Glenoid wear after humeral head replacement with using a single implant in patients with cuff tear arthropathy more than five years.

BACKGROUND: The aim of this study was to investigate glenoid wear in patients with humeral head replacement with a smaller humeral head, who were observed for >5 years, and to examine the relationship between radiographic changes and clinical outcome. METHODS: In this study, 41 shoulders of 41 patients (13 men, 28 women) were followed up for >5 years. The mean patient age at the time of surgery was 70.5 years. The average follow-up period at short-term was 26.0 months, and intermediate-term was 66.5 months. We classified glenoid wear into four grades (i.e., Grade 0 to Grade 3). Age, sex, clinical scores, and range of motion were investigated in relation to the grade of glenoid wear. Radiographs of glenoid wear evaluated in the short-term were subsequently compared to radiographs obtained in the intermediate-term period. RESULTS: At the final follow-up, 16 (39%) patients had Grade 0 wear, 11 (27%) patients had Grade 1 wear, 10 (24%) patients had Grade 2 wear, and 4 (10%) patients had Grade 3 wear. The University of California-Los Angeles score, Japanese Orthopaedic Association score, and active forward flexion were significantly lower in the Grade 3 patients; however, Grade 3 patients did not have significant pain. No significant difference in age, sex, Constant score, active external rotation, and active internal rotation in relation to the grade of glenoid wear was observed. In total, 25 (61%) patients showed a progression of glenoid wear. Cases in which glenoid wear progressed after 4 years after surgery were rare. Two patients of Grade 3 underwent total shoulder arthroplasty revision at 16 months and 38 months, respectively. CONCLUSIONS: Glenoid wear occurred in 61% of patients at 5 years follow-up. Pain of Grade 3 patients was mild, therefore, if pain is not severe, revision surgery may not be necessary.