Mallet Finger
Upper LimbOverview
Mallet finger is a deformity caused by disruption of the extensor digitorum tendon at its insertion on the distal phalanx, resulting in loss of active extension at the distal interphalangeal (DIP) joint. This injury typically results from blunt trauma to the fingertip, such as a ball strike during sports, and presents with a characteristic drooping posture of the distal phalanx. Early appropriate management with prolonged immobilization can achieve excellent functional outcomes without surgical intervention in most cases.
Pathophysiology
The extensor digitorum tendon inserts on the dorsal base of the distal phalanx and is responsible for DIP joint extension. Blunt force trauma causes either rupture of the tendon directly (Type 1) or avulsion of the bone insertion with tendon attachment (Type 2). In some cases, a large bony fragment may be avulsed with the tendon (Type 3). The resultant loss of active extension at the DIP joint leads to characteristic mallet posturing, with the distal phalanx adopting a flexed position. Secondary dorsal skin tightness and PIP hyperextension compensation can develop if not properly managed during the healing phase (typically 6-12 weeks).
Patient Education
Consistent immobilization of your fingertip joint in full extension for 6-12 weeks is critical for healing; even brief periods without immobilization can significantly delay recovery or result in permanent deformity.
Typical Presentation
Site
Distal interphalangeal (DIP) joint of the affected finger; most common in index through ring fingers, particularly the dominant hand
Quality
Sharp or aching pain at the time of injury; subsequently characterized by functional loss rather than pain
Intensity
Acute pain at injury (often mild), followed by variable discomfort dependent on immobilization tolerance and secondary joint stiffness
Aggravating
Attempts to actively extend the DIP joint; removal of immobilization; activities requiring precision grip; trauma to the digit
Relieving
Immobilization of the DIP joint in full extension; rest; ice application in acute phase; pain relief medications
Associated
Loss of active DIP extension with preserved passive range (early stages); visible drooping of fingertip; swelling and bruising over dorsal DIP joint; potential PIP joint hyperextension compensation; secondary stiffness if immobilization is inadequate
Orthopaedic Tests
Mallet Finger Test (Loss of DIP Extension)
Procedure
Patient is asked to actively extend the distal interphalangeal (DIP) joint while the proximal interphalangeal (PIP) joint is held in extension by the examiner. Observe for inability to achieve full DIP extension.
Positive Finding
Inability to actively extend the DIP joint; the fingertip droops into flexion (typically 20–45° lag)
Sensitivity / Specificity
Unknown / Unknown
Interpretation
Hallmark sign of mallet finger injury. Indicates disruption of the extensor digitorum tendon insertion or avulsion fracture at the DIP joint. Presence confirms diagnosis; absence makes mallet finger unlikely.
DIP Joint Hyperextension Test
Procedure
Examiner stabilizes the PIP joint in neutral and gently attempts to passively extend the DIP joint beyond neutral. Assess for hypermobility or abnormal laxity.
Positive Finding
Excessive passive DIP extension (>10–15° past neutral) or visible instability suggests chronic mallet with possible joint cartilage damage or ligamentous involvement
Sensitivity / Specificity
Unknown / Unknown
Interpretation
May indicate chronic mallet finger with secondary OA changes or joint involvement. Helps guide prognosis and treatment decisions (conservative vs. surgical).
Tenodesis Test
Procedure
Passively flex the wrist and observe whether the DIP joint extends passively (tenodesis effect). Then passively extend the wrist and observe for passive DIP flexion.
Positive Finding
Loss of normal tenodesis effect; DIP joint fails to move passively with wrist motion, or movement is diminished compared to contralateral hand
Sensitivity / Specificity
Unknown / Unknown
Interpretation
Confirms loss of extensor tendon continuity or function. Useful in distinguishing mallet finger from other causes of DIP extension loss (e.g. nerve injury, central slip involvement).
Paperclip or Lapicid Test (Functional Assessment)
Procedure
Patient is asked to pick up and hold a paperclip or small object using pinch. Observe ability to flex DIP joint and grip strength.
Positive Finding
Inability to flex DIP joint against gravity or resistance; loss of grip dexterity and fine motor control
Sensitivity / Specificity
Unknown / Unknown
Interpretation
Functional assessment of impact on activities of daily living. Helps determine severity and functional impairment, guiding treatment urgency and rehabilitation goals.
Radiographic Assessment (DIP Joint Alignment & Fracture)
Procedure
Obtain posterior-anterior (PA), lateral, and oblique radiographs of the affected finger. Measure DIP joint angle and assess for avulsion fracture fragments.
Positive Finding
DIP joint in flexion (>10–20°); avulsion fracture of the dorsal base of the distal phalanx; loss of dorsal cortical contour
Sensitivity / Specificity
Unknown / Unknown
Interpretation
Confirms diagnosis and determines fracture type (bony vs. soft tissue mallet). Guides treatment decision: splinting for soft tissue and small fractures; consideration of surgical repair for large fracture fragments (>30% joint surface) or with volar subluxation.
⚠ Red Flags
- •Large bony avulsion (>30% of articular surface) on imaging without specialist review
- •Signs of infection (increasing pain, erythema, purulent drainage after 48 hours)
- •Vascular compromise (pale, cold, mottled fingertip; absent capillary refill)
- •Nerve injury indicated by sensory loss in fingertip distribution
- •Inability to achieve full passive extension at DIP joint (suggests advanced contracture or missed diagnosis)
⚡ Yellow Flags
- •Previous poor compliance with immobilization-based treatment
- •Work or occupational demands incompatible with required immobilization period
- •Anxiety regarding permanent deformity leading to avoidance behaviors
- •Secondary depressive symptoms from functional hand impairment
- •Catastrophizing about injury severity or prognosis
Osteopathic Techniques
Region
Distal phalanx and DIP joint
Technique
Functional
Rationale
Once acute inflammation subsides (typically after 1-2 weeks), gentle functional positioning in slight extension can maintain proprioceptive feedback and prevent excessive stiffness while respecting immobilization requirements; supports patient confidence in movement.
Region
PIP joint and proximal phalanx
Technique
Articulation
Rationale
Gentle PIP joint mobilizations prevent hyperextension compensation and secondary stiffness during the DIP immobilization phase; maintains proximal interphalangeal mobility to optimize overall finger function during healing.
Region
Dorsal forearm extensor compartment
Technique
Soft Tissue
Rationale
Gentle soft tissue techniques to extensor muscles and fascia reduce excessive tension and improve circulation to support healing; addresses secondary muscle guarding that develops from protective immobilization.
Region
Wrist and forearm
Technique
MET
Rationale
Muscle energy techniques to wrist extensors and finger muscles promote contractile unit relaxation and proprioceptive re-education without forcing movement; particularly valuable during transition from immobilization to active mobilization.
Region
Cervical and thoracic spine with upper limb referral
Technique
HVLA
Rationale
Cervical and upper thoracic HVLA normalizes segmental motion and reduces neural sensitization patterns affecting upper limb; improves postural mechanics to prevent secondary compensation during recovery period.
Region
Lymphatic drainage pathways of forearm and hand
Technique
Lymphatic
Rationale
Gentle lymphatic drainage techniques to axillary and epitrochlear nodes reduce swelling and inflammation in the affected digit and surrounding tissues, supporting tissue healing and reducing pain.
Add-On Approaches
Chinese Medicine
Acupuncture to local points (LI-3, LI-5) and distal points (LI-4) may reduce inflammation and pain; moxibustion on dorsal hand and forearm supports qi circulation; herbal formulas containing dan shen and chi shao promote blood circulation and tissue repair.
Chiropractic
Upper cervical manipulation and full spine assessment to optimize neurological function; biomechanical analysis of wrist and finger posture to identify and correct compensation patterns during recovery.
Physiotherapy
Progressive active range of motion exercises commencing at 6-8 weeks post-injury; isolated DIP extension strengthening in gravity-reduced positions; fine motor dexterity and coordination retraining; gradual return-to-activity protocols for sports or occupational demands.
Remedial Massage
Gentle soft tissue massage to forearm extensors, wrist stabilizers, and intrinsic hand muscles to reduce protective muscle guarding; massage to upper arm and shoulder to address referred tension from compensatory posturing.
Rehabilitation Exercises
Passive DIP Joint Extension (Early Phase)
PIP Joint Flexion and Extension Mobilization
Dorsal Hand and Forearm Extensor Stretch (Wrist Flexion with Fingers Extended)
Intrinsic Hand Muscle Stretch (Finger Abduction Against Resistance)
Isolated DIP Extension Against Gravity (Post-Immobilization)
Finger Extensor Strengthening with Resistance Band (Late Phase)
Grip Strengthening Progression (Therapy Putty or Stress Ball)
Fine Motor Dexterity: Coin Manipulation and Transfer
Pinch Grip Coordination (Tripod Pinch with Progressive Resistance)
Wrist and Finger Neutral Posture Awareness (Functional Positioning)
Upper Limb Ergonomic Positioning and Activity Modification
Whole-Body Cardiovascular Conditioning (Non-Impact Modalities)
Referral Criteria
- •Large bony avulsion fragments (>30% of articular surface) requiring surgical consultation
- •Failure to achieve or maintain full passive DIP extension suggesting advanced soft tissue contracture
- •Signs of compartment syndrome or vascular compromise
- •Evidence of infection that does not resolve within 48-72 hours of conservative management
- •Persistent loss of DIP extension after 12 weeks of appropriate immobilization despite compliance
- •Secondary PIP joint hyperextension contracture that limits functional grip and cannot be managed conservatively
- •Significant swelling or stiffness unresponsive to conservative care after 4-6 weeks
- •Occupational or functional demands requiring earlier return to activity that may compromise healing