Carpometacarpal Joint Dislocation

Other Names

• Thumb CMC Dislocation
• Thumb Carpometacarpal Joint Dislocation

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Background

• This page references dislocation of all 5 Carpometacarpal Joints

Epidemiology

• Account for less than 1% of hand injuries
• More common in dominant hand
• More often multiple dislocations rather than single isolated
• 50% involve 5th MCPJ, 25% 2nd MCPJ

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Pathophysiology

• Mechanism
  • Punching
  • Fall
  • Thumb: axial load on flexed thumb or dorsal force applied to 1st webspace
• Associated injuries
  • Hamate Fracture
  • Metacarpal Fractures
  • Fracture-dislocation

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Risk Factors

• Young males

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Differential Diagnosis

• Fractures
  • Distal Radius Fracture
    • Barton's Fracture
    • Chauffer's Fracture
    • Colles' Fracture
    • Die-Punch Fracture
    • Radial Styloid Fracture
    • Smith's Fracture
  • Distal Ulna Fracture
  • Carpal Fractures
    • Scaphoid Fracture
    • Lunate Fracture
    • Triquetrum Fracture
    • Pisiform Fracture
    • Trapezium Fracture
    • Trapezoid Fracture
    • Capitate Fracture
    • Hamate Fracture
  • Essex Lopresti Fracture
• Dislocations
  • Wrist Dislocation (Radiocarpal and/or Ulnocarpal)
  • Carpometacarpal Joint Dislocation
  • Distal Radioulnar Joint Dislocation
  • Lunate Dislocation
  • Perilunate Dislocation
• Instability & Degenerative
  • Scapholunate Instability
  • Lunotriquetral Instability
  • Scaphoid Nonunion Advanced Collapse
  • Distal Radial Ulnar Joint Instability
  • Kienbocks Disease
  • Dorsal Wrist Impingement
• Tendinopathies & Ligaments
  • De Quervain's Tenosynovitis
  • Intersection Syndrome
  • TFCC Injury
  • Wrist Tendinopathies
  • Extensor Carpi Ulnaris Instability
• Neuropathies
  • Carpal Tunnel Syndrome
  • Pronator Teres Syndrome
  • Anterior Interosseus Nerve Syndrome
  • Posterior Interosseus Nerve Syndrome
  • Guyon Canal Syndrome
• Pediatric Considerations
  • Distal Radial Epiphysitis (Gymnast's Wrist)
  • Torus Fracture
• Arthropathies
  • Wrist Osteoarthritis
  • Rheumatoid Arthritis
  • Gout
• Cartilage
  • Osteochondral Defect
• Vascular
  • Hypothenar Hammer Syndrome
• Other
  • Ganglion Cyst of Wrist
  • Ulnar Impingement Syndrome
  • Infectious Tenosynovitis

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Clinical Features

• General: Physical Exam Wrist
• Patients will report swelling, pain at affected joint(s)
• Deformity may or may not be obvious depending on degree of swelling
• Inability to form a fist

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Evaluation

Radiographs

• Standard Radiographs Wrist, Standard Radiographs Hand
• 3 view radiographs generally sufficient to make the diagnosis
• Evaluate integrity of Gilulas Lines
• Thumb: Roberts view

MRI

• Recurrent instability after reduction, evaluate soft tissue injuries

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Classification

• N/A

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Management

Nonoperative

• Thumb Indications
  • Stable after reduction
  • Splint: Thumb Spica Splint, Thumb Spica Cast

Operative

• Thumb Indications
  • Unstable joint

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Return to Play

• Highly variable

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Complications

• Persistent pain
• Joint instability or stiffness
• Posttraumatic arthritis

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See Also

• Internal
  • Forearm Pain (Main)
  • Wrist Pain (Main)
  • Hand Pain (Main)
  • Hand and Wrist Anatomy (Main)
  • Physical Exam Wrist

External

• Sports Med Review Hand Pain: https://www.sportsmedreview.com/by-joint/hand/
• Sports Medicine Review Wrist Pain: https://www.sportsmedreview.com/by-joint/wrist/

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