High Yield Topics

Extensor Tendon Avulsion from the Distal Phalanx/Mallet Finger

By admin



Ovid: 5-Minute Sports Medicine Consult, The


Extensor Tendon Avulsion from the Distal Phalanx/Mallet Finger
Rachel A. Coel
Quynh Hoang
Basics
Description
  • Mallet finger is defined as a stretching or tearing of the extensor tendon or a complete avulsion of the tendon insertion from the dorsal base of the distal phalanx with or without bony avulsion.
  • The injury results in the inability to completely extend the distal interphalangeal (DIP) joint.
  • It is most commonly caused by sudden forced flexion of the fingertip while the DIP joint is actively extended.
  • Less commonly, it can occur when the DIP joint is forcefully hyperextended with a resulting fracture at the dorsal base of the distal phalanx (1,2)[C].
Epidemiology
  • Usually occurs during sports participation when an extended finger is struck on the tip by a ball.
  • Also occurs in the work environment or with minor household trauma.
  • The most commonly injured digit is the 3rd (middle) finger of the dominant hand, although any digit, including the thumb, can be involved.
Risk Factors
Sports, especially those involving ball contact and hand-to-hand contact
Diagnosis
History
  • Patient reports axial loading and/or hyperflexion of the DIP joint while the finger is held in extension. Classically, the extended finger is struck on the tip by a ball.
  • Patient complains of pain and swelling at the DIP joint of the affected finger, especially the dorsal aspect, with inability to actively extend the DIP joint.
Physical Exam
  • There is tenderness to palpation over the dorsum of the DIP joint.
  • Patient is unable to actively extend the DIP joint, although passive extension is possible.
  • To effectively establish the diagnosis, hold the proximal interphalangeal (PIP) joint in a fixed position, and then have the patient extend at the DIP joint.
  • An extensor lag at the DIP joint generally is present immediately after injury, but the deformity may be delayed by hours and even days or weeks.
  • In general, also evaluate for open skin lesions, collateral stability, and digit rotation or angulation.
Diagnostic Tests & Interpretation
Using the Doyle classification scheme (3), mallet finger injuries can be divided into four types:
  • Type I: Closed injury ± small dorsal avulsion fracture
  • Type II: Open injury/laceration at DIP joint with loss of tendon continuity
  • Type III: Open injury with deep abrasion causing loss of skin, subcutaneous tissue, and tendon substance
  • Type IV: Mallet fracture
    • Transepiphyseal injury fracture in children
    • Fracture fragment involving 20–50% of articular surface
    • Fracture fragment involving >50% of articular surface
Imaging
  • Radiographs are recommended in all cases to evaluate for accompanying fracture or joint subluxation.
  • Three views of the affected finger: posteroanterior, lateral, and oblique
  • Three patterns: No avulsion fracture, small avulsion fracture (<30% articular surface), large avulsion fracture (>30% articular surface)
  • Consider obtaining repeat radiographs at conclusion of continuous splinting to evaluate fracture healing.
Differential Diagnosis
  • Tuft or distal phalanx fracture with deformity
  • In the pediatric age group, injury to the epiphysis at the base of the distal phalanx may mimic a mallet finger.
Treatment
  • The involved finger should be splinted in full extension or slight hyperextension at the DIP joint.
  • No flexion should occur at any time until treatment is complete.
  • Splint continuously for 6–8 wks, followed by an additional 2 wks of nighttime splinting (1)[C],(4)[B],(5)[A].
  • If bone avulsion fracture, extension splint should be applied for 6 wks.
  • If tendon injury without bone involvement, splint in extension for 8 wks.
  • If large avulsion fracture, consider surgical consultation.
  • Compliance should be assessed at 2-wk intervals until healing has occurred.
  • Monitor dorsal skin for signs of vascular compromise owing to compressive splinting.
  • Controversy still exists regarding the optimal treatment of each type of mallet finger with respect to the type of splint used, the length of immobilization, and the surgical technique used if operative repair is indicated.
  • A recent Cochrane Review (2009) concluded that there is insufficient evidence from existing studies to establish the relative effectiveness of different types of finger splints used versus the standard Stack splint. Additionally, there is insufficient evidence to determine when surgery is indicated (5)[A].
  • A systematic review by Geyman and colleagues suggested that conservative treatment with splinting was safe and effective in more than 80% of mallet finger injuries (4)[B].
  • Most quantitative research studies indicated that splinting is the treatment of choice and is effective for most mallet finger injuries involving less than a third of the articular surface or without DIP joint subluxation.

P.151


Additional Treatment
Additional Therapies
  • DIP joint often is stiff after prolonged immobilization.
  • After 6–8 wks of continuous splinting, start DIP joint gentle active and passive range-of-motion (ROM) exercises.
  • At the end of continuous immobilization, if a mallet deformity of >20 degrees recurs, continue splinting for an additional 1–2 mos.
  • Consider extension splinting during athletic activities for an additional 2 mos after continuous splinting has been completed.
  • For chronic mallet finger injury (patients who present more than 4 wks after injury), treatment with continuous splinting for 10 wks followed by 2 wks of nighttime splinting has been shown to be successful (2)[C].
Surgery/Other Procedures
  • Surgical treatment with direct repair of the tendon or with open reduction and internal fixation is usually reserved for open injuries or for unstable mallet fractures involving more than a third of the articular surface or with associated DIP joint subluxation (1)[C].
  • However, based on a recent Cochrane Review, there is insufficient evidence to determine when surgery is specifically indicated (5)[A].
Ongoing Care
Follow-Up Recommendations
  • Regular physician assessment and diligent patient compliance are critical for successful nonoperative treatment.
  • Assess compliance with continuous splinting at follow-up visits at 2-wk intervals.
  • Consider repeat radiographs at the conclusion of continuous splinting to assess for bone healing.
Patient Education
  • This injury requires careful patient compliance.
  • The patient must understand the necessity of keeping the finger in extension for the entire duration of treatment, including during splint changes and skin care.
  • The patient must monitor dorsal skin for signs of vascular compromise from continuous extension splinting.
Complications
  • Patients may develop a slight extensor lag (5–10 degrees) with a mild loss of total motion, but it should not result in a functional deficit.
  • Complications tend to be related to splinting and typically are short term, such as skin ulcerations, splint-related pain, and tape allergies.
  • Other complications include permanent DIP joint stiffness and deformity.
  • If patient has failed 10 wks of continuous splinting, he or she may require surgical consultation.
  • Surgical complications may be long term, including pain, deformity, and treatment failure.
References
1. Bendre A, Hartigan B, Kalainov D. Mallet finger. J Amer Acad Orthop Surg. 2005;13:336–344.
2. Tuttle HG, Olvey SP, Stern PJ. Tendon avulsion injuries of the distal phalanx. Clin Ortho and Related Research. 2006:157–168.
3. Doyle JR. Extensor tendons—acute injuries. Green DP, Hotchkiss RN, Pederson WC, eds. Green's operative hand surgery. 4th ed. Philadelphia, PA: Churchill Livingstone; 1999:1962–1971.
4. Geyman JP, Fink K, Sullivan S. Conservative versus surgical treatment of mallet finger: a pooled quantitative literature review. J Amer Board of Fam Pract. 1998;11(5):382–390.
5. Handoll H, Vaghela M. Interventions for treating mallet finger injuries. Cochrane Database of Systematic Reviews. 2009;2.
Codes
ICD9
736.1 Mallet finger
Clinical Pearls
Special considerations for the pediatric population:
  • Physeal and epiphyseal involvement at the base of the distal phalanx is common in pediatric mallet finger injuries.
  • Children <12 yrs of age are more likely to have a Salter-Harris type I or II injury rather than a true mallet finger injury.
  • In the pediatric age group, nondisplaced mallet finger injury may be treated with continuous splinting of the DIP joint in extension or slight hyperextension for 4–6 wks, with 2 additional weeks of nighttime splinting. Extension splints should be worn for sports activities for an additional 4 wks.
  • Reduction is necessary for displaced fractures.
  • If closed reduction is unsuccessful, then referral for surgical repair is indicated.


Continue Reading
You might also like More from author

This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish. Accept Read More