Julie Marie O'Brien MBBCh, Presenter: Nothing to Disclose

Julia Grebenyuk MD, Abstract Co-Author: Nothing to Disclose

Gordon Ted Andrews MD, Abstract Co-Author: Nothing to Disclose

Bruce B. Forster MD, Abstract Co-Author: Nothing to Disclose

To describe the incidence of glenoid chondral abnormalities in relation to Hill Sachs (HS) lesions in MR arthrograms of patients with anterior shoulder instability versus controls. Such glenoid lesions can directly impact surgical decision-making and approach, and could potentially negatively impact outcome if missed.

Retrospective analysis of direct MR shoulder arthrograms in 177 subjects; 102 patients with anterior instability (clinical gold standard) and 75 controls; was performed independently by 2 blinded musculoskeletal radiologists. Outcome measures, based on standard MR arthrographic criteria, were used for the presence of a HS lesion and glenoid chondral injury. Size of HS lesions was semi-quantitatively graded on a 5 point scale. Kappa statistic was used to evaluate inter-observer variability and Pearson chi-square analysis were utilised to determine the relationship between outcome measures in control and patient cohorts.

Inter-observer variability for the presence of HS and chondral lesions was 0.964 and 0.858 respectively. 59% of patients and 7% of controls had HS lesions (p<0.001). 36% of patients and 8% of controls had glenoid chondral lesion (p<0.001). 47% of anterior instability patients with HS defects had chondral injury as opposed to 21% of patients without HS defects (p=0.009). The size of the HS lesion did not increase the likelihood of a chondral lesion (p=0.222).  

In our cohort of patients with clinical anterior instability, we have demonstrated that there is a statistically significant higher incidence of HS lesions and of glenoid chondral lesions than in controls. In patients with clinical anterior instability, the presence of a HS lesion confers a statistically significant greater likelihood of having a glenoid chondral lesion when compared to patients with clinical instability and no HS lesion.

The incidence of potentially important glenoid chondral lesions in patients with anterior instability has not previously been reported in the literature.

O'Brien, J, Grebenyuk, J, Andrews, G, Forster, B, Frequency of Glenoid Chondral Lesions on MR Arthrography in Patients with Anterior Shoulder Instability.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9003030.html