Radial Club Hand
Radial Club Hand (RCH) is a longitudinal deficiency of the radius bone in the arm. It includes a spectrum of deficiencies involving the radius, the radial side of the carpus, and the thumb. It is a congenital deformity that occurs between 1 in 30,000 to 1 in 100,000 live births. Affected individuals have the deformity bilaterally (both hands) about half of the time. RCH is usually associated with other upper extremity deformities and deficiencies, including:
- Absent or Hypoplastic Thumb
- TAR Syndrome
- Fancomi’s Anemia
- Holt-Oram Syndrome
- VACTERL Association
Radial Club Hand was originally classified by Bayne and Klug according to the length of the radius and the extent of deficiency:
- Type 1 – Short Radius
- Type 2 – Hypoplastic Radius
- Type 3 – Partial Absence of the Radius
- Type 4 – Complete Absence of the Radius
Radial Club Hand is an aesthetically unappealing deformity that also results in significant functional impairment (due to absent or hypoplastic thumb) and instability and restricted motion in the elbow, wrist, and finger joints. Parents of children with RCH seek treatment for the condition shortly after birth.
The deformity of the radius in RCH results in the ulna becoming the primary forearm bone. Due to this, there is little or no support for the carpus (wrist joint) on the radial side; furthermore, the carpus may be displaced off the ulna altogether. As the wrist and fingers are flexed, the flexion force results in radial deviation of the hand and volar displacement of the carpus (toward the palm side). Individuals with RCH have poor grip strength due to the lack of a fulcrum and the forearm shortening resulting in shortened muscles. To easily understand this, try flexing your wrist downwards, palm side down, and then try and make a fist. You will find it is much more difficult to make a fist then it is with your wrist in a neutral position.
Although children who have RCH (especially unilaterally) adapt adequately to this anomalous condition, obvious functional deficits occur that limit activities. Motion of the elbow joint might be decreased, or the joint might be fixed in extension. Motion of the wrist and fingers is limited, with the deficit being most severe in the index finger and progressively less severe in the other fingers.
Patients with RCH often have absent or hypoplastic thumbs. They often develop a side-to-side pinch between adjacent fingers that is useful for handling small objects but is ineffective for grasping large objects. Decreased forearm length reduces the patient’s reach. Activities involving the use of two hands are difficult to perform when a normal hand must be brought to meet a shorter extremity. When both extremities are involved, activities are greatly impaired by the absence of at least one upper extremity of normal length.
For these reasons, surgical treatment for RCH is frequently requested. At the Paley Institute we treat RCH with the Ulnarization surgery, a technique modified by Dr. Paley from an earlier surgery called a Radialization. With the Ulnarization surgery we can safely correct Radial Club Hand with no recurrence and low risk of complication, restoring function and cosmetic appearance to the patient.
Many surgical procedures have been developed over the years to treat the deformity of Radial Club Hand. Some of these procedures include:
- Distal Ulnar Osteotomy
Centralization is a technique in which the carpus is placed over the center of the distal end of the ulna. It was considered the gold standard for RCH treatment for many years. However, the treatment was plagued by partial or complete recurrence of the RCH deformity.
An alternative to Centralization was proposed by Buck-Gramcko, which he termed Radialization. With Radialization, the hand and carpal bones are translocated to the ulnar side of the ulnar head. In addition, the extensor and flexor carpi radialis (FCR) tendons are transferred to the ulnar side to weaken the forces of radial deviation and strengthen the ulnar motors. The name Radialization refers to conversion of the ulna into a radius. Buck-Gramcko’s technique resulted in much lower recurrence rates compared to Centralization. The radialization technique works using the following rationale:
- Create a fulcrum to the radial deviation forces of the forearm without impeding wrist motion,
- Balance muscle forces on the radial and ulnar sides of the wrist using tendon transfers.
In 1999 Dr. Paley developed a new procedure to treat RCH based on a modification of the Buck-Gramcko Radialization. He termed the procedure an Ulnarization to describe the direction of movement of the carpus relative to the forearm (ulna) and to distinguish it from Radialization, which is performed differently.
The development of the Ulnarization procedure was based on some of Dr. Paley’s observations of the Radialization procedure. First, Radialization is performed through a dorsal incision (top of the hand), resulting in poor to no visualization of the neurovascular structures as well as excessive dissection of the ulna. In Dr. Paley’s Ulnarization approach, the incision is volar (palm side) which allows visualization of the neurovascular structures of the hand and limits dissection of the ulna. Second, the flexor and extensor carpi radialis tendons, which are transferred to balance the wrist in the Radialization procedure, are usually absent and thus unavailable for transfer. In the Ulnarization technique, the flexor carpi ulnaris (FCU) is transferred to balance the wrist. Unlike the other tendons, the FCU is always present and never hypoplastic. Lastly, the term Radialization is confusing in English. Ulnarization more accurately describes the procedure.
One of the major goals of the Ulnarization surgery is to correct the poor grip strength in individuals with RCH. Poor grip strength is due to:
- Lack of a fulcrum
- Forearm shortening affects muscle length curve
- Excessive palmar flexion pull: dorsi flexion of hand increases grip strength
To easily understand this, try flexing your wrist downwards, palm side down, and then try and make a fist. You will find it is much more difficult to make a fist then it is with your wrist in a neutral position. In order to correct this, Dr. Paley transfers the flexor carpis ulnaris (FCU) tendon which will give a stronger grip force.
In the Ulnarization technique, Dr. Paley converts the head of the ulna into the fulcrum. This makes recurrence impossible since the ulna physically blocks the wrist from reverting to the deformed position. The FCU is transferred from the palmar side to the dorsum (top) of the wrist. The FCU is a very strong tendon and transferred becomes the new extensor for the wrist, allowing increased grip strength and finger range of motion.
First, Dr. Paley will make the volar incision (palm side) of the wrist in order to minimize soft tissue complications. The wrist is then carefully dissected and the pisiform and FCU released.
If there is any radial fibrous anlage present, it is resected at this time.
In order to transfer the wrist, it must be disconnected from the ulnar, a process known as a volar capsulotomy. The ulnar head is completely disconnected from the wrist, but the muscles and blood vessels are preserved and protected.
The ulnar head will come to rest in the radial pocket and the wrist is moved to the ulnar side. A pin is then inserted through the ulna and the cartilage of the wrist in order to hold everything in the proper alignment.
The FCU is then transferred and reattached to the cartilage of the wrist, usually over the fourth metacarpal. Internal K-wires are applied to hold the new alignment in place.
The final step is to distract the ulna away from the wrist joint. Dr. Paley used to use an external fixator, but he has now developed a new method using internal fixation.
The patient is admitted postoperatively with strict elevation of the upper extremity and neurovascular checks performed by the staff every 4 hours. Pain and muscle spasm control are administered. Distraction of the external fixator will begin on postoperative day one, with pin care to be performed immediately after. The distraction is performed with one-third turn 3 times per day for a total of 0.8 mm per day. The distraction continues until the proximal end of the carpus is at the level of the tip of the distal ulnar epiphysis. Physical therapy begins on postoperative day one and consists of elbow and finger range of motion exercises.
The external fixator is maintained for a total of approximately three months, at which time it is removed in a minor outpatient procedure. A wrist splint will be constructed and should be worn between therapy sessions full time for two months and then during the night thereafter. Therapy continues after frame removal and should focus on obtaining maximum range of motion of the wrist, elbow, and fingers.
The Ulnarization technique results in a completely mobile wrist joint with no recurrence and no growth arrest. These are remarkable results for Radial Club Hand. In conclusion, the Ulnarization is a safe surgical technique that has resulted in:
- No recurrence
- No growth arrest
- Low complication rate
- Improved grip strength
- Active wrist flexion and extension
- Improved activities of daily living
- Improved cosmetics
- Normal alignment of the wrist