B2 and B3 glenoid osteoarthirtis: outcomes of corrective and concentric (C2) reaming of the glenoid combined with pyrocarbon hemiarthroplasty.

BACKGROUND

Posterior humeral subluxation (PHS) in B2 and B3 glenoid is a cause of asymmetric long-term stress on the glenoid and the potential reason for glenoid loosening in anatomic total shoulder arthroplasty and painful glenoid erosion in hemiarthroplasty with metallic heads. We hypothesized that corrective and concentric (C2) reaming of the glenoid associated with pyrocarbon hemiarthroplasty (HA-PYC) could improve the centering of the humeral head and decrease the risk of persistent painful glenoid erosion in young and active patients with B2 and B3 glenoid.

METHODS

Between 2014 and 2020, 41shoulders (in 35 patients, mean age of 57.9 years) underwent HA-PYC combined with C2 reaming for B2 (n = 30) or B3 (n = 11) osteoarthritis. Patients were prospectively followed with computed tomography (CT) scans performed preoperatively, immediate postoperatively, and at last follow-up (>2 years). The primary outcomes were 3D-corrected CT scan measurements of glenoid version, PHS, and progression of glenoid erosion. Secondary outcomes included functional outcome scores, return to activities, and revision rate and complications.

RESULTS

At a mean follow-up of 4.5 years (2-9.5 years), the prosthesis survival was 95% (39 of 41). No patient has been reoperated for painful glenoid erosion. The mean glenoid retroversion decreased from 17.1° ± 7.5° preoperatively to 8.3° ± 8.2° at last follow-up (P = .001), and the mean PHS from 74% to 56.5% (P = .001) based on the scapular plane and from 59.9% to 50.3% based on the glenoid plane. The humeral head was recentered in 97% according to the glenoid surface and 71% according to the scapular plane. Correction of PHS in the scapular plane was highly correlated to correction of glenoid retroversion (P < .001). CT scan measurements showed that the average total medialization was 3.7 ± 3.2 mm (2.0 ± 1.8 mm due to reaming and only 1.7 ± 2.4 mm due to erosion). The adjusted Constant Score increased from 43% ± 13% to 97% ± 16% and the Subjective Shoulder Value from 38% ± 14% to 84% ± 12% (P < .001). Overall, 84% of active patients returned to work, and all patients returned to sports.

CONCLUSION

In B2 and B3 glenoid arthritis, corrective, concentric glenoid reaming combined with HA-PYC improves centering of the humeral head and shows a low risk of painful glenoid erosion at midterm follow-up. The combined procedure results in excellent functional outcomes and high prosthesis survivorship at midterm follow-up. HA-PYC and C2 reaming of the glenoid is an alternative shoulder arthroplasty for young/active patients with type B glenoid osteoarthritis who want to return to work or sports practice.