Keywords
digital hypoplasia - reconstruction - symbrachydactyly - toe phalanges
Introduction
Free nonvascularized toe phalangeal transfer is an established surgical option for
the reconstruction of hypoplastic digits.[1]
[2] Functional hand deficiencies with absent or shortened digits are indications for
this technique.[3] Symbrachydactyly is a unilateral hand malformation characterized by failure of formation
of fingers and presence of rudimentary nubbins. Typically, the central digits are
absent and the border digits are relatively spared, and syndactyly may be present.[4]
The best candidate for this procedure seems to be a patient with an adequate skin
envelope to accommodate the transferred phalanx, good metacarpal development, and
intact flexor and extensor tendons, as evidenced by retractile digital nubbins when
these are gently distracted.[5] The primary goal is the improvement of digital length to enhance mechanical advantage
and prehension.[3] In comparison to free vascularized toe transfer, for the parents this surgery is
viewed as a less morbid procedure, and for the surgeons, it is a relatively straightforward
technique.[1] Nonetheless, it has an intensive postoperative period; thus, a noncompliant family
is an important contraindication. Less severe functional impairment, including an
isolated short digit excluding the thumb, and appearance only are relative indications.[3]
[6]
Surgery is ideally recommended at an early age (varying from 6 to 18 months), as it
appears to enhance the growth of the transferred phalanx and to retain the aperture
of the epiphysis. Neural plasticity also seems to be at its greatest at this age,
which enables an optimal functional incorporation.[2]
[5]
[6] However, surgery may be considered later based on the age of the child at presentation.[2]
Several surgical techniques have been described since it was first performed by Wolff
in 1910.[1]
[2]
[7] It can be part of a staged treatment in combination with syndactyly release, with
local flaps or full-thickness skin graft and lengthening of the phalangeal distraction.[5] Various reports have confirmed the importance of the intact periosteum and physeal
plate.[3] However, transferred phalangeal growth, epiphysis closure, functional results of
the reconstructed metacarpophalangeal joint, and donor-site morbidity are incompletely
understood.[8]
The purpose of the present study was to evaluate our experience with nonvascularized
toe phalanx transfers in patients with symbrachidactyly. We aimed to assess bone growth
and digit function as well foot morbidity.
Material and Methods
We reviewed all children with symbrachidactyly submitted to free nonvascularized toe
phalangeal transfer between 2002 and 2017. We retrospectively examined the clinical
records of every patient. A total of 8 patients were included (3 boys and 5 girls).
The right and left hands were equally affected, and all patients had unilateral hand
deformity. All surgical procedures and associated complications were recorded.
We summoned every patient to an appointment to clinically assess the range of motion,
the stability, and the alignment of the neo-joint. According to a scale previously
used by Kawabata and Tamura,[8] the range of motion was divided into 3 categories: good (active extension greater
than 0°, and active flexion greater than 45°), fair (active extension between 0° and
-30°, and active flexion between 30° and 45°), and poor (extension lag greater than
30°, or active flexion lower than 30°, or total active motion lower than 30°). Lateral
instability and malalignment were graded as good if they were lower than 10°, fair
if between 10° and 30°, and poor if greater than 30°. As Garagnani et al.,[1] we also evaluated the foot for shortening (measured by toe length compared with
the contralateral side), deviation (lateral shifting of the longitudinal axis), crossing
(the laterally-shifted longitudinal axis of one toe intersects the axis of a neighboring
toe), overriding (angular deformity with hyperextension or dorsal dislocation of the
donor toe at the level of the metatarsophalangeal joint) and malrotation (abnormal
pronation or supination of the toe). Three children didn't attend the follow-up clinical
reevaluation.
In this appointment, we assessed the patients for growth or resorption of the transferred
phalanx on plain anteroposterior radiographs. We measured the initial and final length
of the transferred phalanx (gain in length) and the percentage of growth compared
with the nontransferred phalanx in the contralateral foot. We also evaluated the presence
and growth of the remnant native phalanx.
The clinical and radiologic parameters were measured by two authors to control for
inter- and intra-examiner error.
All surgeries were performed by the senior author according to the following technique.
Dissection is performed with the patient under general anesthesia with a tourniquet
first on the thigh and then on the arm. A central dorsal incision is made over the
proximal or middle phalanx of the toe, and the extensor tendon is split longitudinally.
The phalanx is harvested extraperiosteally along with the joint capsule, the collateral
ligaments, and the volar plate. The extensor tendon is repaired with an absorbable
suture, followed by skin closure. The phalanx is then transferred to the hand and
sutured to the recipient periosteum and adjacent soft tissue. A 1-mm Kirschner wire
is inserted longitudinally from the harvested phalanx to the receptor metacarpal or
remnant phalanx to hold it in a straight position. A sterile well-padded dressing
is applied with a splint which is maintained for 4–6 weeks.
The protocol of the present study was approved by the hospital ethics review board.
Results
Besides the diagnosis of symbrachydactyly, one patient was also diagnosed with preaxial
polydactyly type II on the contralateral hand, and another patient had Poland syndrome.
Amniotic band syndrome or other diseases were not diagnosed.
The mean age at the time of the first surgery was 19 months (range: 8–42 months).
A total of 20 phalanges were harvested: 16 total proximal phalanges (80%), 2 middle
phalanges (10%), 1 subtotal proximal phalanx (5%), and 1 accessory thumb phalanx (5%).
The distal part of one proximal phalanx was trimmed because the skin pocket was too
tight. A mean of 2.5 transfers per patient were performed ([Fig. 1]). Only 1 patient was submitted to phalanx transfers in 2 different procedures (36
months apart). All other transfers were performed simultaneously during the same procedure.
The thumb was the recipient in 2 patients (10%), the second digit, in 5 patients (25%),
the third digit, in 7 patients (35%), the fourth digit, in 4 patients (20%), and the
fifth digit, in 2 patients (10%). The second toe was the donor in 4 patients (20%),
the third toe, in 8 patients (40%), the fourth toe, in 5 patients (25%), and the fifth,
in 2 patients (10%).
Fig. 1 Number of phalanges harvested per patient (n = 8).
Three patients underwent a secondary procedure for the release of the syndactyly in
an average of 24 months (range: 9–39 months) after the transfer surgery.
One transfer required revision surgery for distal tip necrosis and exposure of the
transferred phalanx four days after the initial surgery. As this patient missed his
recent appointment, we cannot provide the current clinical and radiologic evaluations.
No other surgery-related complications were reported.
The active motion of the metacarpophalangeal joint was rated as good in 7 (50%), fair
in 4 (29%), and poor in 3 (21%) transfers ([Fig. 2A]). The average active motion was of 11° in extension (range: -30–45°) and of 54°
in flexion (range: 10–90°). The stability was rated as good in 13, and fair in 1 transfer.
The alignment was rated as good in 5 (36%), fair in 7 (50%), and poor in 2 (14%) transfers
([Table 1]). Regarding the clinical evaluation of the donor toes, 12 (60%) had shortening,
3 (15%), deviation, 3 (15%), overriding, 4 (20%), malrotation, and none had crossing
([Table 2]) ([Fig. 2B]). Of the 14 donor toes evaluated, only 2 (14%) did not show any abnormality.
Fig. 2 A girl with symbrachydactyly. The proximal phalanges were harvested from the second,
fourth and fifth right toes and the middle phalanx was harvested from the third right
toe at the age of 9 months. Clinical appearance of the hand (A) and foot (B) at the age of 8 years. Anteroposterior radiographs at 5 months and 8 years of age
(C).
Table 1
|
Good
|
Fair
|
Poor
|
|
Active motion
|
7
|
4
|
3
|
|
Stability
|
13
|
1
|
–
|
|
Alignment
|
5
|
7
|
2
|
Table 2
|
Toe
|
Second
(n = 3)
|
Third
(n = 6)
|
Fourth
(n = 4)
|
Fifth
(n = 1)
|
|
Shortening
|
100%
|
83%
|
75%
|
100%
|
|
Deviation
|
–
|
17%
|
25%
|
100%
|
|
Crossing
|
–
|
–
|
–
|
–
|
|
Overriding
|
33%
|
33%
|
–
|
–
|
|
Malrotation
|
–
|
17%
|
50%
|
100%
|
Radiographically, the transferred phalanx showed growth in 12 transfers, resorption
in 1 transfer, and no alteration in growth in 1 transfer ([Fig. 2C]). The mean gain in length of the transferred phalanx was of 4.5 mm in total (range:
−5 mm–12 mm). The mean gain in length in children with less or more than 18 months
of follow-up was of 2 mm and 7 mm respectively (p = 0.068). The percentage of growth of the transferred phalanx compared with the nontransferred
phalanx in the contralateral foot was of 77% (range: 16%–117%). The length of the
transferred phalanx was 74% of what was expected in children with less than 4 years
of follow-up, and of 81% in children with more than 4 years of follow-up (p = 0.623).
Concerning age, there was a trend towards better results related to active motion
(mean flexion: 56° versus 50°, p = 0.767; and mean extension: 13° versus 3°, p = 0.583), gain in length (5 mm versus 3 mm, p = 0.616) and percentage of expected length (92% versus 73%, p = 0.249) in patients submitted to transfer at the age of 18 months or younger, although
it was not statistically significant ([Table 3]).
Table 3
|
|
≤ 18 months
|
> 18 months
|
p
|
|
Active motion (°)
|
Flexion
|
56
|
50
|
0.767
|
|
Extension
|
13
|
3
|
0.583
|
|
Gain in length (mm)
|
|
5
|
3
|
0.616
|
|
Percentage of expected length (%)
|
|
92
|
73
|
0.249
|
There was a remnant of the native proximal phalanx in the finger of 13 transfers (65%),
while no remnant was present in the other 7 transfers (35%). The mean difference in
length of the remnant phalanx was of 1.3 mm (range: −0.7 mm–4.1 mm). In total, 16
transfers (80%) had a normal metacarpal, 3 (15%) had a hypoplastic metacarpal, and
1 (5%) had an absent metacarpal. The presence of a phalangeal remnant or a complete
metacarpal did not seem to be associated with different results for each of the evaluated
parameters (p = 0.845 and p = 0.713).
The clinical and radiologic outcomes in the transfer of the middle phalanges and the
subtotal trimmed proximal phalanx were not statistically different in comparison to
those of the transfers of the proximal phalanges (p = 0.213 and p = 0.483).
The mean follow-up was of 66 months (range: 18–216 months) after the first surgery.
Two children (five transfers) missed a recent reevaluation appointment; therefore,
their clinical and radiographic parameters were not assessed.
Discussion
The main limitation of the nonvascularized toe phalanx transfer is the preexisting
soft tissue envelope of the finger and the limited growth potential of the transferred
bone.[8]
[9] That is, the best candidates for this technique are those who have adequate soft
tissue and are young enough to retain the growth potential of the transferred toe
phalanx. Concerning age, the ideal age seems to be up to 18 months, as it appears
to be related to the largest phalangeal growth.[6]
[7]
[10] Even so, most authors perform it up to the age of 4.[6]
[11] Earlier transfer also stimulates soft-tissue growth of the nubbins, which adapt
their size to receive the phalanx.[12] Besides age, extraperiosteal dissection of the transferred phalanx is stated to
be crucial in order for the physes to remain open and for growth.[3]
[9]
[10] Some authors report a 90% physeal survival and 90% of the expected growth when the
physes remained open at 3.4 years of mean follow-up, or similar.[7]
[10]
[13] Kawabata and Tamura[8] reported that the final phalangeal length was of 71% of that of the control bone.
In the present study, we achieved nearly the same result, with an expected percentage
of growth of the transferred phalanx of 77%. Physeal patency and phalangeal growth
reports differ in the literature; however the latest series state a positive growth
in transverse dimension, strengthening and stability of the digits.[10]
We only had to trim one proximal phalanx to adjust it to the recipient soft-tissue
envelope. This case presents a short follow-up, and it is not possible to evaluate
if our trimming technique influenced the growth rate of the phalanx. Even so, the
literature suggests that excessive trimming is associated with poor growth.[8] This can also be related to loss in the integrity of the periosteum and gradual
resorption of the bone.[1]
In the present study, we found no difference in gain in length between proximal or
middle transferred phalanges. However, some studies suggest that proximal phalangeal
transfer produces a better gain in length to the recipient finger than middle phalangeal
transfer.[1]
[11]
We experienced one case of distal transferred phalanx necrosis. As previously described
in the literature, this is a common complication which can significantly compromise
growth.[8]
[10] As this patient missed his recent appointment, we cannot provide his current clinical
and radiologic evaluation.
The hand function of most of the congenital hand deformities can be improved by digit
lengthening.[6] We achieved a positive gain in length and percentage of expected growth compared
with the contralateral nontransferred phalanx in the contralateral foot. However,
the actual growth achieved with a phalangeal transfer should not be regarded as the
end result, but rather as a means of providing a stable and mobile finger.[5] More so, the patients' ability to handle objects and perform daily activities is
more significant than the separate evaluation of the range of motion.[6] In the present series, the overall clinical outcome concerning the range of motion,
the stability, and the alignment was compatible to that of other studies.[8] Non-vascularized free toe phalangeal transfer seems to provide reconstructed digits
that are sensitive, capable of performing pinching movements, and able to tolerate
heavy use.[6]
[10]
Apart from the clinical issues, it is of extreme importance to also consider the children's
social well-being and adjustment to the hand deformity, which can deteriorate as they
grow older. On that account, improvement of the esthetic appearance can be considered,
although it cannot be restored to normal in most cases of aphalangia.[6]
[10]
[11]
Kawabata and Tamura[8] hypothesized that the remnant of the proximal phalanx provides better support to
the epiphysis of the transferred toe phalanx and might help physeal viability. Although
the presence of a phalangeal remnant correlated with a good active range of motion
and appeared to improve function, it did not influence physeal closure.[8] In our study, the presence of a phalangeal remnant or a complete metacarpal did
not seem to be associated with different results regarding the clinical and radiologic
outcomes.
Donor-site morbidity for free toe phalangeal transfer is one of the greatest parental
concerns.[8] The literature reports are highly variable concerning the dissatisfaction of the
patients and parents, the cosmetic appearance, the footwear and the physical problems.[6]
[8] Raizman et al.,[2] in a recent study, found almost no measurable lower extremity morbidity or dysfunction
over the mid- to long-term after follow-up after toe-phalanx harvest. Even so, donor-site
morbidity for free toe phalangeal transfer could be greater than documented, as reported
by Garagnani et al.[1] regarding the clinical and radiographic features. Long-term follow-up of the donor
site is essential to accurately assess the results, as donor-site defect can worsen
over time. This should be considered during the surgical decision-making and preoperative
counseling.[1] We found evident deformities in almost all of the donor toes. We didn't assess the
radiographic measurements or the functional repercussion for the donor site, which
could have added information to the clinical evaluation.[1]
Further lengthening can be achieved by secondary procedures using distraction and
intercalary bone graft techniques.[5]
[10] No other surgical technique was used in the present study. Still, a combination
of nonvascularized multiple toe phalangeal transfers, web space deepening, and distraction
lengthening may provide excellent function in children with symbrachydactyly.[5]
There are several limitations to the present study. We can mention its small sample
size and retrospective nature, as well as the different periods of follow-up of the
evaluated children. Enhancing the function of the hand is the primary goal of non-vascularized
free toe phalangeal transfer. Still, we assessed the function of each isolated finger,
and improvement in the full function of the hand was not studied.
Conclusion
Nonvascularized toe-phalanx transfer offers a relatively simple method to lengthen
short digits and to provide satisfactory function in patients diagnosed with symbrachydactyly.
Irrespective of the amount of growth achieved in the transferred phalanx, the actual
transfer and growth attained should not be viewed as the end result, but rather as
a means of providing a stable and functional joint. A thorough screening of the patient
and family are crucial to ensure compliance with this complicated postoperative care.
