Radial Clubhand - Practice Essentials

Radial clubhand is a deficiency along the preaxial or radial side of the extremity. Learn about the history, potential etiologies, relevant pathoanatomy, treatment regimens, expected outcome, and potential complications in this blog.

Radial clubhand is a deficiency along the preaxial or radial side of the extremity. Although considerable forearm and hand anomalies are the classic findings, proximal deficiencies also can occur throughout the arm and shoulder girdle. The elbow abnormalities can include deficiences of the olecranon, capitellum, coronoid fossa, and medial epicondyle.

In 1733, Petit first described radial clubhand in an autopsy of a neonate with bilateral clubhands and absent radii. Learn more about Radial Clubhand in this blog.

Anatomy

Bone and joint abnormalities Clinical features of radial deficiency (types II, III, and IV; see Presentation, Classification) are dramatic, with abnormalities of the entire extremity. The scapula is often small, and the clavicle is often shorter, with an increased curvature. The humerus may or may not be short, and deficiencies of the capitellum and trochlea are common. Elbow motion is usually diminished more in flexion than in extension.

The forearm is always decreased in length, and the ulna is approximately 60% of the normal length at the time of birth. This discrepancy persists throughout the growth period and into adulthood. True forearm rotation is absent in patients with partial or complete aplasia of the radius.

The wrist is radially deviated and develops a perpendicular relation to the forearm over time. The articulation between the carpus and ulna is usually fibrous and abnormal, though some hyaline cartilage can be found. Wrist motion is primarily in the radial/ulnar plane, with some flexion/extension. Ossification of the carpal bones is delayed, with the scaphoid and trapezium often absent or hypoplastic. The capitate, hamate, and triquetrum are usually present but ossify late.

The fingers are often stiff, with limited motion at the metacarpophalangeal (MCP) and interphalangeal (IP) joints.

Etiology

In the 19th century, the etiology of radial clubhand was theorized to be either a congenital absence or an acquired defect secondary to syphilis. In 1895, Kummel proposed the cause to be abnormal pressure upon the embryo along the radial bud between the third and seventh week of gestation.

A more recent theory has related the etiology of radial clubhand to the apical ectodermal ridge (AER). This structure is a thickened layer of ectoderm that directs differentiation of the underlying mesenchymal tissue and limb formation.

Clinical Features

The diagnosis of radial clubhand is based on physical examination and radiographic evaluation. Clinical presentation of radial clubhand varies with the degree of radial deficiency (see Classification) and the presence of associated anomalies.

Treatment

The objective of treatment in radial clubhand is to reduce the functional deficit incurred by a short or absent radius, a short ulna, an abnormal muscular anatomy, and a radial deviation of the wrist.

Type I radial clubhands have minor radial deviation of the wrist, which creates less of a functional problem than types II, III, and IV (see Presentation, Classification). In those children with considerable absence of the radius, the wrist assumes severe radial deviation that increases to 90° over time. This further compromises the flexor and extensor tendons, creating functional difficulty.

Thumb hypoplasia also requires consideration in the formulation of a treatment plan for radial clubhand. An absent or deficient thumb inhibits use of the hand. Reconstruction or pollicization is necessary to optimize hand function.

A successful centralization still results in a shortened forearm segment secondary to altered growth of the ulna. The short forearm is both a cosmetic and a functional problem for the teenager with radial deficiency. Lengthening of the ulna can be accomplished by using distraction osteogenesis.

These procedural changes represent new concepts to correct radial clubhand. These technologic advances in limb lengthening and microsurgery add innovative methods to better correct the deformity and provide osseous support. Follow-up results of vascularized second metatarsophalangeal (MTP) joint transfer to stabilize the carpus are encouraging with respect to motion and less recurrence.

Sources

• https://emedicine.medscape.com/article/1245468-overview
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3636664/
• https://www.sciencedirect.com/topics/medicine-and-dentistry/radial-club-hand
• https://www.childrensortho.com/conditions-and-treatments/hand-and-upper-extremity/radial-clubhand