Finger Curving: What is Clinodactyly?
Clinodactyly is a condition that causes the fingers to curve towards the pinky finger. It is most common in the pinky finger and is often bilateral. The condition is usually harmless and does not require treatment.
DEFINITION
Clinodactyly refers to an abnormal about of radioulnar angulation of a digit (>15 degrees). The small finger is most commonly observed.
This condition is often bilateral.
ANATOMY
The finger consists of three phalanges (proximal, middle, and distal).
The normal phalangeal physis is located at the proximal portion of each phalanx.
PATHOGENESIS
The angulation is result of abnormal development of one of the phalanges (most often the middle phalanx [p2]).
Abnormal development of the phalanx may be due to an irregular physis (longitudinal bracket epiphysis). This may also be referred to as a delta phalanx.
The tethering effect of the bracket epiphysis on the radial side of the finger causes abnormal growth of the phalanx resulting in a triangular or trapezoidal shape.
Extra bones may be encountered.
NATURAL HISTORY
The natural history of clinodactyly is variable and poorly documented, owing to the great number of cases that are asymptomatic and do not require treatment.
Angulation may be stable or rapidly progressive at times of growth, depending on the extent of the involvement of the physis and/or presence of extra phalanges.
PATIENT HISTORY AND PHYSICAL EXAM FINDINGS
Clinodactyly may be present at birth or develop during a period of growth (FIG 1). Clinodactyly is often bilateral in the small finger.
Clinodactyly is an autosomal dominant condition with variable penetration. Involvement of the thumb is rare and is associated with varying syndromes.
IMAGING AND OTHER DIAGNOSTIC STUDIES
Standard radiographs (three views: anteroposterior[AP], lateral [LAT], and oblique [OBL]) of the hand and affected digit are sufficient to determine the area of involvement.
Contralateral images are useful for comparison.
Advanced imaging such as computed tomography (CT) is rarely needed. Magnetic resonance imaging (MRI)
may be useful to delineate the shape of a bracket diaphysis.
DIFFERENTIAL DIAGNOSIS
The diagnosis of clinodactyly is straightforward; clinical examination and radiographs are sufficient to make the diagnosis.
Associated syndrome should be screened for, these include Down, Rubinstein-Taybi, Apert, and Russell-Silver.
NONOPERATIVE MANAGEMENT
Observation may be considered for angulated digits that do not impair function. Splinting is not effective.
Most cases can be treated nonoperatively; surgery should be considered for significant angular deformity that compromises hand function.
SURGICAL MANAGEMENT
Preoperative Planning
Timing of surgery is variable, depending on the degree of angulation and how much growth potential remains. Small amounts of angulation with little remaining growth potential may be addressed when the child is older.
Larger amounts of angulation or children with the potential for worsening angulation may consider earlier intervention.
Positioning
The patient is positioned supine on the operating room table and the body is pulled over to the affected side.
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FIG 1 • Clinodactyly of the index finger from osteochondroma in a child with multiple hereditary exostosis.
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The arm is placed on a radiolucent hand table and an arm tourniquet is applied.
Prepping and draping are performed in the standard fashion.
Approach
Several approaches may be considered for clinodactyly correction, but the principles remain consistent regardless of surgical approach.
Skin incisions must address the excess skin on the convex side of the angulation and the lack of skin on the concave side.
Extensile incisions are preferred.
Bony correction of the angulation can be accomplished via osteotomy, physiolysis of the bracket diaphysis, excision of extra phalanx, or a combination of all three.
TECHNIQUE
- Physiolysis
This technique is favored for the younger child with significant growth potential. Skin incisions are made over the radial aspect of the digit.
Flaps are developed and the flexor and extensor tendons are identified and protected. Fluoroscopy is used to identify the physis.
The physis is incised with a no. 15 blade transversely and the central portion of the physis is removed with a small curette. Local fat may be placed in the void but may not be necessary.
The skin is closed and a cast is applied.
- Phalanx Excision
Elliptical skin incisions along the convex side of the angulation are favored. These incisions allow for excision of redundant skin, aiding the cosmetic appearance on completion of the case (TECH FIG 1).
The extensor tendons are protected and the extra phalanx is identified.
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TECH FIG 1 • Clinodactyly of the thumb. A. Clinical photograph. B. Radiograph demonstrating triangular phalanx. C. Postoperative photograph after excision of triangular phalanx and pinning.
The phalanx is excised and the collateral ligaments are preserved. The joint is inspected and reduced.
The collateral ligaments are tightened with interrupted suture and the joint is pinned with a single K-wire along the long axis of the joint.
Skin is closed with absorbable suture and a cast is applied.
- Osteotomy
Closing wedge, opening wedge, or reverse wedge osteotomy can be strongly considered for large amounts of angulation in patients who are close to or skeletally mature (TECH FIG 2).
Incisions are made along the convex side (ulnar side of the finger) for closing wedge osteotomies and along the concave side (radial side of the finger) for opening wedge ostetomies.
Skin flaps are developed.
The digital neurovascular bundles are protected as well as the extensor tendons. The periosteum is elevated off the phalanx and the osteotomy is templated.
The closing wedge osteotomy can be performed with either thin narrow rongeur or oscillating saw.
A rongeur is favorable in smaller children where the bone is small.
Using this method, the far cortex is left in place and the finger is bent back to a neutral alignment using the far cortex as hinge.
The osteotomy is stabilized with one or two K-wires.
The opening wedge osteotomy is performed in a similar fashion as the closing wedge, only the incision is made on the radial border of the digit; no wedge of bone is removed.
A single osteotomy is made in the radial aspect of the phalanx, leaving the ulnar cortex intact. The osteotomy is opened and stabilized with one or two K-wires.
Bone graft is often not necessary in young children.
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TECH FIG 2 • Small finger clinodactyly. A. Preoperative clinical photograph. B. Intraoperative photograph after osteotomy and pinning. C. Postoperative photograph demonstrating surgical correction of the left and no correction on the right.
The reverse wedge is useful when large amounts of angulation correction are necessary. This technique allows for correction of angulation with preservation of length.
This osteotomy is performed with an oscillating saw.
A wedge of bone is taken from the near side and flipped and inserted in the far side. The osteotomy is stabilized with one or two K-wires.
Undercorrection or overcorrection of
angular deformity
- Precise surgical planning with good radiographs and
measured correction
Redundant skin causing uneven
appearance of finger after phalanx excision
- Elliptical skin incisions can reduce redundant skin on
the convex side when excising a phalanx.
Lack of motion after angular correction
- Excessive periosteal stripping leading to tendon
adhesions. Limit soft tissue dissection.
PEARLS AND PITFALLS
POSTOPERATIVE CARE
Occupational therapy is started after the first postoperative visit. The parents are instructed to wash and clean the hand. A progressive active and passive range of motion program is initiated.
In cases where an osteotomy is performed, the patient is placed in a cast until the osteotomy has healed (typically 4 weeks). At this time, the pins are removed and occupational therapy is initiated.
Patients are followed until full range of motion has been achieved, typically 6 to 8 weeks.
OUTCOMES
Outcomes from clinodactyly correction are generally good.
Patient satisfaction is correlated to the degree of preoperative angulation and degree of correction.
COMPLICATIONS
Residual angulation may persist, usually due to initial undercorrection or continued abnormal growth. This usually is not an issue especially when the amount of angulation is mild and when the magnitude of the correction is great.
Digital stiffness may be encountered. Tendon adhesions and scar tissue are usually the cause. Occupational therapy and parental education are helpful to address a loss of full digital motion.
SUGGESTED READINGS
- Ali M, Jackson T, Rayan GM. Closing wedge osteotomy of abnormal middle phalanx for clinodactyly. J Hand Surg Am 2009;34: 914-918.
- Al-Qattan MM. Congenital sporadic clinodactyly of the index finger. Ann Plast Surg 2007;59:682-687.
- Bednar MS, Bindra RR, Light TR. Epiphyseal bar resection and fat interposition for clinodactyly. J Hand
Surg Am 2010;35:834-837.
- Strauss NL, Goldfarb CA. Surgical correction of clinodactyly: two straightforward techniques. Tech Hand Up Extrem Surg 2010;14: 54-57.
- Ty JM, James MA. Failure of differentiation: part II (arthrogryposis, camptodactyly, clinodactyly, Madelung deformity, trigger finger, and trigger thumb). Hand Clin 2009;25:195-213.