Extract
To The Editor:We read with interest the article by Nyffeler et al. entitled
"Association of a Large Lateral Extension of the Acromion with Rotator
Cuff Tears"
(2006;88:800-805). We would like
to draw attention to the fact that during the natural progression of rotator
cuff tears and cuff tear arthropathy, osseous changes in the glenoid and
greater tuberosity can modify the radiographic "acromion index"
described by the authors. Medialization of the humeral head secondary to
glenoid erosion can be present with or without superior migration of the
head1. This would result in a higher acromion index as a result of
an increase in the glenoid plane-acromion distance, thereby erroneously
suggesting a larger lateral extension of the acromion. Similarly, osteolysis,
cysts, and erosion of the greater tuberosity can influence the "acromion
index."2