Current concepts in the surgical management of primary glenohumeral arthritis with a biconcave glenoid.

Glenoid morphology has an important impact on outcomes and complication rates after shoulder arthroplasty for primary glenohumeral arthritis. The B2 glenoid, or a biconcave glenoid with posterior humeral head subluxation, in particular has been associated with a poorer outcome with shoulder arthroplasty compared with other glenoid types. A variety of techniques may be used to address the bone deficiency and instability seen with this glenoid type. Studies suggest that total shoulder arthroplasty may have a reasonable result in the short term but be associated with a high complication rate in the mid term because of recurrence of instability and early glenoid loosening when neoglenoid retroversion is greater than 27° or posterior humeral head subluxation is greater than 80%. Particularly in older patients with a substantial B2 deformity, primary reverse shoulder arthroplasty may be a more predictable means of addressing bone deficiency and restoring stability.