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ABOS Surgery of the Hand study materials
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ABOS Surgery of the Hand practice questions

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Question 1Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

Which carpal bone is most frequently fractured?

  1. Hamate
  2. Triquetrum
  3. Scaphoid Correct answer.
  4. Capitate

Explanation

The scaphoid accounts for roughly 60-70% of all carpal fractures, most often through the waist after a fall onto an outstretched hand. Its retrograde blood supply from the radial artery explains the high rates of nonunion and proximal pole avascular necrosis.

Question 2Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A Bennett fracture is best described as which of the following?

  1. An extra-articular fracture of the first metacarpal shaft
  2. An intra-articular fracture of the trapezium with a radial fragment
  3. A comminuted intra-articular fracture of the first metacarpal base
  4. An intra-articular fracture of the first metacarpal base with a single volar-ulnar fragment Correct answer.

Explanation

Bennett described a two-part intra-articular fracture at the base of the first metacarpal in which the small volar-ulnar fragment stays attached to the anterior oblique ligament while the shaft is pulled proximally and radially by the abductor pollicis longus. The result is a characteristic subluxation of the first carpometacarpal joint.

Question 3Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A fifth metacarpal neck fracture typically produces which deformity?

  1. Pure rotational deformity without angulation
  2. Apex dorsal angulation Correct answer.
  3. Apex volar angulation
  4. Volar translation of the distal fragment

Explanation

The distal fragment of a fifth metacarpal neck fracture flexes volarly under the pull of the intrinsic muscles and the extensor mechanism, so the fracture apex points dorsally. This apex dorsal angulation is what must be measured and corrected if excessive.

Question 4Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A mallet finger deformity results from injury to which structure?

  1. The central slip at the proximal interphalangeal joint
  2. The flexor digitorum profundus insertion
  3. The volar plate of the proximal interphalangeal joint
  4. The terminal extensor tendon at the distal interphalangeal joint Correct answer.

Explanation

The terminal extensor tendon inserts at the base of the distal phalanx, and its disruption produces loss of active distal interphalangeal extension with a resultant flexion lag. The injury may be a tendon rupture or a bony avulsion of the dorsal base of the distal phalanx.

Question 5Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

Closed avulsion of the flexor digitorum profundus insertion, known as a jersey finger, most commonly involves which digit?

  1. Long finger
  2. Index finger
  3. Ring finger Correct answer.
  4. Small finger

Explanation

The ring finger is involved in the majority of jersey finger injuries because its profundus insertion is relatively weak and its position during grasp exposes it to the greatest force. The patient typically cannot flex the distal interphalangeal joint after a forced extension injury.

Question 6Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A Colles fracture is characterized by which displacement pattern?

  1. Volar displacement of the distal radial fragment
  2. Dorsal displacement of the distal ulna with an intact radius
  3. Dorsal displacement of the distal radial fragment Correct answer.
  4. An intra-articular volar rim fracture of the radius

Explanation

Colles described a distal radius fracture with dorsal displacement and dorsal tilt of the distal fragment, usually after a fall onto an extended wrist. The resulting deformity gives the classic dinner fork appearance.

Question 7Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A patient falls onto a flexed wrist and radiographs show a distal radius fracture with volar displacement of the distal fragment. This pattern is best termed which of the following?

  1. Barton fracture
  2. Smith fracture Correct answer.
  3. Colles fracture
  4. Chauffeur fracture

Explanation

A Smith fracture is the reverse of a Colles fracture, with the distal radial fragment displaced and tilted volarly after a fall onto a flexed wrist. It is less common than the Colles pattern and often requires operative stabilization for instability.

Question 8Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

Which finding on a lateral wrist radiograph indicates a lunate dislocation rather than a perilunate dislocation?

  1. The radiolunate angle is decreased on the lateral view
  2. The lunate is displaced volarly so that it no longer articulates with the radius Correct answer.
  3. The scaphoid demonstrates a cortical ring sign on the posteroanterior view
  4. The capitate lies dorsal to the lunate while the lunate remains in the lunate fossa

Explanation

In a perilunate dislocation the lunate keeps its normal position in the lunate fossa of the distal radius while the capitate and carpus displace dorsally. In a lunate dislocation the lunate itself is extruded volarly in the spilled teacup configuration, losing its articulation with the radius while the capitate comes to sit in the lunate fossa.

Question 9Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A patient has a six-month-old scaphoid waist fracture with a 3 mm radiolucent gap, sclerotic fracture margins, and cystic changes. What does this presentation represent?

  1. Normal healing of the scaphoid at six months
  2. An acute fracture that can still be treated in a cast
  3. Avascular necrosis confined to the distal pole
  4. Established nonunion requiring operative treatment Correct answer.

Explanation

A persistent lucent gap with sclerotic, cystic margins at six months defines an established scaphoid nonunion. Because union will not occur with immobilization alone at this stage, operative treatment with bone grafting and internal fixation is usually indicated.

Question 10Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

Which structure is the primary stabilizer of the distal radioulnar joint?

  1. Triangular fibrocartilage complex Correct answer.
  2. Lunotriquetral interosseous ligament
  3. Radioscaphocapitate ligament
  4. Scapholunate interosseous ligament

Explanation

The triangular fibrocartilage complex, particularly its foveal insertion on the ulnar styloid base, is the principal soft tissue stabilizer of the distal radioulnar joint. Disruption allows instability with forearm rotation and is evaluated with the fovea sign and stress testing.

Question 11Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A skier falls onto an abducted thumb and examination reveals laxity with valgus stress at the metacarpophalangeal joint. Which structure is injured?

  1. Radial collateral ligament of the metacarpophalangeal joint
  2. Volar plate of the metacarpophalangeal joint
  3. Ulnar collateral ligament of the metacarpophalangeal joint Correct answer.
  4. Ulnar collateral ligament of the interphalangeal joint

Explanation

Valgus stress at the thumb metacarpophalangeal joint tensions the ulnar collateral ligament, the structure injured in skier's or gamekeeper's thumb. Stress testing with the joint in extension and in slight flexion helps distinguish a ligament tear from volar plate involvement.

Question 12Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

Zone II of the flexor tendon system is defined as which region?

  1. From the wrist crease to the A1 pulley
  2. From the A1 pulley to the flexor digitorum superficialis insertion Correct answer.
  3. Within the carpal tunnel
  4. From the flexor digitorum superficialis insertion to the fingertip

Explanation

Zone II extends from the proximal edge of the A1 pulley to the insertion of the flexor digitorum superficialis, the region historically called no man's land. Injuries here carry a high risk of adhesion formation because both tendons glide within a tight fibro-osseous sheath.

Question 13Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

Zone I of the extensor tendon system corresponds to which level?

  1. Metacarpophalangeal joint
  2. Distal interphalangeal joint Correct answer.
  3. Dorsum of the hand
  4. Proximal interphalangeal joint

Explanation

Extensor zone I covers the distal interphalangeal joint and the terminal tendon, so injuries here produce a mallet finger. The zones progress proximally, with zone III at the proximal interphalangeal joint and zone V over the metacarpophalangeal joint.

Question 14Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A patient cannot oppose the thumb and has diminished sensation over the tip of the index finger. Which nerve is most likely injured?

  1. Ulnar nerve
  2. Median nerve Correct answer.
  3. Posterior interosseous nerve
  4. Radial nerve

Explanation

Thumb opposition is mediated by the median-innervated thenar muscles, and the median nerve supplies sensation to the volar index, long, and radial half of the ring fingers. Combined thenar weakness and index fingertip sensory loss therefore points to a median nerve lesion.

Question 15Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

Which finding is the earliest reliable indicator of compartment syndrome in the hand?

  1. Absent radial pulse
  2. Paralysis of the intrinsic muscles
  3. Pallor of the fingertips
  4. Pain out of proportion to the injury that worsens with passive stretch Correct answer.

Explanation

Compartment syndrome is a clinical diagnosis in which disproportionate pain, particularly pain provoked by passive stretch of the involved compartment, is the earliest dependable sign. Pulses typically remain palpable because the condition affects the microcirculation rather than the major vessels.

Question 16Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

What is the initial management priority for an open phalangeal fracture with gross wound contamination?

  1. Primary closure over a drain
  2. Immediate internal fixation through the wound
  3. Irrigation, debridement, and intravenous antibiotics Correct answer.
  4. Withholding antibiotics until intraoperative cultures return

Explanation

Open fractures are treated with urgent intravenous antibiotics, tetanus prophylaxis, and surgical irrigation and debridement to reduce the risk of deep infection. Definitive skeletal stabilization follows once the wound has been adequately cleaned.

Question 17Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

Which injury is the strongest indication for replantation?

  1. Thumb amputation proximal to the interphalangeal joint in a healthy adult Correct answer.
  2. Crush amputation with four centimeters of segmental bone loss in the index finger
  3. Single-finger amputation at the distal interphalangeal joint in a smoker with chronic bronchitis
  4. Amputation in a patient with severe peripheral vascular disease

Explanation

Thumb amputation is a classic strong indication for replantation because loss of the thumb causes disproportionate impairment of pinch and grip, and a replanted thumb far outperforms any reconstruction. Absolute contraindications include severely compromised general health and extensive segmental destruction.

Question 18Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

Kienböck disease is avascular necrosis of which carpal bone?

  1. Scaphoid
  2. Triquetrum
  3. Capitate
  4. Lunate Correct answer.

Explanation

Kienböck disease refers to idiopathic avascular necrosis of the lunate, presenting with dorsal wrist pain and sclerosis or collapse of the bone on imaging. Negative ulnar variance and a tenuous intraosseous blood supply are associated factors.

Question 19Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

Which structures are most at risk from a fracture of the hook of the hamate?

  1. Ulnar nerve and ulnar artery Correct answer.
  2. Median nerve and radial artery
  3. Posterior interosseous nerve and extensor pollicis longus tendon
  4. Radial artery and flexor carpi radialis tendon

Explanation

The hook of the hamate forms the lateral wall of the ulnar tunnel, so fractures with callus or displacement can compress the ulnar nerve and injure the ulnar artery. Attritional rupture of the flexor digitorum profundus to the small finger is also associated with this injury.

Question 20Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

Which injury characteristic most strongly predicts instability of a distal radius fracture treated without surgery?

  1. Side of injury
  2. Initial dorsal tilt greater than 20 degrees with intra-articular comminution Correct answer.
  3. A small avulsion fracture of the ulnar styloid
  4. Patient sex

Explanation

Loss of reduction after casting is predicted by initial dorsal tilt beyond about 20 degrees, dorsal comminution, intra-articular fracture extension, and shortening greater than a few millimeters. These features identify fractures that are unlikely to hold a reduced position and warrant operative fixation.

Question 21Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

Which metacarpal fracture pattern is most prone to rotational malalignment that requires anatomic reduction?

  1. Small avulsion fracture of the fifth metacarpal base
  2. Nondisplaced fifth metacarpal neck fracture
  3. Spiral fracture of the metacarpal shaft Correct answer.
  4. Nondisplaced second metacarpal base fracture

Explanation

Spiral and long oblique fractures of the metacarpal shaft tend to shorten and rotate, and even a small amount of malrotation produces obvious digital overlap when the fingers are flexed. These patterns often require open reduction and internal fixation to restore rotation.

Question 22Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A fracture of the proximal phalanx shaft characteristically angulates in which direction?

  1. Apex volar Correct answer.
  2. Apex ulnar
  3. Apex radial
  4. Apex dorsal

Explanation

The intrinsic muscles flex the proximal fragment while the extensor mechanism extends the distal fragment, producing apex volar angulation at the fracture site. Recognition matters because the resulting deformity can limit flexion and requires reduction when angulation exceeds acceptable limits.

Question 23Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A 12-year-old sustains a distal radius fracture that runs through the physis and exits through a metaphyseal corner fragment, with the epiphysis itself intact. This is a Salter-Harris type injury of which number?

  1. Type IV
  2. Type II Correct answer.
  3. Type I
  4. Type III

Explanation

A Salter-Harris type II fracture passes through the physis and exits through the metaphysis, creating the characteristic Thurston-Holland fragment. Type I involves only the physis, type III involves the physis and epiphysis, and type IV crosses the physis, metaphysis, and epiphysis.

Question 24Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A patient has a laceration along the ulnar aspect of the index finger at the middle phalanx with reduced two-point discrimination in that distribution. Which structure is most likely injured?

  1. Flexor digitorum superficialis tendon
  2. A2 pulley
  3. Proper digital nerve Correct answer.
  4. Radial digital artery

Explanation

The proper digital nerve runs along the volar-ulnar aspect of the digit, and a laceration in this location with diminished two-point discrimination indicates nerve transection. Sensory testing of both digital nerve territories should be documented before any wound exploration or repair.

Question 25Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

Long-standing scaphoid nonunion characteristically produces which pattern of wrist arthritis?

  1. Uniform pancarpal arthritis beginning at the ulnocarpal joint
  2. Radiolunate arthritis with sparing of the radioscaphoid joint
  3. Radioscaphoid arthritis with sparing of the radiolunate joint Correct answer.
  4. Isolated arthritis of the first carpometacarpal joint

Explanation

In scaphoid nonunion advanced collapse the scaphoid rotates into a flexed posture, and the abnormal radioscaphoid contact leads to arthritis there first while the spherical lunate fossa spares the radiolunate articulation. The arthritic progression then advances to the scaphocapitate interval.

Question 26Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

In a Bennett fracture, the thumb metacarpal shaft is displaced in which direction by the pull of the abductor pollicis longus?

  1. Distal and ulnar
  2. Dorsal and radial
  3. Proximal and radial Correct answer.
  4. Volar and ulnar

Explanation

The abductor pollicis longus inserts at the base of the first metacarpal and pulls the metacarpal shaft proximally and radially. The small volar ulnar fragment remains attached to the trapezium through the anterior oblique ligament, producing the characteristic subluxation.

Question 27Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A mallet finger deformity results from disruption of which structure?

  1. The terminal extensor tendon insertion Correct answer.
  2. The central slip insertion
  3. The volar plate insertion
  4. The flexor digitorum profundus insertion

Explanation

The terminal extensor tendon inserts at the base of the distal phalanx and is responsible for active distal interphalangeal extension. Its disruption, whether tendinous or bony, prevents active extension at that joint and produces the mallet deformity.

Question 28Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A jersey finger injury is avulsion of which tendon?

  1. Abductor pollicis longus at the first metacarpal
  2. Flexor digitorum superficialis at the proximal phalanx
  3. Flexor digitorum profundus at the distal phalanx Correct answer.
  4. Extensor indicis proprius at the index metacarpal

Explanation

A jersey finger is avulsion of the flexor digitorum profundus from its insertion at the base of the distal phalanx. It typically occurs when the finger is forcibly extended while the profundus is actively contracting, and the ring finger is most commonly affected.

Question 29Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A boxer's fracture most commonly involves which location?

  1. Base of the first metacarpal
  2. Shaft of the fourth metacarpal
  3. Neck of the second metacarpal
  4. Neck of the fifth metacarpal Correct answer.

Explanation

A boxer's fracture is a fracture of the fifth metacarpal neck, usually caused by a direct blow with a clenched fist. It typically angulates with the apex dorsal because of the pull of the intrinsic muscles.

Question 30Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

Why is a fracture through the proximal pole of the scaphoid at particularly high risk of nonunion?

  1. Its nutrient artery is torn in most wrist sprains
  2. Its articular cartilage limits soft tissue blood supply
  3. It bears the greatest compressive load across the wrist
  4. Its blood supply enters distally and flows proximally Correct answer.

Explanation

The scaphoid receives its main blood supply through dorsal branches that enter near the distal pole and travel proximally in a retrograde fashion. A proximal pole fracture can therefore interrupt the blood supply to the proximal fragment and lead to avascular necrosis or nonunion.

Question 31Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A laceration over the dorsum of the proximal interphalangeal joint disrupts the central slip. Which deformity develops if untreated?

  1. Claw deformity with metacarpophalangeal extension
  2. Mallet deformity with distal interphalangeal flexion
  3. Boutonniere deformity with proximal interphalangeal flexion Correct answer.
  4. Swan-neck deformity with proximal interphalangeal extension

Explanation

The central slip extends the proximal interphalangeal joint, and its loss allows the joint to flex. The lateral bands migrate volarly and subsequently produce distal interphalangeal hyperextension, creating the classic boutonniere posture.

Question 32Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

Which structure is primarily injured in a hyperextension sprain of the proximal interphalangeal joint?

  1. The ulnar collateral ligament
  2. The volar plate Correct answer.
  3. The central slip
  4. The terminal extensor tendon

Explanation

The volar plate is a strong fibrocartilaginous structure that resists hyperextension of the proximal interphalangeal joint. A hyperextension injury can avulse the volar plate and may produce a small volar lip fracture at the base of the middle phalanx.

Question 33Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A metacarpal shaft fracture typically angulates apex dorsal because of the pull of which muscle group?

  1. The interossei Correct answer.
  2. The abductor pollicis longus
  3. The lumbricals
  4. The flexor digitorum superficialis

Explanation

The interossei insert on the proximal phalanx and the metacarpal base and exert a flexion moment at the fracture site, producing apex dorsal angulation in metacarpal shaft fractures. This deforming force is important when deciding whether reduction can be maintained.

Question 34Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A patient falls onto an outstretched hand and radiographs show a widened scapholunate interval. Which ligament is most likely injured?

  1. The radioscaphocapitate ligament
  2. The triangular fibrocartilage complex
  3. The lunotriquetral ligament
  4. The scapholunate ligament Correct answer.

Explanation

A scapholunate interval greater than about 3 mm after trauma suggests disruption of the scapholunate interosseous ligament. If untreated, this can progress to scapholunate advanced collapse and a dorsal intercalated segment instability pattern.

Question 35Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A patient has a subungual hematoma involving more than half the nail with a visible nail bed laceration. What is the most appropriate management?

  1. Observation with splinting and delayed nail bed repair
  2. Trephination of the nail plate alone
  3. Immediate amputation of the distal phalanx
  4. Nail bed repair with nail plate replacement Correct answer.

Explanation

A nail bed laceration associated with a large subungual hematoma requires meticulous repair to optimize nail growth and prevent deformity. The nail plate or a stent can be replaced to splint the eponychium and maintain the nail fold.

Question 36Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A worker sustains a high-pressure injection injury to the index fingertip from a grease gun. What is the most appropriate initial management?

  1. Urgent surgical exploration and debridement Correct answer.
  2. Oral antibiotics and outpatient follow-up in 48 hours
  3. Warm soaks and splinting
  4. Aspiration of the injected material in the emergency department

Explanation

High-pressure injection injuries are surgical emergencies because injected material tracks along tendon sheaths and fascial planes, causing ischemia and severe infection. Urgent exploration, debridement, and decompression are required; delay increases the risk of amputation.

Question 37Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A patient presents with a small laceration over the metacarpophalangeal joint after punching another person in the mouth. What is the most important next step in management?

  1. Obtain an MRI before any surgical intervention
  2. Irrigate and refer to hand therapy in one week
  3. Explore through full motion and give intravenous antibiotics Correct answer.
  4. Close primarily and prescribe oral antibiotics

Explanation

A fight bite can inoculate oral flora into the metacarpophalangeal joint or extensor tendon sheath, and the skin wound may be small while the underlying injury is deep. The wound should be explored with the joint through a full range of motion, and intravenous antibiotics with washout are typically required.

Question 38Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A patient has a lunate dislocation with the lunate displaced volarly and the capitate remaining dorsal to it. According to Mayfield's classification of progressive perilunar instability, which stage is this?

  1. Stage III
  2. Stage I
  3. Stage IV Correct answer.
  4. Stage II

Explanation

Mayfield's stages progress from scapholunate ligament disruption in stage I to perilunate dislocation in stages II and III, and finally to volar lunate dislocation in stage IV. A volarly displaced lunate with the capitate dorsal to it therefore represents stage IV perilunar instability.

Question 39Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A patient sustains a ring avulsion with complete amputation of the digit. Using the Urbaniak classification, how is this injury categorized?

  1. Class I
  2. Class III Correct answer.
  3. Class II
  4. Class IV

Explanation

The Urbaniak classification has three classes: class I has adequate circulation, class II has impaired circulation with an intact skeleton, and class III is complete degloving or amputation. A complete amputation therefore falls into class III.

Question 40Hand and Wrist Trauma (fractures, dislocations, tendon and nerve injuries)

A patient has a bony mallet finger with an avulsion fragment involving 40% of the articular surface and volar subluxation of the distal phalanx. What is the most appropriate treatment?

  1. Continue extension splinting for six weeks
  2. Open reduction and internal fixation Correct answer.
  3. Immediate distal interphalangeal joint arthrodesis
  4. Closed reduction and percutaneous pinning without fragment fixation

Explanation

A bony mallet fracture with a large articular fragment and volar subluxation of the distal phalanx is unstable and requires operative reduction and fixation. Extension splinting alone cannot restore articular congruity or correct subluxation in this setting.

Question 41Congenital and Pediatric Hand Conditions

In a young child with simple syndactyly of the fingers, what is the main goal of surgical release?

  1. Allow normal nail plate growth
  2. Prevent progressive tethering and functional impairment Correct answer.
  3. Improve the appearance of the hand
  4. Reduce the risk of malignant change in the web

Explanation

Syndactyly release is performed chiefly to prevent progressive angular deformity and functional loss as the hand grows. The tethered digits can deviate and the web space can contract, so surgery is timed before these changes become fixed. Appearance may improve, but it is not the primary functional indication.

Question 42Congenital and Pediatric Hand Conditions

What is the typical clinical presentation of a pediatric trigger thumb?

  1. Hyperextension deformity of the interphalangeal joint
  2. Fixed flexion contracture of the interphalangeal joint Correct answer.
  3. Ulnar deviation of the thumb at the interphalangeal joint
  4. Painful snapping at the metacarpophalangeal joint

Explanation

Pediatric trigger thumb usually presents as a fixed flexion posture of the interphalangeal joint, often with a palpable Notta nodule. Unlike adult trigger digits, young children seldom report painful snapping. Many cases resolve spontaneously during the first year of life.

Question 43Congenital and Pediatric Hand Conditions

Which Wassel type is the most common form of radial polydactyly?

  1. Type II
  2. Type I
  3. Type IV Correct answer.
  4. Type VI

Explanation

Wassel type IV, with duplication of both the proximal and distal phalanges of the thumb, is the most frequently encountered pattern. Type I and type II duplications are less common. Recognition matters because type IV often requires reconstruction of both collateral ligaments and the extrinsic tendon insertions.

Question 44Congenital and Pediatric Hand Conditions

A newborn has an absent radius and a ventricular septal defect. Which syndrome is most likely?

  1. Holt-Oram syndrome Correct answer.
  2. Marfan syndrome
  3. Apert syndrome
  4. Poland syndrome

Explanation

Holt-Oram syndrome is caused by TBX5 mutations and combines radial ray deficiency with cardiac septal defects. The cardiac findings often include ventricular or atrial septal defects and conduction abnormalities. This combination should prompt cardiac evaluation and genetic counseling.

Question 45Congenital and Pediatric Hand Conditions

What is the characteristic pattern of a typical cleft hand?

  1. A transverse deficiency at the wrist
  2. A ulnar deficiency with an absent small finger
  3. A central longitudinal deficiency with an absent middle ray Correct answer.
  4. A radial deficiency with an absent thumb

Explanation

Cleft hand, or split hand, is a central longitudinal deficiency that produces a V-shaped cleft through the metacarpal area, often with absence of the middle ray. The radial and ulnar digits are usually present, although they may be hypoplastic. This contrasts with transverse deficiency, in which all distal elements are absent at a given level.

Question 46Congenital and Pediatric Hand Conditions

Constriction ring syndrome of the newborn is best characterized by which finding?

  1. Annular soft-tissue bands that can cause distal swelling Correct answer.
  2. Fusion of adjacent digits at the distal phalanges
  3. Absence of the radius and thumb
  4. Progressive bony overgrowth of a digit

Explanation

Constriction bands are congenital annular grooves that can obstruct lymphatic and venous drainage, producing distal edema. Severe bands may cause neurovascular compromise or autoamputation in utero. Treatment is staged release of the bands when circulation or growth is threatened.

Question 47Congenital and Pediatric Hand Conditions

Macrodactyly is most commonly associated with enlargement of which nerve territory?

  1. Median nerve Correct answer.
  2. Radial nerve
  3. Ulnar nerve
  4. Axillary nerve

Explanation

Macrodactyly, particularly macrodystrophia lipomatosa, most often occurs in the median nerve distribution. The index and middle fingers are commonly affected. The enlargement involves fibrofatty tissue and can be progressive, requiring debulking or epiphysiodesis.

Question 48Congenital and Pediatric Hand Conditions

Which Salter-Harris fracture pattern is most common in children?

  1. Type I
  2. Type II Correct answer.
  3. Type IV
  4. Type III

Explanation

Salter-Harris type II fractures, which pass through the physis and exit through the metaphysis, are the most common physeal injuries in children. Type I injuries are also seen but are less frequent and may be radiographically occult. Types III and IV are intra-articular and less common.

Question 49Congenital and Pediatric Hand Conditions

What is the recommended timing for release of syndactyly involving a border digit such as the thumb-index web?

  1. At 5 to 7 years of age
  2. At 6 to 12 months of age Correct answer.
  3. At 2 to 3 years of age
  4. After skeletal maturity

Explanation

Border-digit syndactyly can tether the digit and cause progressive angular deformity, so release is usually performed at 6 to 12 months. Central syndactyly is often released somewhat later, around 12 to 24 months. Early release preserves joint alignment and web-space function.

Question 50Congenital and Pediatric Hand Conditions

Which principle is most important during surgical release of syndactyly?

  1. Avoid straight-line scars across joint creases Correct answer.
  2. Use a straight longitudinal incision across the web
  3. Close the web space primarily without grafts
  4. Preserve all digital nerves regardless of course

Explanation

Syndactyly release should avoid straight-line scars that cross joint creases because they can cause contracture. Zigzag incisions and skin grafting of the web space and lateral defects are standard. Careful neurovascular dissection is required, but the key design principle is scar placement.