Hand CASE 29

CASE                               29                               

An 8-month-old patient presents with her parents for evaluation of her right thumb.

The parents report that the left thumb is smaller. At times the patient attempts to use the thumb to pinch, at other times she attempts to pinch objects with her index and long fingers (Fig. 4–16A and B).

 

 

 

Figure 4–16 A–B

 

Which of the following anomalies is not associated with this condition?

1. Tracheoesophageal fistula

2. Thrombocytopenia present at birth

3. Pancytopenia present at birth

4. Ventricular septal defects

5. Anal atresia

 

Discussion

The correct answer is (C). This patient has a hypoplastic thumb. Associated syndromes include VACTERRL (vertebral, anal atresia, cardiac defects, trachea-esophageal fistula, renal, and radial limb anomalies), Holt–Oram syndrome, or thumb hypoplasia, and congenital heart defects including atrial or ventricular septal defects. Pancytopenia associated with Fanconi anemia does not often present until later in childhood but can be lethal. Thrombocytopenia with absent radius (TAR) has thrombocytopenia present at birth, and the platelet count typically improves with

time.

 

Which of the following associated conditions is autosomal recessive?

1. VACTERRL

2. VATER

3. Holt–Oram

4. Fanconi Anemia

 

Discussion

The correct answer is (D). VACTERRL and VATER are often sporadic. Holt–Oram syndrome has an autosomal dominant inheritance pattern. TAR has an autosomal recessive inheritance pattern but can also be sporadic in nature. Fanconi anemia is autosomal recessive.

The patient undergoes genetic testing and is not found to have any associated anomalies. The parents want to know more about possible surgical treatment options.

Which of the following is contraindicated in hypoplastic thumb reconstruction?

1. Abductor digiti quinti opponensplasty

2. Flexor digitorum superficialis tendon transfer opponensplasty

3. Stabilization of the metacarpophalangeal joint with free tendon graft

4. Stabilization of the carpometacarpal joint with free tendon graft

5. Excision of a floating thumb, or pouce flottant

 

Discussion

The correct answer is (D). Opponensplasty can be performed with either an ADQ (Huber) transfer or an FDS (often from the ring) transfer. The MCP joint is often unstable and can be stabilized as part of reconstruction. The instability of the carpometacarpal joint is most likely due to an underdeveloped proximal metacarpal, so attempts at stabilization with soft tissue will not be successful. A floating thumb has no bony attachment to the hand and no function. Therefore, excising the severely hypoplastic thumb is a common step in thumb reconstruction.

On physical examination, the patient is found to have a thumb in the plane of the hand and absent thenar muscles, a narrow first web space, and instability of the thumb carpometacarpal joint.

What is the most appropriate next step in surgical management?

1. Pollicization

2. Chondrodesis of the carpometacarpal joint

3. First web space deepening with four flap z-plasty

4. Opponensplasty with abductor digiti quinti transfer

5. Progressive splinting to improve the first web space

 

Discussion

The correct answer is (A). A stable carpometacarpal joint is tantamount to proceeding with thumb reconstruction that preserves the native thumb. Chondrodesis of the CMC joint is contraindicated because it would severely limit opposition. First web space deepening and opponensplasty are utilized in hypoplastic thumbs with stable CMC joints. Progressive splinting will not deepen a congenitally narrow web.

The patient’s parents were so inspired by the successful treatment of their son that they adopted a child with radial club hand. They present with this child for treatment. On physical examination, he has an absent thumb, radial deviation of the hand at the wrist, and a foreshortened humerus.

Centralization of the hand is contraindicated in which of the following?

1. A patient without antecedent pollicization

2. Absent scaphoid and trapezium

3. Absent extensor carpi radialis longus and brevis

4. Stiff elbow held in extension

5. Minimal active shoulder abduction

 

Discussion

The correct answer is (D). The radial longitudinal deficiency often involves multiple radial-sided structures including absence of intrinsic and extrinsic muscles, an absent thumb, and absent radial carpal bones. If the patient is unable to bend the elbow, then the deviated wrist may act as an elbow in order to get the hand to the mouth. By centralizing the hand on the wrist, the patient may therefore lose function if he cannot reach his mouth. Shoulder abduction is not necessary to perform centralization.

 

Objectives: Did you learn...?

 

Recognize the associated syndromes with hypoplastic thumb, their inheritance patterns, and their expected clinical course?

 

Identify the indications for opponensplasty versus pollicization?

 

Pinpoint the contraindication for wrist centralization in radial hypoplasia?