Anatomy

• Tendons are strong fibres of collagen that attach muscles to bones and therefore enable muscles to produce movement
• Tendons slide within a tissue that forms a tunnel called a sheath
• The sheath helps keep the tendons close to the bones
• Extensor tendons run on the back side of the wrist:
• Their function is to straighten the fingers and extend the wrist
• The extensor tendons are organised into 6 compartments at the level of the wrist
• The 1^st compartment is on the side of the thumb and the 6^th on the side of the little finger
• De Quervain’s tenosynovitis affects the 1^st compartment which contains two tendons:
• Abductors pollicis longus:
• Its function is to tilt the wrist towards the thumb and abduct the thumb (moving the thumb vertically away from the palm)
• Extensor pollicis brevis:
• Its function is to tilt the wrist towards the thumb and extend the thumb (moving the thumb sideways away from the palm)

Pathophysiology

• It occurs due to thickening and/or swelling of the tendon or its covering sheath
• This causes friction and pain as the tendon struggles to slide through the sheath

How often does it occur?

• It is seen more commonly in patient who have tennis elbow or golfer’s elbow
• Often seen on both wrists in new mothers or those who look after children and resolves on its own once lifting the child is less frequent

Symptoms

• Pain occurs on the side of the wrist at the base of the thumb
• Pain is made worse when gripping
• The symptoms come on gradually
• Pain on moving the thumb especially when gripping objects
• Swelling at the base of the thumb has also been noted

Risk factors

• It is more common in women than men: 
• Especially mothers of newborns who repeatedly lift the newborn with the thumbs away from the rest of the fingers
• Typically affects 30-50 year olds
• Most commonly affects the dominant wrist
• It is an overuse injury of the thumb particularly from repetitive grasping
• Can also be caused by a direct blow to the thumb or arthritis
• Provocative movement in particular is the sideways wrist motion whilst gripping such as:
• Lifting young children
• Gardening
• Racquet sports
• Skiing
• Using a hammer
• Long hours pressing playing computer games that involve pressing a button repeatedly with the thumb

Diagnosis

• The classic test for De Quervain’s tenosynovitis is the Finkelstein test
• The patient is asked to make a fist by wrapping their fingers over the thumb (as opposed to the more conventional thumb over fingers)
• Whilst keeping their fist in this position the doctor then moves the wrist sideways away from the thumb
• If this causes pain then it is a positive test for De Quervain’s tenosynovitis as the irritated tendons are forced down the narrowed overlying sheath

Treatment

• Most cases will settle with conservative management
• High rate of recurrence i.e. can come back once the symptoms settle
• First line treatment should be:
• Rest
• Avoiding repetitive thumb movements as much as possible
• Anti-inflammatory medications
• Thumb immobilisation splint
• Ice
• Physiotherapy to strengthen muscles used to move the thumb
• Steroid injection into the affected tendon compartment of the wrist to help reduce
• Studies have shown that 20% of patients using thumb immobilisation splint alone for 6 weeks had improvement in symptoms and this increased to 60% when combined with anti-inflammatory medications
• The splint should allow some movement of the thumb as opposed to completely immobilising it
• Surgical treatment is considered for cases when conservative management has failed:
• It has a high success rate
• A small cut is made on the wrist over the painful side and the sheath is released over the irritated tendons
• This removes the pressure on the tendons and allows them to heal
• The operation can be performed under local or regional anaesthesia
• There is a nerve (superficial radial nerve) around the surgical incision site which provides sensation to the area so it is important to avoid this potential complication

Prevention

• Avoiding provocative movements that cause pain
• Taking breaks when having to carry out a repeated wrist motion
• Keeping your hand and forearm muscles strong

Further helpful information can be found here on: 

• Bursitis
• Repetitive strain injury
• Tennis elbow
• Carpal tunnel syndrome
• Cubital tunnel syndrome