ABOS Part I & AAOS OITE Review: Hand & Wrist Trauma, Fight Bites, Scaphoid Fractures | Part 22205

ABOS Part I Comprehensive Review - Batch 5

This module contains 20 advanced orthopedic multiple-choice questions developed to mirror the American Board of Orthopaedic Surgery (ABOS) Part I and AAOS OITE examinations. Questions are derived directly from high-yield clinical teaching cases.

Generated MCQ Transcript

Question 1: A 32-year-old male presents to the emergency department 8 hours after sustaining a laceration over the dorsum of his dominant right hand during an altercation. He admits to striking another individual in the mouth. On examination, a 2 cm transverse laceration is noted over the metacarpophalangeal (MCP) joint of the ring finger. There is moderate swelling and tenderness, and pain with passive flexion of the digit. Which of the following is the most critical immediate step in the management of this patient?

• A: A. Initiate oral broad-spectrum antibiotics and arrange for outpatient follow-up in 24 hours.
• B: B. Obtain plain radiographs of the hand and wrist, then discharge with splinting.
• C: C. Copiously irrigate the wound, perform thorough debridement, and surgically explore the joint capsule.
• D: D. Apply a sterile dressing, prescribe topical antibiotics, and instruct on wound care.
• E: E. Immediately culture the wound surface and await sensitivities before starting antibiotics.

Explanation: Correct Answer: CThe correct answer is C because the most critical immediate step for a suspected 'fight bite' over an MCP joint is aggressive surgical management. This involves copious irrigation, thorough debridement of devitalized tissue, and surgical exploration to assess for joint capsule violation, tendon injury, or retained foreign bodies (e.g., tooth fragments). Delaying aggressive management significantly increases the risk of severe complications like septic arthritis, osteomyelitis, and tenosynovitis. Oral antibiotics alone (A) are insufficient for deep infections. Radiographs (B) are important but should not delay definitive surgical intervention if indicated. Topical antibiotics (D) are ineffective for deep-seated infections. Awaiting culture results (E) is impractical and dangerous, as empiric antibiotics must be initiated promptly.

Question 2: Regarding the microbiology of human bite infections, particularly 'fight bites,' which of the following statements is most accurate?

• A: A. Infections are predominantly monomicrobial, typically caused by Staphylococcus aureus.
• B: B. Eikenella corrodens is a rare isolate, usually found only in severely immunocompromised patients.
• C: C. Polymicrobial infections involving both aerobic and anaerobic bacteria are characteristic.
• D: D. Fungal pathogens are the most common cause of delayed presentation infections.
• E: E. Viral coinfection, such as Herpes simplex, is a frequent finding and requires specific antiviral therapy.

Explanation: Correct Answer: CThe correct answer is C because human bite infections, including 'fight bites,' are characteristically polymicrobial, involving a complex mixture of aerobic and anaerobic bacteria from the oral flora. Common aerobes include Staphylococcus aureus (which can be MRSA), Streptococcus species, and Corynebacterium. Key anaerobes include Bacteroides, Fusobacterium, and Peptostreptococcus. Eikenella corrodens, a fastidious Gram-negative rod, is a hallmark pathogen of human bite wounds and is found in over 25% of infections, even in immunocompetent individuals. Monomicrobial S. aureus (A) is inaccurate. Eikenella is not rare (B). Fungal (D) and viral (E) infections are uncommon in the acute setting of a fight bite.

Question 3: A 45-year-old male presents with a 3-day history of pain, swelling, and redness over the dorsum of his hand following a fight. He has a small, punctate wound over the third MCP joint. X-rays show no fracture or foreign body. Examination reveals significant swelling, warmth, and exquisite pain with any movement of the third MCP joint. Which of the following is the most appropriate next step in management?

• A: A. Prescribe oral clindamycin and discharge with instructions for warm soaks.
• B: B. Admit for intravenous broad-spectrum antibiotics and emergent surgical irrigation and debridement.
• C: C. Perform an aspiration of the MCP joint for Gram stain and culture.
• D: D. Order an MRI to evaluate for soft tissue involvement prior to any intervention.
• E: E. Splint the hand and review in clinic in 24 hours to monitor for improvement.

Explanation: Correct Answer: BThe correct answer is B because the patient's presentation, including a punctate wound over an MCP joint and signs of significant inflammation with exquisite pain on movement, is highly suggestive of septic arthritis of the MCP joint, a serious complication of fight bites. Given the delayed presentation and severe symptoms, emergent surgical irrigation and debridement of the joint, combined with intravenous broad-spectrum antibiotics, is the standard of care. Oral antibiotics (A) are insufficient. While joint aspiration (C) can confirm the diagnosis, it should not delay definitive surgical management once septic arthritis is clinically suspected. An MRI (D) may provide further detail but is not necessary before proceeding with emergent surgical exploration for a clear clinical picture of septic arthritis. Delaying definitive treatment (E) can lead to rapid joint destruction.

Question 4: Which antibiotic regimen is considered first-line empiric therapy for a human bite infection involving the hand, pending culture results?

• A: A. Ciprofloxacin and Rifampin
• B: B. Amoxicillin-clavulanate (Augmentin)
• C: C. Doxycycline and Metronidazole
• D: D. Cephalexin (Keflex) alone
• E: E. Vancomycin and Gentamicin

Explanation: Correct Answer: BThe correct answer is B because Amoxicillin-clavulanate (Augmentin) is widely considered the first-line empiric antibiotic for human bite infections. It provides excellent coverage against common oral flora, including Staphylococcus (non-MRSA), Streptococcus species, anaerobes, and notably, Eikenella corrodens. Ciprofloxacin and Rifampin (A) lack adequate anaerobic coverage. Doxycycline (C) has activity against some oral flora, but Metronidazole alone does not cover aerobic organisms like Staphylococci/Streptococci. Cephalexin (D) has good Gram-positive coverage but lacks activity against anaerobes and Eikenella. Vancomycin and Gentamicin (E) are typically reserved for more severe, resistant, or nosocomial infections, with Vancomycin targeting MRSA and Gentamicin providing Gram-negative coverage, but this combination is not optimal for initial empiric human bite coverage.

Question 5: What is the primary reason for performing an X-ray in a suspected 'fight bite' injury to the hand?

• A: A. To assess for intrinsic muscle atrophy.
• B: B. To identify potential foreign bodies such as tooth fragments or associated fractures.
• C: C. To evaluate for early signs of carpal tunnel syndrome.
• D: D. To determine the extent of soft tissue edema.
• E: E. To visualize the integrity of the joint capsule directly.

Explanation: Correct Answer: BThe correct answer is B because the primary reasons for obtaining plain radiographs in a suspected fight bite injury are to identify associated fractures (most commonly a 'boxer's fracture' of the metacarpal neck or head) and to detect retained foreign bodies, particularly tooth fragments, which can be radiopaque. Tooth fragments can act as a nidus for ongoing infection. While X-rays can show gross soft tissue swelling, they do not directly visualize the joint capsule (E) or assess for intrinsic muscle atrophy (A) or carpal tunnel syndrome (C). Assessing soft tissue edema (D) is a secondary finding, not the primary indication.

Question 6: Which of the following is an absolute indication for surgical exploration and debridement of a human bite wound to the hand?

• A: A. A small, superficial laceration less than 1 cm without joint involvement.
• B: B. Presentation within 6 hours of injury with minimal surrounding inflammation.
• C: C. Any wound penetrating the joint capsule, tendon sheath, or involving bone.
• D: D. A patient with well-controlled diabetes mellitus.
• E: E. Mild swelling and tenderness responsive to oral antibiotics.

Explanation: Correct Answer: CThe correct answer is C because any human bite wound that is suspected or confirmed to penetrate the joint capsule, a tendon sheath, or directly involve bone is an absolute indication for emergent surgical exploration and debridement. These injuries carry a high risk of developing severe infections like septic arthritis, tenosynovitis, or osteomyelitis. Superficial lacerations (A) or early presentations without deep involvement (B) might sometimes be managed non-operatively, but caution is paramount. Diabetes (D) increases risk but doesn't, by itself, mandate surgery without deep involvement. Response to oral antibiotics (E) suggests a less severe infection, but deep involvement would still warrant surgical management.

Question 7: A patient is undergoing surgical exploration for a fight bite over the third MCP joint. What position should the finger be held in during the initial assessment and irrigation to best expose potential joint capsule violation and aid in debridement?

• A: A. Full flexion
• B: B. Full extension
• C: C. Neutral position, midway between flexion and extension
• D: D. Hyperextension
• E: E. Passive resistance against the surgeon's manipulation

Explanation: Correct Answer: AThe correct answer is A because for a suspected 'fight bite' over an MCP joint, the finger should be held in full flexion during initial assessment and irrigation. The injury typically occurs with the hand clenched in a fist, which causes the skin and extensor tendon to shift proximally relative to the MCP joint capsule. When the hand is then extended, the damaged joint capsule and any penetrating wound tract move distally and are no longer aligned with the initial skin laceration, effectively sealing off the wound and potentially trapping bacteria within the joint. Flexing the finger realigns the entry portal, allowing for thorough irrigation and exploration of the joint capsule. Full extension (B) or neutral (C) will obscure the primary injury tract.

Question 8: Following surgical debridement and intravenous antibiotics for a septic MCP joint secondary to a fight bite, which of the following splinting positions is most appropriate for initial immobilization?

• A: A. MCP joints in full extension, IP joints in full flexion.
• B: B. MCP joints in approximately 70-90 degrees of flexion, IP joints in full extension.
• C: C. MCP and IP joints in full extension.
• D: D. MCP and IP joints in full flexion.
• E: E. Wrist in full extension, all digits free for active range of motion.

Explanation: Correct Answer: BThe correct answer is B because the 'intrinsic plus' or 'safe position' splint is generally recommended for hand immobilization following injury or surgery to prevent joint contractures. This position involves placing the wrist in 20-30 degrees of extension, the MCP joints in approximately 70-90 degrees of flexion, and the IP joints in full extension. This position maintains the collateral ligaments of the MCP joints in their elongated state, preventing shortening contractures, and avoids shortening of the IP collateral ligaments. Full extension of MCPs (A, C) can lead to MCP collateral ligament shortening. Full flexion of IP joints (A, D) can lead to IP collateral ligament shortening. Active range of motion (E) is generally not indicated initially for a severe infection requiring immobilization.

Question 9: A patient presents with a persistent discharging sinus tract over the third metacarpal following a poorly managed fight bite 6 weeks ago. Plain radiographs reveal cortical irregularity and lucency of the metacarpal head. What is the most likely diagnosis?

• A: A. Chronic tenosynovitis
• B: B. Septic non-union
• C: C. Osteomyelitis
• D: D. Reactive arthritis
• E: E. Chronic cellulitis

Explanation: Correct Answer: CThe correct answer is C because a persistent discharging sinus tract, especially following a human bite with radiographic evidence of cortical irregularity and lucency of the bone, is highly suggestive of chronic osteomyelitis. The fight bite can directly inoculate bacteria into the bone or lead to septic arthritis which then spreads to the bone. Chronic tenosynovitis (A) would primarily involve the tendon sheath. Septic non-union (B) would be if there was a fracture that failed to heal and became infected, but the question describes bone changes not specifically related to a fracture non-union. Reactive arthritis (D) is a sterile inflammatory arthritis following infection elsewhere. Chronic cellulitis (E) is a soft tissue infection that typically would not present with bone changes or a persistent sinus tract for this duration.

Question 10: Which specific anatomic structure is most commonly violated in a 'fight bite' injury over the dorsal aspect of the MCP joint?

• A: A. Flexor tendon sheath
• B: B. Digital nerve
• C: C. Joint capsule
• D: D. Palmar aponeurosis
• E: E. Dorsal veins

Explanation: Correct Answer: CThe correct answer is C because the joint capsule of the metacarpophalangeal (MCP) joint is the most commonly violated specific anatomical structure in a 'fight bite' injury. The injury typically occurs with the hand clenched in a fist, where the MCP joint is exposed. The opponent's tooth directly impacts and often lacerates the skin and the underlying joint capsule, inoculating bacteria directly into the joint space. Flexor tendon sheaths (A) are on the palmar side. Digital nerves (B) and dorsal veins (E) can be injured, but the joint capsule is the most characteristic and critical violation. The palmar aponeurosis (D) is on the palmar aspect of the hand.

Question 11: A 28-year-old male sustains a fall onto an outstretched hand (FOOSH) injury. Initial radiographs are negative, but clinical suspicion for a scaphoid fracture remains high due to persistent anatomical snuffbox tenderness. After 10 days of immobilization, repeat radiographs show a non-displaced fracture in the most common anatomical location.Which of the following fracture patterns is most likely present, and what is its approximate incidence among all scaphoid fractures?

• A: Distal pole fracture; 5-10%
• B: Tubercle fracture; <5%
• C: Waist fracture; 70-80%
• D: Proximal pole fracture; 15-20%
• E: Vertical oblique fracture; Not specified, but rare

Explanation: Correct Answer: CThe case describes a non-displaced fracture in the most common anatomical location. According to the provided text, waist fractures are the most common, accounting for approximately 70-80% of all scaphoid fractures. Distal pole fractures are 5-10%, proximal pole fractures are 15-20%, and tubercle fractures are rare. Vertical oblique fractures are a pattern of waist fracture, but not a distinct anatomical location with a separate incidence percentage in the provided text.Incorrect Options:A) Distal pole fracture; 5-10%: While a possible location, it is not the most common.B) Tubercle fracture; <5%: These are rare and generally stable, but not the most common type.D) Proximal pole fracture; 15-20%: These are less common than waist fractures and carry the highest risk of AVN, but are not the most frequently encountered.E) Vertical oblique fracture; Not specified, but rare: This describes a fracture pattern, often mechanically unstable, but not the most common anatomical location in terms of overall incidence.

Question 12: A 35-year-old male presents with a displaced scaphoid fracture. Surgical planning reveals a fracture through the proximal third of the scaphoid, with significant displacement.Given this fracture pattern, which statement accurately describes the primary blood supply to the proximal pole and its implication for healing?

• A: Primarily supplied by the palmar superficial branch of the radial artery, leading to a low risk of AVN.
• B: Primarily supplied by the dorsal carpal artery branch of the radial artery, providing an antegrade flow to the proximal pole.
• C: Primarily supplied by the dorsal carpal artery branch of the radial artery, providing a retrograde flow to the proximal pole, increasing AVN risk.
• D: Primarily supplied by direct branches from the ulnar artery, ensuring robust vascularity.
• E: Receives dual blood supply from both dorsal and palmar branches, making AVN rare.

Explanation: Correct Answer: CThe text explicitly states that the scaphoid's blood supply is highly vulnerable. The dorsal carpal artery branch (from the radial artery) supplies the majority (70-80%) of the scaphoid via intraosseous branches entering the dorsal ridge. Crucially, these vessels provide a retrograde blood supply to the proximal pole. Fractures through the scaphoid waist or proximal pole often compromise this retrograde flow, especially if displaced, which explains the heightened susceptibility of the proximal pole to avascular necrosis (AVN).Incorrect Options:A) Primarily supplied by the palmar superficial branch of the radial artery, leading to a low risk of AVN: The palmar superficial branch supplies only the distal tubercle and a small portion of the distal pole (20-30%), not the majority of the scaphoid or the proximal pole.B) Primarily supplied by the dorsal carpal artery branch of the radial artery, providing an antegrade flow to the proximal pole: While the dorsal carpal artery branch is the primary supply, the flow to the proximal pole is retrograde, not antegrade.D) Primarily supplied by direct branches from the ulnar artery, ensuring robust vascularity: The primary blood supply to the scaphoid is from the radial artery, not the ulnar artery.E) Receives dual blood supply from both dorsal and palmar branches, making AVN rare: While there are dorsal and palmar contributions, the proximal pole's reliance on retrograde flow makes it highly susceptible to AVN, not rare.

Question 13: A 55-year-old patient presents with chronic wrist pain and stiffness, 15 years after an untreated scaphoid nonunion. Radiographs show advanced degenerative changes consistent with a SNAC wrist.Which of the following accurately describes the typical progression of degenerative arthritis in a SNAC (Scaphoid Nonunion Advanced Collapse) wrist?

• A: Begins at the radiolunate joint, then progresses to the capitolunate joint, and finally the radioscaphoid articulation.
• B: Begins at the capitolunate joint, then progresses to the radioscaphoid articulation, and finally the radiolunate joint.
• C: Begins at the radial styloid-scaphoid articulation, progresses to the capitolunate joint, and spares the radiolunate joint until late stages.
• D: Begins simultaneously at all carpal articulations due to global carpal collapse.
• E: Primarily affects the scaphotrapeziotrapezoid (STT) joint, with later involvement of the proximal carpal row.

Explanation: Correct Answer: CThe text clearly describes the progression of SNAC wrist: "It typically begins at the radial styloid-scaphoid articulation, progresses to the capitolunate joint, and spares the radiolunate joint until late stages." This specific pattern of degenerative arthritis is a hallmark of SNAC wrist, resulting from altered carpal mechanics due to chronic scaphoid nonunion.Incorrect Options:A) Begins at the radiolunate joint, then progresses to the capitolunate joint, and finally the radioscaphoid articulation: This is incorrect as the radiolunate joint is typically spared until late stages, and the initial involvement is at the radioscaphoid articulation.B) Begins at the capitolunate joint, then progresses to the radioscaphoid articulation, and finally the radiolunate joint: This sequence is incorrect. The radioscaphoid articulation (specifically radial styloid-scaphoid) is the initial site of degeneration.D) Begins simultaneously at all carpal articulations due to global carpal collapse: SNAC wrist follows a predictable, sequential pattern of degeneration, not simultaneous involvement of all joints.E) Primarily affects the scaphotrapeziotrapezoid (STT) joint, with later involvement of the proximal carpal row: While the STT joint can be affected in other carpal pathologies, the primary progression of SNAC wrist is as described in option C.

Question 14: A 22-year-old professional baseball player sustains a scaphoid fracture. Initial radiographs show a non-displaced waist fracture. However, a follow-up CT scan reveals a scaphoid sagittal angle of 65 degrees and a 1.5 mm displacement at the fracture site.Based on the provided case information and general guidelines, which of the following is the most compelling indication for operative management in this patient?

• A: Patient's profession as a high-demand athlete.
• B: Non-displaced waist fracture.
• C: Scaphoid sagittal angle > 60 degrees and >1 mm displacement.
• D: Risk of prolonged immobilization with non-operative treatment.
• E: The fracture being a waist fracture.

Explanation: Correct Answer: CThe text lists specific indications for operative management. A scaphoid sagittal angle > 60 degrees (indicating humpback deformity) and displacement > 1 mm are both explicit criteria for surgical intervention, as they signify an unstable fracture pattern with a high risk of malunion and altered carpal kinematics. The patient's CT scan confirms both of these critical findings.Incorrect Options:A) Patient's profession as a high-demand athlete: While a valid consideration for operative management (high-demand patients desiring early return to activity), it is a patient factor, not a direct fracture characteristic indicating instability or displacement. The fracture characteristics in option C are more compelling indications for surgery in this specific case.B) Non-displaced waist fracture: The initial radiographs showed a non-displaced fracture, but the CT scan revealed displacement and angulation, making this option incorrect based on the full clinical picture. Non-displaced waist fractures can often be treated non-operatively.D) Risk of prolonged immobilization with non-operative treatment: This is a general advantage of surgical fixation (allowing earlier mobilization), but it is not the primary or most compelling indication for surgery based on the specific fracture characteristics of displacement and angulation.E) The fracture being a waist fracture: Waist fractures are the most common type, and while many are treated operatively, the location alone is not a definitive indication for surgery without other factors like displacement, angulation, or instability.

Question 15: A 68-year-old sedentary female presents with wrist pain after a minor fall. Radiographs show a non-displaced fracture of the scaphoid tubercle. She has significant medical comorbidities, including uncontrolled diabetes and severe cardiac disease.Considering her fracture pattern and comorbidities, which of the following is the most appropriate initial management strategy?

• A: Open reduction and internal fixation with a headless compression screw.
• B: Percutaneous screw fixation.
• C: Immobilization in a short arm thumb spica cast.
• D: Vascularized bone grafting due to age-related vascular compromise.
• E: Proximal row carpectomy to prevent future arthritis.

Explanation: Correct Answer: CThe text states that distal tubercle fractures are generally stable and heal reliably with short-term immobilization, making them an indication for non-operative management. Furthermore, the patient has significant medical comorbidities (uncontrolled diabetes, severe cardiac disease) which are listed as contraindications for operative management due to increased surgical risk. Therefore, conservative management with immobilization is the most appropriate initial strategy.Incorrect Options:A) Open reduction and internal fixation with a headless compression screw: This is an operative intervention. Given the stable nature of a tubercle fracture and the patient's severe comorbidities, surgery is contraindicated.B) Percutaneous screw fixation: This is also an operative intervention, and while minimally invasive, it still carries surgical risks that are heightened by the patient's comorbidities. It is not indicated for a stable tubercle fracture.D) Vascularized bone grafting due to age-related vascular compromise: Vascularized bone grafting is a complex procedure reserved for nonunions with AVN or challenging cases, not for an acute, non-displaced tubercle fracture. Age alone does not necessitate this.E) Proximal row carpectomy to prevent future arthritis: Proximal row carpectomy is a salvage procedure for advanced arthritis (e.g., SNAC wrist) and is not indicated for an acute, non-displaced fracture.

Question 16: A 30-year-old construction worker presents with persistent anatomical snuffbox tenderness after a FOOSH injury, despite initial radiographs being negative. A scaphoid fracture is highly suspected.Which advanced imaging modality is considered the gold standard for assessing fracture displacement, comminution, and fragment orientation, and is crucial for surgical planning?

• A: Magnetic Resonance Imaging (MRI)
• B: Bone Scan
• C: Computed Tomography (CT) Scan
• D: Ultrasound
• E: Repeat plain radiographs in 10 days

Explanation: Correct Answer: CThe text explicitly states: "Computed Tomography (CT) Scan: The gold standard for assessing fracture displacement, comminution, and fragment orientation, especially in waist and proximal pole fractures. Axial, coronal, and sagittal reconstructions are critical for 3D understanding. It aids in surgical approach selection and screw trajectory planning." This makes CT the ideal choice for detailed fracture assessment and surgical planning.Incorrect Options:A) Magnetic Resonance Imaging (MRI): MRI is highly useful for diagnosing occult scaphoid fractures not visible on radiographs or CT, and for detecting bone contusion or ligamentous injuries. However, for detailed assessment of fracture geometry, displacement, and comminution for surgical planning, CT is superior.B) Bone Scan: Rarely used for acute fractures, it can confirm occult fractures by showing increased uptake but provides limited anatomical detail for surgical planning.D) Ultrasound: While useful for soft tissue assessment, ultrasound has limited utility for diagnosing scaphoid fractures and assessing their detailed characteristics.E) Repeat plain radiographs in 10 days: This is a common initial strategy for occult fractures, but it is not an advanced imaging modality and does not provide the detailed 3D information needed for surgical planning, especially if displacement or comminution is suspected.

Question 17: A surgeon is performing an open reduction and internal fixation of a scaphoid waist fracture via a volar (Henry) approach.During the deep dissection for this approach, which of the following neurovascular structures must be carefully identified and protected, typically retracted radially?

• A: Ulnar artery
• B: Median nerve
• C: Radial artery
• D: Dorsal cutaneous branch of the ulnar nerve
• E: Posterior interosseous nerve

Explanation: Correct Answer: CThe text describes the deep dissection for the Volar (Henry) Approach: "Deep to the FCR, the radial artery is identified. It runs between the FCR and the flexor pollicis longus (FPL). The radial artery is carefully retracted radially, often with the FPL." Protection of the radial artery is critical to prevent vascular compromise.Incorrect Options:A) Ulnar artery: The ulnar artery is located on the ulnar side of the wrist and is not typically encountered or at risk during a volar radial approach to the scaphoid.B) Median nerve: The median nerve is located more centrally in the carpal tunnel and is not the primary neurovascular structure retracted radially in this approach. The palmar cutaneous branch of the median nerve should be protected, but the main trunk is not typically retracted radially.D) Dorsal cutaneous branch of the ulnar nerve: This nerve is on the dorsal aspect of the wrist and is not relevant to a volar approach.E) Posterior interosseous nerve: This nerve is a branch of the radial nerve, located dorsally in the forearm, and is not at risk during a volar approach to the scaphoid.

Question 18: A 40-year-old patient presents with a symptomatic scaphoid nonunion of the proximal pole, diagnosed 18 months after initial injury. CT scan confirms nonunion with evidence of avascular necrosis (AVN) of the proximal fragment and early carpal collapse.Given the presence of AVN and early carpal collapse, which of the following is the most appropriate surgical management strategy?

• A: Non-vascularized bone grafting with revision internal fixation.
• B: Scaphoidectomy and four-corner arthrodesis (4CA).
• C: Proximal row carpectomy (PRC).
• D: Vascularized bone grafting (e.g., 2,3-ICSRA pedicled graft) with fixation.
• E: Total wrist arthrodesis.

Explanation: Correct Answer: DThe text outlines the management of nonunion and AVN: "For cases with established AVN of the proximal pole or recalcitrant nonunions, vascularized bone grafts (e.g., 2,3-ICSRA pedicled graft, free medial femoral condyle flap) have shown superior union rates by providing a direct blood supply." The presence of AVN in the proximal pole makes a vascularized graft the preferred option to enhance revascularization and promote healing, especially with early carpal collapse, indicating a need to restore scaphoid integrity.Incorrect Options:A) Non-vascularized bone grafting with revision internal fixation: This is typically used for stable nonunions without significant AVN or bone loss. Given the established AVN of the proximal pole, a non-vascularized graft would be less effective in promoting revascularization.B) Scaphoidectomy and four-corner arthrodesis (4CA): This is a salvage procedure for advanced stages of post-traumatic arthritis (SNAC wrist). While there is early carpal collapse, it's not described as advanced arthritis, and the primary goal should still be to achieve union and preserve the scaphoid if possible.C) Proximal row carpectomy (PRC): Similar to 4CA, PRC is a salvage procedure for established arthritis. It involves removing the entire proximal carpal row and is considered when the articular surfaces are significantly damaged.E) Total wrist arthrodesis: This is an end-stage salvage procedure for severe, pan-carpal arthritis or failed previous surgeries, resulting in complete loss of wrist motion. It is too aggressive for a case with early carpal collapse where scaphoid reconstruction is still feasible.

Question 19: A patient undergoes open reduction and internal fixation of a scaphoid waist fracture with a headless compression screw. The fixation is deemed stable.According to typical post-operative rehabilitation protocols for stable scaphoid fixation, when would the patient most likely transition from full-time cast immobilization to controlled active wrist range of motion?

• A: Immediately post-operatively.
• B: At 2-3 weeks, after initial wound healing.
• C: At 6-8 weeks, after initial radiographic signs of healing.
• D: At 12 weeks, regardless of radiographic healing.
• E: At 4-6 months, after complete radiographic union.

Explanation: Correct Answer: CThe text describes Phase 2 of rehabilitation (Controlled Active Range of Motion) as typically beginning at "Weeks 6/8-12." It explicitly states: "Repeat radiographs (and potentially CT scan) at 6-8 weeks to confirm signs of fracture healing. If healing is sufficient, progress to active ROM." This indicates that the transition from full-time immobilization to active ROM is contingent on radiographic evidence of initial healing, usually around 6-8 weeks for stable fixation.Incorrect Options:A) Immediately post-operatively: While some surgeons may allow immediate gentle ROM with exceptionally rigid fixation and high patient compliance, the typical protocol for stable fixation still involves an initial period of immobilization (4-6 weeks) to protect healing.B) At 2-3 weeks, after initial wound healing: This is generally too early for active wrist ROM, as significant bone healing has not yet occurred, and the fracture site remains vulnerable.D) At 12 weeks, regardless of radiographic healing: While 12 weeks is within the broader range for rehabilitation progression, the text emphasizes that progression is based on "initial radiographic signs of healing," which typically occur earlier than 12 weeks for stable fixation. Waiting until 12 weeks regardless of healing might delay rehabilitation unnecessarily.E) At 4-6 months, after complete radiographic union: This timeframe is typically for return to full activity or contact sports, not for initiating controlled active wrist ROM. Complete union often takes longer, but active ROM starts earlier.

Question 20: A 25-year-old patient presents with persistent anatomical snuffbox tenderness after a FOOSH injury. Initial plain radiographs are negative for a scaphoid fracture.According to current literature and guidelines, which advanced imaging modality has demonstrated superior diagnostic accuracy over plain radiographs and bone scans for detecting occult scaphoid fractures?

• A: Computed Tomography (CT) Scan
• B: Magnetic Resonance Imaging (MRI)
• C: Diagnostic Ultrasound
• D: Arthrography
• E: Fluoroscopy with stress views

Explanation: Correct Answer: BThe text states under "Diagnostic Algorithms": "MRI is highly sensitive for occult fractures and bone contusions... Meta-analyses have demonstrated the superior diagnostic accuracy of MRI over plain radiographs and bone scans for occult scaphoid fractures." This directly supports MRI as the superior modality for detecting occult fractures when initial radiographs are negative.Incorrect Options:A) Computed Tomography (CT) Scan: While CT is the gold standard for assessing fracture displacement, comminution, and fragment orientation for surgical planning, MRI is generally considered more sensitive for detecting occult fractures (bone edema/contusion) not visible on initial radiographs or even early CT.C) Diagnostic Ultrasound: Ultrasound has limited diagnostic accuracy for scaphoid fractures, especially occult ones, compared to MRI or CT.D) Arthrography: Arthrography is primarily used to assess ligamentous injuries and cartilage integrity, not for diagnosing occult bone fractures.E) Fluoroscopy with stress views: Fluoroscopy is used intraoperatively for guiding fixation or dynamically assessing carpal instability, but it is not an advanced imaging modality for detecting occult fractures.

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