55 yo F presents with shoulder pain after fall from bicycle:
Also known as “luxatio erecta” – to place upward
Inferior shoulder Dislocation
Mechanism of injury: fall and sudden grasp of object above head resulting in hyperabduction
Presentation: Patients hold arm above head and is unable to adduct, looks like a person raising their hand to ask a question
Exam: Can palpate humeral head along lateral chest wall, forearm is pronated, unable to adduct, elbow usually flexed above head. Check distal radial pulse and axillary nerve pin prick sensation at shoulder.
Assoc injuries: Axillary artery, brachial plexus – most often axially nerve. Neurovascular deficits usually resolve with prompt reduction. Also associated with rotator cuff tears and greater tuberosity fractures.
Imaging: Reveals humeral head beneath glenoid
Reduction: Closed reduction often successful with traction-countertraction and slow gentle adduction of affected arm. Open surgical reduction is required when humeral head in a tear of the inferior capsule, also known as “buttonhole deformity”
Simon and Sherman, Emergency Orthopedics 6th Ed, pgs 353-54