Mallet Finger: Symptoms, Types, Causes and Treatment

Mallet finger, also known as “baseball finger” or “drop finger,” is a common hand injury that affects the ability to straighten the tip of a finger. Whether you’re an athlete, a DIY enthusiast, or someone who’s simply had an unlucky accident, understanding mallet finger is crucial for prompt recognition and effective management. In this article, we’ll walk you through the key aspects of mallet finger—its symptoms, the different types, the most common causes, and up-to-date treatment options—synthesizing the latest research to provide a clear, comprehensive guide.

Symptoms of Mallet Finger

Recognizing mallet finger early is vital to preventing long-term dysfunction and deformity. The symptoms are typically quite distinctive, making it easier to identify than some other hand injuries.

Symptom	Description	Severity/Duration	Source(s)
Drooping Tip	Inability to extend fingertip	Persistent	2 4 6 8
Pain	At the site of injury, sometimes mild	Acute or chronic	1 2 5
Swelling	Localized, may develop quickly	Acute (minutes-hours)	2 6 8
Bruising	Discoloration at the distal joint	Varies	2 5 8
Tenderness	On dorsal aspect of DIP joint	On touch/movement	2 8
Cold Sensitivity	Intolerance to cold	Chronic in some cases	1

Table 1: Key Symptoms

Drooping of the Finger Tip

The hallmark symptom of mallet finger is the inability to actively straighten (extend) the tip of the finger at the distal interphalangeal (DIP) joint. This is often described as the fingertip “drooping” or hanging in a flexed position, even when you try to straighten it with your muscles 2 4 6 8. This deformity occurs because the extensor tendon, responsible for lifting the fingertip, is no longer attached or functional.

Pain and Tenderness

Most patients experience pain at the time of injury, which can range from mild to moderate. The pain is usually localized to the back (dorsal side) of the DIP joint and is often accompanied by tenderness when the area is touched or moved 2 5 8.

Swelling and Bruising

Swelling develops rapidly after the injury and is often confined to the injured finger. Bruising may also occur, depending on the severity and nature of the trauma 2 5 8.

Chronic Symptoms

While many patients recover well, some report long-term symptoms such as pain, cold intolerance, or sensitivity at the injury site, even years after the injury 1. However, the degree of deformity or delay in treatment does not always correlate with the persistence of symptoms.

Types of Mallet Finger

Mallet finger is not a one-size-fits-all diagnosis. Understanding the various types is crucial for choosing the right treatment and predicting the likely outcome.

Type	Defining Feature	Typical Cause/Pattern	Source(s)
Soft Tissue	Pure tendon rupture (no fracture)	Sudden/extreme flexion	4 5 6 8
Bony (Avulsion)	Tendon pulls off bone fragment	Forceful impact	4 5 6 8
Laceration	Tendon cut by sharp object	Cuts/lacerations	7 8
Crush Injury	Mixed bone and soft tissue damage	Heavy/blunt trauma	7 8

Table 2: Types of Mallet Finger

Soft Tissue Mallet Finger

This is the classic form, involving a rupture of the extensor tendon where it inserts onto the dorsal base of the distal phalanx. There is no associated fracture. It usually follows a sudden, forceful flexion of the fingertip 4 5 6 8.

Bony Mallet Finger (Avulsion)

Here, the extensor tendon pulls off a small fragment of bone from the base of the distal phalanx. This type is seen when the force of injury is high, and may be complicated by joint subluxation (partial dislocation) 4 5 6 8.

Laceration Mallet

Less common, this occurs when a sharp object cuts through the extensor tendon at or near its insertion, leading to loss of extension 7 8.

Crush Injuries

Crushing trauma can cause a combination of bone and tendon damage, often resulting in more complex injuries and sometimes open wounds 7 8.

Causes of Mallet Finger

While sports injuries are a well-known cause, mallet finger can result from a variety of incidents. Recognizing the mechanism can help in both prevention and diagnosis.

Cause	Mechanism/Trigger	Common Settings	Source(s)
Direct Trauma	Forceful blow to fingertip	Ball sports, falls	4 5 8
Hyperflexion	Sudden flexion of DIP joint	Sports, accidents	5 8
Laceration	Sharp cut over tendon	Kitchen, workplace	7 8
Crush Injury	Heavy object crushes finger	Industrial, home	7 8
Age-related	Lower-energy in elderly	Household tasks	5

Table 3: Common Causes

Direct Trauma

Most mallet finger injuries occur when an extended fingertip is struck by an object—commonly a ball—causing a sudden force that bends the DIP joint beyond its normal range. This action can rupture the tendon or avulse a piece of bone 4 5 8.

Hyperflexion Injury

This mechanism, often seen in sports and accidents, involves a rapid, forced flexion of the fingertip. The extensor tendon is unable to resist the force, leading to rupture or avulsion 5 8.

Lacerations and Crush Injuries

A sharp laceration across the back of the finger, such as with a knife or glass, can sever the extensor tendon. Crush injuries, though less common, can damage both the bone and tendon, often with more serious consequences 7 8.

Population Differences

Younger, active individuals, particularly men, tend to sustain mallet finger through high-energy sports or work-related injuries, while elderly women may experience the injury from lower-energy incidents at home 5. This may influence the pattern and severity of injury.

Treatment of Mallet Finger

Effective treatment is key to restoring hand function and preventing long-term deformity. Management strategies vary depending on the type and severity of the injury, as well as patient factors.

Treatment Option	Indication	Outcome/Effectiveness	Source(s)
Splinting	Most cases (tendon or small bony)	High success, low risk	4 6 10 11 13
Surgery	Large fracture, failed splinting	Comparable to splints, more risk	4 5 6 11 12
Internal Fixation	Unstable/subluxated fracture	Good outcomes, higher risk	5 11 12
Salvage (Arthrodesis)	Chronic, unresponsive cases	Restores stability	11

Table 4: Treatment Options

Splinting: The Mainstay of Therapy

• Overview: Splinting the DIP joint in slight hyperextension (for tendon injuries) or straight (for bony injuries) for 6-8 weeks is the gold standard for most mallet finger injuries 4 6 10 11 13.
• Types of Splints: There are many commercial and custom-made splints available, including Stack, aluminum, and thermoplastic designs. No single type has been proven superior, but the splint must be robust and comfortable for prolonged wear 10 13.
• Adherence: The key to success is strict adherence—removing the splint, even briefly, can disrupt healing. Night splints may be used after initial immobilization if needed 10 13.
• Outcomes: Most patients regain good finger function. Minor extensor lag or mild stiffness may persist but is usually not functionally limiting 3 12 13.

Surgical Management

• Indications: Surgery is generally reserved for:
  • Large bony avulsions involving more than one-third of the joint surface
  • Fractures with joint subluxation that cannot be reduced with splinting
  • Open (laceration) injuries
  • Chronic or recurrent mallet finger unresponsive to conservative therapy 4 5 6 11 12
• Procedures: Options include percutaneous pinning, open reduction and internal fixation, or direct tendon repair 5 11 12.
• Outcomes & Risks: Surgical and nonsurgical outcomes are generally similar, but surgery carries higher risks of infection, joint stiffness, and other complications. Decisions should be individualized 12.

Chronic Mallet Finger and Salvage Procedures

• Persistent Deformity: If pain and dysfunction persist despite standard treatments, procedures such as tenodermodesis, central slip tenotomy, or DIP joint arthrodesis may be considered to restore function and alleviate symptoms 11.

Complications and Prognosis

• Common Complications: Include residual extension lag, joint stiffness, infection (after surgery), and, less commonly, swan-neck deformity if left untreated 4 5 12.
• Long-Term Outlook: Most patients do very well with proper management, returning to full activity. Persistent symptoms such as pain or cold intolerance are uncommon and not always related to the severity of the initial injury or delay in treatment 1 3 12.

Conclusion

Mallet finger is a frequent and distinct injury affecting the fingertip’s ability to straighten. Early recognition and prompt, appropriate management are essential for restoring hand function and preventing long-term deformity.

Key Points:

• Symptoms: Drooping fingertip, pain, swelling, bruising, and tenderness; rarely, chronic cold intolerance.
• Types: Includes soft tissue (tendon rupture), bony (avulsion fracture), laceration, and crush injuries.
• Causes: Most commonly due to direct trauma or forced flexion; can also result from lacerations or crush injuries.
• Treatment: Most cases respond well to splinting; surgery is reserved for severe or complex injuries. Patient adherence is crucial for a good outcome.

By understanding the symptoms, injury types, causes, and evidence-based treatments, patients and providers can work together to ensure optimal recovery from mallet finger injuries.