01Approach to the Critical Patient/attcp36

Urgent assessment triggers

›Red flags requiring urgent orthopedic referral

›Open mallet injury (skin violation over DIP joint)

›Irrigation, wound care, and referral same day

›Antibiotic prophylaxis indicated

›Volar subluxation of distal phalanx on lateral radiograph

›Indicates significant joint instability

›Surgical stabilization required

›Avulsion fracture involving >30% of articular surface

›Risk of joint subluxation without fixation

›Orthopedic hand surgery referral

›Inability to passively extend the DIP joint

›Suggests interposed tissue or complex injury

›Urgent hand surgery evaluation

›Neurovascular compromise

›Digital nerve or artery injury

›Emergent hand surgery referral

Immediate stabilization

›Initial management priorities

›DIP joint in extension to prevent further tendon retraction

›Dorsal aluminum splint or stack splint as temporizing measure

›Avoid DIP flexion at all times

›Pain control

›Ice and elevation acutely

›NSAIDs or acetaminophen as first-line

›Radiograph before splint application

›AP and lateral views of affected finger

›Lateral view is critical for fracture classification

02History/hx46

Mechanism and presentation

›Mechanism of injury

›Forced flexion of an extended DIP joint

›Ball striking the fingertip (basketball, baseball, volleyball, cricket)

›Trivial mechanism in older females (bed-making, pulling on socks)

›Timing of injury

›Acute vs. delayed presentation

›Delayed presentation still responds well to splinting

›Activity at time of injury

›Sports participation

›Occupational or domestic activity

›Symptom profile

›Inability to actively extend the fingertip

›Onset immediately after injury

›Persistent droop despite attempts to straighten

›Pain and swelling over dorsal DIP joint

›Tenderness at dorsal base of distal phalanx

›Ecchymosis common

›Prior ability to straighten finger

›Pre-injury baseline clarification

Risk factors and context

›Patient demographics

›Sex and age pattern

›More common in males overall

›Older females sustain injury from trivial mechanisms

›Dominant hand affected in approximately two-thirds of cases

›Middle, ring, and little fingers most commonly affected

›Index finger and thumb are rare

03Physical Exam/exam47

DIP joint assessment

›Classic findings

›DIP joint resting flexion deformity (finger droop)

›Pathognomonic for mallet finger

›Magnitude of droop does not always predict injury severity

›Inability to actively extend the distal phalanx

›With PIP joint held in neutral

›Distinguishes mallet from other injuries

›Passive DIP extension preserved in uncomplicated cases

›If passive extension absent, suspect interposed tissue or complex fracture

Soft tissue and neurovascular exam

›Local findings

›Swelling and ecchymosis over dorsal DIP joint

›Tenderness at dorsal base of distal phalanx

›Open wound assessment

›Skin integrity assessment

›Open vs. closed injury determination

›Maceration or skin breakdown at DIP dorsum

›Neurovascular status

›Capillary refill of the affected fingertip

›Normal <2 seconds

›Impairment suggests vascular compromise

›Two-point discrimination of fingertip

›Normal <5 mm

›Digital nerve injury if abnormal

Functional testing

›Adjacent joint and tendon assessment

›FDP function testing

04Differential Diagnosis/ddx36

Tendon injuries

›Jersey finger (FDP avulsion)

›ICD-10: S66.1 — Injury of flexor muscle, fascia and tendon at wrist and hand level

›Inability to flex DIP joint (opposite of mallet)

›Forced extension of a flexed DIP

›Most common in ring finger

›Requires urgent surgical referral within 7 to 10 days

›Boutonniere deformity

›ICD-10: S63.6 — Dislocation of finger

›Central slip rupture at PIP joint

›PIP flexion with DIP hyperextension (opposite pattern)

›Elson test positive

›Splint PIP in extension not DIP

Bony injuries

›Distal phalanx fracture (non-avulsion)

›ICD-10: S62.5 — Fracture of distal phalanx of finger

›Crush mechanism with subungual hematoma

›DIP extension preserved (extensor tendon intact)

›Management directed at fracture not tendon

›DIP joint dislocation

›ICD-10: S63.1 — Dislocation of finger

›Obvious deformity, typically dorsal

›Reducible with appropriate analgesia

›Assess post-reduction stability and extensor function

Mimics

›Trigger finger

›ICD-10: M65.3 — Trigger finger

›Intermittent locking or catching at A1 pulley

05Laboratory Tests/lt21

Routine labs

›No labs required for uncomplicated closed mallet finger

›Mallet finger is a clinical and radiographic diagnosis

›History and physical sufficient for Type I injuries

›No hematologic or metabolic workup indicated

›CBC and inflammatory markers only if infection suspected

›Open injury with erythema, warmth, or purulence

›CRP and ESR may support early septic arthritis diagnosis

Pre-operative labs

›If surgical intervention planned

›Standard pre-operative panel per institutional protocol

›CBC, BMP, coagulation studies

›Type and screen if significant hemorrhage anticipated

›Anticoagulation review

›Warfarin, DOAC, or antiplatelet use

›Discuss with surgical team prior to reversal

Infection workup (open injuries)

›Open mallet injury assessment

›Wound culture if purulence present

›Gram-positive cocci (Staph aureus) most common

›MRSA risk stratification

›Blood cultures if systemic signs of infection

›Fever, rigors, leukocytosis

›Septic arthritis of DIP joint can complicate open mallet

06Diagnostic Tests/dt82

Scoring Systems

›Doyle Classification for mallet finger severity

›Type I: Closed injury with or without small avulsion fracture

›Standard conservative splinting

›Most common presentation

›Type II: Open injury (laceration) without significant tissue loss

›Wound care and orthopedic referral

›Antibiotic prophylaxis

›Type III: Open injury with loss of skin and tendon substance

›Surgical reconstruction required

›Urgent hand surgery referral

›Type IV subtypes

›Type IVA: Epiphyseal plate fracture in skeletally immature patients

›Type IVB: Fracture involving 20 to 50% of articular surface

›Type IVC: Fracture >50% with volar subluxation of distal phalanx

›Crawford Outcome Criteria for treatment success assessment

›Excellent: Full extension, full flexion, no pain

›Target outcome for all patients

›Achieved in majority with compliant splinting

›Good: 0 to 10 degree extension lag, full flexion, no pain

›Clinically acceptable outcome

›Residual lag <10 degrees generally well-tolerated

›Fair: 10 to 25 degree extension lag or any loss of flexion, no pain

›Consider extended splinting or referral

›Poor: >25 degree extension lag or persistent pain

›Referral for surgical evaluation

MRI

›MRI of finger (rarely indicated for mallet finger)

›Indications

›Diagnosis uncertain after clinical and radiographic assessment

›Soft-tissue mallet without bony involvement and unclear tendon status

›Suspected concurrent ligamentous or volar plate injury

›Findings

›Extensor tendon discontinuity or gap at DIP level

›Tendon thickening, edema, or partial tear

›Marrow edema at dorsal base of distal phalanx without fracture line

›Limitations

›Not required for clinical diagnosis

›Cost and availability limit routine use

›Rarely changes management in straightforward cases

CT

›CT of finger (limited role in mallet finger)

›Indications

›Complex intra-articular fracture with plain film ambiguity

›Pre-operative planning for large articular fragments

›Assessment of fragment size and displacement when radiographs inconclusive

›Findings

›Precise articular surface involvement percentage

›Fragment comminution and displacement

›Joint alignment and subluxation detail

›ACR appropriateness

›Radiographs are usually appropriate first-line imaging for acute hand trauma

›CT usually appropriate when complex fracture management is needed

Ultrasound

›High-frequency musculoskeletal ultrasound

›Indications

›Point-of-care adjunct when radiograph is non-diagnostic

›Differentiate tendon rupture from tendon contusion

›Identify bony avulsion when radiograph equivocal

›Technique

›High-frequency linear probe (>12 MHz) over dorsal DIP joint

›Dynamic assessment in longitudinal and transverse planes

›Compare with contralateral finger

›Findings

›Extensor tendon discontinuity at insertion on distal phalanx

›Bony cortical defect at dorsal base of distal phalanx

›Hematoma or fluid collection at tendon insertion

›Performance

›High-frequency ultrasound demonstrates good accuracy for tendon and bony mallet

›Operator-dependent; less standardized than radiograph

Plain Radiograph

›Finger radiographs (primary imaging modality)

›Views required

›AP, lateral, and oblique views of affected finger

›Lateral view is most critical for mallet assessment

›Key lateral radiograph findings

›Avulsion fragment presence and size

›Articular surface involvement percentage

›Volar subluxation of distal phalanx

›Joint congruency

›ACR appropriateness

›Radiographs are usually appropriate for acute hand and wrist trauma

›Obtain before splint application to classify injury

›Indications for repeat radiograph

›Bony mallet: repeat at 2 to 4 weeks to confirm alignment

›Clinical concern for displacement during treatment

›Failure to improve after adequate splinting trial

07Disposition/dispo28

Discharge criteria

›Discharge with splint and follow-up (majority of cases)

›Closed mallet finger without subluxation or large fracture fragment

›Doyle Type I appropriate for ED discharge

›Splint applied in ED before departure

›Patient education completed

›Never remove splint or flex DIP for 6 to 8 weeks

›Any episode of DIP flexion resets the treatment clock

›Follow-up arranged

›Every 2 weeks with hand therapist or orthopedics

›Skin integrity and splint fit check at each visit

Orthopedic referral indications

›Same-day or urgent hand surgery referral

›Avulsion fracture involving >30% of articular surface

›Risk of DIP joint subluxation without operative fixation

›Orthopedic evaluation within 24 to 48 hours

›Volar subluxation of distal phalanx on lateral radiograph

›Surgical stabilization required

›Do not discharge without specialist contact

›Open mallet injury (Doyle Type II, III)

›Wound care, antibiotics, and same-day referral

›Inability to passively extend DIP joint

›Suggests interposed tissue or complex injury

›Pediatric epiphyseal fracture (Doyle Type IVA)

›Growth plate involvement requires pediatric orthopedic input

Admission criteria

›Admission is rarely required for isolated mallet finger

›Consider admission only with

08Treatment/t71

Conservative splinting (standard of care)

›DIP extension splinting protocol

›Splint position

›DIP joint in full extension to 5 to 10 degrees of hyperextension

›PIP joint left free to prevent stiffness

›Continuous wear — no removal for any reason for 6 to 8 weeks

›Splint duration

›6 to 8 weeks of continuous DIP extension splinting

›Followed by 2 to 4 weeks of nighttime-only splinting

›Total treatment 8 to 12 weeks

›Compliance education

›Any DIP flexion during splinting period resets the 6 to 8 week clock

›If splint must be removed for skin care, hold finger in extension on flat surface

›Do not allow finger to droop at any time

›Splint options (comparable outcomes across types)

›Stack splint (prefabricated 3-point orthosis)

›Convenient for compliance

›Multiple sizes available

›Dorsally padded aluminum splint

›Customizable to patient finger size

›Monitor for skin pressure under splint

›Volar splint

›Alternative when dorsal access preferred

›Equivalent outcomes per Cochrane review

›Thermoplastic custom splint

›Ideal fit for complex anatomy

›Fabricated by hand therapist

Pain management

›Analgesia protocol

›NSAIDs first-line for acute pain

›Ibuprofen 400 to 600 mg PO every 6 to 8 hours with food

›Maximum 2400 mg/day over-the-counter; 3200 mg/day prescription

›Naproxen 250 to 500 mg PO every 12 hours as alternative

›Acetaminophen as adjunct or when NSAIDs contraindicated

›500 to 1000 mg PO every 6 to 8 hours

›Maximum 4000 mg/day (3000 mg/day in elderly or liver disease)

›Ice and elevation acutely

›Ice 20 minutes on, 20 minutes off for first 48 to 72 hours

›Elevate hand above heart level to reduce swelling

Surgical treatment

›Surgical indications

›Avulsion fracture >30% articular surface

›Extension block pinning or ORIF

›Performed by hand surgery specialist

›Volar subluxation of distal phalanx

›K-wire fixation of DIP in extension

›Restores joint congruency

›Open mallet (Doyle Type II, III)

›Wound debridement and repair

›Possible tendon repair or reconstruction

›Failed conservative management

›Persistent significant extension lag after 8 weeks of compliant splinting

›Patient unable to comply with splinting (K-wire fixation as alternative)

›Surgical options

›K-wire fixation of DIP joint in extension

›Maintains extension without patient compliance requirement

›Wire removed at 6 to 8 weeks

›Extension block pinning

›For large articular fragments

›Maintains reduction without ORIF

›Open reduction and internal fixation (ORIF)

›For large, displaced articular fragments

›Mini-screw or K-wire construct

Wound care (open injuries)

›Open mallet management

›Irrigation and wound debridement

›Normal saline irrigation of open wound

›Remove devitalized tissue

›Antibiotic prophylaxis

›Cephalexin 500 mg PO four times daily for 5 to 7 days (first-line)

›Amoxicillin-clavulanate 875 mg/125 mg PO twice daily if contaminated wound

›Clindamycin 300 to 450 mg PO four times daily if penicillin-allergic

›Tetanus prophylaxis

›Update tetanus if >5 years since last booster for contaminated wounds

›Tetanus immune globulin if unimmunized and contaminated wound

09Special Populations/sp48

Pregnancy

›Mallet finger in pregnancy

›Mechanism and prevalence

›Mechanism is the same as in non-pregnant patients

›No specific increase in incidence during pregnancy

›Falls and domestic activities are the most common mechanism

›Diagnostic considerations

›Radiograph of a single finger with appropriate shielding is safe

›Radiation exposure is negligible with finger radiograph

›MRI safe alternative if radiograph declined; not routinely needed

›Treatment modifications

›DIP extension splinting is the treatment of choice — no modification required

›NSAIDs: avoid in the third trimester (premature closure of ductus arteriosus)

›Acetaminophen preferred analgesic throughout pregnancy

›Surgery rarely required; if needed, first trimester elective surgery avoidance preferred

Geriatric

›Mallet finger in older adults

›Injury pattern

›Trivial mechanism common — minimal force sufficient due to tendon degeneration

›Older females most susceptible to low-energy mallet injury

›May present late due to minimized symptoms

›Skin and splint tolerance

›Increased risk of skin maceration, pressure necrosis under splint

›More frequent splint checks recommended — every 1 to 2 weeks

›Use well-padded custom splint to minimize skin complications

›Medication considerations

›NSAIDs with caution in renal impairment, gastropathy, or anticoagulation use

›Acetaminophen preferred first-line in elderly

10Background/b73

Epidemiology

›Incidence and demographics

›One of the most common closed tendon injuries of the hand

›Exact incidence varies by population and activity level

›More common in sports participants and manual workers

›Sex and age distribution

›Males more commonly affected overall

›Females affected by trivial mechanisms with increasing age

›Peak incidence in active sports-participating age groups

›Finger distribution

›Middle, ring, and little fingers most commonly affected

›Index finger and thumb rare

›Dominant hand affected in approximately two-thirds of cases

›Activity context

›Non-sports activities account for majority of cases

›Bed-making, pulling on socks, tucking in sheets

›Ball sports historically emphasized but minority of total cases

›Ball sports most commonly cited sporting mechanism

›Basketball, baseball, volleyball, cricket

›Ball striking an extended fingertip

Pathophysiology

›Anatomy and injury mechanism

›Terminal extensor tendon anatomy

›Inserts onto dorsal base of distal phalanx

›Thin and vulnerable to forced flexion loads

›No muscular belly distal to DIP; relies on tendon integrity

›Injury mechanism

›Forced flexion of actively extended DIP joint

›Avulses tendon from insertion or produces bony avulsion fragment

›Results in unopposed FDP flexion of distal phalanx

›Injury subtypes and natural history

›Tendinous mallet (soft-tissue only)

›Pure extensor tendon rupture without osseous avulsion

›Median initial extension lag approximately 28 degrees

›Slightly inferior outcomes with conservative treatment compared to bony type

›Bony mallet (avulsion fracture)

›Avulsion fracture at dorsal base of distal phalanx

›Tends to present in younger patients

›Median initial extension lag approximately 15 degrees

›Better outcomes with splinting than tendinous type

›Complications

›Swan-neck deformity

›Chronic mallet leads to compensatory PIP hyperextension

›Volar plate laxity at PIP joint

›May require surgical correction if symptomatic

›Persistent extension lag

›Most common complication of undertreated or noncompliant cases

›Residual lag <10 degrees generally asymptomatic and accepted

›Lag >25 degrees functionally significant

Therapeutic Considerations

›Evidence for conservative management

›Cochrane review on splinting (Handoll and Vaghela 2004)

›Insufficient evidence to determine optimal splint type

›All common splint types show comparable outcomes

›Continuous immobilization for 6 to 8 weeks well-supported

›Splint type equivalence

›Stack splint, aluminum, volar, and 3-point orthosis show similar results

›RCT (Algar et al. 2023) found 3-point prefabricated orthosis comparable to cast

›Splint selection guided by patient anatomy and compliance likelihood

›Surgical vs. conservative outcomes

›No clear superiority of surgery over splinting for most mallet injuries

›Complications of surgery (pin-track infection, nail deformity, wound problems)

›Conservative management preferred for Type I injuries

›Surgery reserved for specific structural indications

›Fragment >30% articular surface, volar subluxation, open injuries

›K-wire fixation option for noncompliant patients (Aksan et al. 2021)

›Delayed presentation

›Splinting effective even with delayed presentation weeks to months after injury

›Still reasonable first-line treatment if no chronic fixed deformity

›Discuss realistic outcomes with patient — extension lag may persist

›ICD-10 coding

›S66.300A — Unspecified injury of extensor muscle, fascia and tendon at wrist and hand level, initial encounter

›Used for tendinous mallet finger

›S62.500A — Fracture of unspecified phalanx of finger, initial encounter

›Used for bony mallet finger

›SNOMED CT: 302284003 — Mallet finger

11Patient Discharge Instructions/pdi34

copy discharge instructions

›Diagnosis and injury explanation

›You have a mallet finger — a tear or avulsion of the tendon that straightens the tip of your finger

›This causes the fingertip to droop and prevents you from straightening it on your own

›The treatment is a splint that holds the tip of your finger straight so the tendon can heal

›Splint instructions

›Wear the splint on the tip of your finger 24 hours a day, 7 days a week

›Do NOT remove it — not for bathing, sleeping, or any other reason

›The total time for splinting is 6 to 8 weeks

›If the splint must come off to clean the skin, hold your finger straight on a flat surface while doing so

›Never let the tip bend — even one bend resets your healing clock back to zero

›Replace the splint immediately and resume constant wear

›After 6 to 8 weeks of continuous wear, your provider will start you on nighttime-only splinting for 2 to 4 more weeks

›Activity and pain management

›Keep your hand elevated above heart level as much as possible for the first few days

›This reduces swelling and pain

›Ice the finger for 20 minutes on, 20 minutes off for the first 2 to 3 days

›Take ibuprofen 400 to 600 mg every 6 to 8 hours with food or acetaminophen 500 to 1000 mg every 6 to 8 hours for pain

›Do not exceed the maximum daily dose on the package

›Follow-up instructions

›Return to your doctor or hand clinic every 2 weeks for splint and skin checks

›The skin under the splint can break down — early detection prevents complications

›A repeat X-ray may be ordered at 2 to 4 weeks if you had a fracture with your injury

›After the splint comes off, begin gentle active range of motion exercises as directed by your provider

›Return to Emergency Department immediately if

›The skin under the splint becomes red, blistered, or breaks open

›Skin breakdown is a common complication that needs prompt treatment

›Your finger becomes increasingly painful, red, warm, or swollen

12References/r36

Guidelines and key sources

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

›Primary evidence source for classification, treatment, and disposition

›PMID 35704814

›Dinh V, Market M, Cheung K. Approach to Mallet Finger Injury: Practical Guide for Canadian Primary Care Physicians. Canadian Family Physician. 2026

›Mechanism epidemiology; activity-related incidence data

›PMID 41679948

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

›Doyle classification and surgical indications

›PMID 16148359

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

›Systematic review of splint types — evidence for equivalence of splint designs

›Cochrane Library DOI 10.1002/14651858.CD004574.pub2

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

›Outcome data; tendinous vs bony mallet comparison

›PMID 40736493

Imaging and procedural references

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

›Radiograph as primary imaging; CT indications for complex fractures

›DOI 10.1016/j.jacr.2019.02.029

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

›Ultrasound performance data for tendon and bony mallet identification

›PMID 28887523

›Algar L, Backe H, Richer R, et al. Prospective Randomized Clinical Trial Comparing 3-Point Prefabricated Orthosis and Elastic Tape Versus Cast Immobilization. Journal of Hand Surgery. 2023

›RCT supporting equivalence of prefabricated orthosis to cast immobilization

›PMID 35466009

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

›Comparative outcomes data for bony vs tendinous subtypes

Evidence & Review

Evidence & Review