Shoulder instability Flashcards
What is shoulder instability?
Shoulder instability occurs when the structures around the shoulder that stabilize the joint fail, leading to the humeral head moving away from the glenoid either partially (subluxation) or completely (dislocation)
What are the directions of shoulder instability?
- Anterior
- Posterior
- Inferior
- Multidirectional
What are the main aetiological factors for shoulder instability?
- Trauma
- Repetitive use
- Non-traumatic
Why is the shoulder considered unstable?
The shoulder has the highest degrees of freedom including flexion, extension, abduction, adduction, circumduction, and combined movements
What are the stabilizers of the shoulder?
- Bones
- Soft tissues (Labrum, Ligaments)
- Muscles (Rotator cuff, Deltoid, Conjoint tendon)
- Nerves and vessels
- Tone and nutrition
What is a Bankart lesion?
An avulsion of the antero-inferior glenoid-labrum complex resulting in a physical defect
What is a Hill-Sachs lesion?
A bony defect on the antero-superior aspect of the humeral head caused by the sharp edge of the glenoid
How does age affect the risk of recurrence after a traumatic dislocation?
The amount of force required for dislocation is inversely proportional to age and directly proportional to the risk of recurrence
What is the predictive formula for recurrence percentage after a traumatic dislocation?
100 - age
What are some common symptoms indicating shoulder instability?
- History of index traumatic dislocation
- Chronic pain
- Recurrent dislocations with minimal force
- Easy relocation or spontaneous dislocation
- Constant feeling of shoulder giving way
What is the Anterior Apprehension test?
A test where the shoulder is at 90° abduction, elbow flexion, and external rotation, which can elicit apprehension in the patient
What does a positive Posterior Apprehension test indicate?
It indicates apprehension when the shoulder is flexed forward at 90° with elbow flexed 90°, and pressure is applied posteriorly
What is the purpose of the Relocation test?
To note the patient’s sense of relief after applying a posterior force on the humerus following the anterior apprehension test
What imaging techniques are used for diagnosing shoulder instability?
- X-rays
- CT scan
- MRI scan
What is the management approach for traumatic shoulder instability?
- Surgical fixation for physical defects or ligament damage
- Bony Bankart requires bone graft
- Soft tissue repair or tightening
- Mnemonic: TUBS (Traumatic, Unilateral, Bankart, Surgery)
What is the management approach for atraumatic shoulder instability?
- Generally, surgery is not indicated
- Physical therapy to strengthen
- Attempts made for inferior capsule tightening
- Mnemonic: AMRI (Atraumatic, Multidirectional, Rehabilitation, Inferior capsular shift)
What key concepts should be known regarding shoulder instability?
- Anatomy and stabilizing factors
- Types and aetiology
- Clinical presentation and provocative tests
- Management and rationale
