Tendon Injuries
Cuts, ruptures or damage to the cords that connect muscle to bone and make the fingers and thumb move.
Tendons are the cables that transmit the power of forearm muscles to the fingers. The flexor tendons, on the palm side, bend the fingers. The extensor tendons, on the back of the hand, straighten them.
A cut tendon does not repair itself. When a tendon is divided, the muscle pulls the cut end away, and the two ends separate. That is why a finger that will not bend or straighten after a cut needs prompt assessment, even when the wound itself looks small.
Tendon injuries also occur without any cut - a tendon can pull off the bone, tear, or rupture where it has been weakened by rubbing against a bone or an implant.
Loading anatomy
Common symptoms
- Inability to bend or straighten a finger or thumb after an injury
- A finger that rests in an unusual position compared with its neighbours
- A cut on the hand, wrist or forearm followed by loss of movement
- A drooping fingertip that cannot be straightened actively
- Pain along the course of a tendon, particularly with resisted movement
- A sudden snap or pop followed by loss of a specific movement
Causes and contributing factors
- Cuts from knives, glass, tools or machinery
- Crush injuries and degloving injuries
- A forceful bend or extension of a finger, as when a fingertip is struck by a ball
- Tendons pulling away from bone at their attachment
- Gradual wear where a tendon rubs against a bone spur, a fracture fragment or surgical hardware
- Inflammatory conditions that weaken tendon tissue
How it is evaluated
Each tendon has a specific job, so examination works through them individually - testing each joint in each finger to establish exactly which tendon is not working.
Because tendons run alongside nerves and arteries, an injury that divides a tendon may well have divided something else, and those structures are tested at the same time.
- Testing each finger joint individually for active movement
- Observing the resting posture of the hand, which can reveal a divided tendon
- Assessment of sensation and circulation in the same territory
- Careful examination of the wound, including its depth and the position of the hand at the moment of injury
- Ultrasound or MRI in selected cases, particularly for closed ruptures
- X-rays where a bone fragment may have been pulled off with the tendon
Clinical detail
Flexor and extensor injuries are described by anatomical zone, and the zone has a significant bearing on both technique and expected outcome - flexor injuries within the digital sheath being the classic example.
The position of the digit at the time of laceration determines where the divided tendon end lies relative to the skin wound, which is why the level of the tendon injury and the level of the skin wound often do not correspond.
Partial lacerations, associated neurovascular injury and pulley integrity all influence the reconstructive plan.
Nonsurgical treatment
Some tendon injuries are treated without surgery. The clearest example is a mallet finger - where the tendon that straightens the fingertip pulls off - which is often treated in a splint that holds the tip straight continuously while the tendon heals.
Tendon inflammation and irritation, as opposed to a division, is usually managed without an operation.
- Splinting in a position that takes tension off the injured tendon
- A specific, uninterrupted splinting period where that is what the injury requires
- Hand therapy with a graded programme of movement
- Activity modification and, in inflammatory tendon conditions, injection in selected cases
Surgical treatment
A completely divided tendon generally requires surgical repair, and the timing matters. Repaired early, the ends can usually be brought back together directly. After a delay, the muscle shortens and the tendon ends retract, and a more involved reconstruction may be needed.
Repair is only part of the treatment. The tendon has to glide, and scar tissue is the enemy of gliding. The therapy programme afterwards is as important as the operation itself.
- Direct repair of the divided tendon
- Repair of associated nerve and vessel injuries at the same time where present
- Tendon grafting or staged reconstruction when direct repair is not possible
- Tendon transfer, where a working tendon is redirected to take over a lost function
- Tenolysis - release of scar tissue restricting a tendon that has healed but does not glide
Recovery
Recovery after tendon repair follows a carefully staged programme run with a hand therapist. Move too little and the tendon scars down; move too much, too soon, and the repair can rupture. The programme is designed to navigate between the two.
Protective splinting is typically followed by graduated movement, and then strengthening. Full recovery is measured in months.
- A protective splint, with a specific therapy protocol from the early days after surgery
- Strict avoidance of gripping and lifting until permitted
- Progressive strengthening in the later phase
- Some permanent loss of motion is possible, particularly after injuries within the finger
When to seek urgent care
Seek immediate medical attention - an emergency department - if you experience:
- Any cut to the hand, wrist or forearm followed by inability to move a finger
- A wound with numbness in the finger beyond it
- A wound that bleeds heavily or spurts
- Any high-pressure injection injury - from a paint or grease gun - even when the entry wound looks tiny. This is a surgical emergency.
- Increasing pain, redness and swelling after a hand wound, which may indicate infection
This list is not exhaustive. If something about your hand worries you, have it looked at.
Frequently asked questions
The cut was small and it healed. Why can I still not bend my finger?
The size of a skin wound says very little about what happened underneath. A short cut from glass or a blade can divide a tendon completely. If a finger will not move after a cut, that needs assessment regardless of how the skin looks.
Is it too late to repair a tendon cut weeks ago?
Not necessarily, but the approach changes. Once the tendon ends have retracted and scarred, direct repair may no longer be possible, and reconstruction using a graft or a tendon transfer may be considered instead. It is worth being assessed rather than assuming nothing can be done.
Why is hand therapy so strict after a tendon repair?
Because a repaired tendon has to do two things that pull in opposite directions: heal, and glide. Therapy protocols are designed to allow controlled movement that encourages gliding without putting enough load through the repair to rupture it.
Related conditions
Peripheral Nerve Injuries
Damage to the nerves that carry signals between the brain and the hand, causing numbness, weakness or pain in the territory that nerve supplies.
Complex Hand Trauma
Severe injuries that damage more than one tissue system at once - bone, tendon, nerve, blood vessel and skin together.
Hand & Finger Fractures
Broken bones in the fingers or the metacarpals - the long bones of the palm - which may be treated with or without surgery depending on position and stability.
Discuss tendon injuries with Dr. Champagne
A consultation begins with understanding your symptoms, how they affect what you do, and what has already been tried.