Morphological Characteristics After Single Versus Recurrent Traumatic Posterior Shoulder Dislocation Events.

Area of Science:

• Orthopedic surgery
• Sports medicine
• Radiology

Background:

• Posterior shoulder dislocations are uncommon but pose challenges in active individuals.
• Limited data exist on the bony consequences of initial and repeated posterior shoulder dislocations.

Purpose of the Study:

• To measure posterior glenoid bone loss (pGBL), glenoid version, reverse Hill-Sachs lesions, and acromial morphology.
• To compare these features between patients with single versus recurrent traumatic posterior shoulder dislocations.

Main Methods:

• Retrospective review of 39 patients with traumatic posterior shoulder dislocations.
• Morphological features assessed included pGBL, glenoid version, reverse Hill-Sachs lesions, and acromial morphology.
• Statistical analysis compared single versus recurrent dislocation groups, with linear regression for pGBL and dislocation number.

Main Results:

• Patients with recurrent dislocations had significantly greater mean pGBL compared to those with single dislocations across all measurement techniques (P < .05).
• No significant differences were found in glenoid retroversion, reverse Hill-Sachs lesion dimensions, or acromial morphology between groups.
• A weak positive correlation existed between the number of dislocations and the extent of pGBL (R² = 0.054).

Conclusions:

• Mean pGBL after a first-time traumatic posterior dislocation is approximately 11%, increasing with recurrent events.
• Progression of pGBL may reach levels associated with instability after soft tissue repair.
• Early recognition and intervention are recommended for high-risk populations to mitigate pGBL progression.