Journal of Hand Surgery - June 2022 - S475

Abstract
S475
a standard technique of opponensplasty to stabilize
the thumb MCP joint and to obtain appropriate opponens
function. The first step was the double-opposing
Z-plasty with common pedicle, based on the
dorsal web. The next step was to expose the APB
muscle. A radial skin incision was started on the
radial side of the base of the proximal phalanx of
the thumb. The incision continued proximally at the
level of the base of the first metacarpal bone radial
to the thenar muscles. We confirmed the thumb
moves radially when an exposed APB muscle was
retracted with a vessel loop. The APB tendon was
cut at the insertion and passed beneath the extensor
pollicis longus (EPL) tendon with release of surrounding
tissue. It was anchored to the adductor pollicis
insertion on the ulnar side of the thumb MCP
joint at the pronated and abducted position of the
thumb. This anchoring point made another important
contribution in that the transferred muscle acts not
only as an abductor, but also as a strong pronator of
the thumb. By the anchoring point the transferred
APB tendon runs across the ulnar side of the
thumb MP joint and is expected to act as if it were
an ulnar collateral ligament. Surgical intervention
was undertaken in 21 thumbs with types II and IIIA
congenital hypoplastic thumb presenting with
marked laxity of the MCP joint using the modified
procedure described. Ages at the time of operation
ranged from 1 to 7 years. In all patients the APB
tendon reached the ulnar side of the MCP joint with
no excessive tension. No reconstructions of the
flexor pollicis longus or the EPL were performed in
this series. All patients except one were satisfactory
regarding both stability and opposition. Surgical
treatment of types II and IIIA is focused on the restoration
of opposition. Although instability of the
thumb MCP joint has not always been recognized
as a component of types II and IIIA, it is an important
factor in thumb function. This instability introduces
an ulnar collapse pattern during pinching activities,
and disruption of pinching and gripping functions.
The other advantage is good restoration of the contour
of the thenar eminence. Our APB rerouting is
simpler than any of these procedures, although the
ADM is used widely as a donor for opponensplasty.
Anchoring the APB tendon to the ulnar side of the
MCP joint can produce stability in addition to a strong
pronation effect. The procedure might be also indicated
for the other congenital differences, which
need opponensplasty, such as clasped thumb,
thumb polydactyly after the resection of extra
thumb, and cleft hand.
A-2292 Comparison of Patterson and modified
Hennigan Classification in amniotic band syndrome
and review of 21 cases
Xiuyue Xu, Yousheng Fang, Yuzhou Liu and Jie Lao
Huashan Hospital Affiliated to Fudan University, Shanghai,
China
Objective: To compare Patterson and modified
Hennigan Classification system and review the features
of 21 cases.
Methods: From January 2019 to April 2020, 21 cases
of amniotic band syndrome were enrolled. Basic
information of the patients were recorded, medical
history and the photos were reviewed to record
the conditions on the affected limbs. Patterson
Classification and the modified Hennigan
Classification were used on these patients separately
to compare the features of these two classification
system. Then data was collected and calculated to
have a brief view of the status of affected limbs.
Results: 21 cases were enrolled, including 7 boys
and 14 girls. In 9 cases, only upper limbs were affected.
In 5 cases, only lower limbs were affected. In
7 cases, both upper and lower limbs were affected.
In 16 cases with upper limbs affected (18 limbs), one
different Patterson classification was counted as 1.
In these cases, 13 Patterson type 2, 5 type 3 and
5 type 4 were included. There were 16 fingers of
type 3, including 6 index-middle finger acrosyndactyly,
6 middle-ring finger acrosyndactyly and 4 ringlittle
finger acrosyndactyly. 13 fingers of type 4 were
seen, including 6 index finger, 4 middle finger,
1 thumb, 1 ring finger and 1 little finger. In the
same way, in 13 cases with lower limbs affected
(15 limbs), 13 Patterson type 2, 2 type 3 and 5 type
4 were included. 2 type 3 were seen, including 2nd to
5th toe acrosyndactyly and 3rd to 5th toe acrosyndactyly.
Besides on one amputation at the ankle level,
there were 14 toe of type 4 affected, including 31st,
2nd, 3rd toes separately and 2 4th, 5th toes separately.
While using modified Hennigan Classification, one
different classification was also counted as 1.
10 finger zone (zone 1), 1 palm (zone 2), 7 forearms
(zone 3) and 2 arms (zone 4) were affected in all
upper limbs. 1 thigh (zone 1), 11 shanks (zone 2)
and 4 toe zone (zone 4) were affected in all lower
limbs.
Conclusion: Patterson and modified Hennigan
Classification system in amniotic band syndrome
can be combined to get clear records of the level
and severity of the disease, leading to accuracy of
data collection and a more precise guide of treatment,
providing more reliable data for further studies.
Forearm, fingers, shanks, toes were most
Journal of Hand Surgery - June 2022

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