Background: The reverse Delta III shoulder prosthesis can relieve
pain and restore function in patients with cuff tear arthropathy. The most
frequently reported radiographic complication is inferior scapular notching.
The purpose of the present study was to evaluate the clinical relevance of
notching and to determine the anatomic and radiographic parameters that
predispose to its occurrence.
Methods: Seventy-seven consecutive shoulders in seventy-six patients
with an irreparable rotator cuff deficiency were managed with a reverse Delta
III shoulder arthroplasty and were followed clinically and radiographically
for a minimum of twenty-four months. The effects of cranial-caudal glenoid
component positioning and the prosthesis-scapular neck angle on the
development of inferior scapular notching and clinical outcome were
Results: All shoulders that had development of notching did so in
the first fourteen months. Of the seventy-seven shoulders that were studied,
thirty-four (44%) had inferior scapular notching, twenty-three (30%) had
posterior notching, and six (8%) had anterior notching. Osteophytes along the
inferior part of the scapula occurred in twenty-one (27%) of the seventy-seven
shoulders. The angle between the glenosphere and the scapular neck (r = 0.667)
as well as the craniocaudal position of the glenosphere (r = 0.654) were
highly correlated with inferior notching (p < 0.001). A notching index was
calculated with use of the height of implantation of the glenosphere and the
postoperative prosthesis-scapular neck angle. This allowed prediction of the
occurrence of notching with a sensitivity of 91% and specificity of 88%. The
height of implantation of the glenosphere had approximately an eight times
greater influence on inferior notching than the prosthesis-scapular neck angle
did. Inferior scapular notching was associated with a significantly poorer
Conclusions: Inferior scapular notching after reverse total shoulder
arthroplasty adversely affects the intermediate-term clinical outcome. It can
be prevented by optimal positioning of the glenoid component.
Level of Evidence: Prognostic Level II. See Instructions
to Authors for a complete description of levels of evidence.