There are two types of club hand: Radial club hand and the more rare Ulnar club hand.
Club Hand is classification type I: Failure of Formation.
Radial Club Hand: The deficiency of the upper extremity along the radial side, radial dysplasia / underdeveloped or absent radius. Wrist rests in radial deviation.
Ulnar Club Hand: Deficiencies of the ulna and/or ulnar sided carpal structures. Underdeveloped ulna or ulnar sided carpal bones. Wrist rests in ulnar deviation.
This chapter will cover radial club hand. The cause of radial club hand is unclear. Current theory: A defect of the apical ectodermal ridge (AER) during limb development is the most probable cause.
Time to Play the Brain Game:
Q) Radial dysplasia is another term for radial club hand. True or False?
A) True. It can also be termed radial longitudinal deficiency. the patient displays with radial deviation of the wrist and shortening of the forearm.
Clinical presentation of radial club hand:
- Deficiency of the radius
- Forearm is always decreased in length
- Ulna is about 60% normal length
- True forearm rotation is absent
- The wrist is radially deviated
- Wrist motion is primarily in the radial / ulnar plane
- Limited wrist extension and flexion
- Ossification of the carpal bones is delayed
- The fingers are often stiff
- Muscles in the arm can be hypoplastic, partially absent or have and abnormal insertion
- The radial nerve usually terminates at the elbow
- Absent or deficient thumb, hypoplastic thumb
Additional anomalies can be proximal, involve the forearm or hand.
Example of radial club hand with X-Ray
Complete absence of the radius and hypoplastic thumb level 5, (absent thumb)
Time to Play the Brain Game:
Q) Is Type 5 the worst type of club hand?
A) True. Here are the various types…
Type N: Isolated thumb anomaly
Type 0: Deficiency of the carpal bones
Type I: Short distal radius
Type II: Hypoplastic radius in miniature
Type III: Absent distal radius
Type IV: Complete absent radius
Type V: Complete absent radius and manifestations in the proximal humerus
Bonus… here is another classification system:
Type 1 – Short Radius
Type 2 – Hypoplastic Radius
Type 3 – Partial Absence of the Radius
Type 4 – Complete Absence of the Radius
The angled position of the wrist further shortens the limb and limits the ability for the child to reach into space and places the extrinsic flexors and extensors at a mechanical disadvantage making it difficult for finger motion.
Time to Play the Brain Game:
Q) When reconstruction is done what bone becomes the primary forearm bone?
A) The ulna
There are 5 types of radial club hand:
Type I: Distal radius is short
Type II: Hypoplastic radius, 1-2 cm short, deficient proximally and distally
Type III: Absence of the distal portion of the radius
Type IV: Complete absence of the radius (most common type)
Type V: Complete absence of the radius with manifestations in the proximal humerus
Radial club hand is an upper extremity malformation that may or maynot require surgery. Children develop prehension with their hands as they play and they are not self-conscious of the difference until they become socialized in school. The hand surgeon may offer non-surgical management or may offer surgery to improve the child’s function and cosmesis.
Time to Play the Brian Game:
Q) What is a genetic disorder commonly detected later in childhood due to limited development of the distal radius?
A) Madelungs deformity is characterized by a shortening of the radius a the wrist. Inadequate development of the distal radius results in an ulna that is longer than the radius. Patients appear with a prominent ulnar head.