Orthopedics Book

Cardiovascular Medicine


Extensor Tendon Injury at the DIP Joint

Aka: Extensor Tendon Injury at the DIP Joint, DIP Extensor Tendon Avulsion, Mallet Finger, Mallet Fracture, Drop Finger, Baseball Finger
  1. See Also
    1. Hand Fracture
  2. Epidemiology
    1. Most common closed finger Tendon Injury
  3. Mechanism
    1. Forced flexion of extended distal interphalangeal joint
      1. Ball strikes fingertip on catching a ball
    2. Trauma at DIP joint results:
      1. Avulsion of distal phalanx (Bony Mallet) as extensor tendon tears away bony insertion or
      2. Pure extensor tendon rupture (Tendinous Mallet)
        1. Tendon stretched, or partially or completely torn
    3. Images
      1. FingerExtensorTendonInjury.png
  4. Symptoms
    1. Pain, Bruising and swelling at dorsal DIP joint
  5. Signs
    1. DIP joint with flexion deformity at rest
      1. Intact flexor tendon unopposed by the ruptured extensor tendon
    2. Isolate the DIP joint to test active extension
      1. Variable loss of active finger DIP extension
      2. Confirm extension weakness due to extensor tendon
        1. Central slip at PIP joint can also extend DIP
  6. Associated Conditions
    1. Volar subluxation of distal phalanx with bony mallet
  7. Imaging: XRay of digit (esp. lateral)
    1. Assess for bony mallet at dorsal base of distal phalanx
      1. Type I: No avulsion fragment
      2. Type II: Small bony avulsion
      3. Type III: Avulsion with volar subluxation
    2. Post-reduction XRay to confirm proper alignment
    3. Repeat XRay every 2 weeks if bony mallet (DIP avulsion Fracture)
  8. Management: Splinting
    1. General
      1. Splints are equally effective: Aluminum, Stack, Ring
      2. Splints are as effective as surgical repair
      3. May participate in sports with splinted DIP
    2. Precautions
      1. See Orthopedic referral indications below
      2. Splint should not reduce range of motion of PIP
      3. Splinting must be continuous for entire period (DIP must remain in extension)
        1. Splinting time (6-8 weeks) restarts if the finger falls back into flexion
      4. Delayed presentation (e.g. month old injury) requires a longer period of Splinting
      5. Risk of skin necrosis with Splinting
        1. Avoid pressure to dorsum of DIP
        2. Avoid hyperextension of DIP joint
          1. Skin will blanch if DIP hyperextended
    3. Assessment
      1. Post-reduction XRay to confirm proper alignment
    4. Protocol
      1. First 6-8 weeks
        1. Splint finger in neutral extension for 6-8 weeks
        2. Splinting must be continuous without fail
          1. Twenty four hours per day
          2. Every day for 6-8 weeks
        3. Hold extension when changing splint
          1. Support distal phalanx against flat surface
          2. Ask for assistance when changing splint
          3. Allow skin to air for 10 minutes at splint change
            1. Reduces maceration at splint
        4. Restart 8 week Splinting period if finger flexes
      2. Next 3-6 weeks
        1. Splint finger in extension only at night
  9. Management: Orthopedic Referral Indications (see prognosis below)
    1. Joint incongruent
    2. Inability to passively extend DIP joint
      1. Suggests bone or soft tissue entrapment
    3. Fracture involves >30% of joint space
    4. Fragment displaced >2mm
    5. Open Growth Plate
    6. Bony avulsion >1/3 of distal phalanx
    7. Volar subluxation of distal phalanx
  10. Management: Follow up
    1. Re-examine every two weeks until healed
    2. XRay every two weeks if bony avulsion
  11. Management: Anticipatory Guidance
    1. Warn that patient that outcome will not be perfect
  12. Prognosis
    1. Outcomes are similar for conservative therapy versus surgical management (regardless of referral indications above)
      1. Kalainov (2005) J Hand Surg Am 30(3): 580-6 [PubMed]
  13. Complications
    1. Chronic loss of full distal phalanx extension
  14. References
    1. Brandenburg (1996) Consultant p.331-340
    2. Calmbach (1996) Lecture in Minneapolis
    3. Dvorak (1996) Lecture in Minneapolis
    4. Lillegard (1996) Lecture in Minneapolis
    5. Childress (2022) Am Fam Physician 105(6): 631-9 [PubMed]
    6. Leggit (2006) Am Fam Physician 73(5):810-6 [PubMed]
    7. Simpson (2001) J Hand Surg 26:32-3 [PubMed]
    8. Wang (2001) Am Fam Physician 63(10):1961-66 [PubMed]

Mallet finger (C0158473)

Concepts Acquired Abnormality (T020)
ICD9 736.1
ICD10 M20.01
SnomedCT 156861001, 64298006
Dutch hamervinger
French Doigt en marteau
German Hammerfinger
Italian Dita a martello
Portuguese Dedo em martelo
Spanish Dedo de la mano en mazo, dedo de beisbolista, dedo de la mano en martillo (trastorno), dedo de la mano en martillo
Japanese つち指, ツチユビ
English mallet finger (flexion deformity DIP), acquired mallet finger, mallet finger, acquired mallet finger (diagnosis), mallet finger (physical finding), finger mallet, Mallet finger, Baseball finger, Mallet finger (disorder), baseball finger
Czech Paličkovitý prst
Hungarian Kalapácsujj
Derived from the NIH UMLS (Unified Medical Language System)

Dropped finger (C0231665)

Concepts Sign or Symptom (T184)
SnomedCT 83927003
Spanish dedo en martillo, dedo de beisbolista, dedo en martillo (hallazgo), dedo caído (hallazgo), dedo caído
English dropped finger, finger drop, drop finger, Dropped finger, Fingerdrop, Dropped finger (finding), dropping; finger, finger; dropping
Dutch dropping; finger, finger; dropping
Derived from the NIH UMLS (Unified Medical Language System)

Rupture extensor digitorum tendon (C0434349)

Concepts Injury or Poisoning (T037)
SnomedCT 209774007
English Rupt extensor digit tndn, Rupture extensor digitorum tendon, Rupture extensor digitorum tendon (disorder)
Spanish ruptura del tendón del extensor común de los dedos de la mano (trastorno), ruptura del tendón del extensor común de los dedos de la mano
Derived from the NIH UMLS (Unified Medical Language System)

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