Glenoid wear after shoulder hemiarthroplasty: quantitative radiographic analysis.

Symptomatic glenoid arthrosis may limit the long-term success of shoulder hemiarthroplasty in patients who are young and functionally demanding. The principal objective of the current study was to quantify glenoid wear after proximal humeral replacement in young, active subjects. Eight patients, ages 21 to 60 years (mean, 45 years), met inclusion criteria. The mean followup was 43 months. Functional scores for the cohort averaged 60% of age and gender-adjusted healthy subjects (range, 28%-84%). Glenohumeral joint space was measured on serial axillary radiographs using a Microscribe 3-DX digitizing device (measurement accuracy, 0.23 mm). Progressive glenoid wear was found in all eight patients. The mean decrease was 2 mm (range, 1.3-2.8 mm), a 68% decrease in glenohumeral joint space. Glenoid cartilage wear also was correlated with Constant and Murley scores. Patients with residual joint spaces less than 1 mm had a mean score of 50%, compared with a score of 71% for patients with joint spaces greater than 1 mm. There were no correlations between wear and mechanism of injury, duration of symptoms, and prior surgery. This study suggests that glenoid cartilage erosion can be expected routinely after humeral head replacement in young, active individuals, and that such wear may adversely affect function or necessitate conversion to total shoulder arthroplasty.