Progressive glenoid bone loss caused by erosion in humeral head resurfacing.

BACKGROUND

Cementless surface replacement of the shoulder represents an alternative to conventional stemmed anatomic prostheses. Glenoid erosion is a well-known complication in hemiarthroplasty. However, there is limited data concerning radiographic evaluation and prognostic factors for this phenomenon.

OBJECTIVES

The aim of our study was to determine the development of glenoid erosion following shoulder resurfacing using a new measurement technique and detect potential prognostic factors.

MATERIALS AND METHODS

We performed a retrospective analysis on 38 shoulders undergoing humeral head resurfacing with a mean follow-up of 65.4 ± 43 months. Clinical and radiographic evaluation followed a standardized protocol including pre- and postoperative Constant score, active range of motion, and X‑rays in true anteroposterior view. Three independent observers performed measurements of glenoid erosion.

RESULTS

We found good interobserver reliability for glenoid erosion measurements (intraclass correlation coefficient [ICC] 0.74-0.78). Progressive glenoid erosion was present in all cases, averaging 5.5 ± 3.9 mm at more than 5 years' follow-up. Male patients demonstrated increased glenoid bone loss within the first 5 years (p < 0.04). The mean Constant score improved to 55.4 ± 23.6 points at the latest follow-up. Younger age was correlated to increased functional outcome. Revision rate due to painful glenoid erosion was 37%.

CONCLUSIONS

Glenoid erosion can be routinely expected in patients undergoing humeral head resurfacing. Painful glenoid erosion leads to deterioration in functional outcome and necessitates revision surgery in a high percentage of cases.