Extensor Tendon Injuries

What are the Extensor Tendons?

Extensor tendons are fibrous tissues that connect the forearm muscles to the fingers and thumb bones. These tendons run along the back of the hand and allow for the straightening or extension of the fingers and thumb. For instance, when you spread your fingers out or give a thumbs-up, you use your extensor tendons.

The extensor tendons are close to the skin surface on the back of the hand, so they are more susceptible to injury than the tendons on the palm side of the hand.

What are Extensor Tendon Injuries?

Extensor tendon injuries refer to damage sustained by the extensor tendons of the hand or fingers, which facilitate the straightening of the fingers and thumb. These tendons run along the back of the hand and are close to the skin's surface, making them particularly susceptible to injuries. They can occur as partial tears, complete ruptures, or avulsion injuries where the tendon detaches from its attachment site.

Impact of Extensor Tendon Injuries on Anatomy and Health

Extensor tendon injuries can disrupt the delicate balance between flexor and extensor tendons, leading to hand and finger movement difficulties. They may cause pain, weakness, swelling, limited range of motion, and functional impairment.

Who is Most at Risk for Extensor Tendon Injuries?

Individuals engaged in activities that put repetitive strain on the hand and wrist, such as athletes, musicians, and manual labourers, are at a higher risk. Trauma, direct blows, lacerations, and sudden excessive force can also result in extensor tendon injuries.

Causes of Extensor Tendon Injuries

Extensor tendon injuries can occur due to a variety of causes, including:

Trauma: Direct trauma to the hand or fingers, such as a forceful blow or impact, can result in extensor tendon injuries. This can happen during sports activities, falls, or hand accidents.
Lacerations: Deep cuts or lacerations that affect the back of the hand or fingers can damage the extensor tendons. This can occur from sharp objects or machinery accidents.
Overuse and Repetitive Strain: Engaging in repetitive activities that involve excessive or prolonged use of the hand and wrist can lead to extensor tendon injuries. Examples include typing on a keyboard for long hours, playing certain musical instruments, or participating in sports that require repetitive gripping or wrist movements.
Sports Injuries: Participating in sports that involve hand-intensive activities, such as racquet sports, weightlifting, or rock climbing, can increase the risk of extensor tendon injuries. Sudden and forceful movements or improper technique can cause tendon strains, tears, or ruptures.
Degenerative Changes: Over time, the extensor tendons may undergo degenerative changes, making them more prone to injury. This can result from age-related wear and tear, underlying medical conditions like rheumatoid arthritis or osteoarthritis, or chronic repetitive stress on the tendons.
Occupational Factors: Certain occupations that involve repetitive hand and wrist movements, high-force gripping, or exposure to vibrations, such as construction work, assembly line work, or using power tools, can increase the risk of extensor tendon injuries.

Symptoms of Extensor Tendon Injuries

Pain, tenderness, and swelling at the back of the wrist, hand or fingers
Inability to extend or straighten the affected finger(s) fully
Finger deformities, such as a bent fingertip or thumb
A cut across the back of the wrist, hand or finger
Inability to fully straighten the finger or thumb
Pain on trying to straighten the finger or thumb

Types of Extensor Tendon Injuries

Extensor tendon injuries come in various forms, often distinguished by their cause and location. Some common types of extensor tendon injuries include:

Lacerations: These are injuries usually caused by a sharp object that cuts the tendon, such as a knife or glass shard.
Tendonitis: Inflammation of the tendon, often caused by overuse or repetitive motions. It is common in people who perform repetitive tasks, such as typing or certain sports activities.
Ruptures: Occur when the tendon tears or breaks apart. This may happen due to a traumatic injury or a degenerative condition like rheumatoid arthritis.
Boutonnière Deformity: A condition where the finger's middle joint droops downwards while the fingertip bends back. It happens when the central slip of the extensor tendon becomes damaged, often due to trauma or uncontrolled rheumatoid arthritis.
Mallet Finger: Occurs when the extensor tendon is damaged at the tip of the finger, causing the finger's end joint to droop. It's often caused by a forceful blow to the tip of an extended finger.

Stages of Extensor Tendon Injuries

Stage 1: Partial tear or inflammation without complete tendon disruption.
Stage 2: Complete tendon tear or rupture, causing functional impairment.
Stage 3: Delayed presentation or chronic tendon injury that may require specialised treatment.

Extensor Tendon Injuries Diagnosis

The diagnosis of extensor tendon injuries typically involves a comprehensive evaluation that may include the following diagnostic approaches:

Medical History: Your doctor will inquire about the details of the injury, including how it occurred, the location of pain or symptoms, and any previous hand or finger injuries or conditions. Understanding the mechanism of injury and the patient's medical history helps formulate an accurate diagnosis.
Physical Examination: A thorough physical examination of the hand and affected finger(s) is conducted to assess the range of motion, strength, presence of deformities, and any visible signs of injury or swelling. Your doctor may perform specific tests to evaluate the integrity of the extensor tendons, such as the "active extension" test, where the patient is asked to extend the finger(s) against resistance actively.
Imaging Studies: X-rays may be ordered to evaluate the bones and rule out associated fractures or dislocations. X-rays can help identify avulsion fractures or bony abnormalities that may accompany extensor tendon injuries. In some cases, advanced imaging techniques like ultrasound or MRI may be used to assess the extensor tendons, especially for complex or difficult-to-diagnose cases.

Extensor Tendon Injuries Treatment

Non-Surgical Treatment

Sometimes, non-surgical treatment may be recommended for partial tears or minor injuries.

Splinting and Immobilisation: This involves immobilising the finger(s) or hand with a splint or cast to protect the injured extensor tendon and promote healing. The immobilisation duration depends on the injury's severity and your doctor's recommendation.
Hand Therapy and Rehabilitation: Hand therapists guide patients through exercises and activities that promote tendon healing, improve the range of motion, and strengthen the surrounding muscles. Therapy may include range-of-motion exercises, tendon gliding exercises, and progressive strengthening exercises tailored to the individual's specific injury and stage of healing.

The stages of healing for an extensor tendon injury include the inflammatory stage, the proliferative stage (where new tissue starts to form), and the remodelling stage (where the new tissue strengthens and matures). The timeline for these stages varies depending on the severity of the injury.

Surgical Treatment

Complete tendon tears or severe injuries often require surgical intervention to restore proper tendon alignment and function.

Tendon Repair: The extensor tendon is carefully repaired during surgery. The surgical technique used may vary depending on the location and extent of the injury. In some cases, tendon grafts or transfers may be necessary to restore function if the injured tendon cannot be repaired directly.
Tendon Reconstruction: In cases where the extensor tendon is extensively damaged or unable to be repaired directly, tendon reconstruction techniques may be employed. This involves using healthy donor tendons to reconstruct the damaged extensor tendon, providing stability and function to the affected finger(s) or hand.
Post-Surgical Rehabilitation: The rehabilitation process may involve splinting, controlled movement exercises, scar management, and gradually returning to normal activities.

What if Extensor Tendon Injuries are Untreated?

Untreated extensor tendon injuries can result in chronic pain, decreased finger function, joint stiffness, deformities, and loss of grip strength. Prolonged neglect may require more complex surgical interventions and may lead to permanent functional limitations.