Anterior deltoid atrophy is common after RTSA (42%) and is significantly associated with the superolateral approach. The absence of a neurophysiological correlate is consistent with a mechanical aetiology related to deltoid reinsertion technique, although causality cannot be established from this observational study. These findings generate a testable hypothesis warranting prospective evaluation of bony acromial flap reinsertion in future comparative studies.
Lópiz et al. (Thu,) studied this question.