Procedures · Hand & Upper Extremity Surgery

Flexor Tendon Injury

Medically reviewed by Dr. Khalid Almutairi, Consultant Plastic Surgeon — updated 2026-08-13

The flexor tendons are strong cords that transmit the force of the forearm muscles to bend the fingers and thumb. When a tendon is divided — usually by glass or a knife — that connection is broken: the finger looks intact, but it cannot bend actively, or bends with obvious weakness. A completely divided tendon does not usually heal by itself, because the pull of the muscle draws the two ends apart.

Care is led by Dr. Khalid Almutairi, a consultant plastic and reconstructive surgeon, fellowship trained in hand surgery and microsurgery in Canada and the USA.

Why is a healed wound not enough?

The skin can heal completely while the tendon beneath it remains divided — which is why a closed wound does not mean a sound hand. Any cut on the palm or fingers followed by weak or absent bending — or numbness along one side of a finger — needs specialist examination: the digital nerves run immediately beside the tendons and are frequently injured with them.

The glide principle: the heart of tendon surgery

It is not enough for a sutured tendon to heal; it must glide freely again inside its sheath and beneath its fine restraining pulleys for muscle force to become movement. All of tendon surgery is therefore built on a precise balance: a repair strong enough to heal, and early protected movement to prevent the adhesions that restrict glide. That balance is what makes rehabilitation part of the operation, not an afterthought.

Assessment

Examination covers the resting posture of the fingers and bending of each finger individually to identify the injured tendon and its level, testing of sensation and circulation to detect associated nerve and vessel injury, and assessment of the wound and tissues. Factors such as the level of division, wound cleanliness, and the time elapsed shape the treatment plan.

Treatment options

The plan differs with the state of the tendon, the tissues, and the timing:

• Primary repair: suturing the tendon ends in the early period after injury when conditions allow — the preferred option where feasible.
• Delayed repair: in some cases presenting after a short delay, direct repair remains possible if the ends have not retracted far.
• Tendon grafting: when direct repair is not possible, the gap is bridged with a tendon graft from another site.
• Staged reconstruction: in complex or neglected cases, a tendon pathway may first be rebuilt around a temporary rod, with the graft placed at a second stage.
• Tenolysis: releasing adhesions when a tendon has healed but scar restricts its glide, provided passive joint movement is good.
• Tendon transfer: in selected cases, another well-functioning tendon is used to replace the lost function.

Rehabilitation: half the treatment

After repair, a protected-movement programme begins under a hand therapist with a purpose-made splint: enough movement to prevent adhesions, enough protection to prevent rupture of the repair. Precise adherence to the programme and to individual instructions is a decisive factor in the outcome — early overloading can rupture the repair and require further surgery.

Recovery: the wound heals first, strength comes later

Skin heals within weeks, but the tendon regains its strength gradually over months, and movement and power improve with continued rehabilitation. The final result varies with the level of injury, the condition of the sheath, associated injuries, and adherence to therapy — and a full return of movement cannot be guaranteed.

Limitations and risks

Risks specific to tendon surgery include rupture of the repair, motion-restricting adhesions, stiffness, reduced range of bending, and the later need for tenolysis or secondary reconstruction — in addition to general surgical risks such as infection and scar tenderness. The risks relevant to your case are discussed before any decision.

What if months have passed since the injury?

Assessment is still worthwhile. Direct repair may no longer be possible, but secondary reconstruction — grafting, staged reconstruction, tendon transfer, or tenolysis — is considered according to the state of the finger, its joints, and its tissues. Restoring passive joint movement is an important requirement before any tendon reconstruction.

Will a partially divided tendon work without surgery?

A partial division may preserve some movement, but it can rupture later or cause catching and pain. It is assessed by examination to determine whether repair or monitoring is appropriate.

When does movement start after repair?

Early protected movement usually begins within the first days, following the hand therapist's programme designed for your case; the individual programme is always the reference.

Medical-information notice

This is general information and does not replace consultation and examination. Hand wounds with weak bending, numbness, or a pale finger need urgent assessment; loss of circulation or severe bleeding requires immediate attendance at an emergency department.