Flexor Tendon Repair

What is a flexor tendon repair?

A flexor tendon repair is the surgical repair of a torn or lacerated flexor tendon of the hand or fingers. Flexor tendons allow the fingers and thumb to bend (flex) and are critical for grip and fine motor function. Unlike extensor tendons, flexor tendons almost always require surgery if completely ruptured.

Anatomical Structures Involved:

Flexor tendons are located on the palm side of the hand and fingers. Major flexor tendons include:

• Fingers
  • Flexor digitorum profundus (FDP)
  • Flexor digitorum superficialis (FDS)
• Thumb
  • Flexor pollicis longus (FPL)
  • Flexor pollicis brevis (FPB)

Other important structures that can also be impacted are the pulley system. The pulleys provide stabilization and proper positioning.

Much like extensor tendons, flexor tendons also have zones, that indicate where the injury occurred. An injury to a specific zone will dictate the rehabilitation approach.

What can cause a flexor tendon injury?

One of the more common causes of flexor tendon injuries include a laceration from a sharp object, such as knives or glass. Other causes include crush injuries, sports trauma, avulsion injury (“jersey finger”), Rheumatoid arthritis, degenerative rupture, or human/animal bites (high infection risk).

What are the symptoms of a flexor tendon injury?

If you do have an injury to a flexor tendon, you may experience the inability to actively bend finger(s), finger(s) rests in straight posture, or an abnormal finger cascade. Noted increased pain and swelling, or reduced motion of the finger(s)/thumb. You will also have a loss of grip and pinch strength and possible sensory loss if the nerve has also been impacted.

How are flexor tendon injuries diagnosed?

To diagnose a flexor tendon injury, as well as extent of the injury, a clinical exam with isolated tendon testing must be conducted by a physician. In addition, X-rays, ultrasound, or an MRI may be ordered to rule out fractures and avulsions. Lastly, wound exploration for direct repair may also be completed with open injuries.

What are the treatment options of a flexor tendon injury?

A surgical repair, which is the standard of care, would be indicated for a complete rupture, most partial tears (>60%), and open lacerations. Surgical repairs are ideally performed within 48 hours after the initial injury. It is important to seek a hand Surgeon as soon as possible. Delayed repair may impede progress and ability to perform a direct end to end repair. In some cases, with delayed intervention, a tendon transfer may be needed.  A physician can complete several options during the surgical repair depending on the extent of the injury:

• Core suture repair (4–6 strand)

• Epitendinous sutures
• Tendon grafts (chronic injuries)
• Tendon transfer (non-repairable cases)

In some cases, a flexor tendon injury does not require surgical treatment. Non-surgical approaches are reserved for partial tears <60% or high surgical risk patients.

Rehabilitation

An important part of flexor tendon repair rehabilitation includes balancing tendon healing and movement to prevent scar and stiffness. This should be completed with the supervision of a Certified Hand Therapist (CHT) or therapist working alongside a CHT. If the rehabilitation is not guided properly, this could result in permanent loss in motion, as well as potential need for additional surgery to restore mobility. Custom orthotic fabrication by a CHT to protect healing structures and may be modified to improve or advance mobility throughout the rehabilitation process.

Much like extensor tendon rehabilitation, flexor tendons also follow phases:

• Phase 1 – Early protected motion (0–4 weeks)
• Phase 2 – Early Active Motion (4–6 weeks)
• Phase 3 – Strengthening (6–8 weeks)
• Phase 4 – Return to Function (8–12+ weeks)

Full recovery may take 3–6 months

The rehabilitation process and timeline will vary based on multiple factors such as instability, delayed healing, or other guidelines from the surgeon. It is important that you see a therapist that specializes in Orthopedic care of the Upper Extremity such as a Certified Hand Therapist, to ensure proper progression through the rehab process to avoid re-injury.