A 11-year-old boy with a painless but gradually progressive deformity of
bilateral little fingers noticed for the past 1 year was referred to us
by a pediatrician for a rheumatology consultation. A diagnosis of
fractured distal phalanges was offered previously, and a surgical
correction was advised. There was no significant family history or
previous trauma or infection to his finger. Physical examination showed
palmar and radial curving of distal phalanges of bilateral little
fingers. Nails of the affected fingers were also curved in volar
direction (Fig. 1). Radiological findings showed
ventro-radial angulations of terminal phalanx relative to middle phalanx
with an apparent overgrowth of epiphysis – a tiny bony spur, which
projected distally and fitted into a groove in the basal part of the
shaft. Physeal plate appeared widened with sharply narrowed and
sclerosed diaphysis. (Fig. 2). A diagnosis
of Kirner’s syndrome was made and parents were counselled accordingly.
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(b) |
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Fig. 1 Symmetrical deformity of tip of
both right (a) and left (b) little fingers with shortening of
the terminal phalanx, making it stubby and deflected in a palmar-radial
direction.
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Kirner’s deformity or dystelephalangy is an uncommon
condition that presents in late childhood or early adolescence (8-14
years) with painless, progressive, bilateral radiovolar curving of the
terminal phalanges of the little fingers. It is a clinico-radiological
diagnosis. Clinically, Kirner’s deformity is characterized by a short
and stubby terminal phalanx of the little finger, and deviated in a
palmar and radial direction, typically described as ‘eagle-claw-like’,
and a dysmorphic nail.
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Fig. 2 Radiograph showing ventro-radial
angulations of terminal phalanx relative to middle phalanx with
an apparent overgrowth of epiphysis.
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The deformity needs to be differentiated from other
similar deformities such as clinodactyly (radial deviation at the distal
interphalangeal joint) and camptodactyly (flexion deformity at the
proximal interphalangeal PIP joint). Association has been reported with
musculoskeletal (genu valgus, pes cavus, myositis ossificans, absence of
flexor digitorum superficialis tendon in the little finger) and
cardiovascular abnormalities, and with syndromes such as Turner
syndrome, Cornelia de Lange syndrome and Silver syndrome. Treatment
modalities recommended are observation, splinting and osteotomy. As the
deformity usually ceases after physis closure, reassurance may be
sufficient. Temporary splinting may be of help in painful cases. Volar
osteotomies leaving an intact dorsal periosteal hinge with K-wire
fixation for correction of the deformity has been advocated. Surgery is
delayed until physeal closure to prevent recurrence of the deformity.
