Congenital Hand Flashcards
A neonate is born with unilateral edema of the arm. During the ensuing day, there is worsening edema and bullae formation. Which of the following is the most appropriate next step in management of this patient?
A) Administration of intravenous antibiotics and elevation of the arm
B) Compartment release
C) Continued observation and dressing change
D) Debridement and skin grafting
E) Treatment in a hyperbaric chamber
The correct response is Option B.
Compartment release should be performed early and urgently. The other treatments above may play a role in secondary treatment. Volkmann’s ischemia is not rare and awareness of the diagnosis is important. The sentinel lesion of neonatal compartment syndrome is bullous formation on the dorsum of the hand or arm. Etiology is often in utero and can be amniotic bands, umbilical cord loops, forceps extraction, oligohydramnios, preeclampsia, and excessive maternal weight. Diastolic pressures in neonates are usually 40 mmHg or less. Small increases in compartment pressure are therefore not tolerated well. The six P’s of compartment syndrome, which include pain, paresthesias, pulselessness, pallor, paralysis, and pressure, will not be seen in the neonate. The three A’s, which precede the six P’s in children, are agitation, anxiety, and increasing analgesic requirements; and will not be seen in the neonate.
2018
A 1-year-old boy is brought to the office by his parents for evaluation and correction of the findings shown in the photograph. The patient is otherwise healthy. Which of the following techniques is most appropriate to reconstruct the apex of the web space in this patient?
A) Bilobed flap from the dorsal hand B) Cross-finger flap C) Full-thickness skin grafting D) Proximally based dorsal rectangular flap E) Split-thickness skin grafting
The correct response is Option D.
Full-thickness skin grafts are usually used to close the resultant defects of the fingers after release of congenital syndactyly. Several local dorsal flaps have been described to reconstruct the web space with differing shapes to avoid the use of skin grafts, including rectangular, a V-Y island, a dorsal flap interdigitated with a small palmar V and a dorsal V-shape. A bilobed flap has been described for treating web creep in adults, but would not routinely be used.
2018
A 4-month-old infant is brought to the office for evaluation of a unilateral, seven-fingered hand with a central index finger flanked on each side by long, ring, and little fingers, with no thumb present. Abnormal expression of which of the following controlling substances is most likely responsible for this developmental anomaly?
A) Bone morphogenetic protein
B) Fibroblast growth factor
C) Sonic hedgehog protein
D) Wingless protein
The correct response is Option C.
The infant’s described anomaly is that of a mirror hand, which is an abnormality of the anteroposterior (radioulnar) axis of limb development. Sonic hedgehog protein (SHH) is expressed in the zone of polarizing activity (ZPA) on the posterior (ulnar) surface of the developing limb bud and is the main controlling substance for this axis of development. Direct expression of SHH results in development of the ulna, the ulnar two columns of the carpus, the little finger, the ring finger, and the ulnar half of the long finger. Diffusion of SHH, or long range signaling, results in development of the radial half of the long finger and the index finger. Absence of SHH results in the development of the radius, the radial column of the carpus, and the thumb. Ectopic expression of SHH, such as with duplication of the ZPA at the anterior (radial) margin of the limb bud, results in duplication of the ulnar-sided structures found in a mirror hand.
Fibroblast growth factors (FGF) are the main controlling substances in the apical ectodermal ridge (AER) and are responsible for the proximodistal axis of limb bud development. Bone morphogenetic proteins (BMP) are expressed in the AER and are also thought to be involved in digital separation, the lack of which leads to syndactyly. Wingless proteins (WNT) are also expressed in the AER, but it is the WNT signaling pathway from the dorsal surface of the limb bud that controls the dorsoventral axis of limb development. Dorsal ectodermal WNT also maintains SHH in the ZPA such that lack of WNT leads to lack of ulnar ray development. This is contrary to the ectopic expression of SHH leading to duplication of the ulnar rays in mirror hand. Fibroblast growth factors, bone morphogenetic proteins, and wingless proteins are not principal controlling substances for the anteroposterior (radioulnar) axis of development of the limb.
2018
A 6-month-old boy is brought to the office with a Blauth type IV (pouce flottant) thumb deficiency. Reconstruction with pollicization is planned. Which of the following is the most appropriate new function of the first palmar interosseous muscle?
A) Abductor pollicis brevis B) Abductor pollicis longus C) Adductor pollicis D) Extensor pollicis longus E) Flexor pollicis brevis
The correct response is Option C.
The most appropriate new function of the first palmar interosseous muscle is the adductor pollicis.
Thumb deficiencies can be categorized according to the Blauth classification, ranging from hypoplasia (type I) to complete absence (type V). In deficiencies of type IIIB and greater, pollicization of the index finger is the recommended treatment.
In pollicization, the index finger is transferred on its neurovascular bundle and a new thumb carpometacarpal (CMC) joint is created using the metacarpophalangeal joint of the index finger. The tendons and muscles of the index finger are used to recreate functions of the new thumb. The extensor digitorum communis is used for the abductor pollicis longus, the dorsal interosseus becomes the abductor pollicis brevis, and the palmar/volar interosseous becomes the adductor pollicis. The extensor indicis proprius is used for the extensor pollicis longus. The flexor tendon is not typically disturbed.
2018
A 2-year-old boy is treated for congenital constriction band of the left upper extremity with distal edema. The child undergoes excision of 50% of the circumferential constriction band with direct closure. This intervention is most likely to have which of the following effects on the edema of the distal limb?
A) Gradual improvement during childhood development
B) Gradual worsening during childhood development
C) Significant improvement within a few weeks of surgery
D) Significant worsening during childhood development
E) No effect
The correct response is Option C.
Congenital constriction band syndrome is a sporadic condition with an incidence varying from 1:1200 to 1:15,000 live births. There is a significant predilection for the upper extremities and distal limbs. The two main objectives for the treatment of congenital constriction band syndrome are improvement of function and improvement of cosmetic appearance. Different surgical techniques, such as Z-plasty, have been described and used for decades; however, direct closure after the excision of the constricting band is a simple yet effective treatment.
With complete circumferential constriction bands, it is recommended that a two-stage correction approach be used. At the first operation, one-half of the circumference is excised; the other half can be excised after 3 to 6 months. This will avoid any problems to the distal circulation in the limb, which may already be compromised. Edema, when present, will significantly improve within a few weeks of the first surgery.
2018
A 14-month-old girl is evaluated for surgical management of the condition shown in the photograph. Which of the following is the most appropriate classification of this congenital difference?
A) Duplication B) Failure of differentiation C) Failure of formation D) Overgrowth E) Undergrowth
The correct response is Option C.
The image shown is a patient with a typical cleft hand, or ectrodactyly. This is classified as a Swanson type I (failure of formation) congenital difference of the upper extremity. This deformity is caused by a longitudinal growth deficiency of one or more central digits. This condition may have a genetic underpinning and is most commonly inherited in autosomal dominant fashion with approximately 70% penetrance.
Ectrodactyly presents with significant heterogeneity. Many patients with cleft hand do not require any type of surgical management. The most important determinants of surgical management are establishment of an appropriate thumb to index webspace for gripping and grasping and release of syndactyly. Surgical management includes elevation of skin flaps, transposition of the index finger to the ulnar side of the cleft, and creation of a web space between the thumb and index finger.
Cleft hand is classified with the Thumb-Index Classification of Central Deficiency proposed by Manske. This generally guides the treatment approach in conjunction with management of syndactyly. A myriad of techniques have been employed based upon the severity of the webspace contraction and the presence of syndactyly adjacent to the cleft.
Type / Web Description / Characteristics
I: Normal
IIA: Mild narrowing / thumb web mild narrowing
IIB: Severe narrowing / thumb web severe narrowing
III: syndactyly / thumb and index rays are syndactylized
IV: merged / index ray is suppressed, thumb web space is merged w the cleft
V: absent / thumb elements are suppressed, ulnar rays remain, and thumb web space not present
2018
During embryonic limb development, limb bud outgrowth is controlled by which of the following families of signaling proteins?
A) Bone morphogenetic proteins B) Fibroblast growth factor C) Retinoic acid D) Sonic hedgehog (SHH) E) Wingless-type proteins
The correct response is Option B.
The most appropriate answer is fibroblast growth factor. Limb bud development begins at the fourth week of gestation via an outgrowth of lateral plate somatic mesoderm covered by ectoderm. The lower limb bud forms a few days after the upper limb and is formed opposite of the L3-5 vertebrae. The cells at the tip of the limb bud ectoderm thicken to form the apical ectodermal ridge (AER). Fibroblast growth factor 10 (FGF10) from the mesenchyme induces the formation of the AER, which produces FGF8. This signaling induces mitosis of the underlying cells leading to limb elongation.
A group of mesenchymal cells on the posterior of the limb bud form the zone of polarizing activity (ZPA). Cells from the ZPA secrete sonic hedgehog protein, which acts as a short range signaling molecule. The ZPA is responsible for the anteroposterior axis formation of the limb bud.
Retinoic acid, a derivative of vitamin A, plays a role in the proximal-distal development of the limb but is not the primary signaling molecule. The precise mechanism and action of retinoic acid is debated. A retinoic acid gradient is necessary for normal limb development. Retinoic acid may act as an inhibitor of FGF8, which then allows forelimb budding to occur. Retinoic acid is not thought to be involved in hindlimb formation.
During limb development, the digits are initially connected by tissue that regresses via apoptosis. Apoptosis of interdigital tissue is dependent on BMP signaling under the influence of sonic hedgehog from the ZPA. Proteins from the wingless type family, especially Wnt7a, are responsible for the dorsal-ventral patterning of the overlying ectoderm. The presence of Wnt7a is necessary to dorsalize the limb.
2017
A 3-month-old male infant is evaluated for polydactyly and mirror hand. Which of the following is the most likely genetic anomaly in this patient?
A) Engrailed-1 (EN1) B) Fibroblast growth factor-2 (FGF2) C) LIM homeobox transcription factor 1-beta (LMX1B) D) Sonic hedgehog (SHH) E) Wingless type (WNT)
The correct response is Option D.
This patient presents with polydactyly and mirror hand. The most likely genetic anomaly is in sonic hedgehog (SHH).
Limb development is controlled by signaling pathways that are located within 3 different signaling centers. These control the proximal-distal, anterior-posterior, and dorsal-ventral axes of limb development.
The limb develops in a proximal-distal direction, from shoulder to wrist, which is controlled by the apical ectodermal ridge (AER), a thickened layer of ectoderm over the limb bud. Fibroblast growth factors secreted within the AER signal the underlying mesoderm to differentiate. Disruption of the AER results in truncation of the limb.
Growth in the anterior-posterior (radioulnar) axis is determined by the zone of polarizing activity (ZPA). This is located in the posterior margin of the limb bud. The sonic hedgehog protein (SHH) acts to signal development of the limb into radial and ulnar aspects. Alterations in this pathway can result in mirror duplication.
Dorsal-ventral limb development is signaled by the Wnt signaling pathway, which produces a transcription factor, Lmx-1 that induces the development of dorsal structures. In the ventral portion of the limb, the Engrailed-1 gene product blocks the Wnt pathway, leading to ventralization.
A variety of other transcription factors encoded by Hox and T-Box genes also govern limb and organ development, and alterations in these can give rise to various developmental differences.
2017
A 3-year-old boy is scheduled to undergo the first stage of separation of syndactyly of the right hand. Photographs are shown. Which of the following anatomical structures is most likely to limit how far the digits can be separated proximally?
A) Artery B) Extensor tendon C) Flexor tendon D) Nerve E) Vein
The correct response is Option A.
Digital veins, due to their larger number and relative redundancy, do not normally limit which tissues can be separated to what level. Division of one branch of the digital artery is not normally a problem when only two digits are involved in syndactyly; the digital artery on the unaffected side is normally sufficient to perfuse the digit. For a central digit when three or more digits are involved, dissection must either stop at the bifurcation of the artery, or revascularization, such as with a vein graft, must be done.
The digital nerve often exists as a single unit at least partially down the length of the joined fingers, but it can be separated into two proper digital units with intrafascicular dissection to a level proximal to the neo-web space.
Flexor and extensor tendons are not involved in syndactyly.
2017
A 7-month-old male infant with complete syndactyly is evaluated for surgical release. Which of the following is the most appropriate technique for reconstruction of the web space?
A) Coverage with a distally based zigzag flap
B) Coverage with a dorsal rectangular flap
C) Coverage with a volar triangular flap
D) Full-thickness skin grafting
E) Split-thickness skin grafting
The correct response is Option B.
The most appropriate technique for reconstruction of the web space in patients with complete syndactyly is coverage with a dorsal rectangular flap.
In patients with compete syndactyly, separation does not typically result in sufficient skin to resurface both digits entirely. Reconstruction of the web space is a priority and is typically achieved with a proximally-based dorsal rectangular flap. Interdigitating skin flaps are designed, and skin grafts are placed to replace skin deficiency. Full-thickness skin grafts are preferred to split-thickness skin grafts because of the decreased likelihood of contracture; however, these grafts are not typically placed in the web space.
2016
A 3-month-old boy is brought for evaluation because of bilateral simple syndactylies between the long and ring fingers. During which gestational age range did this developmental anomaly most likely occur?
A) Days 0-15 B) Days 20-35 C) Days 40-55 D) Days 65-80 E) Days 85-100
The correct response is Option C.
Syndactyly is the most common congenital limb malformation. Digital separation is the result of distal to proximal apoptosis, likely mediated by bone morphogenic proteins (BMP) signaling TGF-beta. Overexpression of BMP inhibitors and persistent fibroblast growth factor (FGF) function have been found to lead to syndactyly.
The exact dates of digital separation vary by publication, but occur approximately between days 44 and 54. Limb buds appear by day 26, and a hand paddle by day 33. By day 56, the phalangeal tips are ossified.
2016
A 3-month-old male infant is brought to the clinic by his parents for evaluation of craniofacial and hand anomalies. Genetic testing confirms an FGFR2 abnormality consistent with Apert syndrome. Which of the following hand anomalies is most likely in this infant?
A) Camptodactyly B) Clinodactyly C) Ectrodactyly D) Macrodactyly E) Syndactyly
The correct response is Option E.
The hand anomaly most associated with Apert syndrome is syndactyly.
Apert syndrome, or acrocephalosyndactyly, is a syndrome resulting from a defect in chromosome 10q, the site of the fibroblast growth factor-2 receptor. This syndrome consists of coronal craniosynostosis, mid face hypoplasia with retrusion, and syndactylies of the hands and feet.
These may be type I (syndactyly of digits 2–4 with a free thumb; “spade hand”),
- type II (syndactyly of digits 2–4 with a simple syndactyly of the thumb; “mitten hand”), or
- type III (complex syndactyly of all digits with complex thumb syndactyly; “rosebud hand”).
The other choices are not typically associated with Apert syndrome. Camptodactyly is a fixed-flexion deformity of the proximal interphalangeal (PIP) joint(s), most commonly the little finger. Macrodactyly involves the localized overgrowth of bone and soft tissue. Clinodactyly is congenital deviation of a digit in the radioulnar plane. Ectrodactyly refers to a split-hand/split-foot malformation.
2015
A 52-year-old man is evaluated because of a congenital deficiency of the upper extremity. A photograph is shown. This patient’s developmental abnormality most likely occurred during which of the following periods of gestation?
A) 0–4 weeks B) 5–8 weeks C) 9–13 weeks D) 14–18 weeks E) 19–23 weeks
The correct response is Option B.
The most likely period of time during gestation for this abnormality is 31 to 45 days.
This patient presents with transverse deficiency of the upper limb (phocomelia). This can result from abnormal development of the limb with an interruption in longitudinal growth.
The limb develops with formation of a limb bud at 26 days after gestation, which rapidly enlarges with growth of the embryo until approximately 47 days. At around 52 to 53 days after gestation, the fingers are separate. Embryogenesis is complete by 8 weeks, and all limb structures are present.
Limb development is controlled by signaling pathways that are located within three different signaling centers. These control the proximal-distal, anterior-posterior, and dorsal-ventral axes of limb development.
The limb develops in a proximal-distal direction, from shoulder to wrist, which is controlled by the apical ectodermal ridge (AER), a thickened layer of ectoderm over the limb bud. Fibroblast growth factors secreted within the AER signal the underlying mesoderm to differentiate. Disruption of the AER results in truncation of the limb.
Growth in the anterior-posterior (radioulnar) axis is determined by the zone of polarizing activity (ZPA). This is located in the posterior margin of the limb bud. The sonic hedgehog protein acts to signal development of the limb into radial and ulnar aspects. Alterations in this pathway can result in mirror duplication.
Dorsal-ventral limb development is signaled by the Wnt signaling pathway, which produces a transcription factor, LMX1 that induces the development of dorsal structures. In the ventral portion of the limb, the EN1 gene product blocks the Wnt pathway, leading to ventralization.
A variety of other transcription factors encoded by Hox and T-Box genes also govern limb and organ development, and alterations in these can give rise to various developmental differences.
Most limb abnormalities occur during the period of 4 to 8 weeks. In this case, the transverse deficiency likely occurred earlier in the process of limb outgrowth, while abnormalities of the digit would have taken place towards the end of this period.
2015
A 1-month-old male newborn is brought to the office by his parents for evaluation of complete simple syndactyly between the second and third toes of the left foot. The parents are concerned about the newborn’s development and ability to achieve normal ambulation. Which of the following is the most appropriate intervention at this time?
A) Surgical correction is optional but not necessary because there is no functional deficit
B) Surgical correction with a dorsal local flap and ligament reconstruction
C) Surgical correction with a dorsal local flap only
D) Surgical correction with a dorsal local flap, skin grafting, and ligament reconstruction
E) Surgical correction with skin grafting only
The correct response is Option A.
Syndactyly of the toes most commonly affects the second and third digits of the lower extremities. Various levels of webbing are possible, from partial to complete. In general, syndactyly is a condition that is primarily cosmetic and rarely requires treatment. If surgery is desired, it should be postponed until the child is old enough to take part in the decision-making process. Surgery is often performed to avoid emotional and psychological problems.
Surgical correction most commonly consists of a dorsal rectangular flap and simultaneous full-thickness or split-thickness skin grafts. However, some surgeons are performing syndactyly repair of both the upper and lower extremities with dorsal local flaps and allowing the skin defects to epithelialize in order to avoid donor-site morbidity of a skin graft. If there is only soft-tissue involvement, ligament reconstruction is not needed.
2014
A full-term male newborn is evaluated because of Blauth Type IV (pouce flottant) thumb hypoplasia. Physical examination shows no other abnormalities. A pollicization procedure is planned. At which of the following ages is it most appropriate to perform this procedure?
A) 1 Month B) 1 Year C) 5 Year D) 10 Year E) 15 Year
The correct response is Option B.
Pollicization for thumb hypoplasia Types IIIB and IV, and for aplasia, has been successful when performed when the patient is between 3 months and 3 years of age.
Most surgeons will prefer to do pollicization procedures when the patient is between 6 and 12 months of age because there is a more natural integration and adaptation process in using the pollicized digit as a thumb while the child becomes more involved with manual activities. Nevertheless, the outcome also depends on the quality of the anatomical structures of the pollicized digit.
Technically, the procedure can be done at any time; however, at less than 3 months of age, the child’s cardiopulmonary maturation may be incomplete. Also, the child becomes aware of the thumb after the age of 3 months, so performing the procedure earlier than this age only raises the degree of technical difficulty because of the minute size of structures and potential circulatory issues, without any further advantage.
The older the child is at the time of the procedure, the more difficult it becomes to change the patterns of pinch and prehension that have already begun in the first 3 years of life. Fine coordination is achieved at 3 years of age. Reorganization of cortical representation of the index finger as a thumb is a slower and incomplete process in older children or adults. Exposure of the new configuration of the hand to the process of neuromuscular growth of the child is a key consideration.
2013
A female newborn is evaluated in the neonatal intensive care unit because of severe congenital constriction band syndrome of the left lower extremity. Examination shows cyanosis and severe swelling of the distal affected extremity. The constriction is located at the distal thigh and is very deep, extending down to the anterior distal femur. A Doppler popliteal pulse is audible. Plantar stimulation shows no sensory pain withdrawal reflex. Which of the following is the most appropriate immediate treatment?
A) Application of medicinal leeches to the foot
B) Constriction excision and Z-plasties
C) Leg elevation and edema wrapping
D) Limb amputation
E) Microsurgical repair of popliteal artery and vein and of the sciatic nerve
The correct response is Option B.
The patient described has type IIIB constriction (amniotic) band syndrome. Constriction banding affects 1:1,200 live births. Severity of the banding is classified as follows:
Type I (mild) – Shallow indentation of skin and soft tissue without distal lymphedema; Type II (moderate) – Distal lymphedema, acrosyndactyly, and even discontinuous neurovascular or musculotendinous structures, but without vascular compromise; Type III (severe) – Progressive lymphaticovenous or arterial compromise; Type IV – Intrauterine amputation. Weinzweig introduced the concept of a dynamic, or type IIIB, subtype in which there is evolving vascular compromise and in which “limb rescue” can be performed with emergency surgery despite a severe band. The dynamic progressive swelling and cyanosis and certain ischemic necrosis can be reversed by surgery.
However, there are consequences, and these are neurologic deficits and long-term leg-length discrepancies that may even require leg-lengthening procedures or appropriately timed opposite extremity epiphysiodesis. Early release of such a severe constriction band does not result in long-term neurologic improvement. Early excision of the involved nerve segment may be required, accompanied by nerve grafting.
2013
A 12-month-old boy is brought to the office for evaluation of complete absence of the right thumb. Examination shows no other extremity abnormalities. X-ray study confirms absent thumb metacarpal. Which of the following is the most appropriate method of reconstruction?
A) Great toe-to-thumb transfer B) Huber transfer C) Index finger pollicization D) Osteoplastic procedure E) Prosthesis
The correct response is Option C.
The most appropriate reconstruction of Type V deformity is pollicization of the index finger. It is the only satisfactory method of a basal joint reconstruction. Pollicization refers to the neurovascular pedicle movement of a finger, often with its metacarpal, for thumb reconstruction.
Great toe-to-thumb microsurgical reconstruction is appropriate when most of the first metacarpal is present. When the carpometacarpal (CMC) joint is absent or unstable, a great toe-to-thumb reconstruction will not reconstruct an adequate basilar joint.
A Huber transfer is used to create functional opposition when absent. Type IIIA deformities can be reconstructed with the Huber transfer, which involves transfer of the hypothenar muscle to recreate the thenar musculature.
Osteoplastic thumb reconstruction is rarely performed today because it results in a stiff, broad, floppy thumb with limited sensation. It involves the combination of a bone graft and flap to lengthen the thumb. At least three stages are required: bone graft from iliac crest covered in a tubed distant flap; flap pedicle division; and transfer of neurovascular sensory flap from the long finger to the thumb’s pinch contact surface.
A prosthesis would provide a stable post, but it would also lack sensation. The prosthesis will be more of an encumbrance and is not used in congenital thumb reconstruction.
2012
A 36-year-old pregnant woman undergoes routine fetal ultrasonography. Examination of the embryo shows the formation of limb buds without digital separation. Based on the timeline of the development of the upper extremity, it is most likely that the fetus has reached which of the following points in gestation?
A) 2 Weeks B) 5 Weeks C) 8 Weeks D) 11 Weeks E) 14 Weeks
The correct response is Option B.
Embryonic development has been studied closely. The stages of human upper extremity development have also been studied closely. The limb bud is present without digital separation at 5 weeks. At 2 weeks of gestation, the limb buds have not yet formed. At 8 weeks, digital separation is nearly complete.
2012
An 8-year-old girl is brought to the office because her right breast has not developed like the left breast. Physical examination shows hypoplasia of the right breast, absence of the sternal head of the pectoralis major, and a congenital abnormality of the right hand. Which of the following categories of congenital abnormalities best describes this patient’s hand condition?
A) Constriction ring syndrome B) Duplication C) Failure of differentiation D) Failure of formation E) Overgrowth
The correct response is Option C.
The category of congenital abnormality that is most likely to be associated with the abnormality described is failure of differentiation.
In the patient with absence of the sternal head of the pectoralis major muscle, the diagnosis is Poland sequence. Poland sequence is associated with symbrachydactyly of the ipsilateral hand. A system of classification has been adopted by the American Society for Surgery of the Hand (ASSH) and the International Federation of Societies for Surgery of the Hand (IFSSH) in an attempt to provide a unified system to catalog congenital hand deformities. In this system, congenital hand differences have been categorized into seven types:
Type I – Failure of formation
The type I congenital deformities include scenarios in which there is a lack of formation. This includes longitudinal arrest, which can be found at any level from the shoulder to the phalanx, or transverse arrest with varying degrees of preaxial, central, or postaxial deficits, such as radial or ulnar clubhand.
Type II – Failure of differentiation
Failure of differentiation involves a variety of conditions with inadequate separation of parts, such as syndactyly, carpal coalitions and synostoses, camptodactyly, and clinodactyly. Symbrachydactyly, as seen in Poland syndrome, falls into this category.
Type III – Duplication
Duplication may apply to the whole limb or occur as mirror hand. It includes radial or ulnar polydactyly and triphalangeal thumb.
Type IV – Overgrowth
Macrodactyly and hemihypertrophy are types of overgrowth disorders.
Type V – Undergrowth
Undergrowth of the whole limb or parts of the hand may occur. Common manifestations include brachysyndactyly or brachydactyly.
Type VI – Constriction ring syndrome
Constriction ring syndrome may involve amputation at any level.
Type VII – Generalized skeletal deformities
These deformities include generalized syndromes, such as Apert syndrome, various craniosynostoses, and Holt-Oram/thrombocytopenia-absent radius (TAR) syndrome.
2012
A 6-year-old boy is brought to the office by his mother because she is concerned about a deformity of the little finger of his right hand. She says the deformity has been present for approximately 3 years but has become progressively pronounced during the past year. On examination, the patient can flex the proximal interphalangeal joint but cannot extend it beyond the position shown in the x-ray. The little finger of his left hand is similarly affected, but the condition is less severe. Which of the following is the most likely diagnosis?
A) Camptodactyly B) Delta phalanx C) Kirner deformity D) Symphalangism E) Trigger finger
The correct response is Option A.
Camptodactyly is a congenital abnormality accounting for 5% of congenital hand anomalies. There is a flexion deformity that is often noted within the first year of life, but a second, “noncongenital” group occurs around age 10 years. It generally appears at the proximal interphalangeal (PIP) joint. It may occur as part of a syndrome but is often an individual defect. It is classified by the International Federation as Type II (failure of differentiation). It may be accompanied by subtle radiographic changes seen on the lateral view of the PIP joint with flattening of the circular surface of the proximal phalanx and an indentation in the neck of the proximal phalanx; dorsal positioning of the head of the proximal phalanx into the articulation of the base of the middle phalanx is also present.
A delta phalanx (or bracketed epiphysis) will result in clinodactyly. Clinodactyly is an excessive radial or ulnar angulation of the digit. Involvement of the little finger is common and often inherited as a dominant trait. It may be associated with a delta middle phalanx. If the deformity is severe enough, it may require surgical correction.
Kirner deformity is a progressive palmar and radial curvature of the distal phalanx of the little finger that presents in preadolescence. It is caused by an idiopathic, nontraumatic disruption of the epiphysis of the distal phalanx. It may be caused by cold exposure and frostbite and would affect multiple digits.
Symphalangism describes a congenital clinical stiffness of the PIP joints of the fingers. It is also included in the failure of differentiation classification category. Flexion creases are absent, and the fingers may be longitudinally foreshortened. Multiple digits are affected most commonly.
Trigger digits may occur in children but most commonly affect the thumb with a flexion deformity of the interphalangeal joint. They may occur with a flexion deformity of the PIP joints of the fingers, but the fingers are much less commonly affected than the thumb.
2011
A 2-year-old boy with VATER syndrome is brought to the office for evaluation because his parents are concerned that the thumb of the right hand appears small and weak. Physical examination shows weakness of intrinsic function of the right thumb. The flexor pollicis longus flexion crease is absent and the thenar eminence is flat. The left hand, including the thumb, appears normal. The patient uses a pincer-type motion between the right index and long fingers to pick up small objects. The ulnar collateral ligament at the metacarpophalangeal joint of the right thumb is lax. There is no gross dislocation at the carpometacarpal joint of the right thumb, but 6 mm of passive dorsoradial mobility is noted. An x-ray study and photograph are shown. Which of the following is the most appropriate management?
A) Amputation of the thumb and pollicization of the index finger
B) Flexor digitorum sublimis opponensplasty and ulnar collateral ligament stabilization
C) Huber transfer and ulnar collateral ligament stabilization
D) Tendon graft reconstruction of the flexor pollicis longus and ligament stabilization
E) Observation and occupational therapy until the child is age 4 to 5 years, followed by reassessment of function
The correct response is Option A.
The child described has a classic Blauth Type IIIB hypoplastic thumb. Although the carpometacarpal (CMC) joint does not dislocate, the subluxation described is consistent with the instability noted in Blauth Type IIIB thumbs. The photograph shows a thumb with a broad base, which is distracting to the examinee who is not familiar with this disorder. However, the thumb described has significant hypoplasia and pollex abductus. The x-ray study shows the classic finding of a narrowed and underdeveloped metacarpal base, the hallmark of CMC instability.
X-ray study is essentially diagnostic of the Blauth Type IIIB thumb. The most accepted treatment for this type of thumb is ablation/amputation of the existing thumb and replacement with the index finger in the thumb position (pollicization).
In the scenario described, the patient has no significant cortical representation or intentional control of the right thumb. The child picks up objects between the index and long finger, ignoring the thumb. No matter what maneuvers are undertaken to power and stabilize the existing thumb with tendon transfers, the child will still have little to no natural predilection to actually use the thumb. Although opponensplasty and ulnar collateral ligament stabilization are common solutions for Types II and IIIA thumbs, they would not be appropriate. These treatments are often combined with first web space deepening.
Treatment is recommended earlier than age 4 or 5 years to avoid resistance to the thumb ablation and pollicization, which can occur with time on the part of the parents and the child. The younger child will accommodate the pollicized digit better. Treatment of the hypoplastic thumb should be decisive and performed at the appropriate age, if possible.
Flexor pollicis longus reconstruction with a tendon graft will not improve thumb function in the scenario described. This type of surgery is not a standard therapy for hypoplastic thumbs in general. Ulnar collateral ligament stabilization is not recommended because the thumb requires pollicization.
2011
A 3-year-old girl is brought to the office because the second and third toes of both of her feet are webbed. The patient’s mother desires correction of the deformity. Physical examination shows a simple complete syndactyly. Which of the following is the most appropriate surgical treatment after release of syndactyly?
A) Local flaps
B) Local flaps and full-thickness skin grafts
C) Local flaps and split-thickness skin grafts from the lateral thigh
D) Primary closure
The correct response is Option B.
Syndactyly of the toes is a common congenital deformity of the lower extremity. Syndactyly of the toes is less of a functional problem than that of the hand, but it can represent a significant emotional and psychological toll on the patient and his or her family. Patients in cultures that are accustomed to open-toe footwear and sandals may have difficulty wearing shoes. Surgery is indicated for patients who desire correction of this deformity. Incomplete syndactyly of the toes can be repaired with local flaps without the use of grafts, but complete syndactyly requires the use of full-thickness skin grafts. Thinning of the fat from around the neurovascular bundles is essential to assure closure with local flaps. Skin grafts are seldom required for incomplete syndactyly. If they are required, full-thickness grafts should be obtained from the lateral groin. Full-thickness skin grafts harvested from the medial groin may produce undesirable hair growth as the child matures.
2011
A 5-day-old male newborn is evaluated in the neonatal intensive care unit because of hypoplasia of the thumb. His parents are distressed and would like him treated immediately. Physical examination shows Buck-Gramcko Grade V thumb hypoplasia. At which of the following ages is it most appropriate to perform reconstruction?
A ) 1 Month B ) 1 Year C ) 4 Years D ) 10 Years E ) 14 Years
The correct response is Option B.
A Buck-Gramcko Grade V or Type V thumb is the most severe form of thumb hypoplasia, as it constitutes an absence of the thumb. Therefore, the patient described will need a pollicization procedure. Though the literature is unclear as to the exact timing of such a procedure, it is recommended by Kozin that it be performed prior to the patient developing an undesired side-to-side pinch pattern between fingers, which is a compensatory mechanism that will develop after the first year. Furthermore, arguments have been made by Kleinman and Strickland to await the proper development of a newborn patient’s cardiopulmonary system, development of bimanual grasp, involution of embryonic endosteal circulation, and development of the digital vessels to a more substantial thickness. Each of these considerations will help to decrease complications in carrying out such a difficult procedure in a small hand. Therefore, the most appropriate timing would be at 1 year of age.
2010
A 1-year-old child is evaluated because of a radial polydactyly deformity with a duplicated distal phalanx of the thumb (Wassel Type II). Excision of the radial-sided thumb and reconstruction of the ulnar-sided thumb are planned. Which of the following is most likely to reestablish stability of the thumb?
A ) Early mobilization of the thumb 3 days after surgery
B ) Excision of the central bone and soft tissue (Bilhaut-Cloquet procedure)
C ) Pollicization of the index finger
D ) Reinsertion of the flexor pollicis brevis and abductor pollicis brevis muscles
E ) Use of a ligamentous and periosteal flap for radial collateral ligament reconstruction
The correct response is Option E.
Careful collateral ligament reconstruction in thumb duplication Types II and IV is critical in achieving stability during reconstruction. This is best done through the technique described by Manske, using a ligamentous and periosteal flap for reconstruction of the radial collateral ligament. In this technique, the radial thumb is excised, with care given to detaching the radial collateral ligament with a periosteal sleeve of tissue. The periosteal sleeve provides additional length to achieve a good repair of the radial collateral ligament.
Early mobilization of the thumb 3 days after surgery would likely be premature and may lead to destabilization of the reconstruction, rather than assisting with final stability. A thumb spica splint is typically used to immobilize such reconstructions for 4 to 6 weeks to aid healing.
Excision of central bone and soft tissue, commonly known as the Bilhaut-Cloquet procedure, can be used in Type II or Type IV duplications but would not be appropriate in the scenario described, in which the surgeon chooses to remove the radial-sided thumb and reconstruct the ulnar-sided thumb.
Pollicization of the index finger would not be appropriate at this level of duplication (Wassel Type II) because a very effective thumb can be made without resorting to the sacrifice of the index finger.
Reinsertion of the flexor pollicis brevis and abductor pollicis brevis muscles is not necessary in a Type II duplication, as the duplication is too distal (distal phalanx) to require any disinsertion or reinsert
2010
