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7. Hand and Wrist MCQs

Practice Set 183 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 3641

Topic: Wrist & Carpus

A 60-year-old patient develops symptomatic ulnar positive variance and impaction pain 1 year after non-operative management of a distal radius fracture with 4mm radial shortening. All conservative measures have failed. What is the most appropriate surgical option?

. Radial shortening osteotomy
. Ulnar shortening osteotomy
. DRUJ fusion
. Total wrist fusion
. Excision of the ulnar head (Darrach procedure)

Correct Answer & Explanation

. Ulnar shortening osteotomy

Explanation

Symptomatic ulnar positive variance (the ulna is longer relative to the radius) leading to ulnocarpal impaction pain is a common sequela of distal radius malunion with radial shortening. The most appropriate surgical correction for this, assuming the DRUJ is stable, is an ulnar shortening osteotomy. This procedure restores length balance between the radius and ulna, decompressing the ulnocarpal joint. Radial shortening osteotomy would worsen the problem. DRUJ fusion and total wrist fusion are salvage procedures. Darrach procedure (ulnar head excision) is also a salvage procedure for DRUJ arthritis/instability, not typically for ulnocarpal impaction with a stable DRUJ.

Question 3642

Topic: 7. Hand and Wrist

The brachioradialis muscle plays a significant role in the displacement pattern of certain distal radius fractures due to its insertion onto the:

. Radial tuberosity
. Distal radius
. Scaphoid
. First metacarpal
. Ulna

Correct Answer & Explanation

. Distal radius

Explanation

The brachioradialis muscle originates from the humerus and inserts into the lateral surface of the distal radius, near the styloid process. Its pull, particularly in dorsally displaced fractures, contributes to radial shortening and often dorsal and radial displacement of the distal fragment, making closed reduction challenging to maintain without counteracting this force.

Question 3643

Topic: Wrist & Carpus

Which of the following factors is considered the strongest independent predictor of developing post-traumatic arthritis after a distal radius fracture?

. Age > 60 years
. Female gender
. Dorsal tilt > 10 degrees
. Intra-articular step-off > 2mm
. Radial shortening > 3mm

Correct Answer & Explanation

. Intra-articular step-off > 2mm

Explanation

Intra-articular step-off or gap greater than 1-2mm is widely recognized as the strongest independent predictor of post-traumatic arthritis following a distal radius fracture. Articular incongruity directly disrupts the smooth gliding surfaces of the joint, leading to focal high-stress areas and accelerated cartilage degeneration. While other factors contribute to overall outcome, articular step-off directly causes arthritis.

Question 3644

Topic: Wrist & Carpus

The Sauve-Kapandji procedure is a surgical option primarily used for the management of:

. Nonunion of the distal radius
. Scapholunate dissociation
. Symptomatic malunion of the distal radius
. Symptomatic arthritis and instability of the distal radioulnar joint (DRUJ)
. Flexor tendon rupture

Correct Answer & Explanation

. Symptomatic arthritis and instability of the distal radioulnar joint (DRUJ)

Explanation

The Sauve-Kapandji procedure involves fusing the distal radioulnar joint (DRUJ) and creating a pseudoarthrosis of the distal ulna proximal to the fusion. This procedure is performed to treat symptomatic DRUJ arthritis and/or instability while preserving forearm rotation. It essentially converts a painful, stiff DRUJ into a stable, painless, albeit pseudoarthrotic, rotational unit.

Question 3645

Topic: 7. Hand and Wrist

A common pitfall contributing to loss of reduction after closed reduction and casting of a dorsally displaced distal radius fracture is:

. Excessive traction during reduction
. Insufficient palmarflexion and ulnar deviation of the wrist in the cast
. Applying a sugar tong splint instead of a circumferential cast
. Early initiation of active range of motion
. Inadequate patient education

Correct Answer & Explanation

. Insufficient palmarflexion and ulnar deviation of the wrist in the cast

Explanation

After reduction of a dorsally displaced distal radius fracture (e.g., Colles'), the wrist is typically immobilized in slight palmarflexion and ulnar deviation. This position helps to tighten the volar radiocarpal ligaments, which can act as a checkrein against dorsal displacement, and also uses gravity to maintain reduction. Insufficient palmarflexion and ulnar deviation allows the fracture to redisplace dorsally. Excessive traction can lead to increased ulnar variance. Splints are often used initially but converted to casts; the key is the position. Early ROM leads to loss of reduction, but is not a common pitfall ininitialreduction maintenance.

Question 3646

Topic: Wrist & Carpus

Which of the following is often one of the earliest and most commonly overlooked signs/symptoms of developing Complex Regional Pain Syndrome (CRPS) Type I after a distal radius fracture?

. Trophic changes (skin atrophy, hair loss)
. Progressive increase in resting pain out of proportion to injury
. Radiographic osteopenia
. Joint stiffness and contracture
. Profound sweating or dryness of the affected limb

Correct Answer & Explanation

. Progressive increase in resting pain out of proportion to injury

Explanation

The earliest and most consistent symptom of CRPS is typically severe, burning pain that is disproportionate to the inciting injury and persists beyond the expected healing time. This pain often progresses to allodynia and hyperalgesia. Trophic changes, osteopenia, stiffness, and autonomic dysfunction (sweating/dryness) are usually later signs. Early recognition of disproportionate pain is critical for prompt diagnosis and intervention.

Question 3647

Topic: 7. Hand and Wrist

When utilizing a dorsal approach (e.g., Thompson approach) for distal radius fixation, care must be taken to protect which structure in the first dorsal compartment?

. Extensor Pollicis Longus (EPL)
. Extensor Carpi Radialis Longus (ECRL)
. Extensor Pollicis Brevis (EPB) and Abductor Pollicis Longus (APL)
. Extensor Indicis Proprius (EIP)
. Median nerve

Correct Answer & Explanation

. Extensor Pollicis Brevis (EPB) and Abductor Pollicis Longus (APL)

Explanation

The first dorsal compartment contains the Abductor Pollicis Longus (APL) and Extensor Pollicis Brevis (EPB) tendons. During a dorsal approach, especially one that uses an incision radial to Lister's tubercle, these tendons are at risk of injury, adhesions, or tenosynovitis (De Quervain's). EPL is in the third compartment, ECRL/ECRB in the second, EIP in the fourth, and the median nerve is volar.

Question 3648

Topic: Wrist & Carpus

After fixation of a distal radius fracture, a patient continues to have chronic, activity-related ulnar-sided wrist pain. Physical examination suggests a TFCC injury. What is the most definitive imaging modality to confirm the diagnosis and guide further management?

. Plain radiographs
. CT scan
. MRI with arthrogram
. Ultrasound
. Diagnostic wrist arthroscopy

Correct Answer & Explanation

. Diagnostic wrist arthroscopy

Explanation

While MRI with arthrogram can provide excellent detail of the TFCC, the gold standard for definitively diagnosing and characterizing TFCC tears, especially for surgical planning, remains diagnostic wrist arthroscopy. Arthroscopy allows for direct visualization, probing, and dynamic assessment of the TFCC and other intra-articular structures, often leading directly to repair or debridement. Plain radiographs and CT are primarily for bony pathology. Ultrasound has limited utility for deep ligamentous structures like the TFCC.

Question 3649

Topic: 7. Hand and Wrist
On a lateral wrist radiograph, an increased scaphoid-lunate (SL) angle (>60 degrees) is indicative of:
. Ulnar positive variance
. Carpal tunnel syndrome
. Dorsal Intercalated Segment Instability (DISI)
. Volar Intercalated Segment Instability (VISI)
. Radiocarpal arthritis

Correct Answer & Explanation

. Dorsal Intercalated Segment Instability (DISI)

Explanation

The normal Scaphoid-Lunate angle on a lateral radiograph is typically 30-60 degrees. An increased SL angle (>60 degrees) indicates that the lunate is dorsiflexed (extended) and the scaphoid is flexed, a pattern known as Dorsal Intercalated Segment Instability (DISI). This is commonly caused by scapholunate ligament disruption. VISI involves a volarly flexed lunate and is associated with lunotriquetral ligament injury.

Question 3650

Topic: 7. Hand and Wrist

What is the minimum functional range of motion (flexion-extension and radial-ulnar deviation) typically considered necessary for most activities of daily living at the wrist?

. Flexion 10°, Extension 10°, Ulnar Deviation 5°, Radial Deviation 5°
. Flexion 20°, Extension 20°, Ulnar Deviation 10°, Radial Deviation 10°
. Flexion 30°, Extension 30°, Ulnar Deviation 20°, Radial Deviation 10°
. Flexion 40°, Extension 40°, Ulnar Deviation 30°, Radial Deviation 20°
. Full range of motion for all planes

Correct Answer & Explanation

. Flexion 30°, Extension 30°, Ulnar Deviation 20°, Radial Deviation 10°

Explanation

While full range of motion is ideal, studies suggest that a functional range sufficient for most activities of daily living is approximately 30 degrees of flexion, 30 degrees of extension, 20 degrees of ulnar deviation, and 10 degrees of radial deviation. This allows for grasping, feeding, and personal hygiene. Options A and B are too restrictive; D is approaching full ROM.

Question 3651

Topic: 7. Hand and Wrist

Which ligament is critical for maintaining stability between the scaphoid and lunate, and its injury often leads to Dissociated Carpal Instability?

. Lunotriquetral ligament
. Radioscaphocapitate ligament
. Scapholunate ligament
. Dorsal radiocarpal ligament
. Ulnocarpal ligament

Correct Answer & Explanation

. Scapholunate ligament

Explanation

The Scapholunate (SL) ligament is the primary stabilizer between the scaphoid and lunate. A tear of this ligament, especially the dorsal portion, disrupts the normal kinematic coupling of these two bones, leading to scapholunate dissociation and often subsequent Dorsal Intercalated Segment Instability (DISI) and eventually SLAC wrist.

Question 3652

Topic: Wrist & Carpus

In a case of distal radius fracture with a suspected intra-articular extension, which imaging modality provides the most detailed information regarding articular congruity and fragment displacement?

. Standard AP and lateral radiographs
. Oblique radiographs
. CT scan with 3D reconstruction
. MRI
. Ultrasound

Correct Answer & Explanation

. CT scan with 3D reconstruction

Explanation

While plain radiographs (AP, lateral, obliques) are the initial imaging, a CT scan with 3D reconstruction is superior for evaluating the exact configuration of intra-articular comminution, articular step-off, and displacement in distal radius fractures. It provides detailed cross-sectional images, which are crucial for surgical planning. MRI is better for soft tissue injuries (ligaments, TFCC), and ultrasound has limited utility for complex bony fractures.

Question 3653

Topic: 7. Hand and Wrist

What is the primary role of the pronator quadratus muscle in the stability of the distal radius?

. Dynamic wrist flexion
. Dynamic wrist extension
. Dynamic DRUJ stabilization and forearm rotation
. Radial deviation of the wrist
. Prevention of median nerve compression

Correct Answer & Explanation

. Dynamic DRUJ stabilization and forearm rotation

Explanation

The pronator quadratus muscle spans the distal radius and ulna, playing a crucial role in dynamic stabilization of the distal radioulnar joint (DRUJ) and facilitating forearm pronation. It also contributes to volar stability of the distal radius fracture fragments, and its integrity is important for maintenance of reduction.

Question 3654

Topic: 7. Hand and Wrist

When performing open reduction and internal fixation with a volar plate for a distal radius fracture, what is the 'watershed line' a critical anatomical landmark for?

. Location of the radial artery
. Safe zone for screw placement to avoid neurovascular injury
. Distal limit for plate placement to avoid flexor tendon irritation
. Proximal extent of the pronator quadratus
. Midpoint of the carpal tunnel

Correct Answer & Explanation

. Distal limit for plate placement to avoid flexor tendon irritation

Explanation

The 'watershed line' on the volar aspect of the distal radius represents a critical anatomical landmark. It is the distal-most line where the flexor tendons are most likely to impinge upon a prominent volar plate, leading to irritation or rupture, particularly the Flexor Pollicis Longus (FPL). Plates should ideally be placed proximal to this line or be very low-profile and anatomically contoured if crossing it, to prevent complications.

Question 3655

Topic: 7. Hand and Wrist

Which type of external fixator typically relies on ligamentotaxis for indirect reduction of distal radius fractures?

. Dorsal bridging external fixator
. Non-bridging external fixator
. Dynamic external fixator
. Hybrid external fixator
. Forearm-based external fixator

Correct Answer & Explanation

. Dorsal bridging external fixator

Explanation

A dorsal bridging external fixator spans the wrist joint from the radius to the metacarpals (typically 2nd or 3rd). By applying distraction, it utilizes the intact surrounding ligaments (ligamentotaxis) to indirectly reduce and hold the comminuted distal radius fragments. Non-bridging fixators are placed entirely within the radius, while dynamic fixators allow for some wrist motion. Hybrid and forearm-based fixators are used for different indications or in conjunction with internal fixation.

Question 3656

Topic: Wrist & Carpus

In the presence of an unstable DRUJ associated with a distal radius fracture, which component of the TFCC is most commonly implicated in the instability?

. Articular disc
. Meniscal homologue
. Extensor Carpi Ulnaris (ECU) subsheath
. Volar and dorsal radioulnar ligaments
. Ulnar collateral ligament

Correct Answer & Explanation

. Volar and dorsal radioulnar ligaments

Explanation

The volar and dorsal radioulnar ligaments (RULs) are the primary stabilizing components of the TFCC. Tears or avulsions of these ligaments from their radial or ulnar attachments are the most common cause of DRUJ instability associated with distal radius fractures. While the articular disc is part of the TFCC, the RULs are the key static stabilizers preventing excessive translation of the ulna relative to the radius.

Question 3657

Topic: Wrist & Carpus

A patient is undergoing rehabilitation after volar plating for a distal radius fracture. They develop localized pain, swelling, and crepitus with active pronation and supination, which worsens with resisted forearm rotation. What is a likely complication?

. Nonunion of the fracture
. EPL tendonitis
. Hardware failure
. Extensor tendon irritation
. DRUJ impingement or instability

Correct Answer & Explanation

. DRUJ impingement or instability

Explanation

Localized pain, swelling, and crepitus with active pronation and supination that worsens with resisted forearm rotation strongly suggest a problem with the distal radioulnar joint (DRUJ). This could be due to post-traumatic DRUJ arthritis, instability (subluxation), or impingement. Nonunion is unlikely given early post-op. EPL tendonitis would involve thumb motion. Hardware failure is possible but usually presents differently. Extensor tendon irritation is more common with dorsal plating.

Question 3658

Topic: Wrist & Carpus
Which classification system for distal radius fractures emphasizes the mechanism of injury and helps guide treatment based on fracture pattern (bending, shearing, compression, avulsion, combined)?
. Frykman classification
. AO/OTA classification
. Universal classification
. Fernandez classification
. Gartland classification

Correct Answer & Explanation

. Fernandez classification

Explanation

The Fernandez classification system for distal radius fractures specifically emphasizes the mechanism of injury and helps guide treatment based on the fracture pattern (Type I: bending, Type II: shearing, Type III: compression, Type IV: avulsion, Type V: combined/high-energy). This differentiates it from Frykman (articular involvement + ulnar fracture), AO/OTA (fracture location, articular involvement, and stability), and Universal (combines features but less focus on mechanism). Gartland is for pediatric supracondylar humerus fractures.

Question 3659

Topic: Wrist & Carpus

What is the maximum acceptable intra-articular step-off in a distal radius fracture for a younger, active individual to minimize the risk of post-traumatic arthritis?

. 0.5 mm
. 1 mm
. 2 mm
. 3 mm
. 5 mm

Correct Answer & Explanation

. 1 mm

Explanation

For younger, active individuals, the goal is often an anatomical reduction, especially of the articular surface. While some literature accepts up to 2mm, most surgeons aim for less than 1mm of intra-articular step-off or gap to significantly minimize the risk of symptomatic post-traumatic arthritis. A step-off of 0.5mm or less is ideal.

Question 3660

Topic: Wrist & Carpus

A distal radius fracture treated non-operatively develops delayed union. What is the most common reason for delayed union in the distal radius?

. Poor patient compliance
. Smoking
. Inadequate nutritional status
. Infection
. Delayed union is more commonly a diagnosis of exclusion in this well-vascularized bone, often associated with patient factors or severe comminution.

Correct Answer & Explanation

. Delayed union is more commonly a diagnosis of exclusion in this well-vascularized bone, often associated with patient factors or severe comminution.

Explanation

The distal radius has an excellent blood supply, making nonunion and even delayed union relatively uncommon compared to other long bones. When delayed union occurs, it is often a diagnosis of exclusion and can be attributed to factors such as severe comminution, inadequate immobilization, high-energy injury, significant soft tissue damage, or patient-specific factors like smoking or uncontrolled diabetes. While infection, poor compliance, and nutrition can contribute, for a well-vascularized bone like the distal radius, a combination of factors or underlying challenges in healing (rather than a single isolated cause like 'poor vascularity') is often implied.

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