Cut Tendon in Your Hand? Why Flexor Tendon Repair Can’t Wait

You cut your hand or finger on glass, a knife, or a piece of metal. The wound may not look that deep, but now you can’t bend one of your fingers. If this has happened to you, there’s a strong chance you’ve cut a flexor tendon—and this is a hand emergency that requires surgical repair, usually within days.

What Are Flexor Tendons?

Flexor tendons are the rope-like structures that run from the forearm through the wrist and palm into each finger. When your forearm muscles contract, these tendons pull on the fingers and allow you to make a fist, grip objects, and perform fine motor tasks. Each finger has two flexor tendons: the flexor digitorum superficialis (FDS), which bends the middle joint, and the flexor digitorum profundus (FDP), which bends the fingertip.

Because flexor tendons lie just beneath the skin on the palm side of the hand and fingers, they are vulnerable to lacerations.

How Do I Know If My Tendon Is Cut?

• You have a wound on the palm side of your hand or finger

• You cannot bend one or more joints of the affected finger

• Weakness in grip even if partial motion remains (partial tendon laceration)

• The finger may rest in a straighter position compared to the other fingers

Important: The wound may appear small or superficial—don’t let that fool you. Even a small cut over a flexor tendon can completely sever it. If you have any doubt about finger motion after a laceration, see a hand surgeon.

Why Can’t Tendons Heal on Their Own?

Unlike bones, cut tendons do not heal back together without surgery. When a flexor tendon is severed, the muscle pulls the cut end back toward the forearm, creating a gap that cannot bridge itself. Without surgical repair, the ability to bend that finger is permanently lost.

Flexor Tendon Repair Surgery

Flexor tendon repair is performed in the operating room under anesthesia. I retrieve the retracted tendon end, bring the two ends together, and suture them using a strong core suture technique reinforced with a running epitendinous suture. This provides enough strength for early protected motion, which is critical for a good outcome.

Timing matters. Primary repair within 1—2 weeks of injury produces the best results. Delayed repairs become progressively more difficult as the tendon retracts, scars, and the sheath contracts.

Recovery: The Hand Therapy Protocol Is Critical

Recovery after flexor tendon repair is a partnership between surgeon and hand therapist. The repaired tendon must be protected from excessive force while being moved enough to prevent adhesions (scar tissue that tethers the tendon and limits gliding).

• Weeks 1–4: Protective splint with a carefully supervised early motion protocol. Your hand therapist will guide specific exercises.

• Weeks 4–6: Gradual increase in active motion, splint weaning

• Weeks 6–8: Begin gentle strengthening

• Weeks 8–12: Progressive strengthening, return to full activities

Compliance with the therapy protocol is the single most important factor in achieving a good outcome. Missing therapy appointments or advancing too quickly risks rupture of the repair.

Jersey Finger: A Special Case

Jersey finger is a closed flexor tendon rupture—the FDP tendon tears off the bone without an external wound, typically from grabbing a jersey or clothing during sports. The ring finger is most commonly affected. This also requires surgical repair and should be evaluated urgently.

Frequently Asked Questions

How strong will my finger be after tendon repair?

With proper surgery and hand therapy, most patients recover good to excellent finger motion and grip strength. Some degree of stiffness is common but usually does not significantly limit function.

What if my tendon repair was months ago and I’m still stiff?

Tendon adhesions (scarring) are the most common complication. If stiffness persists despite therapy, a secondary procedure called tenolysis (surgically freeing the tendon from adhesions) may be recommended.

Urgent Tendon Repair in Phoenix

If you’ve cut your hand and can’t bend your finger, call our office immediately. Early repair by a hand surgeon produces the best outcomes. I provide urgent flexor tendon repair for patients across the Phoenix metro—Scottsdale, Mesa, Chandler, Gilbert, Goodyear, Peoria, and Buckeye. ☎ Schedule Your Consultation

Call (602) 258-4788 or visit toddrichardsmd.com to book an appointment with Dr. Todd Richards. Most insurance plans accepted. Same-week appointments often available.