Review Question - QID 213967

This patient's preoperative imaging studies reveal primary osteoarthritic changes in the glenohumeral joint, with significant posterior glenoid wear. Preoperative posterior glenoid wear prior to TSA has been associated with early glenoid component loosening.

Walch described the various preoperative glenoid morphologies before TSA. Type A glenoids are well centered, with A1 and A2 representing minor and deeper central erosion, respectively. Type B glenoids are characterized by posterior wear of the glenoid and posterior humeral head subluxation, with B1 and B2 representing posterior wear and severe biconcave wear, respectively. Several studies have demonstrated that a preoperative B2 glenoid is a risk factor for early glenoid component loosening. Different methods exist for obtaining a neutral orientation of the type B glenoid, ranging from anterior reaming of the glenoid, bone grafting and augmentation of the posterior wear. However, there is currently no consensus on how much anterior reaming is safe and how much glenoid retroversion may be accepted.

Walch et al. investigated the influence of different preoperative radiographic measurements on the outcome of TSA. They reported glenoid loosening was significantly associated with posterior bone erosion in depth and wear ratio, and neoglenoid retroversion. They concluded that alternative treatment options, like reverse shoulder arthroplasty, may result in improved outcomes in these patients with posterior wear.

Chin et al. evaluated the outcomes of TSA in type B1 and B2 glenoids. They reported no significant differences in glenoid component lucencies, range of motion, DASH scores, and patient satisfaction between the B1 and B2 glenoid TSA cohorts. They recommended continued clinical and radiographic follow up to assess possible divergence in outcomes in the future.

Figures A and B are plan radiographs demonstrating advanced glenohumeral arthritis with posterior subluxation of the humeral head in the setting of a biconcave glenoid, which is again observed in the axial CT imaging in Figure C. Figure D demonstrates grade 1 Goutallier changes in the supraspinatus and infraspinatus muscles.

Incorrect Answers:
Answer 1: The presence of inferior humeral head osteophytes does not correlate with early glenoid loosening.
Answer 3: Early glenoid loosening correlates highly with the biconcave geometry of the glenoid, which is often associated with posterior (not anterior) humeral subluxation.
Answer 4: This patient has minimal rotator cuff changes, as demonstrated by grade 1 Goutallier changes noted in the supraspinatus and infraspinatus muscle bellies.
Answer 5: Shenton's line is preserved in this patient, as depicted in Figure A.