Acute Shoulder Dislocation

Definition

• Dislocation of Glenohumeral Joint

Aetiology

• Usually as result of indirect force
  • Indirect ER in ABD moment 2° direct force on arm
• Results in
  • Abduction
  • External rotation
  • Extension
• Disruption of anterior stabilisers occurs

Epidemiology

• Commonest type of shoulder instability
• Young males
• Males > Females – 2:1

Anatomy

Pathology

• Bankhart Lesion
• Hillsach’s Lesion

Classification

According to direction seen on x-rays

1. Subcoracoid
   • Most common
2. Subglenoid
3. Intrathoracic

History

• Acute
  • History of Initial Injury
  • Severe pain in shoulder
  • ± Transient parasthesiae
• History of Previous dislocations
  • Onset
    • traumatic, repetitive or voluntary
  • Position
  • Ease of relocation
  • Disability
  • Bilateral
  • Subluxation
• No history of dislocation
  • Sensation of sliding
  • May have pain only
• Neurological “Dead Arm Syndrome”
• Other
  • joint laxity

Examination

• Very painful & tender shoulder
• Significant muscle spasm
• Arm held across abdomen
• Hollow under acromion
• Fullness in anterior shoulder
• Nerve Palsy
  • axillary nerve palsy (10-20%)
  • Brachial plexus injury (20%)
• Rotator cuff tear common in patient > 45 years of age

Investigations

Xray

• True AP
• True Axillary
• If true Axillary impossible, use:
  • Oblique lateral
  • Garth
  • Velpeau axillary lat
• Look for
  • Direction of Dislocation
  • Associated Hill Sach fracture

Differential Diagnosis

Treatment

• Reduction
  • Reduction achieved as soon as is possible
  • Appropriate analgesia & muscle relaxation
  • Atraumatic closed reduction performed
  • Neurolept analgesia – Midazolam + Fentanyl
  • Propofol induction
  • If unsuccessful, may require GA
  • Rarely need open reduction
  • Post-reduction XR to
    • Confirm reduction
    • Rule out associated fracture

Reduction Maneuvers

• Stimpson
  • Patient prone
  • Arm hanging over side of bed
  • Weight applied to wrist
  • Scapula may be manipulated to facilitate reduction
• Harvard
  • Patient supine
  • Traction with abduction
  • Countertraction or pressure in axilla
• Modified Harvard
  • Patient supine
  • Traction with flexion
  • Counter traction in axilla
• Hippocratic
  • Patient on floor
  • Stockinged foot in axilla
  • Axial traction
• Kocher
  • Traction with slow ER & abduction followed by rapid IR & adduction
  • Large lever arm & ↑ risk of humeral fracture

• Immobilisation
  • No effect on redislocation rate
  • No sport for 6/ 52 reduces dislocation rate
  • Protocol
• Sling for comfort
• Avoid provocation 6/52
• No sport until painless FROM
  • Rehabilitation
• Early intervention important

Rehabilitation

• Immobilization (sling or splint)
  • No effect on redislocation rate
• No sport for 6/52 reduces dislocation rate
• Protocol
  • Sling for comfort
  • Avoid provocation 6/52
  • No sport until painless FROM
• Rehabilitation
  • Early intervention important
  • Three components
    • 1. Start with ROM exercises
      • Pendulum Active Assisted Active
    • 2. Then shoulder strengthening
      • Rotator cuff & scapular stabilisers
      • Therabands
      • Isometric exercises
      • Especially internal rotation
    • 3. Avoid provocative arm positions in post injury period
• Rehabilitation response (Rockwood)
  • 12% of TUBS
  • 88% of AMBRI
• Outcome of non-op treatment is much better in the posterior than the anterior dislocations

Early Surgery

• Soft tissue interposition- SSP tendon
• Displaced GT fracture
• Large Glenoid rim fracture
• Special problems – sport or occupation where patient needs absolute stability

Prognosis

• Factors of significance include
  • Age of patient at first dislocation
  • Degree of trauma & associated fractures at first dislocation
  • Activity
  • Rehab

Age at first dislocation

• Increased in young
• Rowe CORR ‘61

Age	Dislocation Rate
< 20yo	75% (55-95)
20-30yo	60% (40-80)
30-40yo	33% (10-50)
> 40yo	10% (0-20)

• Overall rate is 33%

• McLaughlin & MacLellan 1967
  • 95% traumatic dislocations in teenagers recurred.
  • Various authors report 80 – 92 %
• After the age of 40
  • incidence drops sharply to 10% to 15%.
• The majority of recurrences occur within 2 years of the first traumatic dislocation.
• Simonet & Cofield 1982
  • Overall incidence of recurrence
    • 33% over 4 years
    • 66% in patients < 20 years
    • 17% in patients 20 – 40 years
• Athletes younger than 20 years was 80% but only 30% in nonathletes.

Trauma of First Dislocation

• Decreased incidence of redislocation with
  • Severe trauma
  • Associated Fracture

Activity

• Redislocation more common in athletes
• 80% in athletes
• 30% in non-athletes

Rehabilitation

• US Naval Academy study showed reduced redislocation following rehabilitation programme but high level of compliance required
• Activity restriction & effective muscle strengthening reduces redislocation
• Overall redislocation rate 25% at 3 years
• Need strict adherence with program