Extra Thumb

Radial polydactyly is also called split thumb or thumb duplication.  Or, an extra thumb if we really want to keep it simple.  Extra thumbs all share some similarities but each is really unique. 

How most patients with radial polydactyly are similar

•        Both thumbs are smaller than the “normal” thumb should be. 
•      Many extra thumbs have decreased motion.  Fortunately, decreased motion is not a terribly big deal for function as the thumb can be great for function even with limited flexibility. It is more important that the thumb be well aligned and stable.
•       Most thumbs are usable even though there is an extra digit.  However, the extra thumb is often in the way, might limit use of the better thumb, and obviously creates a social issue for the child (with possible mental health impacts).

How patients with radial polydactyly can be different

•         Some extra thumbs are pretty straight and some are really crooked ( really “z” shaped).  This fact is, to me, the most important difference and the one that affects surgical technique and surgical outcome most.  It is also the reason that more than one surgery might be necessary.
•         Some thumbs have really pretty normal underlying tendons and joints whereas other thumbs have abnormal tissues.  This affects motion and may play a role in recurrence of deformity.
•          Sometimes the thumb is positioned right where it should be- a position to maximize holding big objects and pinching against index finger.  Sometimes the thumb is more in the plane of the fingers, thus making pinch more challenging.
•         Some extra thumbs are small and only have a single bone whereas others have 3 or more bones, extra muscles, etc.

The following is a case of an extra thumb treated at a young age with a result that has made the family really happy.  The radial polydactyly surgery was somewhat complicated with excision of the extra, outer thumb and reconstruction of the inner thumb.  That reconstruction included stabilizing the main joint, cutting and angling the bone, and realigning the tendon. 

Some of our research has been on the topic of appearance after the reconstruction of radial polydactyly.

http://www.ncbi.nlm.nih.gov/pubmed/18929199  This paper reviews the appearance outcome from a number of patients that we treated with surgery and concludes that the type of radial polydactyly (i.e., based on the bony appearance before surgery), the angulation after surgery, and the nail itself affect satisfaction with surgery.

Currently, the patient uses the thumb well, has a stable thumb, and has no pain.  The size is good and not noticeably smaller than the other thumb.  However, the thumb is not straight.  At this point, the family is not concerned with the deformity.  Yet, I believe it is something that can be effectively corrected as the child gets a bit older.

The hand doubles in size from birth until 2 years of age and then almost doubles again at an adult size.  As the thumb gets larger, a correction is easier to accomplish and can be done more precisely.  I believe that this patient will benefit from an osteotomy (or cutting) of the bone to straighten the thumb.  I continue to follow patients on a yearly basis and the family and I will continue to discuss this decision.  I have no intention of “talking” the family into a surgery but will make them aware of the option and what an osteotomy surgery would require.  Specifically, it would require an outpatient surgery, require less than1.5 hours of surgery time in most cases, and require pinning of the bone(s) for about 5 weeks.  We may have to work on the soft tissues again as well.  The patient's thumb and hand would be casted during those first 5 weeks and possible splinted later.

Radial polydactyly before surgery.  Note that both thumbs are crooked.  We reconstructed the inner thumb and removed the outer thumb.

X-ray of radial polydactyly

1 year after radial polydactyly surgery.

Another view 1- year after surgery to reconstruct radial polydactyly.  Note that the thumb is crooked.

x-ray after radial polydactyly reconstruction

x-ray after radial polydactyly reconstruction

Madelungs Deformity

Madelungs Deformity is a malformation of the distal radius which creates a deformity of the wrist.  It typically presents in adolescent females and often is bilateral.  Madelungs may be painful and may limit motion of the forearm and wrist.  There is a known genetic pathway for patients with a SHOX gene abnormality.   There genetics are also related to Leri Weill dyschondrosteosis which combines Madelungs with short stature and short forearm segments. We have written about the x- ray appearance of Madelungs and the different x- ray types: http://www.ncbi.nlm.nih.gov/pubmed/17996774.  Also, Relton McCarroll really advanced our understanding of Madelungs with descriptions and measurement techniques for x- rays: http://www.ncbi.nlm.nih.gov/pubmed/16344178

We believe that Madelungs deformity is caused by a growth plate abnormality of the distal radius.  Also, there can be a large ligament (Vickers ligament) which some believe contributes to the deformity. Patients typically present in the early adolescent years (10-14 years) and if conservative care does not help, surgery can be considered. If symptoms are on the thumb side of the wrist, we often consider an osteotomy (cutting) of the radius bone in a very specific way- a dome osteotomy.  Drs Carter and Ezaki pioneered this treatment for Madelungs and describe it in this technique article: http://journals.lww.com/techhandsurg/Fulltext/2002/03000/Volar_Surgical_Correction_of_Madelung_s_Deformity.6.aspx

The same group has published their results twice, short term and more than 10 years after surgery.  Both reports detail the success of the procedure for many patients.  The second article is from July of 2013- hot off the press!
http://www.ncbi.nlm.nih.gov/pubmed/17095381
http://jbjs.org/article.aspx?articleID=1698451

If the pain is related to the pinky side of the wrist, sometimes we only address the ulna bone and shorten it.

I recently had the chance to see a patient back more than one year after a dome osteotomy of the radius for Madelungs.  Her pain and her motion were both better and she and her mom were happy.  However, it is important to note that even if surgery goes very well, the wrist will not be "normal."  Additionally, later surgery can be required to deal with pain on the pinky side of the wrist.

Front view of Madelungs.  There is a great deal of deformity of the wrist

Side view of Madelungs with curving radius and split between the radius and ulna

White metal pins after surgery to hold the bone in place for healing in Madelungs Dome Osteotomy.

Appearance after surgery for Madelungs.  The wrists now look similar.

The wrist does not look "normal" after surgery for Madelungs but looks much more typical.

Side view after surgery for Madelungs.  Note that the radius and ulna line up much better now.

Pollicization at 15 years

Pollicization, or the creation of a thumb from an index finger, is one of my favorite surgeries.  I like it so much because it allows me to accomplish my 2 primary goals for a child- making his or her hand function better and look better with a single operation.  I have written several blog entries on the topic:
http://congenitalhand.wustl.edu/2011/10/pollicization-creating-new-thumb.html
http://congenitalhand.wustl.edu/2011/12/more-thoughts-on-pollicization-decision.html

I believe that the pollicization surgery requires a skill set that the surgeon develops only over time.  In other words, the surgeon must have a perfect understanding of the technical steps of the procedure (cut here, tighten there, etc.) but most also have a greater sense of how the new thumb should look and how to accomplish that goal.  To me, that skill takes time to develop.  While this is a whole other topic, the procedure is why I believe the mentorship model for education is so important for our field of congenital hand surgery.  All surgeons have spent years to finish medical school, residency, and fellowship (for orthopaedic surgeons, that process is 10 years) but I think more time still is required for the very specialized area of congenital hand surgery.  Undoubtedly, a surgeon who has completed his/ her training can recite the steps of the pollization procedure but, to me, more time is required and more experience is required before mastering the procedure.

I was fortunate to work with and learn from Paul Manske, one of the most accomplished congenital hand surgeons.  I learned from Dr Manske during my residency training and then had the good fortune to work with him for 10 years after I was done with my training.  I performed countless pollicizations with him and each time, I learned a little something.  But it was during that time that I felt my skill and confidence with this operation (and others) grow.

Anyway, back to the point of this post: the long term outcome of the pollicization.  These pictures demonstrate a very happy patient with a wonderful thumb, created 15 years ago by Dr Manske.  There is not really anything else for me to say other than this is a good outcome and one that we desire for every patient.  While not all pollicizations will look this good (there are many factors that affect the outcome), all, at least in my experience, improve both function and appearance of the hand.

Long term Pollicization.

Long term Pollicization, resting position

Long term Pollicization, pinch position.  Notice that there is nice tip to tip pinch.

Long term Pollicization from palm view.

Symbrachydactyly of the Foot

Symbrachydactyly, or short webbed fingers, is a birth difference which almost always affects one arm.  I have blogged about this anomaly several times- this is a link to all relevant posts.  http://congenitalhand.wustl.edu/search/label/Symbrachydactyly

One of the ways we differentiate symbrachydactyly from other anomalies is that it is almost always affects only one arm.  When more than one arm is affected or if the feet are also affected, other diagnoses such as amniotic constriction band must be considered.  Very rarely, the foot can be affected with symbrachydactyly (again, typically only one foot with a normal other foot and normal hands).

There are only a few reports of foot involvement in symbrachydactyly.  The most comprehensive is by Uchida in 1995 on 17 patients  http://www.ncbi.nlm.nih.gov/pubmed/7705729.  2 did have hand involvement also and 1 had a Polands syndrome (the most common association with symbrachydactyly of the upper extremity).  Polands syndrome is a lack of normal development of the chest muscles.

The reason to make this diagnosis is twofold.  First, to use the diagnosis to rule out other associated conditions.  What I mean is that if we diagnose symbrachydactyly, we do not expect serious internal organ issues such as problems with the heart, lungs, etc.  And second, symbrachydactyly is almost always a random, sporadic issue so that there is no predictable genetic transmission.  So if the parents have other children or if/ when the affected child has children, we should not expect others to be affected.

Symbrachydactyly of the foot.  Note the short 3rd and 4th toes.  No other extremities or digits were involved.

Despite the "normal" appearance of the great toe, second toe and 5th toe, the x-rays show that all toes are short in this child with symbrachydactyly of the foot.