Extensor Tendon Injuries (Hand)

Other Names

• Extensor tendinopathy

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Background

• Generally a loss of ability to extend the affected digit, hand and/or wrist
• Superficial, susceptible to injury
• Most common finger is pointer/ index finger
• Potential mechanisms are sharp object direct lacerations, burns, blunt trauma, bites, crush injuries, avulsions and deep abrasions

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Pathophysiology

• Can affect MCPJ and/or PIPJ or DIPJ of hand
• Zone 1: Traumatic flexion of DIPJ
• Zone 2: Dorsal laceration or crush injury
• Zone 5: Fight bite

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Risk Factors

• Unknown

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Differential Diagnosis

• Fractures
  • Phalanx Fractures (Hand)
  • Metacarpal Fractures
    • Boxer's Fracture
    • Rolando Fracture
    • Bennett Fracture
• Dislocations
  • Metacarpophalangeal Joint Dislocation
  • Proximal Interphalangeal Joint Dislocation
  • Distal Interphalangeal Joint Dislocation
  • Carpometacarpal Joint Dislocation
• Tendinopathies
  • Extensor Tendon Injuries (Hand)
  • Central Slip Extensor Tendon Injury
  • Flexor Tendon Injuries (Hand)
  • Boutonniere Deformity
  • Swan Neck Deformity
  • Jersey Finger
  • Mallet Finger
  • Trigger Finger
  • De Quervains Tenosynovitis
  • Volar Plate Avulsion Injury
  • Sagittal Band Injury
• Ligament Injuries
  • Gamekeepers Thumb (UCL)
  • Radial Collateral Ligament of the Thumb Injury (RCL)
• Neuropathies
  • Wartenbergs Syndrome
  • Carpal Tunnel Syndrome
  • Guyon Canal Syndrome
• Arthropathies
  • Carpometacarpal Arthritis
  • Finger Arthritis
  • Rheumatoid Arthritis
• Nail Bed Injuries
  • Nail Bed Lacerations
  • Nail Bed Avulsions
  • Subungual Hematoma
  • Paronychia
  • Felon
• Pediatric Considerations
  • Proximal Phalanx Avulsion Fracture (Thumb)
  • Middle and Distal Phalanx Avulsion Fracture
• Other
  • Dupuytrens Contracture

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Clinical Features

• General: Physical Examination Hand
• Universally present with inability to extend at some point on dorsal finger, hand or wrist
• Inspect for etiology (laceration, crush trauma, overuse, etc)
• Zone 1: Loss of extensor mechanism at DIPJ (digits 2-4), IPJ (thumb)
• Zone 3: Elson's Test can help confirm diagnosis

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Evaluation

• Standard Radiographs Hand
• Consider ultrasound
• MRI in complex injuries

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Classification

• Zone 1: DIPJ
  • Injury to terminal extensor tendon distal to or at the DIPJ (digits 2-4) or IPJ (thumb) involving EPL
  • Sequelae: Mallet Finger
• Zone 2: Middle Phalanx
  • Injury of tendon over middle phalanx (digits 2-4), or proximal phalanx thumb
• Zone 3: PIPJ
  • Injury over the PIPJ of digit 2-4 leading to Central Slip Injury or MCPJ of thumb involving EPL, EPB
  • Sequelae: Boutonniere Deformity
• Zone 4: Proximal Phalanx
  • Injury over the proximal phalanx (digits 2-4) or metacarpal of thumb (EPL, EPB)
• Zone 5: MCPJ
  • Injury over MCPJ of digit (2-4) or CMCJ of thumb (EPL, EPB)
  • Sequelae: Fight Bite, Sagittal band rupture
• Zone 6: Metacarpals
  • Injury over the metacarpal
  • Sequelae: Increased risk of neurovascular injury
• Zone 7: Wrist
  • Injury at wrist joint
  • Surgical injury requiring repair of extensor retinaculum
• Zone 8: Distal third of forearm
  • Disruption at the distal forearm
• Zone 9: Muscle belly rather than tendon injury
  • Sequelae: High risk of neurologic injury, requires surgery

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Management

Nonoperative

• Depends on zone of injury
• Immobilization if <50% of tendon cut and extensor tendon remains intact
• DIPJ extension splint
  • Zone 1 (mallet finger)
• PIPJ extension splint
  • Zone 3 (central slip if simple)
• MCPJ extension splint
  • Zone v (closed, uncomplicated sagittal band rupture)

Operative

• Incision & drainage: Open fracture involving joint, fite bite
• Repair: tendon laceration >50%
• Fixation: volar avulsion fracture
• Reconstruction: tendon repair not possible
• Central slip reconstruction

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Return to Play

• Needs to be updated

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Complications

• Neurovascular injury

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See Also

• Hand and Wrist Anatomy (Main)
• Finger Pain (Main)
• Hand Pain (Main)
• Wrist Pain (Main)
• Tendinopathies (Main)

External

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

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