Extensor Tendon Injuries of the Hand - Comprehensive Notes

Extensor Tendon Injuries of Hand

Extensor tendons are responsible for extending the fingers and thumb, enabling movements like straightening the fingers and gripping. Injuries can result from trauma, repetitive use, or disease, significantly impacting hand function.

Etiology

Extensor tendon injuries often arise from direct trauma, lacerations, or forceful impacts. The injury mechanism varies by zone:

  • Zone I (Distal Phalanx):

    • Direct blow (e.g., mallet injury).

    • Traumatic hyperflexion (e.g., jammed finger).

  • Zone II (Middle Phalanx):

    • Direct trauma (e.g., central slip injury).

    • PIP joint dislocation (e.g., sports injury or trauma).

  • Zone III (Proximal Phalanx):

    • Direct trauma (e.g., laceration, crush injury).

    • Fractures (e.g., proximal phalanx or MCP fractures).

    • Hyperflexion injury (e.g., forceful bending).

  • Zone IV (Metacarpals):

    • Lacerations (e.g., knife wound).

    • Fractures (e.g., boxer's fracture).

    • Crush injuries (e.g., industrial accidents).

  • Zone V (Wrist):

    • Lacerations (e.g., traumatic injury).

    • Fractures (e.g., distal radius fractures).

    • Blunt trauma (e.g., MVA, sports injury).

  • Zone VI (Distal Forearm):

    • Direct trauma or lacerations.

    • Fractures (e.g., distal radius fractures).

    • Blunt force trauma (e.g., MVAs, sports injuries).

  • Zone VII (Proximal Forearm):

    • Lacerations or stab wounds.

    • Fractures of the proximal radius or ulna.

    • Crushing injuries or trauma.

    • Elbow dislocations.

  • Zone VIII (Elbow):

    • Direct blunt trauma (e.g., falls, sports injuries).

    • Fractures (e.g., olecranon fracture).

    • Elbow dislocations.

    • Chronic overuse or tendonitis (e.g., tennis elbow).

Clinical Presentation

The clinical presentation depends on the zone of injury. Common signs and symptoms include:

  • Pain: Localized to the injury site.

  • Swelling: Around the injury site, especially in lacerations or fractures.

  • Deformity:

    • Mallet Finger (Zone I): The fingertip remains in flexion, unable to extend.

    • Boutonnière Deformity (Zone II): Flexion deformity of the PIP joint with hyperextension of the DIP joint.

  • Loss of Function: Inability to fully extend fingers or thumb, affecting grip strength.

  • Tendon Rupture or Avulsion: Identifiable in severe trauma, often with open wounds.

  • Other features: Limited range of motion, abnormal finger positioning, or inability to perform fine motor tasks.

Zone-Specific Injuries

  1. Zone I: Distal Phalanx

    • Location: Distal phalanx, including the distal interphalangeal (DIP) joint.

    • Common Injury: Mallet Finger – Rupture or avulsion of the distal extensor tendon.

    • Injury Characteristics: Inability to actively extend the fingertip, leading to flexion at the DIP joint.

  2. Zone II: Middle Phalanx

    • Location: Middle phalanx, including the proximal interphalangeal (PIP) joint.

    • Common Injury: Central Slip Injury – Rupture or injury to the central slip of the extensor tendon.

    • Injury Characteristics: Boutonnière deformity (PIP flexion and DIP hyperextension).

  3. Zone III: Proximal Phalanx

    • Location: Proximal phalanx (between PIP and MCP joints).

    • Common Injury: Injury to extensor tendons due to lacerations, fractures, or trauma.

    • Injury Characteristics: Loss of extension of the PIP and MCP joints, potentially leading to clawing or difficulty extending the finger.

  4. Zone IV: Metacarpals

    • Location: Metacarpal bones and the metacarpophalangeal (MCP) joint.

    • Common Injury: Lacerations or fractures of the extensor tendons at the metacarpal level.

    • Injury Characteristics: Difficulty in MCP joint extension, potentially leading to clawing or flexion at the MCP joint.

  5. Zone V: Wrist

    • Location: Wrist joint, where tendons pass through the extensor retinaculum.

    • Common Injury: Injuries associated with wrist fractures or lacerations affecting extensor tendons.

    • Injury Characteristics: Damage to multiple tendons, affecting wrist and hand function, leading to issues with wrist or finger extension.

  6. Zone VI: Distal Forearm

    • Location: Distal forearm, just above the wrist.

    • Common Injury: Fractures or lacerations of the extensor tendons, often resulting from trauma.

    • Injury Characteristics: Affects the ability to extend the wrist and fingers, with potential complications like wrist drop.

  7. Zone VII: Proximal Forearm

    • Location: Proximal forearm area, extending to the elbow.

    • Common Injury: Lacerations or fractures affecting tendons at the level of the forearm.

    • Injury Characteristics: Impairs extension of both the wrist and the elbow, potentially causing loss of function in the forearm and hand.

  8. Zone VIII: Elbow

    • Location: Elbow joint and the extensor tendons that cross over it.

    • Common Injury: Less common, but can occur with trauma or lacerations.

    • Injury Characteristics: May lead to loss of elbow extension, with minimal involvement of the wrist and hand.

Clinical Tests

  • Mallet Finger Test

    • Purpose: Diagnose Mallet Finger (rupture or avulsion of the distal extensor tendon at the DIP joint).

    • Procedure: Patient attempts to extend their finger actively.

    • Interpretation: If the DIP joint remains in flexion and cannot be actively extended, it suggests an injury to the distal extensor tendon.

  • Bunnell Test

    • Purpose: Assess for flexion contracture or intrinsic tightness; also assesses extensor tendon function in tendon injuries.

    • Procedure: Therapist holds the MCP joint in extension while the patient attempts to flex the PIP joint.

    • Interpretation: Inability to flex the PIP joint with the MCP held extended suggests injury to the extensor tendons or intrinsic muscles.

  • Tripod Test (PIP Extension Test)

    • Purpose: Assess the ability to extend the PIP joint and detect Boutonnière deformity.

    • Procedure: Patient tries to extend the PIP joint actively with the DIP joint held in flexion.

    • Interpretation: If the PIP joint cannot be actively extended, it suggests a central slip rupture typical of Boutonnière deformity.

  • Lateral Band Test

    • Purpose: Assess for injury to the lateral bands of the extensor tendon.

    • Procedure: Therapist applies pressure to the lateral bands of the finger and asks the patient to extend the finger.

    • Interpretation: Pain or inability to extend the finger suggests damage to the lateral bands, which can cause Boutonnière deformity.

  • Active Range of Motion (AROM) Test

    • Purpose: Assess the ability to actively extend the affected joints.

    • Procedure: Patient actively extends fingers and wrist through the full ROM.

    • Interpretation: Limited or absent active extension may indicate extensor tendon dysfunction.

    • Key areas assessed: DIP joint for Mallet Finger, PIP joint for Boutonnière deformity, MCP and wrist for general extensor tendon function.

  • Passive Range of Motion (PROM) Test

    • Purpose: Determine if there is a limitation in joint motion due to tendon adhesions, joint stiffness, or other soft tissue issues.

    • Procedure: Therapist moves the patient's finger or wrist joints through their passive ROM.

    • Interpretation: A reduction in ROM during passive testing compared to normal indicates joint stiffness or tendon tightness is limiting movement.

  • Tendon Gliding Exercises Test

    • Purpose: Evaluate the extent of tendon adhesions and stiffness.

    • Procedure: Patient performs a series of hand positions that glide the extensor tendons across the joints.

    • Interpretation: Limited or painful movement suggests tendon adhesions, weakness, or incomplete healing.

    • Use: Rehabilitation strategy to reduce adhesions and improve tendon mobility.

  • Finkelstein Test

    • Purpose: Assess for De Quervain's Tenosynovitis (not specific to extensor tendon injuries but helps identify pain around wrist and forearm extensors).

    • Procedure: Patient makes a fist with the thumb inside the fingers and bends the wrist toward the ulnar side.

    • Interpretation: Pain over the thumb tendons indicates De Quervain’s Tenosynovitis or generalized tendon irritation.

  • Allen's Test

    • Purpose: Assess circulatory function by evaluating blood flow through the radial and ulnar arteries.

    • Procedure: Patient clenches their fist, therapist compresses both arteries, patient opens hand, and therapist releases one artery at a time.

    • Interpretation: Delayed or no return of color indicates impaired circulation, which could complicate recovery.

  • Tinel's Sign

    • Purpose: Assess for nerve irritation or entrapment.

    • Procedure: Therapist taps gently over the course of the median, ulnar, or radial nerve.

    • Interpretation: Tingling or electric shock-like sensations indicate nerve irritation, which may complicate tendon injuries.

  • Scarf Test

    • Purpose: Check for injury to the extensor tendons and the central slip in suspected cases of Boutonnière deformity.

    • Procedure: Examiner places the affected finger in a position of function and then moves the PIP joint passively.

    • Interpretation: A restricted or painful movement in the PIP joint may suggest central slip injury or damage to the extensor mechanism.

Imaging Studies

  • X-rays

    • Purpose: Rule out associated bone injuries, such as fractures or dislocations.

    • Procedure: X-rays of the hand, wrist, and forearm are taken to assess bones and joints.

    • Interpretation:

      • Fractures or dislocations affecting bony attachments of the tendons can complicate treatment.

      • Avulsion fractures at the distal phalanx are common in Mallet Finger.

      • Joint subluxation or dislocation may suggest a need for more complex surgical repair or tendon reconstruction.

  • Ultrasound

    • Purpose: Evaluate the integrity of the extensor tendons and surrounding soft tissues.

    • Procedure: High-frequency ultrasound is used to visualize the tendon and joint structures in real-time.

    • Interpretation:

      • Can show tendon tears, ruptures, or avulsions.

      • Useful for diagnosing tenosynovitis and detecting tendon adhesions.

  • Magnetic Resonance Imaging (MRI)

    • Purpose: Assess soft tissue injuries, including extensor tendons, ligaments, and associated damage to bones, cartilage, or nerves.

    • Procedure: MRI uses magnetic fields and radio waves to create detailed images.

    • Interpretation:

      • Helpful for visualizing tendon ruptures, avulsions, swelling, and associated injuries.

      • Provides a comprehensive view of the injury, especially in complex tendon injuries and soft tissue tears.

  • CT Scan (Computed Tomography)

    • Purpose: Evaluate bone and joint structures in more detail, especially in complex fractures or dislocations.

    • Procedure: CT scans use X-ray technology combined with computer processing.

    • Interpretation:

      • Used to assess fractures or displaced bone fragments that could affect tendon function.

      • Provides valuable information in cases where tendon damage is associated with complex fractures.

Physiotherapy Assessment

A thorough physiotherapy assessment is essential.

  • Patient History:

    • Mechanism of injury.

    • Time since injury and prior treatments or surgeries.

  • Visual Inspection:

    • Observation of the hand for deformity, swelling, or open wounds.

    • Identification of tenderness, bruising, or signs of infection.

  • Palpation:

    • Palpate the tendon sheath and bony prominences to detect tenderness or abnormalities.

    • Assess for any palpable gaps in the tendon.

  • Range of Motion (ROM):

    • Assess active and passive ROM of the injured joints.

    • Pay particular attention to the PIP, DIP, and MCP joints.

  • Strength Testing:

    • Test strength in the hand and fingers.

    • Note any weakness or loss of grip strength.

  • Clinical Tests:

    • As mentioned above.

Physiotherapy Management

Physiotherapy is essential for restoring full function, reducing complications, and preventing deformities.

  • Initial Phase (0-6 weeks):

    • Immobilization:

      • Extension splint for mallet finger (6-8 weeks).

      • Custom splint for more complex injuries like boutonnière deformity.

    • Pain Management:

      • Ice, elevation, and NSAIDs.

    • Education:

      • Instruct the patient about tendon healing and splint use.

  • Intermediate Phase (6-12 weeks):

    • Gentle Active Range of Motion (AROM):

      • Gentle active exercises to restore movement, avoiding overstretching.

    • Scar Management:

      • Soft tissue mobilization, massage, or silicone gel sheets.

    • Strengthening Exercises:

      • Gradual strengthening exercises once tendon healing is advanced.

  • Advanced Phase (12+ weeks):

    • Full Range of Motion (ROM) and Strength:

      • Progressive strengthening exercises.

    • Return to Function:

      • Specific tasks or work-related exercises.

      • Gradual return to sports or other activities as tolerated.

Complications

Extensor tendon injuries can lead to long-term issues if improperly treated:

  • Stiffness: Joint contractures from prolonged immobilization.

  • Tendon Rupture: Improper healing leading to tendon rupture or reinjury.

  • Deformities: Chronic deformities such as boutonnière or mallet finger.


Term 1: What is the etiology and characteristic of a Zone I extensor tendon injury (Mallet Finger)?
Definition 1: Direct blow or traumatic hyperflexion at the DIP joint, resulting in the inability to extend the fingertip.
Term 2: What is the etiology and characteristic of Zone II extensor tendon injury (Central Slip Injury)?
Definition 2: Direct trauma to the middle phalanx or PIP joint dislocation, leading to Boutonnière deformity (PIP flexion and DIP hyperextension).
Term 3: What is the etiology and characteristic of Zone III extensor tendon injury?
Definition 3: Lacerations, fractures, or hyperflexion injuries to the proximal phalanx, causing loss of extension of the PIP and MCP joints.
Term 4: What is the etiology and characteristic of Zone IV extensor tendon injury?
Definition 4: Lacerations or fractures of the metacarpals, leading to difficulty in MCP joint extension and potential clawing.
Term 5: What is the etiology and characteristic of Zone V extensor tendon injury?
Definition 5: Injuries associated with wrist fractures or lacerations, affecting multiple tendons and wrist/finger extension.
Term 6: What is the etiology and characteristic of Zone VI extensor tendon injury?
Definition 6: Fractures or lacerations of the extensor tendons in the distal forearm, affecting the ability to extend the wrist and fingers.
Term 7: What is the etiology and characteristic of Zone VII extensor tendon injury?
Definition 7: Lacerations or fractures affecting tendons in the proximal forearm, impairing extension of the wrist and elbow.
Term 8: What is the etiology and characteristic of Zone VIII extensor tendon injury?
Definition 8: Trauma or lacerations to the elbow joint, potentially leading to loss of elbow extension.
Term 9: What deformity is associated with Mallet Finger?
Definition 9: The fingertip remains in flexion, unable to extend actively.
Term 10: What deformity is associated with Boutonnière Deformity?
Definition 10: Flexion deformity of the PIP joint with hyperextension of the DIP joint.
Term 11: What is the procedure and interpretation of the Mallet Finger Test?
Definition 11: Patient attempts to extend their finger actively. If the DIP joint remains in flexion, it suggests an injury to the distal extensor tendon.
Term 12: What is the procedure and interpretation of the Bunnell Test?
Definition 12: Therapist holds the MCP joint in extension while the patient attempts to flex the PIP joint. Inability to flex the PIP joint suggests injury to the extensor tendons or intrinsic muscles.
Term 13: What is the procedure and interpretation of the Tripod Test (PIP Extension Test)?
Definition 13: Patient tries to extend the PIP joint actively with the DIP joint held in flexion. If the PIP joint cannot be actively extended, it suggests a central slip rupture typical of Boutonnière deformity.
Term 14: What is the purpose and interpretation of X-rays in diagnosing extensor tendon injuries?
Definition 14: X-rays are used to rule out associated bone injuries, such as fractures or dislocations, particularly avulsion fractures at the distal phalanx (Mallet Finger).
Term 15: What is the purpose and interpretation of Ultrasound in diagnosing extensor tendon injuries?
Definition 15: Ultrasound is used to evaluate the integrity of the extensor tendons and surrounding soft tissues, showing tendon tears, ruptures, or avulsions.
Term 16: What is the purpose and interpretation of MRI in diagnosing extensor tendon injuries?
Definition 16: MRI is used to assess soft tissue injuries, including extensor tendons, ligaments, and associated damage, visualizing tendon ruptures, avulsions, and swelling.
Term 17: What are the key components of the initial phase (0-6 weeks) of physiotherapy management for extensor tendon injuries?
Definition 17: Immobilization with an extension splint for mallet finger (6-8 weeks) or a custom splint for more complex injuries like boutonnière deformity.
Term 18: undefined
Definition 18: Gentle active range of motion (AROM) exercises


Term 1: What is the etiology and characteristic of a Zone I extensor tendon injury (Mallet Finger)?
Definition 1: Direct blow or traumatic hyperflexion at the DIP joint, resulting in the inability to extend the fingertip.
Term 2: What is the etiology and characteristic of Zone II extensor tendon injury (Central Slip Injury)?
Definition 2: Direct trauma to the middle phalanx or PIP joint dislocation, leading to Boutonnière deformity (PIP flexion and DIP hyperextension).
Term 3: What is the etiology and characteristic of Zone III extensor tendon injury?
Definition 3: Lacerations, fractures, or hyperflexion injuries to the proximal phalanx, causing loss of extension of the PIP and MCP joints.
Term 4: What is the etiology and characteristic of Zone IV extensor tendon injury?
Definition 4: Lacerations or fractures of the metacarpals, leading to difficulty in MCP joint extension and potential clawing.
Term 5: What is the etiology and characteristic of Zone V extensor tendon injury?
Definition 5: Injuries associated with wrist fractures or lacerations, affecting multiple tendons and wrist/finger extension.
Term 6: What is the etiology and characteristic of Zone VI extensor tendon injury?
Definition 6: Fractures or lacerations of the extensor tendons in the distal forearm, affecting the ability to extend the wrist and fingers.
Term 7: What is the etiology and characteristic of Zone VII extensor tendon injury?
Definition 7: Lacerations or fractures affecting tendons in the proximal forearm, impairing extension of the wrist and elbow.
Term 8: What is the etiology and characteristic of Zone VIII extensor tendon injury?
Definition 8: Trauma or lacerations to the elbow joint, potentially leading to loss of elbow extension.
Term 9: What deformity is associated with Mallet Finger?
Definition 9: The fingertip remains in flexion, unable to extend actively.
Term 10: What deformity is associated with Boutonnière Deformity?
Definition 10: Flexion deformity of the PIP joint with hyperextension of the DIP joint.
Term 11: What is the procedure and interpretation of the Mallet Finger Test?
Definition 11: Patient attempts to extend their finger actively. If the DIP joint remains in flexion, it suggests an injury to the distal extensor tendon.
Term 12: What is the procedure and interpretation of the Bunnell Test?
Definition 12: Therapist holds the MCP joint in extension while the patient attempts to flex the PIP joint. Inability to flex the PIP joint suggests injury to the extensor tendons or intrinsic muscles.
Term 13: What is the procedure and interpretation of the Tripod Test (PIP Extension Test)?
Definition 13: Patient tries to extend the PIP joint actively with the DIP joint held in flexion. If the PIP joint cannot be actively extended, it suggests a central slip rupture typical of Boutonnière deformity.
Term 14: What is the purpose and interpretation of X-rays in diagnosing extensor tendon injuries?
Definition 14: X-rays are used to rule out associated bone injuries, such as fractures or dislocations, particularly avulsion fractures at the distal phalanx (Mallet Finger).
Term 15: What is the purpose and interpretation of Ultrasound in diagnosing extensor tendon injuries?
Definition 15: Ultrasound is used to evaluate the integrity of the extensor tendons and surrounding soft tissues, showing tendon tears, ruptures, or avulsions.
Term 16: What is the purpose and interpretation of MRI in diagnosing extensor tendon injuries?
Definition 16: MRI is used to assess soft tissue injuries, including extensor tendons, ligaments, and associated damage, visualizing tendon ruptures, avulsions, and swelling.
Term 17: What are the key components of the initial phase (0-6 weeks) of physiotherapy management for extensor tendon injuries?
Definition 17: Immobilization with an extension splint for mallet finger (6-8 weeks) or a custom splint for more complex injuries like boutonnière deformity.
Term 18: What defines the intermediate phase (6-12 weeks) of physiotherapy management for extensor tendon injuries?
Definition 18: Gentle active range of motion (AROM) exercises to restore movement, avoiding overstretching. Scar management. Gradual strengthening exercises.