Risk factors for glenoid erosion in patients with shoulder hemiarthroplasty: an analysis of 118 cases.

BACKGROUND

Glenoid erosion is one of the main concerns in shoulder hemiarthroplasty. The goal of this study was to quantify glenoid erosion and to identify risk factors in patients with humeral hemiarthroplasty.

METHODS

There were 118 shoulders in 113 patients available for a standardized retrospective review. Erosion was graded as follows: grade 1, none; grade 2, mild (erosion into subchondral bone); grade 3, moderate (medialization of subchondral bone with hemispheric deformation); or grade 4, severe. The findings were then analyzed for confounding factors using a multivariate analysis.

RESULTS

Mean follow-up was 31 months (range, 5-86 months). Negative predisposing factors for erosion were glenoid cysts (odds ratio, 5.4; P < .001, approximately 3 times more frequent in women), fatty infiltration of the rotator cuff musculature (R, 0.43; P < .001), and rheumatoid arthritis (odds ratio, 3.6; P = .049). A valgus position of the prosthetic head relative to the glenoid (angle >50°) appeared to lead to local destruction of the cartilage. The degree of erosion did not correlate with age and glenoid or humeral head size. Only 1 patient (of 30) with a fracture-type prosthesis developed progressive glenoid erosion.

CONCLUSION

In this series, favorable conditions for resistance to erosion after hemiarthroplasty were lack of glenoid cysts, intact glenoid cartilage, intact rotator cuff musculature, and a fracture situation. Age, the version of the glenoid, and the size of the prosthetic head showed no importance. The use of hemiarthroplasty seems to be associated with glenoid destruction in female patients with impending osteoarthritis, with rheumatoid arthritis, and if the head is implanted in a valgus position.