Chronic instability of the shoulder | Dislocation subluxation of the shoulder Flashcards
(9 cards)
Summary
Shoulder dislocations are the most common type of dislocations due to the humeral head being much larger than the Glenoid fossa
Dislocations can be classified on the position to where humeral head gets displaced. It can be Anterior [often also inferior together], Posterior or Inferior
Anterior dislocations are usually traumatic or microtraumatic in nature, often following sports activities. These are the most common. They also tend to present with Hill-Sachs lesions [humeral head depression fracture] and Bankart tears [Anterior Inferior labrum tear]
Posterior dislocations are rare but also the most missed. They tend to not be associated with sporting injuries, but they do occur from electrical injuries or post seizures. Can also present with Reverse Bankart tears [posterior labrum tear]
Inferior dislocations are the rarest, and often present with neurovascular damage
All dislocation types must be evaluated for neurovascular damage
Most common treatment involves closed reduction and immobilization [in presence of analgesics or even anaesthesia]
Surgical intervention may be required in fractures, recurrent dislocations, Bankart tears or Hill-Sachs lesions, neurovascular compromise
Etiology
- Traumatic or microtraumatic [contact sports]
- Predisposing conditions like Rotator cuff tears, Glenohumeral ligament damage, Bankar/Hill-Sachs lesions, Loose joint capsule causing recurrent dislocations
- Uncoordinated muscle contracture leading to Posterior dislocation [like seizures or electrical shock injury]
Traumatic Anterior Shoulder Instability [TUBS] Classification
Anteroposterior Translation Grading Scheme [based on Load and Shift test]
- Grade 0: Normal translation
- Grade I: Humeral head up to glenoid rim
- Grade II: Humeral head over glenoid rim wtih spontaneous reduction once force withdrawn
- Grade III: Humeral head over glenoid rim without spontaneous reduction
Instability Severity Score:
- Age
- Degree of Sports participation
- Type of sport [contact/other]
- Shoulder Hyperlaxity
- Hill Sachs on AP Xray
- Glenoid contour loss on AP Xray
Score < 6 [arthroscopic stabilization, recurrence risk ~ 10%]
Score > 6 [Open surgery for stability, Laterjet procedure]
TUBS Presentation
- Severe shoulder pain
- Arm typically in ABduction and slight External rotation
- Limited ADduction and general movement of arm/shoulder
- Humerus head palpable below coracoid process
- Loss of shoulder contour\
- History involves accident or sport incidence [patient may arrive with formally reduced dislocation/spontaneous reduced dislocation]
Physical Exam signs:
- Load and Shift [Graded test; push humerus superiorly??]
- Apprehension sign [Pat arm 90 deg abducted, 90 deg ext rotated. Apprehension or pain to reach those states is positive]
- Relocation sign [Decrease in apprehension or pain with posterior force applied on anterior surface of humeral head]
- Sulcus sign [has to be atleast 2 cms to be true sulcus sign]
- Drawer test [anterior force on posterior humeral head]
- Generalized ligamentous laxity [Beigtons criteria]
Sulcus sign usually also due to laxity of Superior Glenohumeral ligament and Coracohumeral Ligaments. Can be used for Shoulder Instability testing
TUBS Imaging and Treatment
Radiographs:
- True AP, Scapular Y, Axillary views to fully visualize and determine postion of dislocation
- Can detect presence of Hill-Sachs lesion and Glenoid bone loss
CT scan:
- Glenoid bone loss and bony injuries easily visualized
MRI:
- Bankart tears/lesions [labral tears] best visualized
- ABER sequences can be used to better visualize anterio-inferior glenoid labrum]
Treatment:
- Nonoperative
Acute Reduction +/- immobilization, Physiotherapy [Kocher method for reduction; immobilization for 1 week; physio for rotator cuff strengthening, periscapular muscle building]
- Operative
Arthroscopic Bankart repair/Open Bankart repair +/- capsular shift [Open done when arthroscopy fails, glenoid bone loss < 20-25%]
Laterjet [coracoid transfer] or Bristow Procedure [for chronic bony deficiences > 20-25%, glenoid deficiencies]
Bone graft reconstructions for Hill-Sachs defects
Posterior Shoulder Instability and Dislocation
Presentation
- Severe Shoulder pain
- History of trauma or microtrauma
- Chronic Instability or dislocations
- Arm held in ADduction and Internal rotation [pain with these movements in instability; Locked internally rotated in undiagnosed posterior dislocation]
- Limited External rotation
- Humeral head usually not palpable
Provocation tests:
- Jerk Test
- Kim Test
- Posterior Stress Test
- Posterior Load and Shift test [Glenolabrum rim translation, grading same as TUBS, however 4+ complete dislocation]
Posterior Shoulder Instability and Dislocation
Imaging and Treatment
Imaging indications same as TUBS, except MRI look for Reverse Hill-Sachs and Reverse Bankart/Posterior labral tears, rotator cuff tears
Treatments:
Nonoperative
- Acute Reduction and immobilization [in external rotation for 4-6 weeks]
- Physical therapy after 6 weeks [same targets as TUBS] + activity modification
- Chronic instability prefer Physical therapy
Operative
- Open or Arthroscopic Reverse Bankart repair [recurrent post dislocations, continued pain on loading arm, negative Beighton score]
- Open reduction with subscapularis transfer [chronic dislocation < 6 months or Reverse Hill-Sachs < 40%]
- Hemiarthroplasty [Chronic dislocations > 6 months, severe arthritis, Reverse Hill-Sachs > 40%]
- Total Shoulder Arthroplasty [significant glenoid arthritis + one of the above indications]
Inferior Glenohumeral Joint Dislocation
Presentation
Imaging
Treatment
Presentation:
- Arm held in fixed ABduction [~ 125 degrees]
- Humeral head may be palpable in axilla
- Elbow typically in flexion with pronated forearm
- Limited adduction
- Axillary nerve Injury may be present [test for pronation and supination, sensation over upper humeral skin]
- Test for Brachial plexus, Radial, Median and Ulnar nerve damage [Sensory and motor]
Imaging same as other dislocations
Treatment:
Nonoperative:
- Closed reduction and immobilization
- Physio for ROM exercises and Rotator cuff and periscapular muscle strengthening
Operative:
- Arthroscopic or Open repair [active younger patients]
Multidirectional Shoulder Instability
Summary
Multidirectional shoulder instability (MDI) is a condition characterized by generalized instability of the shoulder in at least 2 planes of motion (anterior, posterior, or inferior) due to capsular redundancy
Diagnosis is made clinically with presence a sulcus sign [2+ or more], Apprehension/Relocation test, Anterior and Posterior Load and Shift test [2+ or more], Beightons criteria > 4/9 for generalized hypermobility
Imaging modalities same as other shoulder dislocations
Treatment:
Nonoperative: [most preferred]
- Dynamic stabilization Physical Therapy [3-6 months, strengthening of rotator cuffs and periscapular msucles; Closed kinetic chain exercises]
Operative:
- Capsular shift/Stabilization procedure [open or arthroscopic]
