Poster 168: Notching of the Greater Tuberosity Revisited: A Radiographic Indicator of Degenerative Rotator Cuff Tears

Abstract

Objectives: The greater tuberosity notch (GTN) is an uncommonly reported radiographic finding which has been associated with articular sided partial rotator cuff tears (RCTs) in throwing athletes. This finding has yet to be evaluated in patients with degenerative tears. The purpose of this study is to assess the GTN measurement along with five other previously described radiographic indicators for degenerative RTCs. Methods: After obtaining IRB approval, we prospectively collected and compared 80 standard shoulder radiograph series with an additional “notch view”, a lateral oblique radiograph showing the greater tuberosity in profile. Thirty-four patients had confirmed rotator cuff tears confirmed via arthroscopy and 46 control patients did not have suspected rotator cuff pathology. Two musculoskeletal radiologists independently reviewed radiographs for GTN size and five previously described radiographic indicators of RCTs including: greater tuberosity cyst (GTC), acromiohumeral interval (AHI), critical shoulder angle (CSA), inferior acromial sclerosis (IAS), and lateral acromial spurring (LAS). A receiver operator characteristic (ROC) curve was performed to compare the individual performance of each of the six radiographic markers. Nearest neighbor analysis based on Euclidean distances followed by clustering described the pattern of radiographic variables occurring together in the setting of a RCT. Results: A total of 320 radiographs were reviewed and 1920 measurements were made. RCTs were independently associated with IAS, LAS, GTCs, decreased AHI and large GTNs (P < 0.01), but not the CSA or smaller notch sizes. Overall, the GTN size predicted a RCT with moderate accuracy (AUC=0.676). Cluster analysis suggested the AHI has the strongest correlation with RCTs and is the most closely related to the GTN size (P < 0.003) compared to other indicators based on Euclidean distances. Conclusions: The presence of a medium-sized greater tuberosity notch alone is moderately sensitive for detecting a degenerative RCT. Additionally, the presence of at least one other indicator on radiographs dramatically increases the likelihood of finding a RCT during surgery. The size and presence of these radiographic markers in combination may represent a continuum of increasing severity of cuff pathology.