Overview
Mallet Finger is a common hand injury where the tip of a finger droops and cannot be actively straightened. It occurs when the terminal extensor tendon (which helps extend the fingertip) is damaged or torn. This guide reviews causes, symptoms, diagnosis, treatment options, and key considerations.
Causes and Mechanism of Injury
Mallet finger usually results from a sudden force applied to the tip of an extended finger, which forces it into a bent position. This can cause the tendon to tear or even pull off a piece of bone (an avulsion fracture).
Common scenarios include:
- Sports like baseball, basketball, or volleyball
- Household tasks (e.g., making a bed, scrubbing)
- Workplace or industrial injuries
Symptoms
Typical signs of a mallet finger injury include:
- Pain and swelling at the end of the finger
- Bruising or tenderness on the back (dorsal side) of the fingertip
- Inability to straighten the tip of the finger without assistance
- A drooping fingertip resting at about a 45° angle
Diagnosis
A physical exam is often enough to suspect a mallet finger, but an X-ray is essential to:
- Confirm whether the injury is a soft tissue rupture or a Mallet Fracture (a piece of bone pulled away)
- Check for joint misalignment (subluxation)
Treatment
Nonoperative Management
This is the first-line treatment for most mallet finger injuries.
- A special extension splint is worn on the fingertip, keeping the DIP joint (end joint of the finger) fully straight.
- The splint must be worn continuously for 6 to 8 weeks without bending the joint, even briefly.
- After the initial phase, night splinting may continue for 2 to 4 weeks.
Important: If the joint bends accidentally during the healing period, the treatment duration must restart.
Operative Management
Surgery may be needed in specific situations:
Absolute indications:
- Volar subluxation (palmar dislocation) of the distal phalanx
- Open injuries (cuts that expose the tendon or bone)
Relative indications:
- Fractures involving more than 50% of the joint surface
- Gaps between bone fragments >2 mm
Surgical options may include K-wire fixation or open reduction internal fixation (ORIF).
Complications
Even with correct treatment, complications can arise, such as:
- Extensor lag: Permanent inability to fully extend the fingertip
- Swan neck deformity: A bend at the fingertip and backward curve at the middle finger joint
- Skin irritation or breakdown from splint use
- Stiffness or reduced function, especially if rehabilitation is delayed
Special Considerations for Children
In children, mallet injuries may involve the growth plate (a developing area of bone near the joint). Special care is needed to avoid long-term issues with bone development or finger shape.
Key Definitions (Glossary)
- DIP Joint: End joint of the finger, most affected in mallet finger.
- Terminal Extensor Tendon: Tendon that straightens the DIP joint.
- Avulsion Fracture: A piece of bone pulled off by a tendon or ligament.
- K-wire: A thin pin used during surgery to stabilise bone or joints.
- Swan Neck Deformity: Bending at the fingertip and hyperextension of the middle joint.
Quiz: Short Answer Review
- What is Mallet Finger?
An injury to the terminal extensor tendon, preventing active extension of the fingertip. - Common causes?
Sudden force to the fingertip in sports or daily activities (e.g., ball hits, making a bed). - Symptoms?
Drooping fingertip, pain, swelling, and inability to straighten the finger. - Role of X-ray?
To detect fractures and joint alignment issues. - Main treatment?
Splinting the DIP joint in extension for 6–8 weeks. - Why not bend the finger during treatment?
It disrupts healing and resets the recovery timeline. - When is surgery needed?
For joint subluxation, large fractures, or open injuries. - What is a Mallet Fracture?
A tendon injury with a piece of bone pulled away from the fingertip. - Possible complications?
Extensor lag and swan neck deformity. - Why are children treated carefully?
Risk of growth plate damage affecting bone development.
Clinical Summary
- Mallet finger is usually treatable without surgery if diagnosed early.
- Consistent splint use is essential for successful healing.
- Delays or missed treatment can result in permanent deformity or dysfunction.
- Surgery is reserved for complex or unstable injuries.
To book an appointment or speak to a specialist:
Call 020 3384 5588 or email Info@TheArmDoc.co.uk.
Disclaimer
This guide is for educational purposes and should not replace medical advice from a qualified healthcare provider.