Mallet Finger

Mallet finger (also called "drop finger" or "baseball finger") is a disruption of the terminal extensor tendon at the distal interphalangeal (DIP) joint, resulting in an inability to actively extend the distal phalanx. It may involve a pure tendon rupture or a bony avulsion fracture at the dorsal base of the distal phalanx. [1-3]

The following figure demonstrates the characteristic clinical presentation:

• Mechanism: Forced flexion of an extended DIP joint — classically a ball striking the fingertip, but the majority occur during non-sports activities (bed-making, pulling on socks, tucking in sheets) [5]
• Ask about the specific activity, hand dominance, and which finger is involved (middle, ring, and little fingers most common; index and thumb rare) [5]
• Timing of injury — acute vs. delayed presentation; notably, delayed presentation still responds well to splinting [2]
• Severity of initial trauma — significant force in younger males vs. trivial force in older females [5]
• Ability to straighten the fingertip since injury
• Occupation and hand-use requirements (impacts splint compliance and treatment planning) [6]
• Prior finger injuries or surgeries

• Open wound over the DIP joint (open mallet — requires surgical referral) [2-3]
• Inability to passively extend the DIP joint (suggests interposed tissue or significant injury) [1]
• Volar subluxation of the distal phalanx on lateral radiograph [2][7]
• Fracture fragment involving >30% of the articular surface [1]
• Neurovascular compromise — loss of distal sensation or perfusion [1]
• Signs of infection (open injury with erythema, warmth, purulence)

• Acute pain management: NSAIDs (ibuprofen 400–600 mg PO q6–8h or naproxen 250–500 mg PO q12h) are first-line; acetaminophen as adjunct
• Ice and elevation for initial swelling
• No specific medications are contraindicated
• Caution with anticoagulants if surgical intervention is being considered
• No role for antibiotics in closed injuries; consider prophylactic antibiotics for open mallet injuries

• No specific dietary modifications required
• Adequate protein and calcium intake supports tendon and bone healing
• Smoking cessation counseling — smoking impairs tendon healing

• MSK: Other finger/hand injuries, joint stiffness, prior tendon injuries
• Neuro: Numbness or tingling distal to injury (assess digital nerve integrity)
• Vascular: Color changes, capillary refill of the affected fingertip
• Rheumatologic: History of inflammatory arthritis (may predispose to tendon weakening)
• Dermatologic: Skin integrity over the DIP joint (open vs. closed injury)

• Witness account of mechanism if unclear
• Occupational demands — manual labor, musicians, athletes (impacts compliance and urgency)
• Family history is generally not contributory
• Social context: ability to comply with 6–8 weeks of continuous splinting, hand dominance, ADL impact

• Sports participation — ball-handling sports (basketball, baseball, volleyball, cricket) [5]
• Occupational: Manual labor, housework
• Demographics: More common in males overall; older females sustain injuries from more trivial mechanisms [5]
• Dominant hand affected in approximately two-thirds of cases [5]
• Middle, ring, and little fingers most commonly affected [5][8]
• Rheumatoid arthritis or other connective tissue disorders (tendon weakening)

• Jersey finger (FDP avulsion) — inability to flex the DIP joint (opposite mechanism: forced extension of a flexed finger); most common in ring finger; requires urgent surgical referral [1]
• DIP joint dislocation — obvious deformity, typically reducible
• Distal phalanx fracture (non-avulsion) — crush mechanism, may have subungual hematoma; DIP extension preserved [1]
• Boutonnière deformity — central slip injury at PIP joint (flexion at PIP, hyperextension at DIP — opposite pattern)
• Trigger finger — intermittent locking/catching, not trauma-related
• DIP joint osteoarthritis — chronic stiffness, Heberden's nodes, no acute traumatic onset
• Pseudo-mallet — extensor tendon laceration proximal to DIP (open wound present)

• Prior mallet finger or other tendon injuries
• Rheumatoid arthritis, psoriatic arthritis, or connective tissue disorders
• Diabetes (impaired healing)
• Previous hand/finger surgeries
• Chronic steroid use (tendon weakening)

• Pathognomonic finding: DIP joint resting in flexion (droop) with inability to actively extend [1][3]
• Assess active and passive ROM at the DIP joint — passive extension should be possible in uncomplicated cases
• Swelling, ecchymosis, and tenderness over the dorsal DIP joint
• Evaluate for swan-neck deformity (PIP hyperextension with DIP flexion) — indicates chronic or severe injury [2]
• Test FDP function (ability to flex DIP with PIP held in extension) to rule out jersey finger
• Assess skin integrity — open vs. closed injury
• Neurovascular exam: capillary refill, two-point discrimination of the fingertip
• Evaluate for malrotation by having the patient make a fist (all fingers should point toward the scaphoid)

• No routine labs required for uncomplicated mallet finger
• If open injury with concern for infection: CBC, CRP/ESR
• Pre-operative labs only if surgical intervention is planned

• First-line: AP, lateral, and oblique radiographs of the affected finger [1][9]
• Key findings to assess on X-ray:
  • Presence/absence of bony avulsion fragment
  • Size of fragment relative to articular surface (>30% = referral) [1]
  • Joint congruency and subluxation [2]
• Ultrasound: High-frequency ultrasound can identify tendon rupture vs. contusion vs. bony avulsion and may be useful as a point-of-care adjunct [10]
• MRI: Rarely needed; may be considered if diagnosis is uncertain or to evaluate soft-tissue mallet without bony involvement [10]
• Imaging is unnecessary to repeat unless there is concern for displacement during treatment or failure to improve

• Doyle Classification: [3][7]
  • Type I: Closed injury, with or without small avulsion fracture
  • Type II: Open injury (laceration)
  • Type III: Open injury with loss of skin and tendon substance
  • Type IV: (A) Epiphyseal plate fracture in children; (B) Fracture involving 20–50% of articular surface; (C) Fracture >50% with volar subluxation
• Crawford Criteria — used to assess treatment outcomes: [6][8]
  • Excellent: Full extension, full flexion, no pain
  • Good: 0–10° extension lag, full flexion, no pain
  • Fair: 10–25° extension lag, any loss of flexion, no pain
  • Poor: >25° extension lag or persistent pain
• Elson test — to rule out central slip injury (boutonnière) if PIP involvement is suspected

Mallet finger is a clinical diagnosis confirmed by the inability to actively extend the DIP joint following trauma, with radiographs used to classify the injury and guide management. [2] Two subtypes exist:

• Tendinous mallet (soft-tissue only): Pure extensor tendon rupture; tends to have worse initial extensor lag (median ~28°) and slightly inferior outcomes with conservative treatment [8]
• Bony mallet (avulsion fracture): Tends to present in younger patients with less initial lag (median ~15°) and better outcomes with splinting [8]

Complications of untreated or poorly managed mallet finger include chronic extension lag and swan-neck deformity (compensatory PIP hyperextension). [2-3]

Conservative (standard of care for most cases)

• Continuous DIP splinting in full extension to slight hyperextension for 6–8 weeks, followed by 2–4 weeks of nighttime splinting [1-3]
• Splint options: dorsally padded aluminum splint, volar splint, thermoplastic stack splint, or prefabricated 3-point orthosis — all show comparable outcomes [5][11]
• Critical patient education: The DIP joint must never flex during the splinting period; if the splint is removed (e.g., for skin care), the finger must be held in extension on a flat surface. Any episode of flexion resets the clock [1]
• Follow-up every 2 weeks to assess skin integrity and splint fit [1]
• Splinting is effective even with delayed presentation (weeks to months after injury) [2][12]

Surgical indications: [2-3][7]

• Avulsion fracture involving >30% of the articular surface
• Volar subluxation of the distal phalanx
• Open mallet injury
• Failed conservative management (persistent significant extension lag after adequate splinting trial)
• Patient unable to comply with splinting (K-wire fixation is an alternative) [6]

Surgical options: K-wire fixation of DIP in extension, open reduction and internal fixation (ORIF) for large bony fragments, or extension block pinning. [3][6-7]

• Discharge with splint application and follow-up for the vast majority of cases
• Orthopedic/hand surgery referral indications:
  • 30% articular surface involvement [1]
  • Volar subluxation on lateral radiograph [2]
  • Open injury [2]
  • Inability to passively extend the DIP joint [1]
  • Failed conservative treatment
  • Pediatric epiphyseal fractures [3]
• No indication for admission for isolated mallet finger

• Follow-up: Every 2 weeks during splinting to check skin (maceration, pressure sores) and splint integrity [1]
• Repeat radiograph at 2–4 weeks if bony mallet to assess alignment
• After splint removal at 6–8 weeks, begin gentle active ROM; continue nighttime splinting for an additional 2–4 weeks [3]
• Total recovery: 6–10 weeks; some residual extension lag (<10°) is common and generally well-tolerated [1][8]
• Return precautions — advise patients to return immediately for:
  • Skin breakdown, blistering, or maceration under the splint
  • Increasing pain, swelling, or redness (concern for infection)
  • Worsening droop or loss of extension after splint removal
  • Numbness or color change in the fingertip
• Counsel that premature removal or flexion of the DIP joint during treatment can prolong recovery or lead to treatment failure [1]
• If untreated, chronic mallet finger can lead to swan-neck deformity, which may require surgical correction [2]

1. Common Finger Fractures and Dislocations. — Childress MA, Olivas J, Crutchfield A. American Family Physician. 2022.

2. Approach to Mallet Finger Injury: Practical Guide for Canadian Primary Care Physicians. — Dinh V, Market M, Cheung K. Canadian Family Physician Medecin De Famille Canadien. 2026.

3. Mallet Finger. — Bendre AA, Hartigan BJ, Kalainov DM. The Journal of the American Academy of Orthopaedic Surgeons. 2005.

4. Fingertip Injuries. — Hilgefort J, Becker J, Chu J. American Family Physician. 2025.

5. Interventions for Treating Mallet Finger Injuries. — Handoll HH, Vaghela MV. The Cochrane Database of Systematic Reviews. 2004.

6. A Single K-Wire to Prevent Poor Outcomes in Closed Soft-Tissue Mallet Finger Management Due to Patient Non-Compliance. — Aksan T, Öztürk MB, Özçelik B. Archives of Orthopaedic and Trauma Surgery. 2021.

7. Current Concepts in the Evaluation and Treatment of Mallet Finger Injury. — Bloom JMP, Khouri JS, Hammert WC. Plastic and Reconstructive Surgery. 2013.

8. Outcome Differences Between Conservatively Treated Acute Bony and Tendinous Mallet Fingers. — Rubin G, Ammuri A, Mano UD, et al. Journal of Clinical Medicine. 2023.

9. ACR Appropriateness Criteria Acute Hand and Wrist Trauma. — Expert Panel on Musculoskeletal Imaging:, Torabi M, Lenchik L, et al.' Journal of the American College of Radiology : JACR. 2019.

10. The Role of High Frequency Ultrasonography in Diagnosis of Acute Closed Mallet Finger Injury. — Wang T, Qi H, Teng J, Wang Z, Zhao B. Scientific Reports. 2017.

11. Prospective Randomized Clinical Trial Comparing 3-Point Prefabricated Orthosis and Elastic Tape Versus Cast Immobilization for the Nonsurgical Management of Mallet Finger. — Algar L, Backe H, Richer R, et al. The Journal of Hand Surgery. 2023.

12. Treatment Options for Mallet Finger: A Review. — Smit JM, Beets MR, Zeebregts CJ, Rood A, Welters CFM. Plastic and Reconstructive Surgery. 2010.