Orthopaedic Surgery - Clinodactyly

Basics

Clinodactyly is a congenital deformity in which a finger is angulated in the radioulnar plane.

The little finger is affected most often and typically deviates toward the radial side.

The deformity usually results from an abnormally short, delta-shaped or trapezoidal middle phalanx.

Clinodactyly may occur as an isolated finding or as part of a congenital syndrome such as Down syndrome.

Synonym

Clinodactyly is sometimes referred to simply as a bent finger.

General Prevention

There is no known method for preventing clinodactyly.

There is also no evidence that early nonsurgical intervention alters its natural history when the deformity is caused by abnormal bony growth.

Epidemiology

Clinodactyly is usually apparent at birth or during early childhood.

It is more common in males, and when present in boys it is frequently bilateral.

Incidence

The reported frequency in otherwise healthy children varies widely, from approximately 1–19.5%.

It appears to be least common among Caucasian populations.

Risk Factors

Clinodactyly is strongly associated with several chromosomal and congenital syndromes.

In children with Down syndrome, the reported incidence is approximately 35–70%.

It may also be seen in Klinefelter syndrome, trisomy 18, and other congenital disorders.

Genetics

Clinodactyly may follow an autosomal dominant inheritance pattern with variable expressivity.

Some cases occur sporadically without a known family history.

Etiology

The deformity develops because of asymmetric longitudinal growth of the involved phalanx.

This is commonly related to formation of a physeal bracket, in which the growth plate extends abnormally around part of the phalanx.

Unequal growth on opposite sides of the bone causes progressive angulation.

Associated Conditions

Clinodactyly may be associated with symphalangism, brachydactyly, chromosomal trisomies, Treacher Collins syndrome, Silver syndrome, Holt–Oram syndrome, and Prader–Willi syndrome.

When other skeletal or systemic abnormalities are present, evaluation for an underlying syndrome may be appropriate.

Diagnosis

Signs and Symptoms

The affected finger, usually the fifth digit, is visibly deviated in either the radial or ulnar direction.

The deformity can arise at the PIP joint, middle phalanx, or DIP joint.

Distal involvement is particularly common.

Pain

Clinodactyly is typically painless.

Most patients present because of cosmetic appearance rather than discomfort.

Functional Limitation

Mild deformities usually do not interfere with hand function.

More severe angulation can occasionally cause difficulty with grasp, finger overlap, or interaction with adjacent digits.

Physical Examination

The degree of angulation should be measured carefully.

The examiner should document whether the deformity occurs primarily at the PIP joint, middle phalanx, or DIP joint.

Range of Motion

Both active and passive movement of each finger joint should be recorded.

This helps determine whether the deformity is purely bony or whether associated joint stiffness is present.

Examination for Associated Abnormalities

The remainder of the hand and skeleton should also be examined.

Additional congenital abnormalities may suggest an underlying syndromic diagnosis.

Laboratory Testing

Routine laboratory studies are not required for isolated clinodactyly.

If a chromosomal or congenital syndrome is suspected, chromosome analysis or appropriate genetic testing may be indicated.

Imaging

Plain Radiographs

Conventional radiographs of the affected finger are useful for defining the underlying bony anatomy.

Imaging is particularly important when surgical correction is being considered.

Normal Angulation

Angulation of less than approximately 10° may fall within normal anatomical variation.

Greater deformity should be interpreted in relation to symptoms, function, and progression.

Radiographic Findings

Radiographs may show a shortened, wedge-shaped, delta-shaped, or trapezoidal phalanx.

The joint surface may be oblique because of asymmetric development.

Pathological Findings

The underlying abnormality is maldevelopment of one of the phalanges.

Unequal growth causes angulation of the bone and its associated joint surface.

Differential Diagnosis

Delta Phalanx

A delta phalanx is a wedge-shaped phalanx with an oblique articular surface.

It is closely related to the underlying developmental mechanism of many cases of clinodactyly.

Fracture Malunion

A previously fractured finger that heals in an angulated position may resemble clinodactyly.

History of trauma and radiographic evidence of prior fracture help distinguish malunion from congenital deformity.

Treatment

General Measures

Most cases of clinodactyly are primarily cosmetic and do not require treatment.

Mild deformity without functional impairment should generally be observed.

Manipulation and Casting

Manipulation or casting is usually ineffective because the deformity arises from abnormal bone growth rather than a flexible soft-tissue contracture.

These methods can also be difficult for children to tolerate.

Indications for Surgery

Surgical correction may be considered when there is substantial persistent deformity, functional impairment, overlap with adjacent fingers, or unacceptable appearance, particularly after approximately 6 years of age.

Expectations From Surgery

Surgery can improve finger alignment and appearance.

However, correction may come at the cost of scarring, stiffness, and possible loss of motion.

These trade-offs should be considered carefully in a condition that is often asymptomatic.

Activity

No activity restrictions are necessary for uncomplicated clinodactyly.

Children may participate normally in play, sports, and daily activities.

Physical Therapy

Physical or hand therapy is not usually required before surgery.

After operative correction, therapy may help restore range of motion, strength, and hand function.

Surgery

General Principles

Surgical treatment depends on the child’s age, skeletal maturity, severity of deformity, and underlying physeal abnormality.

Procedures include osteotomy and reconstruction of the abnormal growth plate region.

Young Children

In children younger than approximately 6 years, correction may involve excision of the abnormal central portion of the continuous epiphysis and underlying physis.

A free-fat graft is then inserted to prevent reformation of the physeal bracket and allow more symmetric growth.

Free-Fat Graft Procedure

The aim of fat-graft interposition is to remove the tethering growth abnormality while preserving the remaining growth potential of the phalanx.

Gradual improvement in alignment can then occur as the finger continues to grow.

Older Children

After approximately 6 years of age, a corrective closing-wedge osteotomy can usually be performed more predictably.

The bone is surgically realigned to improve the axis of the digit.

Osteotomy

Corrective osteotomy provides relatively immediate correction of the deformity.

It is generally technically straightforward but still carries risks of stiffness, scar formation, recurrence, or incomplete correction.

Follow-Up

Prognosis

The overall prognosis is excellent.

Clinodactyly does not usually cause pain, progressive disability, or degenerative joint disease.

Observation

Many patients require only periodic observation.

Progression of angulation can be followed clinically as the child grows.

Patient Monitoring

Patients or families can monitor the degree of finger angulation and functional effect over time.

Reassessment is appropriate if the deformity becomes more pronounced, interferes with function, causes finger overlap, or becomes cosmetically unacceptable enough to consider surgical correction.