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 581
Topic: 7. Hand and Wrist
A 12-month-old infant is brought in for surgical evaluation of simple, complete syndactyly of the long and ring fingers. When planning the surgical release, what is the primary reconstructive technique utilized to create the new web space and prevent web creep?
Correct Answer & Explanation
. Dorsal rectangular or hourglass flap
Explanation
Reconstructing the commissure with a local flap, typically a dorsal rectangular or hourglass flap, is critical in syndactyly release to prevent subsequent web creep. Full-thickness skin grafts are used to cover the remaining raw areas on the digits.
Question 582
Topic: 7. Hand and Wrist
A 24-year-old male presents with radial-sided wrist pain after a fall on an outstretched hand. Imaging confirms a displaced proximal pole fracture of the scaphoid. What anatomical characteristic of the scaphoid's blood supply places the proximal pole at the highest risk for avascular necrosis (AVN)?
Correct Answer & Explanation
. The primary blood supply enters dorsally and courses distal to proximal.
Explanation
The scaphoid receives 70-80% of its blood supply from branches of the radial artery that enter the dorsal ridge distally and course in a retrograde fashion (distal to proximal). Consequently, proximal pole fractures frequently disrupt this fragile retrograde flow, leading to high rates of AVN.
Question 583
Topic: Nerve & Tendon
A 5-year-old child sustains a displaced lateral condyle fracture of the humerus that goes unrecognized for 6 weeks, resulting in an established nonunion. If left untreated into adulthood, what is the most likely long-term complication associated with this specific nonunion?
Correct Answer & Explanation
. Cubitus valgus and tardy ulnar nerve palsy
Explanation
An untreated or non-united lateral condyle fracture typically results in progressive growth arrest laterally, leading to a profound cubitus valgus deformity. Over time, the valgus angulation stretches the ulnar nerve, often causing a tardy ulnar nerve palsy years later.
Question 584
Topic: 7. Hand and Wrist
A 40-year-old carpenter falls onto an outstretched hand and complains of severe wrist pain, particularly on the ulnar side. Physical exam reveals tenderness in the 'fovea' between the extensor carpi ulnaris and the flexor carpi ulnaris. X-rays are normal. What is the most likely injury?
Correct Answer & Explanation
. Triangular Fibrocartilage Complex (TFCC) tear
Explanation
Correct Answer: DA fall onto an outstretched hand (FOOSH) can cause various wrist injuries. Ulnar-sided wrist pain, especially with tenderness in the 'fovea' (the soft spot distal to the ulnar styloid between the ECU and FCU tendons), is a classic clinical sign of a Triangular Fibrocartilage Complex (TFCC) tear, particularly involving its foveal attachment. Normal X-rays are common as the TFCC is a soft tissue structure. While other carpal injuries like lunotriquetral tears can cause ulnar wrist pain, fovea tenderness is highly specific for TFCC pathology.
Question 585
Topic: Wrist & Carpus
You are presented with a simulated clinical scenario: a 45-year-old male with a displaced distal radius fracture. When asked to 'discuss your management,' which initial framework demonstrates the MOST structured and comprehensive approach expected by an examiner?
Correct Answer & Explanation
. Outlining a systematic approach encompassing initial assessment, history, examination, investigations, non-operative vs. operative considerations, informed consent, post-operative care, rehabilitation, and potential complications.
Explanation
Correct Answer: CExaminers seek a structured, systematic approach that demonstrates a holistic understanding of patient care, not just technical surgical skills. An initial framework that covers the entire patient journey β from diagnosis (history, exam, investigations) through treatment decisions (non-op vs. op), patient communication (consent), and post-treatment considerations (post-op care, rehabilitation, complications) β demonstrates comprehensive clinical reasoning. While classification and latest research are important, they fit within this broader framework, not as the initial statement of management. Delaying an answer or over-focusing on a single aspect can suggest a lack of structured thinking.
Question 586
Topic: 7. Hand and Wrist
A 45-year-old manual laborer presents with chronic wrist pain. Radiographs reveal a scaphoid nonunion advanced collapse (SNAC) pattern with degenerative changes extending to the capitolunate joint (SNAC Stage III). The radiolunate joint is preserved. What is the most appropriate surgical treatment?
Correct Answer & Explanation
. Scaphoid excision and four-corner fusion
Explanation
In SNAC Stage III, arthritis involves the capitolunate joint, making proximal row carpectomy (PRC) contraindicated due to the wear on the capitate head. Scaphoid excision with a four-corner fusion reliably relieves pain while preserving functional, albeit reduced, wrist motion.
Question 587
Topic: 7. Hand and Wrist
A 40-year-old female undergoes open reduction and internal fixation for a volar-shear distal radius fracture (Goyrand-Smith) using a standard volar Henry approach. Dissection straying too far ulnarly puts which of the following structures at greatest risk?
Correct Answer & Explanation
. Palmar cutaneous branch of the median nerve
Explanation
The palmar cutaneous branch of the median nerve runs longitudinally between the FCR and palmaris longus. It is at high risk of iatrogenic injury during a standard volar Henry approach if the dissection retracts too far ulnarly.
Question 588
Topic: 7. Hand and Wrist
A 25-year-old male sustains a laceration over the volar aspect of his proximal phalanx (Zone II), severing both the FDS and FDP tendons. Following primary repair, what rehabilitation protocol yields the best outcomes?
Correct Answer & Explanation
. Early active extension and passive flexion
Explanation
Early controlled motion protocols (e.g., early active extension/passive flexion or modified Duran) for Zone II flexor tendon repairs prevent restrictive adhesions while protecting the repair from excessive tension.
Question 589
Topic: Wrist & Carpus
A 28-year-old laborer presents with chronic radial-sided wrist pain 18 months after a fall. Radiographs demonstrate a scaphoid waist nonunion with a humpback deformity, dorsal intercalated segment instability (DISI), and established radiocarpal arthrosis. Which of the following is the most appropriate surgical management?
Correct Answer & Explanation
. Scaphoid excision and four-corner fusion
Explanation
Scaphoid excision and four-corner fusion is indicated for scaphoid nonunion advanced collapse (SNAC) with established radiocarpal arthrosis. Bone grafting to achieve union is contraindicated once significant degenerative changes have developed in the midcarpal or radiocarpal joints.
Question 590
Topic: 7. Hand and Wrist
A 38-year-old male presents to the emergency department after a fall onto an outstretched hand. A lateral radiograph of the wrist is obtained, as shown below. Based on this image, which of the following best describes the carpal injury?
Correct Answer & Explanation
. Perilunate dislocation with dorsal displacement of the capitate relative to the lunate.
Explanation
Correct Answer: BA perilunate dislocation is characterized by the dorsal displacement of the capitate and the entire carpus relative to the lunate, while the lunate itself maintains its articulation with the distal radius. On a lateral radiograph, this appears as a loss of the normal collinear relationship between the radius, lunate, and capitate, with the capitate sitting dorsally to the lunate. The lunate remains in its normal position relative to the radius.Option A, a lunate dislocation, would show the lunate itself dislocated volarly into the carpal tunnel, often described as a 'spilled teacup' sign, where it loses articulation with both the radius and the capitate. Option C, scapholunate dissociation with a DISI (Dorsal Intercalated Segmental Instability) deformity, is a common component of perilunate instability but describes the specific posture of the scaphoid and lunate, not the overall dislocation pattern. Option D, a trans-scaphoid perilunate fracture-dislocation, would require a visible scaphoid fracture in addition to the perilunate dislocation. Option E, radiocarpal dislocation, is a broader term and less specific than perilunate dislocation, which precisely defines the carpal bone relationships.
Question 591
Topic: 7. Hand and Wrist
A 45-year-old carpenter falls from a roof, landing on his outstretched hand with the wrist in hyperextension and ulnar deviation. This mechanism typically initiates a progressive pattern of ligamentous injury around the lunate. According to Mayfield's classification, which ligament is the first to fail in this sequence, leading to initial carpal instability?
Correct Answer & Explanation
. Scapholunate interosseous ligament
Explanation
Mayfield's progressive perilunar instability classification describes a sequential pattern of ligamentous disruption that typically begins with a fall onto an outstretched hand (FOOSH) with the wrist in hyperextension and ulnar deviation. Stage I of this injury involves the rupture of the scapholunate interosseous ligament (SLIL) and often the associated volar radioscaphocapitate ligament. This initial disruption allows for dissociation between the scaphoid and lunate, which is the precursor to further carpal displacement. The lunotriquetral interosseous ligament is typically involved in later stages (Stage III). The dorsal radiocarpal ligament and radioscaphocapitate ligament are extrinsic ligaments that also play a role in stability, but the SLIL is considered the 'key' intrinsic ligament whose failure initiates the cascade. The transverse carpal ligament forms the roof of the carpal tunnel and is not the primary ligament involved in initiating perilunar instability, though it can be compressed by dislocated carpal bones.
Question 592
Topic: 7. Hand and Wrist
A 32-year-old athlete presents with an acute perilunate dislocation after a snowboarding accident. On examination, he complains of numbness and tingling in the radial three and a half digits, and weakness in thumb opposition and abduction. What is the most appropriate immediate management step for these neurological findings?
Correct Answer & Explanation
. Perform immediate closed reduction of the wrist.
Explanation
Correct Answer: CThe symptoms described (numbness/tingling in the thumb, index, and middle fingers, and weakness of thumb opposition and abduction) are classic signs of acute median nerve compression within the carpal tunnel. Median nerve compromise is a common and critical complication of acute perilunate dislocations, occurring in up to 30-50% of cases. The dislocated carpus, particularly the capitate, along with associated soft tissue swelling and hematoma, directly compresses the median nerve.The most appropriate immediate management step is prompt closed reduction of the wrist. This maneuver aims to restore carpal alignment, decompress the median nerve, and reduce the risk of permanent nerve damage. Delaying reduction can lead to irreversible nerve injury. Options A, D, and E are inadequate and inappropriate for acute median nerve compression. Option B, an MRI of the cervical spine, is not indicated for acute, wrist-level median nerve symptoms.
Question 593
Topic: 7. Hand and Wrist
In the context of a perilunate dislocation, which carpal bone fracture is most frequently observed in conjunction with the ligamentous injury, often leading to a 'greater arc' injury pattern?
Correct Answer & Explanation
. Scaphoid fracture
Explanation
Correct Answer: CThe scaphoid is the most commonly fractured carpal bone in association with perilunate dislocations, occurring in approximately 50-70% of cases. This combination is referred to as a 'trans-scaphoid perilunate dislocation.' The mechanism involves the carpus 'peeling off' the lunate, and as the forces increase, the scaphoid is loaded in such a way that it fractures, typically through its waist. This type of injury falls under the 'greater arc' injury pattern, which involves both ligamentous disruption and associated carpal bone fractures, as opposed to 'lesser arc' injuries which are purely ligamentous.While other carpal fractures (Options A, B, D, E) can occur in severe wrist trauma, they are significantly less common than a scaphoid fracture in the setting of a perilunate dislocation.
Question 594
Topic: 7. Hand and Wrist
A 28-year-old male is diagnosed with an acute perilunate dislocation in the emergency department. After ensuring patient stability and providing adequate analgesia, what is the most critical immediate next step in his management?
Correct Answer & Explanation
. Attempt prompt closed reduction, typically under sedation.
Explanation
Correct Answer: CFor an acute perilunate dislocation, the immediate priority after patient stabilization and pain control is prompt closed reduction. This should be performed as soon as possible, ideally within hours, to decompress the median nerve (if compromised), restore carpal alignment, and reduce the risk of avascular necrosis of the lunate. This is a critical temporizing measure, even if definitive surgical fixation is anticipated.While an MRI (Option A) is valuable for surgical planning, it is not an acute priority over reduction. Open reduction and internal fixation (Option B) is often the definitive treatment but usually follows a failed closed reduction or is part of a planned surgical approach after initial reduction. Applying a splint without reduction (Option D) is inadequate and can lead to further complications. Initiating physical therapy (Option E) is premature and inappropriate before reduction and stabilization.
Question 595
Topic: 7. Hand and Wrist
A 55-year-old patient presents with a chronic, unreduced perilunate dislocation, diagnosed 8 months after his initial injury. He complains of severe pain, stiffness, and weakness. Radiographs show significant degenerative changes in the radiocarpal joint, but the lunate fossa of the radius appears relatively preserved. Which of the following is the most appropriate definitive surgical management option?
Correct Answer & Explanation
. Proximal row carpectomy (PRC).
Explanation
Correct Answer: CChronic, unreduced perilunate dislocations (typically defined as older than 6-8 weeks) often lead to significant pain, stiffness, and degenerative changes, making anatomical reduction difficult and often impossible without extensive releases. In such cases, the goal shifts from anatomical reduction and primary ligament repair to salvage procedures. Given the presence of significant degenerative changes but a relatively preserved lunate fossa of the radius, a Proximal Row Carpectomy (PRC) is a viable and often preferred salvage option.PRC involves excising the scaphoid, lunate, and triquetrum, allowing the capitate to articulate directly with the lunate fossa of the radius. This procedure aims to provide pain relief and preserve a functional range of motion, provided the capitate head and lunate fossa are healthy. Options A, B, and E are inadequate for a chronic, symptomatic dislocation with established degenerative changes. Total wrist arthroplasty (Option D) is generally reserved for inflammatory arthritis or very low-demand patients, or when other salvage options are not feasible.
Question 596
Topic: 7. Hand and Wrist
Following successful closed reduction of a perilunate dislocation, a post-reduction PA radiograph of the wrist is obtained, as depicted below. Despite apparent overall carpal alignment, what does the finding highlighted in the image most strongly suggest, necessitating further surgical intervention?
Correct Answer & Explanation
. Persistent scapholunate dissociation (Terry Thomas sign).
Explanation
Correct Answer: CThe image depicts a widened scapholunate interval on a PA radiograph, often referred to as the 'Terry Thomas sign' (typically >3mm, or >2mm compared to the contralateral wrist). This finding, even after apparent overall carpal alignment, indicates persistent scapholunate dissociation. It signifies that the scapholunate interosseous ligament, a critical stabilizer of the carpus, remains significantly disrupted and unstable. This persistent instability necessitates surgical intervention, typically open reduction and internal fixation (ORIF) with ligament repair or reconstruction (e.g., K-wire stabilization of the scapholunate joint and repair of the dorsal capsular ligaments) to achieve stable anatomical reduction and prevent long-term instability and arthritis.Option A is incorrect as this is an abnormal finding. Option B, lunotriquetral dissociation, would manifest as widening of the lunotriquetral interval, which is a different pathology. Option D, avascular necrosis of the lunate, is a potential long-term complication but is not directly indicated by an acute widened scapholunate interval. Option E, DRUJ instability, is unrelated to the scapholunate interval.
Question 597
Topic: 7. Hand and Wrist
During open reduction and internal fixation of an acute perilunate dislocation, the surgeon aims to repair the disrupted dorsal capsuloligamentous structures and stabilize the scapholunate joint. Which surgical approach provides the most direct and effective exposure for these specific goals?
Correct Answer & Explanation
. Dorsal approach, typically between the third and fourth extensor compartments.
Explanation
Correct Answer: CThe dorsal approach to the wrist, typically performed through an incision between the third (extensor pollicis longus) and fourth (extensor digitorum communis and indicis proprius) extensor compartments, provides excellent exposure for visualizing and repairing the dorsal carpal ligaments, including the dorsal scapholunate ligament and dorsal intercarpal ligament. This approach also allows for direct reduction of dorsally displaced carpal bones and placement of K-wires to stabilize the scapholunate and capitolunate joints.A volar approach (Option A) is primarily used for addressing median nerve compression, reducing volarly dislocated lunates, or repairing volar ligaments, but it does not offer optimal access for dorsal ligament repair. Other approaches (Options B, D) are less suitable for the primary dorsal instability of a perilunate dislocation. While a combined volar and dorsal approach (Option E) may be necessary for complex or chronic cases, the dorsal approach is specifically for the dorsal structures mentioned.
Question 598
Topic: 7. Hand and Wrist
An untreated or chronically missed perilunate dislocation is highly likely to lead to a specific pattern of progressive carpal collapse and degenerative arthritis. Which of the following long-term complications is most characteristic of this natural history?
Untreated or chronically missed perilunate dislocations inevitably lead to progressive carpal collapse and debilitating post-traumatic osteoarthritis. The most characteristic pattern of this degeneration is Scapholunate Advanced Collapse (SLAC) wrist. If an associated scaphoid fracture is present and fails to unite (nonunion), the condition progresses to Scaphoid Nonunion Advanced Collapse (SNAC) wrist. Both SLAC and SNAC patterns involve progressive arthritis of the radioscaphoid and later the capitolunate joints due to the altered biomechanics and instability caused by the initial injury and subsequent carpal derangement. While KienbΓΆck's disease (avascular necrosis of the lunate) is a potential complication of lunate trauma, SLAC/SNAC describes the broader, progressive arthritic pattern. DRUJ arthrosis is less directly related to perilunar instability. Flexor tendon rupture is not a typical long-term complication. Permanent median nerve palsy can occur if not acutely addressed, but it is usually accompanied by significant carpal changes in chronic cases.
Question 599
Topic: 7. Hand and Wrist
Following open reduction and internal fixation of a perilunate dislocation, K-wires are typically placed across the scapholunate and capitolunate joints. What is the primary purpose of these K-wires, and for approximately how long are they usually maintained?
Correct Answer & Explanation
. To maintain anatomical reduction and protect ligament repairs during healing; 8-12 weeks.
Explanation
Correct Answer: CK-wire stabilization, typically involving wires placed from the scaphoid into the lunate and from the lunate into the capitate, serves to temporarily maintain the anatomical reduction of the carpal bones and protect the repaired or reconstructed ligaments (e.g., scapholunate interosseous ligament, dorsal capsular ligaments) while they heal. This provides a stable environment for soft tissue healing and prevents redislocation.The K-wires are usually maintained for approximately 8-12 weeks post-operatively. This timeframe allows sufficient healing of the repaired ligaments and any associated fractures (like a scaphoid fracture). Removing them too early risks redislocation or nonunion, while leaving them in longer increases the risk of pin tract infection and prolonged stiffness. K-wires do not provide rigid, permanent fixation (Option A), nor are they primarily for median nerve decompression (Option B, which is achieved by reduction) or stimulating bone healing (Option D, though they aid fracture stability). They also do not allow for early active range of motion (Option E); rather, they enforce immobilization.
Question 600
Topic: Nerve & Tendon
During the utility posterior approach for a terrible triad repair, the ulnar nerve is identified, decompressed, and protected in situ. What is the primary reason for protecting the ulnar nerve in situ rather than routinely transposing it anteriorly in this specific surgical context?
Correct Answer & Explanation
. C. In situ protection minimizes devascularization and avoids potential iatrogenic injury associated with transposition.
Explanation
Correct Answer: CThe teaching case specifies 'The ulnar nerve would be identified, decompressed, and protected in situ.' Protecting the nerve in situ, when feasible, minimizes the risk of devascularization and iatrogenic injury (e.g., traction neuropathy, scarring) that can be associated with formal anterior transposition. Transposition is a more extensive procedure with its own set of potential complications, and it is not always necessary if the nerve can be safely protected in its anatomical groove.Option A (Anterior transposition increases the risk of elbow stiffness)is incorrect. While any extensive surgery around the elbow can contribute to stiffness, transposition itself is not a primary cause of elbow stiffness in this context.Option B (The utility posterior approach does not typically expose the ulnar nerve sufficiently for transposition)is incorrect. The utility posterior approach can certainly expose the ulnar nerve, and transposition can be performed if deemed necessary. The decision is based on risk/benefit, not exposure limitations.Option D (Transposition is only indicated for pre-existing ulnar neuropathy)is incorrect. While pre-existing neuropathy is a strong indication, transposition may also be considered if the nerve is highly unstable in its groove, or if extensive hardware placement or soft tissue repair might impinge upon it, even without pre-existing neuropathy. However, the default is in situ protection if possible.Option E (The ulnar nerve is not typically at risk during a terrible triad repair)is incorrect. The ulnar nerve is very much at risk during elbow trauma and surgical approaches to the posterior and medial elbow, hence the emphasis on identifying and protecting it.
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