glenoid loosening. There was no evidence of glenoid loosening in the rTSA group.

CONCLUSIONS

aTSA and rTSA can produce good results in patients with B2 glenoid morphology with low rates of revision with appropriate patient selection. aTSA may result in improved range of motion that may not be clinically relevant.