Study shows association between bony glenoid concavity, anterior shoulder instability
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Recently published data indicated the bony shoulder stability ratio decreased significantly due to a correlation between anterior shoulder instability and bony glenoid concavity flattening, which is observed more in patients with atraumatic instability than in patients with traumatic instability.
From an institutional database, researchers identified patients who had undergone treatment for anterior shoulder instability — 30 patients with atraumatic instability and 30 patients with traumatic instability. These patients were matched to 36 healthy controls. To determine glenoid morphology, researchers used CT scan images and they compared unaffected shoulder images in these patients with instability to ipsilateral shoulder images from the control group.
The mean bony shoulder stability ratio (BSSR) for the different groups was calculated and compared via a mathematical formula. Finite element analysis was used to validate the formula.
According to the findings, the two instability groups and control group were not significantly different for age, sex or affected side, and no bony defects were observed in instability patients’ unaffected shoulders, as well as those in the control group.
Mean BSSR for glenoid concavity radius was 17.9% in the atraumatic instability group and 23.9% in the traumatic instability group. The atraumatic instability group showed a 13.2% decrease in mean BSSR vs. a 31.1% mean BSSR decrease in the control group, which was a significant difference. There was a lesser, yet significant, reduction of 7.2% in the traumatic instability group.
No association was observed between BSSR and age, sex, side measured, amount of dislocations and bone loss amount of the affected side. The humeral head radius’ mean BSSR in the atraumatic and traumatic instability group was 30.8% and 37.2%, respectively, with a 12.4% difference between the two groups, based on the results. ‒ by Monica Jaramillo
Disclosures: Moroder reports he receives financial or material support from Arthrex Inc.