Sunday, September 29, 2019

Untreated Adult Hypoplastic (Small) Thumb

On occasion, an adult comes to my clinic for evaluation of one issue and a previously unrecognized issue is identified.  This type of presentation can come in different varieties and, due to my particular practice type, often we find a birth anomaly that has not been recognized or treated.  This patient is one very interesting example.  She has a left hypoplastic thumb.  There is an appearance difference and a functional difference yet it has not caused major problems for her.  Her right thumb and hand are dominant and the left hand and thumb are used for assist (as we all function).  Her thumb is weaker and more lax and has decreased motion.  But none of these problems were completely troubling to her and she certainly is not interested in treatment at this point. 

From the hand surgeon perspective, she has a classic small thumb on the right (technically a hypoplastic thumb- Type IIIA).  It is thin (and seems long but that is really only because it is thin).  She has small muscles at the base of the thumb (thenar muscles), a decreased web space (between the index and thumb), laxity at her MCP joint, and decreased thumb motion.  In other words, she checks all the boxes for a classic hypoplastic thumb.

These videos demonstrate many of these classic findings for hypoplastic thumb and hopefully are helpful to better demonstrate the limitations of her left thumb.  While I see many children with this condition, it is a little bit more tricky to capture the presentation on video!








Charles A. Goldfarb, MD              
My Bio at Washington University     
email: congenitalhand@wustl.edu

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Sunday, September 22, 2019

Distal arthrogryposis, before and after

Distal arthrogryposis is very different from AMC or other forms of arthrogryposis.  By definition, distal arthrogryposis includes joint tightness (contractures) in the hands and feet.  Here is an excellent Link from NIH.  I have also previous posted on distal arthrogryposis, those links can be found HERE.

I wanted to share some early results on a 5 year old patient with distal arthrogryposis.  This patient had surgery 3 months ago on his right hand and is planned for surgery on the left.  There were two goals with surgery- free the tight thumb while placing it in a better position for function AND releasing the tight middle finger (camptodactyly).  This patient is helpful as an example because the surgically treated right hand previously looked almost exactly like the left hand looks today. 
Distal arthrogryposis, right hand, after surgery.  Note the position of the thumb and middle finger.

Distal arthrogryposis, left hand, before surgery.  Note the tight thumb and middle finger.

These two videos emphasize the same points on distal arthrogryposis of the right hand after surgery and the left hand before surgery.  I apologize for my video skills (trying to multitask) but the improved positioning on the right is striking while recognizing that the hand still has limitations.




The family is very pleased and have noticed functional improvements already. Surgery included
1) Flap to deepen thumb- index web space with release of contracture
2) Stabilization of thumb MCP joint
3) Release of tight PIP joint of middle finger
4) Flap to release tight PIP joint

Charles A. Goldfarb, MD              
My Bio at Washington University     
email: congenitalhand@wustl.edu

Please CLICK HERE to support our research.  
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Thursday, September 19, 2019

Fixators for Lengthening. Fun?

External fixators are devices that rest outside of the skin.  They can be used to stabilize broken bones (although not used very often for this purpose today) or to correct a short or angled extremity/ bone.  We use fixators to lengthen small bones such as the thumb to allow pinch or to grow the forearm to assure that the two bones of the forearm are nearly the same length.  The forearm is interesting because if the bones are not the same length, the wrist can deviate and/ or the elbow can dislocate or shift out of position.  Neither of these are good.  So, if we can avoid those problems by lengthening the short bone, it can be a real help.  I have previously blogged about fixators of different varities HERE.

There are three common reasons why we lengthen a forearm bone
1) Multiple hereditary exostosis (MHE).  In this case, the ulna is often short and the radius is at risk for dislocating at the elbow.  See my other posts on this topic HERE.

2) Radial longitudinal deficiency (RLD).  In this case, the radius is short and, if there is a radius present, it can be lengthening to balance the wrist.  See other posts HERE.

3) A trauma or injury which affects the growth plate of the radius.  This may be a fracture near the growth plate of the distal radius which affects growth and leads to a long ulna.  Or, an infection of the growth plate can have the same effect. 

This patient had multiple infections around the time of birth.  The infection affected her thumb and index finger and has led to a short radius.  We have elected to lengthen her radius with a fixator to achieve balance and hopefully avoid future problems.  Here are x-rays showing the short radius bone.

Short radius related to infection affecting the growth plate

At the time of surgery, we applied a fixator to lengthen the bone.
External fixator to lengthen the radius.  The cut in the one (osteotomy) is visible- this is where we will lengthen the bone
over time.
The idea is that with slow stretching of the bone, the bone will grow.  Typically we 'turn
the dial' on the fixator 2-4 times each day.  This lengthens the bone from 1/2 of a millimeter to a full millimeter each day.  We do this slowly to allow the body to make enough bone so that after we lengthen (and then give the bone time to get stronger), we can remove the fixator and the bone will be strong!  The fixator is on the arm different times for each patient depending on how much length is needed and how much bone is created.

This young lady shows that the fixator is no big deal!  She has had her fixator about 2 weeks and is doing really, really well with it.  Super cute and, surprisingly, a little shy here.



Thanks to mom for allowing her daughter to share her experience!  What an amazing kid and amazing family.  I have had the pleasure of knowing this family since shortly after birth and I am so happy to have had this chance to get to know them and watch her grow!

Charles A. Goldfarb, MD              
My Bio at Washington University     
email: congenitalhand@wustl.edu

Please CLICK HERE to support our research.  
Designate my name.  Thank you!