Flexor & Extensor Tendon Injuries

Tendons are the strong, fibrous cords of connective tissue that connect the muscles of the forearm to the small bones of the hand and fingers. When a forearm muscle contracts, the tendon pulls on the bone, causing the finger to move. Tendons on the palm side of the hand are **flexor tendons** (responsible for bending the fingers to grip), while those on the back of the hand are **extensor tendons** (responsible for straightening the fingers and thumb).

At Erlanger Hayes Hand Center, our orthopedic specialists provide expert evaluation and advanced reconstruction for tendon lacerations and ruptures. Because tendons are under constant physiological tension, a partially or completely severed tendon cannot heal on its own and requires precise surgical adaptation and specialized hand therapy to restore sliding mechanics.

The Complexity of Zone II ("No Man's Land")

Flexor tendon repairs within anatomical Zone II (from the middle of the palm to the middle joint of the finger) are historically difficult due to the tight, unyielding tunnel of fibroosseous sheaths and pulleys. Achieving a smooth repair here is critical to prevent the tendon from catching, scarring, or snapping during post-operative rehabilitation.

Mechanisms of Tendon Trauma

Due to their superficial location, tendons in the hand and wrist are highly vulnerable to various trauma mechanisms:

Deep Lacerations: Accidental cuts from sharp objects such as glass, knives, kitchen tools, or industrial machinery that easily slice through the delicate soft tissue.
Avulsion Injuries ("Jersey Finger"): Occurs when an athlete's finger catches on an opponent's jersey while gripping forcefully, tearing the flexor tendon directly off the distal bone.
Blunt Impact or Rupture: High-energy trauma or progressive wear against a rough edge of bone following a previous wrist fracture or severe rheumatoid arthritis.

Clinical Presentation & Symptoms

A cut or ruptured tendon presents with immediate functional limitations localized to the affected digit:

Loss of Active Motion: Inability to bend (flexor injury) or straighten (extensor injury) a specific finger joint, even though the finger can be moved easily by someone else.
Resting Deformity: The affected finger rests in an unnatural position. For example, a severed flexor tendon causes the finger to lie completely straight while the other fingers remain naturally curled.
Acute Localized Pain & Numbness: Pain over the source of the tear, often accompanied by numbness if the neighboring digital nerves (which run alongside the tendons) were also injured.

Surgical Management and Repair

A completely severed tendon requires surgical intervention, ideally performed within days of the injury before the muscle permanently shortens and pulls the tendon end further up into the palm or forearm.

Our hand surgeons utilize specialized, high-strength **core suture techniques** combined with continuous **epitenon suturing** under magnification. This approach ensures a strong, low-profile repair that can withstand early movement protocols without bulky knots sticking inside the tendon sheaths. If the tissue has been crushed or delayed for several weeks, multi-stage tendon grafting using a tendon from another area may be necessary to rebuild the mechanical connection.

Specialized Post-Operative Rehabilitation

Surgical suturing is only the first step; restoring hand function depends entirely on compliance with a strict physical therapy protocol managed by our **certified hand therapists (CHTs)**:

Early Protected Motion (Kleinert or Duran Protocols): To prevent the healing tendon from scarring down to surrounding tissue (adhesions), CHTs place the hand in a custom thermoplastic orthosis (splint). This splint protects the repair from tension while allowing controlled, gentle movement.
Therapeutic Progression: Over a 12-week framework, therapy carefully transitions from passive motion to active motion, and finally to progressive strengthening exercises to rebuild full grip strength.