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7. Hand and Wrist MCQs

Practice Set 181 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 3601

Topic: 7. Hand and Wrist

What is the primary purpose of a 'holding suture' or 'repair' of the dorsal wrist capsule/ligaments after reduction of a perilunate dislocation?

. To prevent median nerve compression
. To provide rigid bony fixation
. To enhance wrist extension
. To restore dorsal carpal stability and prevent recurrent dorsal displacement
. To increase wrist flexion

Correct Answer & Explanation

. To restore dorsal carpal stability and prevent recurrent dorsal displacement

Explanation

Repair of the dorsal wrist capsule and ligaments (e.g., dorsal intercarpal, dorsal scapholunate ligaments) is a critical step after reducing a perilunate dislocation. These structures are essential for providing dorsal stability to the carpus and preventing recurrent dorsal displacement or subluxation. This soft tissue repair, often augmented with K-wires, is paramount for a stable construct. It does not primarily address nerve compression (which is from the dislocation itself), provide rigid bony fixation (which comes from K-wires or screws), or directly alter wrist extension/flexion beyond restoring normal anatomy.

Question 3602

Topic: 7. Hand and Wrist

Which patient factor is most likely to negatively impact the long-term functional outcome after a perilunate dislocation, even with appropriate surgical management?

. Female gender
. Non-dominant hand injury
. Associated undisplaced scaphoid fracture
. Presence of pre-existing wrist arthritis
. High-energy mechanism of injury

Correct Answer & Explanation

. High-energy mechanism of injury

Explanation

A high-energy mechanism of injury generally correlates with more severe soft tissue and cartilaginous damage, leading to a poorer prognosis regardless of the surgical outcome. The energy involved can cause more extensive ligamentous tears, articular cartilage contusions, and greater initial displacement, making anatomical reduction more challenging and increasing the long-term risk of post-traumatic arthritis and stiffness. While pre-existing arthritis is a confounder, high energy is an intrinsic factor of the injury itself.

Question 3603

Topic: 7. Hand and Wrist

What is the primary goal of early wrist mobilization after K-wire removal and cast discontinuation in a surgically treated perilunate dislocation?

. To prevent avascular necrosis of the lunate
. To accelerate bone healing
. To regain wrist range of motion and prevent stiffness
. To strengthen wrist extensors and flexors immediately
. To improve cosmetic appearance

Correct Answer & Explanation

. To regain wrist range of motion and prevent stiffness

Explanation

The primary goal of early, controlled wrist mobilization after K-wire removal and cast discontinuation is to regain wrist range of motion and prevent post-operative stiffness, which is a common and challenging complication after severe wrist trauma. While strengthening is also important, it comes after regaining motion. Preventing AVN or accelerating bone healing are not primary goals of early mobilization at this stage.

Question 3604

Topic: Wrist & Carpus

Which of the following describes a key finding of a chronic perilunate instability on a lateral radiograph, even if not fully dislocated?

. Volar tilt of the distal radius
. Increased carpal height index
. Dorsal intercalated segmental instability (DISI) deformity
. Absence of a radiocarpal angle
. Flattening of the scaphoid

Correct Answer & Explanation

. Dorsal intercalated segmental instability (DISI) deformity

Explanation

Chronic perilunate instability often manifests as a Dorsal Intercalated Segmental Instability (DISI) deformity. On a lateral radiograph, this is characterized by the lunate being extended dorsally (tilted backward) and the scaphoid being flexed volarly, creating an increased capitolunate and radiolunate angle. This abnormal alignment results from the disruption of the scapholunate ligament, which normally couples the scaphoid and lunate movements. Other options are either incorrect or not specific to perilunate instability.

Question 3605

Topic: 7. Hand and Wrist

When performing closed reduction of a perilunate dislocation, what is the crucial final maneuver after traction and counter-traction?

. Extreme wrist hyperextension to disimpact the carpus
. Ulnar deviation and forearm pronation
. Direct pressure on the dorsal aspect of the capitate with volar flexion of the wrist
. Radial deviation and forearm supination
. Application of a neutral wrist splint immediately

Correct Answer & Explanation

. Direct pressure on the dorsal aspect of the capitate with volar flexion of the wrist

Explanation

After applying longitudinal traction and counter-traction to disimpact the carpus, the crucial final maneuver for closed reduction of a dorsally dislocated perilunate injury involves direct pressure applied volarly to the dorsally displaced capitate, combined with acute volar flexion of the wrist. This maneuver guides the capitate back into articulation with the lunate. The wrist is then typically brought into a neutral or slightly flexed position for temporary immobilization.

Question 3606

Topic: Wrist & Carpus

What is the typical time frame considered for a perilunate dislocation to be classified as 'chronic' versus 'acute'?

. Within 24 hours vs. >24 hours
. Within 1 week vs. >1 week
. Within 3 weeks vs. >3 weeks
. Within 6-8 weeks vs. >6-8 weeks
. Within 6 months vs. >6 months

Correct Answer & Explanation

. Within 6-8 weeks vs. >6-8 weeks

Explanation

Perilunate dislocations are generally considered 'acute' if treated within 6 to 8 weeks of injury. Beyond this timeframe, they are typically classified as 'chronic'. The distinction is critical because chronic dislocations often involve significant soft tissue contracture, articular cartilage damage, and established degenerative changes, making anatomical reduction much more challenging, and often necessitating salvage procedures rather than primary ligament repair.

Question 3607

Topic: 7. Hand and Wrist

Which of the following ligaments is considered an 'extrinsic' carpal ligament?

. Scapholunate interosseous ligament
. Lunotriquetral interosseous ligament
. Radioscaphocapitate ligament
. Capitalunate ligament
. Scaphotrapezial ligament

Correct Answer & Explanation

. Radioscaphocapitate ligament

Explanation

Extrinsic carpal ligaments connect the carpal bones to the radius or ulna, while intrinsic ligaments connect carpal bones to each other within the carpus. The Radioscaphocapitate ligament is a strong volar extrinsic ligament, connecting the radius to the scaphoid and capitate. The scapholunate and lunotriquetral interosseous ligaments are intrinsic. Capitalunate and scaphotrapezial are also intrinsic intercarpal ligaments.

Question 3608

Topic: 7. Hand and Wrist

Which specific view on plain radiographs is most critical for evaluating the alignment of the lunate and capitate in the sagittal plane?

. PA view
. Lateral view
. Oblique view
. Carpal tunnel view
. Scaphoid view

Correct Answer & Explanation

. Lateral view

Explanation

The lateral view of the wrist is absolutely critical for evaluating the alignment of the lunate and capitate (and radius) in the sagittal plane. This view allows for assessment of the radiolunate and capitolunate angles, and identification of loss of collinearity or the 'spilled teacup' sign, which are hallmarks of perilunate and lunate dislocations, respectively. Other views provide different perspectives or focus on specific bones.

Question 3609

Topic: 7. Hand and Wrist

What is the most common presenting complaint of a patient with a chronic, untreated perilunate dislocation?

. Acute, severe pain requiring opioids
. Complete inability to move the wrist
. Progressive dull aching pain, stiffness, and weakness
. Persistent median nerve paresthesias only
. Swelling without pain

Correct Answer & Explanation

. Progressive dull aching pain, stiffness, and weakness

Explanation

A chronic, untreated perilunate dislocation typically presents with progressive dull aching pain, significant wrist stiffness, and weakness. While acute dislocations cause severe pain, chronic conditions evolve into a pattern of chronic discomfort and functional limitation, often with established post-traumatic arthritis. Complete inability to move is less common than severe restriction. Median nerve symptoms can persist but are often not theonlycomplaint.

Question 3610

Topic: 7. Hand and Wrist
A patient is diagnosed with a trans-scaphoid perilunate dislocation. What is a key consideration when planning the surgical approach for this combined injury?
. Prioritizing carpal tunnel release over bony fixation
. Utilizing a single dorsal approach for all components
. Potentially requiring both volar and dorsal approaches for optimal reduction and fixation
. Avoiding K-wire stabilization to allow for early motion
. Focusing solely on scaphoid fixation and ignoring ligament repair

Correct Answer & Explanation

. Potentially requiring both volar and dorsal approaches for optimal reduction and fixation

Explanation

For a trans-scaphoid perilunate dislocation, optimal management often requires both volar and dorsal approaches. The volar approach allows for débridement of the carpal tunnel, reduction of any volar lunate displacement, and repair of volar ligaments. The dorsal approach allows for reduction of the dorsally dislocated carpus and internal fixation of the scaphoid fracture.

Question 3611

Topic: 7. Hand and Wrist

Which of the following is an accepted technique for primary repair of the scapholunate interosseous ligament during open surgery?

. Excision of the ligament
. Suture anchor repair to the scaphoid and lunate bones
. Dynamic wrist splinting instead of repair
. Leaving the ligament unrepaired if K-wires are used
. Grafting with fascia lata

Correct Answer & Explanation

. Suture anchor repair to the scaphoid and lunate bones

Explanation

Suture anchor repair, where the torn ends of the scapholunate interosseous ligament (SLIL) are reattached to the scaphoid and lunate using suture anchors, is an accepted technique for primary repair of acute SLIL tears during open surgery for perilunate dislocations. This directly addresses the ligamentous instability. Excision or leaving it unrepaired is not appropriate for primary repair. Dynamic splinting is not a repair technique. Grafting with fascia lata is a reconstruction technique, typically used for chronic cases or failed primary repairs, not primary repair itself.

Question 3612

Topic: 7. Hand and Wrist

What is the reported incidence of median nerve compromise in acute perilunate dislocations?

. Less than 5%
. 5-10%
. 10-20%
. 30-50%
. Greater than 75%

Correct Answer & Explanation

. 30-50%

Explanation

Median nerve compromise is a well-known and relatively common complication in acute perilunate dislocations, with reported incidences ranging from 30% to 50%. The acute displacement of the carpus, particularly the capitate, into the carpal tunnel, along with associated swelling and hemorrhage, directly compresses the median nerve. Prompt reduction is crucial to alleviate this compression.

Question 3613

Topic: 7. Hand and Wrist

What is the potential consequence of untreated or missed perilunate dislocation in terms of long-term wrist function?

. Permanent improvement in wrist extension
. Rapid spontaneous healing with full recovery
. Progressive carpal collapse, pain, stiffness, and post-traumatic arthritis
. Isolated loss of thumb abduction without other symptoms
. Increased grip strength due to altered biomechanics

Correct Answer & Explanation

. Progressive carpal collapse, pain, stiffness, and post-traumatic arthritis

Explanation

Untreated or missed perilunate dislocations inevitably lead to progressive carpal collapse, chronic pain, significant stiffness, and debilitating post-traumatic osteoarthritis. The severe disruption of carpal alignment and ligamentous integrity results in abnormal joint mechanics that rapidly degenerate the articular cartilage. There is no spontaneous full recovery, and long-term functional impairment is the norm.

Question 3614

Topic: 7. Hand and Wrist

Which of the following describes a key element of post-operative rehabilitation for a surgically treated perilunate dislocation, after immobilization period?

. Immediate full weight-bearing on the affected wrist
. Passive range of motion only, avoiding active movement
. Progressive controlled active and passive range of motion exercises, followed by strengthening
. Complete avoidance of wrist movement indefinitely
. Only grip strengthening exercises from day one

Correct Answer & Explanation

. Progressive controlled active and passive range of motion exercises, followed by strengthening

Explanation

Post-operative rehabilitation for a surgically treated perilunate dislocation, after the period of immobilization (typically K-wire removal and cast discontinuation), involves a carefully structured program of progressive controlled active and passive range of motion exercises. This is followed by gradual strengthening exercises once adequate motion and ligament healing are confirmed. Immediate full weight-bearing, passive-only motion, or complete avoidance of movement are incorrect and would lead to poor outcomes or excessive stiffness.

Question 3615

Topic: Wrist & Carpus

When assessing a lateral radiograph for perilunate stability, what is the normal radiolunate angle?

. 0 to -10 degrees (lunate volar tilt)
. 15 to 30 degrees (lunate dorsal tilt)
. 45 to 60 degrees
. Greater than 90 degrees
. Always 0 degrees

Correct Answer & Explanation

. 0 to -10 degrees (lunate volar tilt)

Explanation

On a true lateral radiograph, the normal lunate has a slight volar tilt, meaning the long axis of the lunate should be collinear with the long axis of the radius, with a radiolunate angle typically between 0 and -10 degrees (representing slight volar tilt of the lunate relative to the radius). A dorsal tilt of the lunate (positive angle) is indicative of a DISI deformity, often seen in scapholunate dissociation. A volar tilt >30 degrees is seen in VISI deformity.

Question 3616

Topic: 7. Hand and Wrist

What is the typical K-wire configuration used for scapholunate stabilization after perilunate reduction?

. One K-wire from the scaphoid to the radius
. One K-wire from the lunate to the capitate
. Two K-wires: one from the scaphoid into the lunate, and one from the lunate into the capitate
. Multiple K-wires connecting all carpal bones to the radius
. A single K-wire connecting the triquetrum to the ulna

Correct Answer & Explanation

. Two K-wires: one from the scaphoid into the lunate, and one from the lunate into the capitate

Explanation

The typical K-wire configuration for scapholunate stabilization after reduction of a perilunate dislocation involves two wires: one K-wire placed from the scaphoid into the lunate to stabilize the scapholunate joint, and another K-wire placed from the lunate into the capitate to maintain the capitolunate alignment. This construct provides a stable environment for ligament healing and prevents redislocation. Other options are incorrect or represent different stabilization strategies.

Question 3617

Topic: 7. Hand and Wrist
Which complication is unique to injuries involving the lunate, such as perilunate dislocation, due to its somewhat tenuous blood supply?
. Carpal tunnel syndrome
. Nonunion of the scaphoid
. Kienböck's disease (avascular necrosis of the lunate)
. Distal radioulnar joint instability
. Flexor tendon rupture

Correct Answer & Explanation

. Kienböck's disease (avascular necrosis of the lunate)

Explanation

Kienböck's disease, or avascular necrosis (AVN) of the lunate, is a specific and severe complication unique to injuries or conditions affecting the lunate bone. Due to its unique and often tenuous blood supply, which can be disrupted by significant trauma like a perilunate dislocation, the lunate is prone to AVN, leading to collapse and subsequent degenerative arthritis. While other options are possible complications of wrist trauma, Kienböck's specifically relates to the lunate's vascularity.

Question 3618

Topic: 7. Hand and Wrist

Which nerve is at highest risk of iatrogenic injury during a dorsal approach to the wrist for perilunate dislocation repair?

. Ulnar nerve
. Median nerve
. Radial nerve proper
. Superficial radial nerve (sensory branch)
. Posterior interosseous nerve

Correct Answer & Explanation

. Superficial radial nerve (sensory branch)

Explanation

During a dorsal approach to the wrist, particularly when dissecting radially or near the first and second extensor compartments, the superficial radial nerve (a sensory branch of the radial nerve) is at highest risk of iatrogenic injury. This nerve courses subcutaneously and can be easily damaged, leading to sensory deficits or painful neuromas. The median and ulnar nerves are volar, and the radial nerve proper and posterior interosseous nerve are deeper and less vulnerable in a standard dorsal wrist approach.

Question 3619

Topic: 7. Hand and Wrist

What is the most appropriate initial splinting technique following a successful closed reduction of an acute perilunate dislocation?

. Volarly based short arm splint
. Dorsally based short arm splint
. Long arm sugar tong splint
. Circumferential plaster cast without padding
. Wrist wrap with elastic bandage

Correct Answer & Explanation

. Long arm sugar tong splint

Explanation

Following a successful closed reduction of an acute perilunate dislocation, the wrist should be immobilized in a long arm sugar tong splint. This provides rigid immobilization of the wrist, prevents pronation/supination (which can affect carpal stability), and helps to maintain the reduction. A short arm splint is insufficient as it does not control forearm rotation. A circumferential cast without padding risks compartment syndrome in an acute injury. A wrist wrap provides inadequate immobilization.

Question 3620

Topic: Wrist & Carpus

If a chronic perilunate dislocation is left untreated, what is the most likely long-term degenerative pattern that will develop?

. Distal radioulnar joint arthritis
. Midcarpal arthritis only
. Scaphoid Nonunion Advanced Collapse (SNAC) wrist or Scapholunate Advanced Collapse (SLAC) wrist
. Isolated radiolunate arthritis
. Pisotriquetral arthritis

Correct Answer & Explanation

. Scaphoid Nonunion Advanced Collapse (SNAC) wrist or Scapholunate Advanced Collapse (SLAC) wrist

Explanation

Untreated chronic perilunate dislocations lead to progressive carpal collapse and arthritis, most commonly in the pattern of Scapholunate Advanced Collapse (SLAC) wrist. If a scaphoid fracture is also present and untreated (trans-scaphoid perilunate), it can progress to Scaphoid Nonunion Advanced Collapse (SNAC) wrist. Both SLAC and SNAC patterns involve progressive osteoarthritis of the radiocarpal and midcarpal joints due to the altered biomechanics and instability caused by the initial injury and subsequent collapse. These are the most common and severe degenerative sequelae.

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