It is a regular occurrence for us in our clinic to see new mothers come in with pain and irritation at the base of the thumb near the wrist. This often occurs within a few weeks of welcoming a new member to their family. Pain in this area is often due to Mummy’s thumb – or de Quervain’s Tenosynovitis.
So what is de Quervain’s Tenosynovitis?
Mummy’s thumb is one of many colloquialisms for this condition. According to Wikipedia is has also been referred to as:
- “Blackberry thumb”
- “PlayStation thumb”
- “texting thumb”
- “cell phone thumb”
- “smartphone thumb”
- “Android thumb”, and
- “iPhone thumb”
Thinking about the names given to the condition above, it can be surmised that de Quervain’s tenosynovitis comes about after repetitive use of the thumb/wrist.
Anatomy of your thumb
The two main tendons of your thumb, extensor pollicis brevis (EPB) and abductor pollicis longus (APL), run closely together at the base of your thumb. These tendons work together to abduct (pull to the side) and extend the thumb.
On their way to the thumb, the EPB and APL tendons travel side by side along the inside edge of the wrist. They pass through a sheath tunnel near the end of the radius bone of the forearm. The sheath tunnel helps hold the tendons in place.
The tendons are surrounded by a soft tissue called synovium and are then encased in a tendon sheath.
‘Tenosynovitis’ is swelling or inflammation of the tendon and synovium causing increased friction on the sheath. This causes difficulty and pain to glide the tendons through the ‘tunnel’ resulting in pain.
Cause of Mummy’s Thumb
As mentioned above, de Quervains tenosynovitis is generally due to repetitive motions of the wrist/thumb. Specifically repeated hand and thumb motions such as:
These repeated motions can cause inflammation or swelling, which can restrict the smooth gliding of the tendons within the sheath/tunnel.
De Quervains tenosynovitis can also be caused by inflammatory/arthritic conditions such as rheumatoid arthritis.
A direct blow to the area can also cause tenosynovitis. Sometimes scar tissue from an injury will cause the tendons to have difficulty moving through the tunnel.
Other times de quervains comes about after no apparent injury cause or change in activity.
In Mummy’s thumb, the tendons tend to become irritated due to the new repeated action of lifting a young child.
When lifting a young child, the wrist will often go from a position of ulna deviation, to a position of radial deviation (or vice versa). Repeating this motion causes to the two main tendons of the thumb to work in a position they may not be accustomed to. The tendons may also rub repeatedly against the radial styloid, a small bony prominence on the side of the wrist.
Certain preceding biomechanics can also lead to the onset of Mummy’s thumb. Muscular tightness or joint stiffness throughout the upper limb can contribute. This is where a physiotherapists knowledge and assessment can be valuable in understanding and treating the condition.
- Pain near the base of the thumb
- Swelling in the wrist or near the base of the thumb
- Difficulty moving the thumb/wrist
- Difficulty grabbing/pinching/lifting objects with the affected hand
- Crepitus (creaking sound) – as the tendons become more constricted they may make a sound as they move through the sheath tunnel.
- Left untreated, pain can extend along the forearm
- Pain can also extend down further along the thumb
Diagnosing Mummy’s Thumb
Diagnosing de Quervains tenosynovitis can be accurately done clinically (without further fancy imaging/investigation). After listening to a client describe their symptoms, a common diagnostic test is the finklestein test. This involves grasping your thumb in a closed fist (same hand), and tilting the wrist in the direction of the little finger. The test is positive for de quervains tenosynovitis when the wrist/thumb pain is reproduced in this position.
Treatment of Mummy’s Thumb
The main focus of physiotherapy is to reduce or eliminate the cause of irritation of the thumb tendons.
Rest or Reduce Hand Movements
After talking to your physiotherapist, it may become apparent that certain activities or movements are irritating you thumb tendons.
- If possible, stop or change the task that has been identified.
- If doing repeated hand and thumb actions take frequent breaks.
- Avoid repetitive hand motions, such as heavy grasping, wringing, or turning and twisting movements of the wrist.
- Aim to keep your wrist in neutral – keeping it straight with your arm while completing tasks. A splint can be beneficial:
Your physiotherapist may suggest that you wear a thumb splint called a ‘thumb-spica’ splint. We recommend a thermoplastic splint called a ‘thumboform.’ This splint keeps the wrist and lower joints of the thumb from moving – particularly restricting ulna and radial deviation. The splint allows the APL and EPB tendons to rest, giving them a chance to begin to heal. Strapping tape can also be useful as a temporary splint.
Icing the aggravated area can be an effective way of soothing the irritated tendons.
Topical anti-inflammatory gel can be beneficial in de Quervains tenosynovitis or Mummy’s Thumb. Before bed, we recommend applying the gel liberally over the sore area, then covering the area in glad wrap to avoid evaporation.
In de Quervains tenosynovitis, the irritated thumb tendons do not take well to being stretched. However other muscles throughout the forearm may be tight and contributing to the onset of the irritation. Common prescribed stretches include stretches for the forearm flexors and extensors:
Exercises to help strengthen and stabilise the elbow, wrist and thumb can be beneficial in Mummy’s thumb. It is possible that a preceding weakness in muscles around the elbow, wrist and thumb can contribute. Exercises to strengthen the wrist extensors are commonly prescribed:
It is important to note that de Quervain’s tenosynovitis or Mummy’s thumb can be successfully treated with physiotherapy.
For advice specific to managing your de Quervain’s tenosynovitis or Mummy’s thumb, please consult your physiotherapist.
Brukner P, Khan K. 2007. Clinical Sports Medicine (3rd Ed). McGraw-Hill, Sydney.