De Quervain' s tenosynovitis is the thickening of the fibrous sheath enclosing the tendons of the thumb causing their compression and pain.
De Quervain's tenosynovitis consists in the inflammation of the extensor pollicis brevis and abductor pollicis longus tendons, which are connected to the homonymous muscles. These tendons are enclosed in a fibrous-osseus sheath or synovium on the dorsal side of the forearm that extends along the lateral thumb. The thickening of the synovium is thought to result from repetitive movement of the thumb in combination with radial deviation of the wrist. Over time this action causes the irritation and swelling of the tendons, which are compressed (stenosis) within thicker synovial sheath. This causes pain over the radial styloid process.
De Quervain's tenosynovitis mostly occurs in women of 30-50 years of age. Overuse of the thumb and wrist seems to be the main cause of this pathology mostly due to manual activities during carpentry work, sport driving and prolonged work with computers. It also occurs with a sudden and direct blow to the dorsal side of thumb/wrist.
The risk factors to develop De Quervain's tenosynovitis are:
Sport (golf, bowling, tennis, mountain bike, rowing, racquets sports)
Manual work (carpentry, painting, sewing, writing, overuse of hammer/screw driver)
Predisposition to rheumatoid diseases
Use of computers
Lifting children or heavy bags (young mothers)
Presence of narrower synovial sheath of the first extensor tendon of the thumb.
De Quervain's tenosynovitis causes pain and tenderness at the radial/thumb side of the wrist below the base of the thumb. These symptoms develop gradually over time. Pain can radiate to the forearm or to the tip of the thumb and is exacerbated during pinching and grasping activities. Other symptoms include:
Catching and snapping sensation during thumb movement
Numbness back of the thumb and index finger
Swelling and redness in the area affected.
De Quervain's tenosynovitis is simply diagnosed with medical examination. It is important to assess the potential causes from life style or professional activities leading or exacerbating the condition to prevent recidivism.
The Finkelstein manoeuvre is used during medical examination. This test is positive if pain is elicited when the thumb is bent across the palm, the fingers are flexed over the thumb and the hand is moved into ulnar deviation.
Ultrasound is an imaging technique used to visualise changes in the structure of the tendons. Occasionally a MRI can be recommended in more severe cases.
Differential diagnosis for arthritis of the first carpo-metacarpal joint of the thumb and other inflammatory conditions of the wrist is recommended.
Conservative treatment includes the immobilisation for up 2 - 4 weeks with a spica cast to allow minimal movement of the thumb. Additional treatments include:
Administration of NSAIDs
Local steroid injection
A physical or occupational therapist recommend exercises to restore flexibility and strength of the thumb and wrist (i.e. thumb opposition, extension and flexion) when most symptoms have subsided. Standard rehabilitative therapy also includes:
Activity modification advice
Return to activity plan
Taping / bracing
The main preventative measures aim at reducing the risk of future De Quervain's tenosynovitis and avoid those repetitive activities that caused the condition. Common preventive strategies are:
Ergonometric education for proper posture while performing physical activities
Exercise to improve flexibility and strength