Mallet Finger

Mallet Finger

Mallet finger is an injury to the thin tendon that straightens the end joint of a finger or thumb. Although it is also known as “baseball finger,” this injury can happen to anyone when an unyielding object (like a ball) strikes the tip of a finger or thumb and forces it to bend further than it is intended to go. As a result, you are not able to straighten the tip of your finger or thumb on your own.

Tendons are tissues that connect muscles to bone. The muscles that move the fingers and thumb are located in the forearm. Long tendons extend from these muscles through the wrist and attach to the small bones of the fingers and thumb.

The extensor tendons on the top of the hand straighten the fingers. The flexor tendons on the palm side of the hand bend the fingers.

The finger is usually painful, swollen, and bruised. The fingertip will droop noticeably and will straighten only if you push it up with your other hand.

Who does it affect and why does it occur?

It can affect anyone.

When a finger is forcibly stubbed the end finger joint (distal interphalangeal joint) bends forwards quite suddenly. This causes the tendon on the back of the finger that straightens the end joint to pull off the bone. Usually, it pulls off without a piece of bone but sometimes it can pull of a fragment.

Symptoms
Sudden inability to fully straighten the end finger joint and the joint is held in a bent position. The finger is usually painful, swollen, and bruised. The fingertip will droop noticeably and will straighten only if you push it up with your other hand.

Risk for Infection
It is very important to seek immediate attention if there is blood beneath the nail or if the nail is detached. This may be a sign of a cut in the nail bed, or that the finger bone is broken and the wound penetrates down to the bone (open fracture). These types of injuries put you at risk for infection.
First Aid
To relieve pain and reduce swelling, apply ice to your finger immediately and keep your hand elevated above your heart.

Clinical Examination
Your doctor will ask you to try and straighten your end finger joint. You will not be able to do this, no matter how hard you try.
Investigations
An x-ray is required to see whether the tendon has pulled off a piece of bone. This will dictate treatment.
Non-operative treatment
The vast majority of mallet finger injuries do not need an operation. 
If an x-ray reveals, the tendon has pulled off a large fragment of bone with it we recommend surgery. If the x-ray is all clear and show the tendon has just pulled away without a fragment of bone, a non-operative approach will yield satisfactory results in most patients. A splint is applied to the front of the finger (pulp side) to straighten the joint. It is worn for 6-8 weeks constantly. It can be removed for washing, but it is vital the finger is held straight at the end finger joint by a helper; otherwise, the healing tendon will become undone. The splints can be off the shelf stack splints, but often my patients prefer a custom made splint by my hand therapist.

Operative treatment
When the x-ray reveals, a large bone fragment has been pulled off with the tendon, an operation may be required.
The surgery is a day case procedure usually under local anaesthetic and takes about 10 minutes. The surgery can be performed using fine wires that hold the bone fragments back in place. The wires can be inserted percutaneously through small1mm stab incisions. The wires are left in place for 4 to 6 weeks and are removed in the clinic with little discomfort.

Complications
Overall greater than 95% are happy with the result. However, complications can occur. If a splint is worn, the skin may become irritated. This requires regular washing but care to keep the finger straight whilst doing this. This may be a recurrence of the dropped finger or what is called a swan neck deformity. This deformity is the mallet appearance of the end finger joint combined with a bending backwards of the middle knuckle joint, the proximal interphalangeal joint (PIPJ). On the side profile, it has the appearance of a swan’s neck. There are surgical options to improve both these complications.