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
Hold the middle phalanx so the PIP joint stays straight and ask the patient to straighten the fingertip.
Positive Finding
The fingertip droops and cannot be actively straightened, although it can usually be straightened passively.
Interpretation
The key sign of a mallet injury: disruption of the terminal extensor tendon at the base of the distal phalanx, with or without a bony fragment. Arrange an X-ray to check for a fracture or joint subluxation, and splint the DIP joint in extension without delay.
Passive DIP Extension (Correctability) Check
Procedure
Gently extend the DIP joint passively to neutral. Do not force it into hyperextension.
Positive Finding
The DIP joint cannot be passively straightened to neutral.
Interpretation
In an acute mallet injury the DIP should straighten passively. A joint that will not straighten suggests a chronic injury, joint subluxation or a fracture, and needs an X-ray and hand surgery advice.
Tenodesis Test
Procedure
Let the hand relax, then passively flex the patient's wrist and watch all the fingers.
Positive Finding
In the injured finger, the fingertip does not straighten with the others as the wrist flexes.
Interpretation
Supports loss of continuity of the terminal extensor tendon. Useful when pain limits active testing.
Radiographic Assessment (DIP Joint Alignment & Fracture)
Procedure
A true lateral X-ray of the affected finger, plus a PA view.
Positive Finding
A fragment from the dorsal base of the distal phalanx and/or palmar subluxation of the distal phalanx (bony mallet), or a flexed DIP with no fracture (tendinous mallet).
Interpretation
Separates tendinous from bony mallet injuries and shows joint subluxation, which changes management. Large fragments or any subluxation need a hand surgery opinion.
⚠ 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
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
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
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
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
Lymphatic drainage pathways of forearm and hand
Technique
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.
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