Introduction 

Fingertip injuries are widespread in sports; mallet finger is among the most common finger injuries. It is also known as ‘baseball finger’ as it often occurs while playing sports related to balls, such as baseball, basketball, cricket, and volleyball.

It has a classical feature of a bent fingertip that cannot be lifted on its own. However, it is often mistaken for other fingertip injuries, such as jersey finger, fingertip fractures, dislocations, or jammed fingers. This mistake can lead to a permanent finger deformity; therefore, it is necessary to take any fingertip injury seriously and get it checked by a professional as soon as possible.

In this article, we will discuss the various causes and risk factors associated with a mallet finger. We will also discuss the clinical presentation of this injury, which will help us better understand the features of a mallet finger and its proper diagnosis and treatment.¹

What is a mallet finger? 

A mallet finger is a fingertip injury commonly occurring in sports, especially baseball or other ball-related sports. It may also occur during everyday activities when the fingertip is forcefully bent or jammed, for example, being hit by a heavy object. Due to a forceful blow to the fingertip, the tendon that straightens the finger gets damaged, and the fingertip droops down and cannot be straightened. There is also difficulty in grasping objects or performing tasks that require a straight finger.^1-3 

Our hand has two types of tendons, extensor and flexor, which run from the arm to the tip of the finger. In a mallet finger, the extensor tendon, which is on the outer side of the hand, is affected. It breaks at the tip of the finger. Specifically, it affects the distal interphalangeal phalanx joint (DIP), which is the last joint of the finger.^1,2

This condition is accompanied by swelling, pain, and the inability to straighten the finger. Treatment usually involves splinting, but surgery may be required in some cases.^1-3

Clinical presentation 

The main characteristic feature of a mallet finger is that the finger droops down, and it is not possible to lift the finger back. This condition is also known as extension lag, where we are not able to lift the finger back on our own. The extensor tendon connects the muscle in the forearm to the distal bone of the finger. It is responsible for the movement of the last joint of the finger. In a mallet finger, it breaks, causing the fingertip to droop and be unable to straighten.^1,2

The pain associated with this condition varies from mild to moderate. Common symptoms include pain in the affected joint, a bent fingertip, and difficulty using the finger. Even with mild pain, a mallet finger may worsen with activities like gripping objects or typing.¹

In a few cases, mallet finger can also be accompanied by a nail injury. It involves a swollen, blue area under the nail bed, which happens due to a harsh blow to the nail. We can see a discoloured nail bed accompanied by tenderness, discolouration, and pain.^1,3,4

With a mallet finger, people usually struggle with:

• Holding objects like a pen or a spoon
• Typing and writing
• Buttoning the shirt
• Grasping any item

A mallet finger is often mistaken for a less serious fingertip injury like a jammed or “banged” finger. Both injuries are accompanied by swelling and pain. The major difference is that in a normal finger injury, there is pain in the movement of the finger, but we can straighten and bend the finger. However, in a mallet finger, we cannot extend the finger even if we try to.^1,2

Mallet finger injury may seem minor, but if left untreated, it can lead to a permanent deformity. Most mallet finger injuries can be managed non-surgically, but occasionally surgery is recommended for either an acute or a chronic mallet finger or for salvage of failed prior treatment.

Causes and risk factors 

Mallet finger is a common injury where the fingertip droops down and cannot be straightened due to a tendon injury. This typically happens when the tip of a finger is struck forcefully, causing the extensor tendon to tear or pull away from the bone. 

This can happen in sports like baseball, basketball, or volleyball, or even during everyday activities such as closing a drawer, tucking in bedsheets, or loading the washing machine. Any force that suddenly pushes the fingertips to bend can cause a mallet finger.^1,5

A few risk factors include:

• Playing sports like baseball, cricket, basketball, and volleyball⁶
• Not using protective gloves while playing sports⁷
• Age-related factors, wear and tear of tendons⁷
• Construction work⁶

Physical examination

If a doctor suspects the fingertip injury to be a mallet finger, they will begin with a physical examination to assess the injury and its severity, followed by diagnostic imaging, typically an X-ray, to confirm the diagnosis and rule out other potential issues like bone fractures.⁵

Inspection

The doctor visually examines the injured finger, noting its position at the DIP joint, the joint at the tip of the finger and compares it with the other hand.¹

Palpation

Next, the doctor will use his hand to check and press the injured area to rule out any suspected fracture. The areas that are palpated are the fingertips and the nails. The area is examined for detecting swelling, bruising, or any nail bed injury.¹

Active extension test

After that, the doctor will ask you to lift your finger and try to extend it. If we are not able to lift it, that means there is some damage to the tendon, which suggests a mallet finger.¹

Passive extension test

Finally, the doctor will perform a passive extension test, where the finger is lifted upwards and left there. If it stays upright, then we can rule out a mallet finger, but if the finger bends down, there is confirmed damage to the tendon.¹

Radiographic examination

While clinical examination often suffices for diagnosing mallet finger, radiographic imaging (X-rays) may be necessary if there's suspicion of an avulsion fracture or other bony injury. X-rays can help determine the extent of the injury and whether it involves a tendon rupture or a fracture, guiding treatment decisions.^1,5

When to see a doctor 

If a fingertip injury occurs, immediate medical evaluation is crucial to rule out fractures or other serious damage. Signs like a bent fingertip that cannot be straightened, persistent pain, swelling, and bruising, especially if they persist after self-treatment, warrant prompt medical attention.^1,2 

Ignoring the injury for a long time and waiting for healing on its own may cause a lifelong deformity in the finger. We must get the finger checked by a medical professional as soon as possible.

FAQs

Can I treat a mallet finger at home?

It is a little challenging to treat a mallet finger at home, as it requires splinting. It needs proper splinting for a few weeks, so it is important to visit a doctor to get early treatment.

Will I need an X-ray?

While physical examination is often sufficient to diagnose mallet finger, an X-ray may be necessary in cases where a fracture is suspected, such as a mallet fracture.

What if I don’t treat it?

If a mallet finger is not treated, it can lead to a permanent deformity. 

Summary 

Mallet finger is a common yet overlooked fingertip injury. It typically occurs during sports activities like baseball, cricket, and basketball. It happens when the fingertip is suddenly and forcefully hit by a heavy object, causing the finger to be in a permanently bent position. It may also occur while carrying out daily activities like tucking in a bed sheet or being hit by the door.

The characteristic feature of a mallet finger is a bent finger with difficulty and pain in extending the finger. There is also difficulty in holding and grasping any object, typing, and writing.

Usually, the physical examinations are enough to diagnose mallet finger, but sometimes a doctor may also advise X-rays to rule out any fractures. Mallet finger is usually mistaken for other injuries, like a jammed finger, due to mild pain. However, this neglect may cause a permanent deformity in the finger; therefore, proper examination by a doctor is advised to get early treatment.