Radial polydactyly is a relatively common congenital anomaly that
frequently presents as thumb duplication. In the treatment of thumb
polydactyly, the simple ablation of one digit has not produced satisfactory
results, and doing so frequently results in retained deviation or ligamentous
instability of the
thumb1-5.
Therefore, modern reconstructive strategies involving the combining of
elements from both thumbs are indicated to achieve a functionally and
cosmetically acceptable
result6.
In 1969, Wassel developed a classification system for different types of
thumb duplications on the basis of the level of
bifurcation1. The
Bilhaut-Cloquet procedure, which has been advocated for Wassel type-I or II
thumbs with a bifid distal phalanx, consists of the coaptation of equal parts
of bone, soft tissue, and nail tissue by resecting the central duplicated
thumb segment7. With
use of this method, correction of the circumference is relatively
straightforward, resulting in a distal phalanx of at least normal size and
usually with a stable interphalangeal
joint5. However, the
results of the Bilhaut-Cloquet procedure are unpredictable because it is
technically demanding to combine elements of both thumbs, including segments
of bone, nail fold, nail bed, and the articular surface. Moreover, the
reconstructed thumb often later develops complications of physeal growth
disturbance, joint stiffness, and a nail-plate deformity or
groove2,3,8,9.
We reviewed the results of a modified technique of the Bilhaut-Cloquet
procedure for type-II and III polydactyly of the thumb, which was devised to
resolve the above problems.
Between 1997 and 2003, we reconstructed seven hands in seven patients using
a modified Bilhaut-Cloquet procedure. The inclusion criterion was Wassel
type-II and III polydactyly, in which the bifid thumbs are symmetric and the
nail size is less than two-thirds of that of the normal contralateral thumb,
or smaller than the inde x fingernail in patients with bilateral involvement.
The parents of all patients gave informed consent prior to surgery. We
retrospectively reviewed the results in seven consecutive patients after
institutional review board approval.
Surgical Technique
The modified Bilhaut-Cloquet procedure differs from the originally
described method because it is an extra-articular procedure; the
interphalangeal joint is reconstructed with one thumb, and the other thumb
contributes only part of the distal phalanx for stability. Because it is not
necessary to approximate the articular surface of the distal phalanx, the nail
bed can be sutured more precisely according to the natural curve of the nail
to minimize nail plate deformity (Fig.
1).
Under tourniquet control, both nails are removed and a longitudinal
incision is made through the nail bed of both thumbs in a manner by which the
combined nail will best resemble a normal thumb. The incision is extended by a
zigzag line proximally to the bifurcation level. The thumb with a greater
range of interphalangeal joint motion is chosen to become the main
articulating digit, as it contains the articular surface, the physis, and a
major part of the distal phalangeal bone with the overlying nail bed. The
other thumb, with lesser interphalangeal joint motion, is made into a fillet
flap containing a minor part of the distal phalangeal bone supporting the
incised nail bed and the collateral ligament attached to the proximal phalanx.
The two distal phalangeal bones do not need to match exactly or to have
intimate contact, but they are approximated and secured with one or two
transverse Kirschner wires to make the combined nail bed look natural. To make
one smooth semicircular nail bed in the axial plane, slight axial rotation is
required because attaching two semicircular nails in a transverse plane alone
creates a so-called seagull deformity (Fig.
2). Then the nail bed is repaired with buried 8-0 nylon sutures
under slight tension. On the basis of our experience, this tension suture can
prevent the formation of a prominent nail ridge, which often occurs after
suture repair of the nail bed with absorbable sutures.
Joint stability is then tested, and, if required, an additional
transarticular Kirschner wire can be driven from the tip of the thumb across
the interphalangeal joint to stabilize it. One of the removed nails is then
placed on the new nail bed, and a stabilizing suture is placed at each side of
the nail. Alternatively, an artificial nail of normal size can be inserted to
facilitate remodeling of the nail bed. A short or long-arm thumb-spica cast is
applied, depending on the age of the patient, with a long-arm cast used in
children under five years of age. The cast and the Kirschner wires are removed
four to six weeks after surgery.
In a type-III deformity, the extra thumb is osteotomized at the bifurcation
level and excised except for the distal bone fragment supporting the nail bed
and the fillet flap. When the angular deformity of the interphalangeal joint
is >20°, a corrective closing-wedge osteotomy is performed at the
proximal phalanx of the retained thumb, and the osteotomy is held by advancing
the transarticular Kirschner wire (Fig.
3).
Patients and Evaluations
There were seven patients, five boys and two girls. The mean age at the
time of the surgery was thirty months (range, seven to sixty-six months). Two
patients had a type-II deformity, and five had a type-III deformity. The five
patients with a type-III deformity had a near normal range of motion of the
interphalangeal joint preoperatively (average, 60°; range, 45° to
90°); however, the two patients with a type-II deformity had marked
limitation of joint motion in both rays, averaging 30° (range, 20° to
40°). All patients had a unilateral symmetric bifid thumb with a nail size
that was less than two-thirds of that of the contralateral thumb. A
closing-wedge osteotomy of the proximal phalanx was performed in two patients
with a type-III deformity, as there was >20° of angulation at the
interphalangeal joint level in both. All procedures were performed by one
surgeon.
The patients were evaluated with respect to the function and appearance of
the thumb by an independent examiner at an average follow-up period of
fifty-two months (range, eighteen to seventy months). The size of the nail and
the alignment, length, and circumference of the thumb were measured. To assess
the function of the thumb, the range of motion and stability of the
interphalangeal joint were tested. The joint was assessed as being unstable if
there was >10° of varus or valgus angulation with stress. Bone-healing
and any growth plate changes were evaluated radiographically. The overall
satisfaction of the parents was determined by their selection of one of the
following responses, indicating whether they were "satisfied,"
"satisfied but with some reservation," or
"dissatisfied." The parents were asked whether they would have
their child undergo the same operation again. The overall satisfaction of the
children was determined by their response to the question: "Is your
thumb pretty?" or "Do you like it?" At the final follow-up
evaluation, the mean age of the children was eighty-two months (range,
fifty-five to 102 months).
Demographic data on the patients and the results of the functional
evaluations are reported in Table
I. All patients and their parents were satisfied with the cosmetic
and functional results at the time of the final assessment. All parents said
they would have their children undergo the same surgical procedure again.
The width of the nail in the combined thumb was nearly the same as that in
the contralateral thumb. However, nail lengths were not similar when the
initial nail lengths in the reconstructed thumb and the length discrepancy
caused a step-off of the lunula (Figs.
4-A,
4-B and
4-C, 4-D and 4-E). No nail
plate deformity or groove developed, and the longitudinal suture line of the
nail became less prominent with time. Residual angular deformity was
<10° in all patients except one (Case 1) with a type-III deformity
(Figs. 5-A and
5-B) who gradually had an
angular deviation deformity develop at the interphalangeal joint. At the time
of the eighteen-month follow-up, the patient had 18° of radial deviation,
but the parents did not want additional surgery.
In patients with a type-III deformity, the postoperative range of motion of
the interphalangeal joint averaged 57° (range, 45° to 90°). The
two patients with a type-II deformity showed improved range of motion of the
interphalangeal joint (from 20° preoperatively to 45° postoperatively
in one and from 40° to 60° in the other). No patient had an unstable
interphalangeal joint.
The time to solid osseous union of the distal phalangeal osteosynthesis
radiographically ranged from four weeks to as much as a year; however, after
removal of the transverse Kirschner wire at four to six weeks postoperatively,
osseus healing was adequate for stability without pain. Remodeling of the
distal phalanx occurred with time. At the latest follow-up evaluation, no
evidence of physeal injury or growth arrest was observed in any patient.
Investigators have reported both satisfactory and disappointing results for
the Bilhaut-Cloquet operation, and some have modified the procedure. Hartrampf
et al.10 adopted
the standard Bilhaut-Cloquet procedure for more proximal duplications and
achieved improved thumb alignment, but most of their patients ended up with a
fused interphalangeal joint. Andrew and
Sykes11 reported
satisfactory results with the original technique, but they did not mention the
interphalangeal joint motion. Naasan and
Page12 found the
procedure helpful in patients with type-III and IV polydactyly of the thumb,
but secondary deformities were observed in 71% of their patients. Ganley and
Lubahn13 reported
five patients with satisfactory results, but four had limited interphalangeal
joint motion.
As a modification of this procedure,
Miura2 removed the
nail and bone from the extra thumb and used only the remaining soft parts to
reconstruct the thumb. Similarly,
Simmons14 treated
type-II duplication by ablating the radial digit and reconstructing the radial
perionychium from the radial soft-tissue flap, and Cheng et
al.4 modified this
approach by resecting the osseous appendages of the thumb while retaining the
soft tissue and a part of the nail. However, the above modifications with use
of only the soft part of the excised thumb cannot produce a nail that is
stable and large enough. Ogino et
al.15 treated four
patients using their modified procedure, in which the periosteum and a minimum
amount of bone were removed from the adjacent sides in order to minimize
damage to the growth plates and articular surfaces; however, the final
postoperative joint motion was not reported.
In our series, the postoperative interphalangeal joint motion was preserved
in type-III deformities and improved in type-II deformities. We believe this
was because we used an extra-articular technique. Additionally, no patient had
a nail deformity develop and the longitudinal line of the sutured nail bed
became less prominent with time. The natural axial curvature of a nail is
semicircular; therefore, attaching two semicircular nails in a transverse
plane alone can create a so-called seagull deformity
(Fig. 2). To prevent this, the
phalangeal bone supporting the nail bed requires slight axial rotation, and at
the same time the nail bed is repaired with more tension than by simple
approximation. If the articular surfaces are to be combined as in the classic
method, there should be no gap between them to ensure a smooth articulating
surface. This technique provides the phalangeal bone with less mobility for
achieving this small amount of rotation or for optimal tensioning of the nail
bed. In our modified technique, no attempt was made to compress the distal
phalangeal bones, thus facilitating easy adjustment and contouring of the
combined nail bed. This concept of osteosynthesis did not cause any problem
during the healing process, ultimately resulting in osseous healing and
remodeling of the distal phalanx.
The limitation of this technique is that, as in the original method, it is
not possible to make a thumb with the same nail length as the normal side when
the initial nail lengths of the duplicated thumb differ from that of the
normal thumb. Although trimming of the nail plates can make this nail length
discrepancy less prominent, a step-off of the lunula is unavoidable in some
cases. Angular deformity of the interphalangeal joint developed gradually in
one of our patients with type-III polydactyly. Eccentric insertions of the
flexor pollicis longus and/or extensor pollicis longus are common in patients
in whom the interphalangeal joints are angulated
preoperatively5.
Therefore, the flexor and extensor tendon insertions should be carefully
examined, and tendon realignment should be performed if
necessary6.
Dobyns et al.5
indicated that the retained thumb should be at least 80% of the size of the
contralateral thumb, and, if not, it should be augmented by some combining
method. Our indication for the combining procedure was when the size of the
nail was less than two-thirds of that of the contralateral nail or less than
the size of the index fingernail in patients with bilateral involvement. It is
our experience that if a hypoplastic thumb is removed at an earlier age and
the patient can use the reconstructed thumb functionally, the thumb usually
grows quickly by so-called catch-up
growth16.
We agree with
Manske17 that a
well-formed smaller thumb can be functionally and cosmetically acceptable. In
selected patients in whom combining thumbs is desirable, our modified
Bilhaut-Cloquet procedure is effective in preserving interphalangeal joint
motion, minimizing nail deformity, and preventing growth arrest. ?