What is De Quervains Tenosynovitis?
De Quervain’s Tenosynovitis is a relatively common Tendonitis seen more often in women than men. It occurs when the two tendons that pass to the thumb and lift the thumb up and away from the hand friction inside their sheath as they pass around a small bony prominence at the end of the radius bone.
As the tendons swell inside the sheath they become compressed. There are a number of conditions associated with De Quervains including arthritis, diabetes, hypothyroidism, and pregnancy.
Causes
De Quervains is most commonly seen in new mums, hence its common name “Mum’s Thumb”. As the baby increases in weight, handling the baby (including lifting and feeding) causes repetitive friction of these two tendons against the radial styloid.
De Quervains can also occur in situations involving repetitive spanning of the thumb around large objects especially if the wrist is also required to deviate toward the little finger (ulna side). This position increases the acute angle that the tendons have to travel and therefore initiates an inflammatory process.
Less commonly the condition can be caused by a direct blow, a sudden forceful movement with the thumb and wrist bent toward the little finger side of the hand or irregularity from a wrist fracture.
Treatment
While this tendonitis will respond to the usual treatments of rest, ice, compression, elevation, ultrasound, massage. The most important aspect of treatment is short term rest (immobilsation.)
1. Splinting
This is the most crucial aspect of treatment. It is best done with fabrication of a custom thermoplastic splint that immobilises the base and middle joints of the thumb, but allowing a pinch grip between thumb and index finger. The splint should be worn for 6 weeks at 80% of the time. Then slowly withdrawing from the splint over a further 2 week period, wearing only for aggravating/painful movements.
There are many commercial splints available but frequently these are bulky to wear and do not adequately immobilize the inflamed tendons.
2. Activity Modification
Activity modification to avoid particularly aggravating movements is also crucial for long term management and prevention of reoccurrence.
3. Cortisone Injection
If symptoms fail to settle with conservative treatment, a cortisone injection may be offered, or surgery as a last resort.
Management
Splinting is the most crucial element in treatment as it allows rest of the tendons involved whilst allowing uninvolved joints to be free to move
Forearm soft tissue release and local treatment.
After the 6 week splinting period it is important to continue to wear the splint for aggravating activities for a short time to prevent re-aggravation.