Objective: The objective of our study was to see whether there is an association between engagement on physical examination and the location or size of a Hill-Sachs lesion and the presence and degree of glenoid bone loss as assessed on MRI.
Materials and methods: Thirty-three consecutive patients (32 males and one female) with a history of anterior shoulder dislocation who underwent preoperative MRI and arthroscopy at our institution and were tested for engagement on physical examination over a 9-month period were included in the study. Two blinded readers reviewed each study independently and documented the presence and size of the Hill-Sachs lesion, location of the Hill-Sachs lesion with a modified biceps angle, and presence and size of glenoid bone loss. Statistical analysis included the Mann-Whitney, logistic regression, Pearson correlation, and intraclass correlation tests.
Results: Eleven patients had evidence of an engaging Hill-Sachs lesion on physical examination and 22 did not. There was no statistically significant difference between any of the dimensions or overall area of the Hill-Sachs lesion when comparing the group with an engaging Hill-Sachs lesion and the group with a nonengaging lesion (surface area, 3.60 vs 3.23 cm(3), respectively; p = 0.272). There was a trend for a larger biceps angle in the engaging group without a statistically significant difference (mean, 154.5° vs 143.9°; p = 0.069). There was a statistically significant difference in the amount of glenoid bone loss in the engaging group compared with the nonengaging group (mean, 20.2% vs 6.0%; p = 0.001).
Conclusion: There is a significant association between an engaging Hill-Sachs lesion on physical examination and the degree of glenoid bone loss as well as a trend toward increased engagement with more medially oriented Hill-Sachs lesions. These findings show the importance of considering both the Hill-Sachs lesion and glenoid bone loss when evaluating patients with engagement.