Finger Dislocation

Deformity, swelling, and pain are signs and symptoms of a dislocated finger.

• Finger dislocations occur at the joints within the finger: metacarpal phalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal (DIP). Dislocations are when the bones of these joints become dislocated from each other.
• Finger dislocation injuries are painful and cause swelling and deformity. The dislocations can be dorsal, volar, or lateral.
• It's possible to reduce or relocate most dislocations at the bedside. Complicated injuries may require surgery.
• All dislocations require rehabilitation to restore range of motion and function.
• Doctors measure recovery time in weeks.

There are three joints located in each finger (just two in the thumb). They allow the finger to flex (bend) and extend (straighten) and give the ability of the hand to perform all its functions from grasping to waving and pinching tiny objects.

The joints in the finger got their names based on which bones in the finger make up the joint and their location in the finger. There are three phalangeal bones that make up each finger (the thumb has two). They got their names based on their position within the finger: proximal phalanx, middle phalanx, and distal phalanx. The fingernail is located near the distal phalanx.

• The metacarpal phalangeal joint (MCP) connects the metacarpal bone of the hand and the proximal phalanx of the finger.
• The proximal interphalangeal joint (PIP) connects the proximal and middle phalanges.
• The distal interphalangeal joint connects the middle and distal phalanges.

The thumb has just two phalanges and therefore two joints within it: the MCP joint and the interphalangeal (IP) joint.

The PIP and DIP joints work like a hinge and move in just one plane. The ligaments and tendons that surround each joint keep them stable. Should the joint hyperflex or hyperextend, the bones that make up that joint can disconnect, and this is a dislocation.

Doctors describe dislocations by the displacement of the bones.

• Dorsal dislocation: The phalanx closer to the tip of the finger is displaced toward the back of the hand.
• Volar dislocation: The phalanx closer to the tip of the finger is displaced toward the palm of the hand.
• Lateral dislocation: The phalanx closer to the tip of the finger is displaced to the side.

The most commonly dislocated joint is the PIP joint.

In addition to the dislocation, fractures (broken bones), ligament and tendon injuries, and nerve damage may accompany the joint injury.

Finger joint dislocations are traumatic and due to injury. They can be due to a fall or a finger being hit with an object, like trying to catching a ball.

In children whose skeleton has not fully developed, finger dislocations are less common, because the ligaments tend to be stronger than bone. A fracture of the phalanx growth plate is a more likely injury.

As with any injury, the signs and symptoms of a finger dislocation include pain, swelling, and deformity. As well, the patient will be unable to move the injured joint.

If there is associated damage to the nerve that runs near the finger joint, there may be numbness and tingling to the finger.

The diagnosis begins with a history of how the injury occurred, and the patient usually knows which joint is injured and cannot move it appropriately. On physical examination, it's possible to feel and see the finger deformity. The exam may also want to focus on the rest of the hand to make certain there are no other associated injuries that might be missed. As well, the health care provider will want to assess the nerve function of the finger beyond the dislocation, since nerve injury is one of the complications of a finger dislocation.

Medical professionals typically take X-rays of the finger to confirm the dislocation and also to look for associated fractures of the bones of the finger that might make reduction of the dislocation (returning the bones to proper alignment within the joint) difficult or cause complications later in healing.

X-rays of the injured finger are important in children, since growth plate fractures are more likely to occur than joint dislocation.

The treatment goal is to reduce the dislocation and restore function to the finger. Often a primary care or emergency provider is able to reduce the dislocation.

After joint reduction, a medical professional splints the finger to protect the joint from dislocating again and to allow the structures around the joint to heal.

The finger is a complex structure, and complications are common with dislocations. For that reason, most patients with dislocated fingers will  receive a referral to an orthopedic or hand specialist for follow-up to minimize the risk of complications and maximize the potential for normal finger function.

Some finger dislocations are complicated and need the attention of an orthopedic or hand surgeon immediately for care. Reasons for their immediate attention include the following:

• Dislocations with phalanx fracture
• Open dislocation, where the skin overlying the injured joint is lacerated or torn
• Damage to the nerves or arteries of the finger
• Dislocations with tendon rupture
• Inability to reduce the dislocation

Some dislocations require an operation to reduce and repair the injury.

Finger dislocations can damage many structures within the finger, including the joint surfaces of the bone, the volar plate (a thickened ligament that helps stabilize the palm side of the joint), ligaments, and tendons.

Acute complications include an inability to reduce the dislocation and associated fractures. These may require surgery to repair the finger.

Open dislocations may become infected.

Long-term complications can include chronic stiffness, swelling, pain, and recurrent dislocation of the injured joint.

Boutonniere deformity is a complication of dorsal dislocation of the PIP joint with tendon damage and subsequent scarring that causes the PIP joint to be held in permanent flexion.

Mallet deformity can occur with a dislocated DIP joint with associated tendon rupture that causes the tip of the finger to droop and not completely straighten.

After reduction of the injury, a medical professional will splint the damaged finger. It needs re-evaluation within a week. At that time, the patient will start range of motion exercises, and hand rehabilitation can begin.

A splint can stabilize uncomplicated PIP and DIP dislocations, and it's possible to return to work or play almost immediately as long as the joint is protected.

MCP dislocations are more complicated and may take 1-2 months to allow fuller function.