De quervain's tenosynovitis

De Quervain's tenosynovitis is also commonly known as

• Washerwoman's sprain
• Mummy thumb
• De Quervain's tendinosis of the sheath
• Blackberry thumb
• Radial styloid tenosynovitis
• De Quervain's disease.

It is basically a tendinosis of the tendon sheath (cover) that wraps around the two tendons of the thumb, the extensor pollicis longus (EPL) and the abductor pollicis brevis (APB).

HOW DOES DE QUERVAIN'S TENOSYNOVITIS HAPPEN?

The EPL and APB tendons run alongside each other, and have closely related functions:

• moving the thumb away from the hand by extension (e.g. to signal "good" with your thumb)
• abduction (make a "C" or an "O" of your thumb and fingers).

These tendons run through a synovial sheath (imagine it to be like a blanket that wraps around the tendons) which contains them. Due to repetitive motion, over time this synovial sheath slowly thickens and degenerates, causing inflammation, swelling and pain.

De Quervain's tenosynovitis is also commonly seen in new mothers and fathers, as they often lift up and put down their newborn babies by holding the babies under their armpits. However, studies show that De Quervain's is more common in women as their wrists have a greater angle at the greater styloid process, causing a higher level of stress for the APB and EPL at the synovial sheath.

CAUSES OF DE QUERVAIN'S TENOSYNOVITIS

It is related directly to:

• wear and tear
• repetitive strain injury
• one's responsibilities, roles and work.

As mentioned earlier, new parents often carry and put down their new borns, causing additional strain and stress repeatedly at their wrists (and their backs).

People whose work involves a flicking of their wrists e.g. opening a can or bottle; or similarly, individuals whose work involves using screwdrivers will also have a high risk of this injury.

This condition is also associated with the use of smartphones, which is how the term "Blackberry Thumb" came about.

SYMPTOMS AND TESTING

Arrow marks where the pain is worsened in DeQuervain syndrome

The main symptoms of De Quervain's tenosynovitis are:

• sharp pain with thumb and wrist flexion
• tenderness at APB/EPL at wrist crease
• swelling
• difficulty using thumb in activities that involve gripping movements.

In our physiotherapy and hand clinics in Singapore, first of all we use the Finkelstein test to diagnose this disease.

To perform this test, we get our patients to bend their affected thumbs into the palm of their hands, close the other four fingers around the thumb, and bend their wrist downwards (see image above with the arrow).

At any point if there is pain, there is an increased likelihood of De Quervain's - the more painful with lesser movements, the more severe.

Next we need to test for tenderness and swelling at the synovial sheath at the wrist for the EPL and APB.

Tenderness and swelling usually confirms the De Quervain's tenosynovitis diagnosis, and it also pinpoints how acute or serious the condition is (there are mild forms and there are severe forms, where movements are locked/too painful to move).

We may also need to do differential diagnosis to rule out possible conditions such as

• wrist fractures
• osteoarthritis
• wrist sprains
• Wartenberg's syndrome

so that we can give accurate and effective hand physiotherapy treatment for the patient's specific hand condition.

PHYSIOTHERAPY AND HAND THERAPY INTERVENTION

Surgeons and physicians will usually recommend four types of medical/surgical solutions, based on severity and how fast the patient wants results:

1. Painkillers and anti-inflammatories
2. H&L injections
3. Surgical "release" intervention
4. Non-invasive hand therapy, occupational therapy and physiotherapy for De Quervain's.

For most cases of De Quervain's tenosynovitis, we will custom make a splint to fit your hand and wrist. This will immobilize the wrist and thumb at the meta-carpo-phalangeal joint (MCP level; at the thumb's knuckle), but at the same time allows your thumb end joint and other fingers to move. It is important to rest the hand and protect it from aggravation due to

• accidental mobilization
• accidentally lifting something
• trauma such as direct hits, blows, etc.

We also will provide cold therapy to reduce inflammation and swelling, and relieve pain. We'll combine this with retrograde massage for a synergistic pattern to drain swelling.

Ultrasound therapy will also help to accelerate the healing process of the soft tissues such as synovial sheath and tendons.

The hand therapist will also need to determine the cause of the injury, so that we will be able to advise on any changes required to activities/exercise. This may include changing the way a task is done if the inappropriate biomechanics were used e.g. ergonomics of keyboard, usage of phone, writing, etc.