The most common closed tendon injury in the hand is mallet finger, an injury to the extensor tendon at the fingertip. It happens when a force pushes the tip of your finger down while the tendon is trying to hold it straight, tearing or stretching the tendon that controls that last joint. Beyond mallet finger, the hand is vulnerable to several other tendon injuries, from lacerations of the flexor tendons on the palm side to chronic conditions like trigger finger. Understanding which injuries are most likely, how they happen, and what recovery looks like can help you recognize a problem early.
Mallet Finger: The Most Common Injury
Mallet finger occurs when the extensor tendon at the very tip of your finger is damaged. This tendon is what allows you to straighten the last joint of your finger on your own. When it tears, gets cut, or pulls away from the bone, the fingertip droops and you can’t lift it back up. The injury is sometimes called “baseball finger” because it often happens when a ball or other object strikes an outstretched fingertip, but it can also result from something as simple as catching your finger on a bedsheet or jamming it against a hard surface.
The telltale sign is a fingertip that hangs down at the last joint and won’t straighten when you try. The joint may also swell and bruise. In some cases, the tendon pulls a small chip of bone away with it, which is called a bony mallet. This distinction matters because it can change how the injury is treated.
Most mallet finger injuries don’t require surgery. The standard treatment is a small splint that holds the fingertip straight, worn continuously for six to eight weeks. Keeping the splint on without interruption is critical. Even briefly bending the fingertip during healing can reset the clock. After splinting, gradual movement is reintroduced over the following weeks. Surgery is typically reserved for cases where a large bone fragment is displaced or the joint has become unstable.
Flexor Tendon Injuries
While mallet finger affects the back of the hand, flexor tendon injuries affect the palm side. These tendons are what let you curl your fingers into a fist and grip objects. Unlike mallet finger, which usually happens from a blunt force, flexor tendon injuries are most often caused by cuts from knives, glass, or sharp tools. They can also result from sudden forceful gripping, like grabbing a jersey during contact sports (sometimes called “jersey finger”).
Surgeons divide the palm and fingers into five zones when describing these injuries. Zone 2, the area within the finger itself, accounts for about 43% of all flexor tendon lacerations. Zone 5, at the wrist, makes up roughly 29%. Zone 2 injuries are particularly challenging because two tendons run through a tight, enclosed tunnel in that part of the finger, making repair and recovery more complex.
If you cut a flexor tendon, you’ll notice that the affected finger won’t bend properly. A simple test your doctor may use involves holding one finger joint still and asking you to bend just the fingertip. If the deep flexor tendon is cut, you won’t be able to do it. Flexor tendon cuts almost always require surgical repair, as these tendons cannot heal on their own when fully severed.
Trigger Finger
Trigger finger is a different kind of tendon problem. Rather than a sudden injury, it develops over time when the sheath surrounding a flexor tendon becomes inflamed and thickened. The tendon can still slide through the sheath, but it catches or locks as it moves, producing a clicking or snapping sensation when you bend and straighten your finger. In more severe cases, the finger gets stuck in a bent position and you have to manually straighten it with your other hand.
The lifetime risk of developing trigger finger is about 2% to 3%, with women affected more often than men. The ring finger and thumb are the most frequently involved. People with diabetes, rheumatoid arthritis, or jobs requiring repetitive gripping are at higher risk. Treatment usually starts with rest, splinting, or a steroid injection into the tendon sheath. If those measures don’t resolve the catching, a minor surgical procedure to widen the sheath opening is highly effective.
How Doctors Check for Tendon Damage
Diagnosing a hand tendon injury relies heavily on a physical exam. Your doctor will ask you to move each finger through specific motions, isolating one tendon at a time. To test the deep flexor tendon, they’ll hold your middle finger joint steady and ask you to bend just the fingertip. If you can’t, that tendon is likely damaged. To test the shallow flexor tendon, they’ll hold all your other fingers straight and ask you to bend the injured finger at its middle joint.
For extensor injuries like mallet finger, the diagnosis is often obvious on sight: a drooping fingertip that won’t straighten. An X-ray is usually taken to check for a bony fragment. For more complex injuries or when the exam is difficult due to swelling and pain, an ultrasound or MRI may be used to visualize the tendon directly.
What Recovery Looks Like
Tendon healing is slow compared to many other injuries because tendons have a limited blood supply. After a surgical repair, you’ll typically wear a rigid splint for the first five to six weeks. During this time, a hand therapist will guide you through specific, controlled exercises designed to prevent the tendon from sticking to surrounding tissues while still protecting the repair.
The general timeline after surgical repair looks like this:
- 6 to 8 weeks: Light activities like typing or writing with a pen
- 8 to 10 weeks: Moderate activities like light lifting
- 10 to 12 weeks: Heavy lifting, manual labor, and return to sports
- 8 to 10 weeks: Driving
A repaired tendon typically reaches full strength around 12 weeks, but regaining the full range of motion can take up to six months. Pain medication is generally only needed for the first two weeks after surgery.
The Risk of Scar Tissue
The most common complication after tendon repair is adhesion formation, where scar tissue binds the repaired tendon to surrounding structures. This limits how freely the tendon can glide, resulting in stiffness and reduced movement. In a study of 305 patients who had extensor tendon repairs, about 25% developed adhesions, and those patients lost an average of 12 weeks of work.
This is why hand therapy after surgery is so important. The controlled movement exercises prescribed during recovery are specifically designed to keep the tendon gliding within its sheath as it heals. Skipping therapy or immobilizing the hand for too long increases the risk of adhesions, while moving too aggressively risks re-rupturing the repair. It’s a careful balance, and following your therapist’s program closely gives you the best chance of a full recovery.