Joint Dislocations

Dislocation Basics - Joint Uncoupling 101

• Dislocation: Total loss of articular congruity between joint surfaces.
• Subluxation: Partial loss of articular congruity.
• Types:
  • Traumatic: Most common; due to injury.
  • Pathological: Underlying joint disease (e.g., infection, RA).
  • Congenital: Present at birth (e.g., DDH).
• Terminology:
  • Acute: Recent.
  • Chronic: Unreduced > 3 weeks.
  • Recurrent: Multiple episodes.
  • Open: Associated skin breach.
  • Closed: Skin intact.

⭐ Always assess neurovascular status distal to a dislocation, as injury is common.

Shoulder Dislocation - Arm Adrift Antics

• Types & Mechanisms:
  • Anterior (>95%): Abduction, external rotation, extension. Arm abducted & externally rotated.

    ⭐ Axillary nerve is the most commonly injured nerve in anterior shoulder dislocation.

  • Posterior (rare): Adduction, internal rotation, flexion. Arm adducted & internally rotated.
  • Inferior (Luxatio erecta): Arm overhead.
• Clinical: Deformity (loss of deltoid contour), pain, ↓ROM.
• X-rays: AP, axillary/Y-view.
  • Lesions: Bankart (anteroinferior labrum), Hill-Sachs (posterolateral humeral head).
• Management:
  • Reduction (Kocher, Stimson). Immobilization.
  • 📌 ALAS: Anterior Luxation Axillary nerve Stimson.
• Complications: Axillary nerve injury, recurrence, rotator cuff tear, adhesive capsulitis. oka

Elbow Dislocation - Olecranon Outbursts

• Types: Posterior (most common, FOOSH with elbow extension), anterior (rare), divergent.
• Clinical: Obvious deformity, severe pain, swelling. Elbow held in flexion.
• X-rays (AP/Lat): Check for associated fractures (radial head, coronoid process).

  ⭐ Terrible Triad: Elbow dislocation + radial head fracture + coronoid process fracture; indicates significant instability.

• Management: Prompt closed reduction. Check neurovascular status (median/ulnar nerves, brachial artery). Immobilize, then early mobilization.
• Complications: Neurovascular injury, stiffness (myositis ossificans), recurrent instability.

Hip Dislocation - Femur's Forced Exit

• Types & Mechanism:
  • Posterior: Most common (dashboard). Limb: flexed, adducted, int. rotated (📌 PIPA).
  • Anterior: Forced abduction. Limb: flexed, abducted, ext. rotated (📌 ABE).
• Clinical: Severe pain, ↓ ROM.
• Investigations: X-rays (AP pelvis, lat. hip). Check associated #.
• Management: Emergency reduction (Allis). Post-reduction CT. Neurovascular check (sciatic).

  ⭐ Sciatic nerve injury (common peroneal) common in posterior dislocation.

• Complications: Sciatic nerve palsy, AVN femoral head, OA, recurrence.

Avascular necrosis of femoral head after hip dislocation

Knee & Patella Dislocation - Popliteal Perils

• Knee (Tibiofemoral) Dislocation: ⚠️ Vascular emergency!
  • Types: Ant, Post, Med, Lat, Rotatory.
  • Popliteal artery injury in ~30-40%.
  • Clinical: Deformity, pain, instability. Check pulses!
  • Ix: X-ray, Angio/Doppler if vascular injury.
  • Mx: Reduce, vascular repair, ExFix/surgery.
  • Complications: Popliteal art/nerve injury, compartment syndrome.
• Patellar Dislocation: Usually lateral.
  • Clinical: Lateral patella, pain, 'giving way'.
  • Ix: X-ray (sunrise view).
  • Mx: Reduction (medial pressure + knee extension), immobilize, physio (VMO).
  • Complications: Recurrence, chondromalacia. ⭐ > Posterior knee dislocations carry the highest risk of popliteal artery injury.

High‑Yield Points - ⚡ Biggest Takeaways

• Anterior shoulder dislocation: most common; risk of axillary nerve injury.
• Posterior shoulder dislocation: from seizures/electric shock; see light bulb sign on X-ray.
• Posterior hip dislocation: sciatic nerve injury; limb shortened, adducted, internally rotated.
• Anterior hip dislocation: limb presents abducted and externally rotated.
• Elbow dislocation (posterior common): brachial artery, median/ulnar nerve at risk.
• Knee dislocation: true vascular emergency; suspect popliteal artery injury.
• Lunate dislocation: most common carpal dislocation; median nerve symptoms, spilled teacup sign.