Extensor Tendon Injuries

Cuts, tears, or ruptures of the tendons on the back of your hand and fingers that straighten your joints.

Extensor tendons on the back of the hand and fingers that allow the fingers and thumb to straighten — The extensor tendons run along the back of your hand and fingers. They straighten each joint.

What is an extensor tendon injury?

Extensor tendons are the cords on the back of your hand, fingers, and thumb. They lie just under the skin, right over the bones. When you open your hand and straighten your fingers, these tendons do the work. Because they sit so close to the surface, they can be hurt by a small cut, a jam to the fingertip, or a blow to the back of the hand. When an extensor tendon is cut or torn, the affected joint will not straighten normally.

Common symptoms

Inability to fully straighten one or more finger joints
A drooping fingertip (mallet finger) or a bent middle joint that cannot be straightened (boutonnière deformity)
Pain, swelling, or bruising on the back of the finger or hand
A cut, puncture, or laceration on the back of the hand or finger
Weakness when trying to open the hand

Why does it happen?

There are three common ways extensor tendons get hurt:

A cut on the back of the hand or finger from a knife, glass, or a sharp edge. Even a small-looking cut can divide the tendon underneath.
A jam to the fingertip (a ball hits the end of the finger, or the finger catches on a sheet or jersey). This can rupture the tendon from its bone attachment.
A blow to the middle joint of the finger. This can tear the central slip and cause a boutonnière deformity.

Side view of a fingertip showing an extensor tendon disruption at the last joint, known as mallet finger — Mallet finger: the extensor tendon pulls off the bone at the last finger joint, causing the fingertip to droop.

Side view of a finger with boutonnière deformity showing tendon disruption over the middle joint — Boutonnière deformity: the central slip of the extensor tendon tears over the middle joint. The middle joint bends and cannot straighten.

Treatment options

Non-surgical treatment

Splinting. Many closed extensor tendon injuries heal well in a splint that holds the joint straight. Mallet finger and some boutonnière injuries are treated this way. The splint typically stays on full-time for 6 to 8 weeks, then part-time for a few more weeks.
Hand therapy. A certified hand therapist custom-fits the splint and teaches you how to care for the finger while it heals.

Surgical treatment

Tendon repair. If the tendon is cut, it usually needs to be sewn back together. This is an outpatient surgery, often done with local or regional numbing.
Pin across the joint. Some injuries are treated by placing a small pin through the bone as an internal splint while the tendon heals.
Later reconstruction. If an injury was missed or healed poorly, a secondary procedure may be needed to restore finger position and movement.

After surgery or splinting, hand therapy is almost always part of recovery. It helps the tendon glide again and prevents stiffness.

What to expect at your visit

Dr. Barrera will examine your hand, test each joint for active extension, and review any imaging if you have it. X-rays are often taken to look for a small bone fragment that can come off along with the tendon. Based on which tendon is involved, whether the skin is cut, and how long it has been since the injury, you will discuss splinting versus surgery together.

When to call the office sooner

Call us if you have a deep cut on the back of your hand or finger, if you cannot straighten a finger joint after an injury, if the skin around a wound is red or draining, or if you have a fever along with the injury.

Questions?

Call your office location for non-urgent questions:

NYU Langone Laurelton · 646-501-4950
NYU Orthopedic, Woodside · 929-429-3222
NYU Orthopedic, Richmond Hill · 718-206-6923
Jamaica Hospital Ambulatory Care Center (ACC) · 718-301-0720

See our office contact information for addresses and fax numbers.