Review Question - QID 213062

Anterior shoulder dislocations in patients older than 40 years may result in rotator cuff tears, with the supraspinatus tendon most commonly affected.

Anterior shoulder dislocation is typically the result of a traumatic event across all age groups. In patients older than 40 years of age, anterior dislocations may cause tears of the supraspinatus and infraspinatus tendons with or without the typical Bankart lesions seen in patients younger than 40 years of age. This is believed to be due to the degeneration of the supraspinatus and infraspinatus tendons and the resultant loss of elasticity of the tendons that occurs as patients age, which makes them more prone to rupture. As a result, persistent symptoms are more likely to be related to rotator cuff injury rather than recurrent instability that is seen with younger patients.

Robinson et al. performed a case series of patients undergoing arthroscopy after an initial traumatic anterior shoulder dislocation in patients older than 35 years of age. Arthroscopic findings included 64.3% with rotator cuff tears, 64.3% with Bankart lesions, 10.7% with HAGL lesions, 7.1% with ALPSA lesion, and all patients had Hill-Sachs lesion of various sizes. They concluded that traumatic shoulder dislocations in older patients result in various pathologies that contribute to recurrent shoulder instability and pain.

Streubel et al. reviewed the literature regarding anterior glenohumeral instability. They reported that anterior shoulder dislocations in young patients commonly result in anteroinferior capsulolabral tears, also known as Bankart lesions, that inherently destabilize the shoulder. Further, dislocations may result in Hill-Sachs lesion which, is an impaction fracture of the posterolateral humeral head due to compression on the anteroinferior glenoid rim. Referenced studies suggest arthroscopic Bankart repair if the Instability Severity Index Score (ISIS) < 7. Open surgical repair is recommended for ISIS scores >/= 7, HAGL lesions, Hill-Sachs lesions, and subscapularis tears.

Murthi et al. reviewed the literature regarding shoulder dislocations in older patients. The authors cited studies that reported a high incidence of rotator cuff tears, brachial plexus injuries, and axillary nerve injuries than younger patients with anterior dislocations. Studies support a better outcome with patients that sustain a greater tuberosity fracture rather than massive rotator cuff tears, and patients outcomes are improved when rotator cuff tears are treated surgically. The literature supports a lower redislocation rate in these patients as the ligamentous stabilizing structures, such as the anteroinferior labrum and the inferior glenohumeral ligament, are not injured in these patients.

Figure A depicts an axial T1-weighted MRI of the shoulder with a posterior Bankart lesion. Figure B depicts a coronal T2-weighted MRI of the shoulder with a massive and retracted supraspinatus tendon tear. Figure C depicts a coronal T2-weighted MRI of the shoulder with a HAGL lesion. Figure D depicts a coronal T2-weighted MRI of the shoulder with a SLAP tear. Figure E depicts an axial T1-weighted MRI of the shoulder with a subscapularis tendon rupture. Illustration A depicts the criteria for ISIS scoring.

Incorrect Answers:
Answer 1: Posterior Bankart lesions are usually the result of posterior shoulder dislocations.
Answer 3: HAGL lesions occur when there is inferior glenohumeral ligament avulsion from the humerus. This injury is more commonly seen after dislocations in younger patients.
Answer 4: SLAP lesions are commonly seen in overhead and throwing athletes. Studies have not correlated SLAP tears with anterior shoulder dislocations.
Answer 5: Subscapularis tendon tears are less commonly seen with anterior shoulder dislocations. They can be seen with posterior shoulder dislocations due to the force vector of the dislocation and the tension placed on the subscapularis tendon.