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7. Hand and Wrist MCQs

Practice Set 182 of 266

This practice set contains high-yield board review questions covering key concepts in 7. Hand and Wrist. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 3621

Topic: Wrist & Carpus

A 30-year-old patient undergoes ORIF for a trans-scaphoid perilunate dislocation. Post-operatively, K-wires are placed across the scapholunate and capitolunate joints. What is the approximate period of time the K-wires are typically left in place before removal?

. 2-3 weeks
. 4-6 weeks
. 8-12 weeks
. 4-6 months
. Indefinitely

Correct Answer & Explanation

. 8-12 weeks

Explanation

K-wires are typically left in place for approximately 8-12 weeks after surgical repair of perilunate dislocations. This duration allows for sufficient healing of the repaired ligaments and the scaphoid fracture (if present). Removing them too early risks redislocation or nonunion, while leaving them in too long increases the risk of infection, pin tract problems, and prolonged stiffness. After removal, a period of protected motion and strengthening follows.

Question 3622

Topic: 7. Hand and Wrist

Which carpal bone is considered the 'intercalated segment' and has no direct tendon attachments, making its position dependent on surrounding ligaments?

. Scaphoid
. Capitate
. Lunate
. Trapezium
. Hamate

Correct Answer & Explanation

. Lunate

Explanation

The lunate is considered the 'intercalated segment' of the carpus. It is unique in that it has no direct muscular or tendinous attachments; its position and motion are entirely dictated by the tension and integrity of the surrounding intrinsic and extrinsic ligaments that connect it to the scaphoid, triquetrum, radius, and capitate. This makes it particularly vulnerable to instability and displacement when these ligaments are injured, as seen in perilunate dislocations.

Question 3623

Topic: 7. Hand and Wrist

What diagnostic imaging is considered the gold standard for defining bony anatomy and displacement in a complex carpal fracture-dislocation like a perilunate injury?

. Plain X-rays (PA, lateral, oblique)
. MRI with contrast
. CT scan with 3D reconstructions
. Ultrasound
. Bone scan

Correct Answer & Explanation

. CT scan with 3D reconstructions

Explanation

While plain X-rays are the initial diagnostic tool and lateral views are crucial, a CT scan with 3D reconstructions is considered the gold standard for precisely defining the complex bony anatomy, articular congruity, and any associated fractures (e.g., scaphoid, capitate, triquetrum) in a complex carpal fracture-dislocation like a perilunate injury. It offers superior detail compared to X-rays and better bony resolution than MRI. MRI is superior for soft tissue/ligamentous injury.

Question 3624

Topic: 7. Hand and Wrist

Which of the following is NOT a recognized component of a 'lesser arc' carpal injury?

. Scapholunate ligament rupture
. Lunotriquetral ligament rupture
. Radiolunate ligament rupture
. Fracture of the waist of the scaphoid
. Capitolunate ligament rupture

Correct Answer & Explanation

. Fracture of the waist of the scaphoid

Explanation

A 'lesser arc injury' refers to perilunate instability patterns that involve only ligamentous disruptions, primarily of the intrinsic intercarpal ligaments (scapholunate, lunotriquetral, and related extrinsic ligaments like radiolunate and capitolunate). A 'greater arc injury' involves a combination of ligamentous disruption and associated carpal bone fractures. Therefore, a fracture of the waist of the scaphoid is a component of a 'greater arc' injury, not a 'lesser arc' injury.

Question 3625

Topic: 7. Hand and Wrist

In the context of surgical repair of perilunate dislocation, what is the purpose of temporary wrist arthrodesis (e.g., with an external fixator) in select severe cases?

. To accelerate bone healing in associated fractures
. To provide prolonged rigid immobilization and protect extensive ligamentous repairs
. To facilitate early range of motion
. To primarily decompress the median nerve
. To substitute for internal K-wire fixation

Correct Answer & Explanation

. To provide prolonged rigid immobilization and protect extensive ligamentous repairs

Explanation

In very severe or comminuted perilunate fracture-dislocations, or cases with extensive soft tissue damage, temporary wrist arthrodesis, often achieved with an external fixator, can be used to provide prolonged, rigid immobilization. This protects extensive ligamentous and bony repairs, allows soft tissues to heal, and prevents collapse or redislocation, especially in highly unstable situations where K-wires alone might be deemed insufficient. It is a more robust form of immobilization, not a substitute for internal fixation or a means to facilitate early motion.

Question 3626

Topic: Wrist & Carpus
In the Frykman classification system for distal radius fractures, what does the term 'Type VII' specifically denote?
. Extra-articular
. Intra-articular involving the radiocarpal joint only
. Intra-articular involving the DRUJ only
. Intra-articular involving both radiocarpal and DRUJ joints
. Open fracture

Correct Answer & Explanation

. Intra-articular involving both radiocarpal and DRUJ joints

Explanation

The Frykman classification categorizes distal radius fractures based on intra-articular extension and associated ulnar fracture. Even numbers (II, IV, VI, VIII) indicate an associated ulnar fracture, while odd numbers (I, III, V, VII) indicate no associated ulnar fracture. The specific articular involvement follows: Type I/II (extra-articular), Type III/IV (radiocarpal intra-articular), Type V/VI (DRUJ intra-articular), and Type VII/VIII (both radiocarpal and DRUJ intra-articular). Therefore, Type VII signifies an intra-articular fracture involving both the radiocarpal joint and the distal radioulnar joint (DRUJ), without an associated ulnar fracture.

Question 3627

Topic: 7. Hand and Wrist

A patient presents to the emergency department with a significantly displaced distal radius fracture and acute carpal tunnel syndrome symptoms (paresthesias in the median nerve distribution, positive Tinel's at the carpal tunnel, decreased two-point discrimination). What is the MOST appropriate initial management step?

. Emergent carpal tunnel release
. Closed reduction of the fracture and immobilization
. Administration of high-dose corticosteroids
. Observation for 24 hours
. Urgent MRI of the wrist

Correct Answer & Explanation

. Closed reduction of the fracture and immobilization

Explanation

Acute median nerve neuropathy associated with a significantly displaced distal radius fracture is often due to direct compression or traction from the fracture fragments or surrounding edema. The MOST appropriate initial step is emergent closed reduction of the fracture. Reducing the fracture often decompresses the median nerve, alleviating symptoms. If symptoms do not improve rapidly after reduction, then an emergent carpal tunnel release may be considered. Corticosteroids, observation, or MRI would delay critical treatment.

Question 3628

Topic: 7. Hand and Wrist

A common and often debilitating complication associated with dorsal plating for distal radius fractures, which is less frequently seen with volar plating, is:

. Median nerve neuropathy
. Carpal tunnel syndrome
. Extensor tendon irritation or rupture
. Flexor tendon irritation or rupture
. Complex Regional Pain Syndrome (CRPS)

Correct Answer & Explanation

. Extensor tendon irritation or rupture

Explanation

Dorsal plating places the hardware (plate and screws) in close proximity to the extensor tendons, particularly the EPL (Extensor Pollicis Longus). This can lead to extensor tendon irritation, tenosynovitis, or, more severely, rupture due to attrition over the prominent hardware or rough bone edges. While median nerve neuropathy and CRPS can occur with any distal radius fracture treatment, flexor tendon issues are more associated with volar plating (though less common with modern low-profile plates). Carpal tunnel syndrome is often due to the injury itself or fracture displacement.

Question 3629

Topic: 7. Hand and Wrist

Which carpal ligament injury is most commonly associated with a high-energy distal radius fracture, potentially leading to carpal instability?

. Lunotriquetral ligament
. Scapholunate ligament
. Capitolunate ligament
. Radioscaphocapitate ligament
. Ulnolunate ligament

Correct Answer & Explanation

. Scapholunate ligament

Explanation

The Scapholunate (SL) ligament is the most frequently injured intercarpal ligament associated with distal radius fractures, especially in high-energy trauma or fractures with significant comminution or displacement. Injury to the SL ligament can lead to scapholunate dissociation and subsequent degenerative changes (SLAC wrist). While other ligaments can be injured, the SL ligament is particularly vulnerable and its injury carries significant implications for wrist stability.

Question 3630

Topic: Wrist & Carpus

Following stable open reduction and internal fixation of a distal radius fracture with a volar locking plate, what is typically the recommended rehabilitation protocol?

. Immobilization for 6-8 weeks, followed by gentle range of motion
. Immediate initiation of active and passive range of motion exercises
. Strict immobilization for 2 weeks, then active range of motion
. Active range of motion after 4 weeks, passive after 6 weeks
. Begin strengthening exercises immediately

Correct Answer & Explanation

. Immediate initiation of active and passive range of motion exercises

Explanation

The primary advantage of stable internal fixation with modern volar locking plates is the ability to initiate early active and passive range of motion (ROM) exercises. This helps prevent stiffness, tendon adhesions, and CRPS. Immobilization is typically minimal (e.g., a splint for comfort for a few days) or not required at all beyond the immediate post-operative period. Strengthening is generally delayed until adequate bone healing is evident (typically 6 weeks or more).

Question 3631

Topic: Wrist & Carpus
A Frykman Type VIII distal radius fracture indicates involvement of:
. Extra-articular, no ulnar fracture
. Radiocarpal joint intra-articular, with ulnar fracture
. DRUJ intra-articular, no ulnar fracture
. Both radiocarpal and DRUJ intra-articular, no ulnar fracture
. Both radiocarpal and DRUJ intra-articular, with ulnar fracture

Correct Answer & Explanation

. Both radiocarpal and DRUJ intra-articular, with ulnar fracture

Explanation

Revisiting Frykman: Odd numbers = no ulnar fracture; Even numbers = with ulnar fracture. Types I/II: Extra-articular. Types III/IV: Radiocarpal intra-articular. Types V/VI: DRUJ intra-articular. Types VII/VIII: Both radiocarpal and DRUJ intra-articular. Therefore, Type VIII combines intra-articular involvement of both the radiocarpal and DRUJ joints with an associated ulnar fracture.

Question 3632

Topic: 7. Hand and Wrist

Which of the following radiographic signs is most indicative of chronic or unstable scapholunate dissociation associated with a distal radius fracture?

. Increased radioscaphoid angle
. Positive ulnar variance
. Terry Thomas sign (increased scapholunate gap)
. Decreased radial inclination
. Loss of volar tilt

Correct Answer & Explanation

. Terry Thomas sign (increased scapholunate gap)

Explanation

The 'Terry Thomas sign' refers to an abnormally widened scapholunate gap (>3mm) on a PA radiograph, indicating a disruption of the scapholunate ligament and dissociation between the scaphoid and lunate. This is a primary sign of scapholunate instability. Increased radioscaphoid angle and loss of carpal height are also features of SLAC wrist, which can develop from chronic SL dissociation. Positive ulnar variance, decreased radial inclination, and loss of volar tilt are signs of radial malunion, not directly SL dissociation.

Question 3633

Topic: 7. Hand and Wrist

What is the typical mechanism of injury for a Reverse Barton's fracture?

. Fall on an outstretched hand with the wrist in dorsiflexion
. Fall on an outstretched hand with the wrist in palmarflexion
. Direct blow to the dorsal aspect of the wrist
. Hyperextension injury with axial load
. Torsional force to the forearm

Correct Answer & Explanation

. Fall on an outstretched hand with the wrist in palmarflexion

Explanation

A Reverse Barton's fracture (or volar Barton's fracture) is an intra-articular fracture of the distal radius with volar displacement of the carpus and a segment of the volar rim. This injury typically occurs from a fall on an outstretched hand with the wrist in forced palmarflexion, driving the carpus volarly and proximally against the distal radius. A Colles' fracture (dorsal displacement) occurs with the wrist in dorsiflexion.

Question 3634

Topic: Wrist & Carpus

According to the AO/OTA classification, what does a '23-C3' distal radius fracture signify?

. Extra-articular, simple
. Extra-articular, multifragmentary
. Intra-articular, partial articular, simple
. Intra-articular, complete articular, simple
. Intra-articular, complete articular, multifragmentary

Correct Answer & Explanation

. Intra-articular, complete articular, multifragmentary

Explanation

The AO/OTA classification for distal radius fractures (23) is hierarchical: Type A: Extra-articular. Type B: Partial articular (part of the joint surface involved). Type C: Complete articular (entire joint surface involved). The subdivisions further define complexity: C1 (complete articular, simple, 2-part), C2 (complete articular, multifragmentary metaphysis), C3 (complete articular, multifragmentary articular). Therefore, 23-C3 indicates a complete articular fracture that is multifragmentary (severely comminuted) at the articular level.

Question 3635

Topic: Wrist & Carpus

After fixation of a distal radius fracture, dynamic instability of the distal radioulnar joint (DRUJ) is suspected. Which maneuver specifically tests for this?

. Ballottement test
. Scaphoid shift test
. DRUJ stress test (provocative rotation)
. Grind test
. Piano key test

Correct Answer & Explanation

. DRUJ stress test (provocative rotation)

Explanation

Dynamic instability of the DRUJ refers to abnormal laxity or subluxation during active pronation and supination. A DRUJ stress test involves stabilizing the radius and actively or passively rotating the forearm while palpating for excessive translation, crepitus, or pain at the DRUJ. The Piano Key test assesses static dorsal/volar laxity of the ulna at rest. The Ballottement test (or radioulnar shear test) assesses static DRUJ stability. Scaphoid shift is for scapholunate instability, and Grind test is for CMC arthritis.

Question 3636

Topic: Wrist & Carpus

An unstable distal radius fracture with a displaced ulnar styloid base fracture is treated with volar plating of the radius. Post-operatively, the DRUJ is found to be stable. What is the most appropriate management for the ulnar styloid fracture?

. Surgical fixation of the ulnar styloid with tension band wiring
. Excision of the ulnar styloid
. Non-operative management with observation
. Immobilization in a long-arm cast
. Fusion of the DRUJ

Correct Answer & Explanation

. Non-operative management with observation

Explanation

The primary role of the ulnar styloid in the context of DRUJ stability is through its attachments to the TFCC, particularly the dorsal and volar radioulnar ligaments. If the DRUJ is stable after radius fixation, even with a displaced ulnar styloid base fracture, non-operative management with observation is typically sufficient. The ulnar styloid fracture often heals without intervention, and its fixation is usually indicated only if it's large, significantly displaced, and contributes to DRUJ instability, or if it causes symptomatic non-union. Surgical fixation of the ulnar styloid is not routine if the DRUJ is stable.

Question 3637

Topic: Wrist & Carpus

To minimize the risk of Extensor Pollicis Longus (EPL) rupture when performing dorsal plating for distal radius fractures, which surgical technique is most critical?

. Using a long, multi-hole plate
. Placing the plate directly over Lister's tubercle
. Ensuring the plate is low-profile and countersunk
. Avoiding bone graft placement
. Aggressive early range of motion

Correct Answer & Explanation

. Ensuring the plate is low-profile and countersunk

Explanation

EPL rupture after dorsal plating is often due to attrition over a prominent plate or screw heads, especially at Lister's tubercle. Using low-profile plates and ensuring the plate is countersunk (recessed into the bone) to minimize prominence above the bone surface is crucial. Placing the plate directly over Lister's tubercle increases risk. A long plate may be needed, but its profile is key. Bone graft doesn't directly prevent EPL rupture. Aggressive early range of motion without a smooth surface can exacerbate friction.

Question 3638

Topic: Wrist & Carpus

Which of the following radiographic parameters is generally considered the most important to achieve and maintain for good long-term functional outcomes in a high-demand patient following a distal radius fracture?

. Restoration of radial height
. Preservation of ulnar variance
. Maintenance of volar tilt
. Anatomical reduction of the articular surface (step-off/gap <1mm)
. Absence of associated ulnar styloid fracture

Correct Answer & Explanation

. Anatomical reduction of the articular surface (step-off/gap <1mm)

Explanation

While all listed parameters are important for anatomical reduction, anatomical reduction of the articular surface (minimal or no intra-articular step-off or gap, typically <1-2mm) is universally considered the most critical factor for preventing post-traumatic arthritis and achieving good long-term functional outcomes, particularly in younger, active patients. Articular incongruity directly disrupts the smooth gliding surfaces of the joint, leading to focal high-stress areas and accelerated cartilage degeneration.

Question 3639

Topic: 7. Hand and Wrist

A 9-year-old child sustains a Salter-Harris Type IV distal radius fracture. What is the most significant potential long-term complication unique to this fracture type?

. Nonunion
. Growth arrest and angular deformity
. Carpal tunnel syndrome
. TFCC tear
. DRUJ instability

Correct Answer & Explanation

. Growth arrest and angular deformity

Explanation

Salter-Harris Type IV fractures involve the metaphysis, physis, and epiphysis. Because the fracture line crosses the physis and enters the articular surface, there is a significant risk of damage to the germinal cells of the growth plate and the formation of a physeal bar (bone bridge across the physis). This can lead to partial or complete growth arrest, resulting in angular deformity (e.g., Madelung-like deformity) or limb length discrepancy. Nonunion is rare. Carpal tunnel, TFCC, and DRUJ issues are less specific to this pediatric fracture type compared to growth disturbance.

Question 3640

Topic: 7. Hand and Wrist

A patient with a significantly displaced distal radius fracture develops fracture blisters on the skin overlying the wrist. What is the most appropriate management?

. Immediately debride the blisters and proceed with surgery
. Apply topical steroids and immobilize in a cast
. Delay definitive surgery until the blisters have re-epithelialized or dried
. Incise the blisters and drain the fluid, then proceed with surgery
. Administer prophylactic antibiotics

Correct Answer & Explanation

. Delay definitive surgery until the blisters have re-epithelialized or dried

Explanation

Fracture blisters occur due to significant soft tissue swelling and shear forces, causing separation of the epidermal layers. While not an absolute contraindication, performing surgery through blistered skin carries a higher risk of infection and wound healing complications. The most appropriate management is to protect the blisters, allow them to re-epithelialize or dry (often takes 7-14 days), and delay definitive surgical fixation until the soft tissue envelope is optimized. Aspiration (incising and draining) can increase infection risk. Debridement is only for necrotic tissue. Topical steroids are not indicated.

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