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2. Trauma MCQs

Practice Set 490 of 640

This practice set contains high-yield board review questions covering key concepts in 2. Trauma. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 9781

Topic: 2. Trauma

Regarding the pathogenesis of avascular necrosis (AVN) of the femoral head, which of the following mechanisms is considered the most common final common pathway leading to osteocyte death?

. Direct mechanical trauma to the osteocytes
. Fat embolism leading to vascular occlusion
. Venous outflow obstruction and increased intraosseous pressure
. Hypercoagulability causing arterial thrombosis
. Corticosteroid-induced adipogenesis and fat cell hypertrophy

Correct Answer & Explanation

. Venous outflow obstruction and increased intraosseous pressure

Explanation

While several factors contribute to AVN (e.g., steroid use, trauma, alcoholism), the final common pathway leading to osteocyte death is often considered to be venous outflow obstruction and increased intraosseous pressure. This increased pressure compromises arterial inflow and results in ischemia. Corticosteroid-induced adipogenesis is a significant etiological factor, leading to fat cell hypertrophy within the confined medullary space, which then contributes to the venous outflow obstruction and increased pressure. Fat embolism and hypercoagulability are also implicated in some cases, but the pressure-induced ischemia is the more unifying pathway.

Question 9782

Topic: 2. Trauma

A 72-year-old woman with a history of osteoporosis falls and sustains an isolated intertrochanteric hip fracture (AO/OTA 31-A2). She is otherwise healthy and active. What is the most appropriate surgical management?

. Dynamic hip screw (DHS)
. Cephalomedullary nail
. Total hip arthroplasty
. Hemiarthroplasty
. External fixation

Correct Answer & Explanation

. Cephalomedullary nail

Explanation

For unstable intertrochanteric fractures (like AO/OTA 31-A2, which implies comminution of the posterior-medial cortex), a cephalomedullary nail is generally preferred over a dynamic hip screw (DHS). The intramedullary position of the nail provides superior biomechanical stability, especially against varus collapse, and has been shown to have lower rates of implant failure in unstable patterns. Arthroplasty is typically reserved for highly comminuted fractures with femoral head involvement or pre-existing severe arthritis. External fixation is rarely used for these fractures.

Question 9783

Topic: 2. Trauma

In the management of open fractures, what is the recommended time frame for debridement and irrigation to minimize infection risk?

. Within 2 hours
. Within 6 hours
. Within 12 hours
. Within 24 hours
. Within 48 hours

Correct Answer & Explanation

. Within 6 hours

Explanation

Historically, the '6-hour rule' was emphasized for debridement of open fractures. However, more recent evidence suggests that while earlier debridement is ideal, the critical factor is thorough and aggressive debridement, rather than a rigid time cut-off. Nevertheless, the general consensus still aims for debridement within 6-8 hours of injury to significantly reduce the risk of infection. Some studies indicate a benefit for even earlier debridement (e.g., within 2-4 hours) for significantly contaminated wounds. So, 'within 6 hours' is the most widely accepted and practical guideline to minimize infection risk.

Question 9784

Topic: 2. Trauma

In the management of adult diaphyseal tibia fractures, what is the primary indication for surgical intervention (e.g., intramedullary nailing) over non-operative treatment (e.g., cast immobilization)?

. Any displaced fracture
. Presence of an associated fibula fracture
. Fracture shortening greater than 1 cm
. Open fractures or highly unstable closed fractures
. Patient preference for earlier return to activity

Correct Answer & Explanation

. Open fractures or highly unstable closed fractures

Explanation

The primary indications for surgical management (most commonly intramedullary nailing) of adult diaphyseal tibia fractures include open fractures (to stabilize after debridement), highly unstable closed fractures (e.g., comminuted, segmental, spiral with significant displacement, or those with significant soft tissue compromise), and failure of conservative management. While other factors like shortening or patient preference play a role, open or unstable fractures necessitate surgical stabilization for optimal healing and function.

Question 9785

Topic: 2. Trauma

Which factor is most predictive of successful union in an operatively managed scaphoid fracture?

. Age of the patient
. Presence of a dorsal intercalated segment instability (DISI) deformity
. Location of the fracture (e.g., waist vs. proximal pole)
. Time from injury to surgery
. Type of fixation (screws vs. K-wires)

Correct Answer & Explanation

. Location of the fracture (e.g., waist vs. proximal pole)

Explanation

The location of the scaphoid fracture is a critical predictor of healing. Proximal pole fractures have a higher risk of nonunion and avascular necrosis due to their precarious blood supply (which enters distally and runs proximally). Waist fractures have a better, but still guarded, prognosis, while distal fractures have the highest union rates. While time to surgery and adequate fixation are important, the inherent vascularity related to fracture location is a dominant factor. DISI deformity is a carpal instability pattern, not a direct predictor of scaphoid union itself.

Question 9786

Topic: 2. Trauma

A 6-year-old boy falls off a jungle gym and sustains an isolated mid-diaphyseal femur fracture. He is hemodynamically stable. What is the most appropriate definitive management?

. Skeletal traction followed by spica cast
. Immediate intramedullary nailing (rigid)
. Flexible intramedullary nailing
. External fixation
. Plate and screw fixation

Correct Answer & Explanation

. Flexible intramedullary nailing

Explanation

For mid-diaphyseal femur fractures in children aged 5-11 years, flexible intramedullary nailing (e.g., Ender nails or titanium elastic nails) is the preferred definitive treatment. It provides stable fixation, allows early mobilization, and avoids the complications associated with rigid intramedullary nails (e.g., AVN of the femoral head, trochanteric apophysis injury) in younger children, or prolonged cast immobilization in older children. Skeletal traction followed by casting is an option for younger children (<5 years) or very short oblique fractures, but flexible nailing is often favored for robust fixation and early mobility in this age group.

Question 9787

Topic: 2. Trauma

A 28-year-old male sustains a spiral fracture of the middle third of the tibia and fibula in a motor vehicle accident. He presents with severe pain, swelling, and a tense compartment in the leg. Dorsiflexion of the ankle and toes is painful and weak, and sensation in the first web space is diminished. Pedal pulses are palpable. What is the most appropriate immediate management?

. Application of a long leg splint and pain medication
. Immediate operative exploration and fasciotomy
. Administration of IV fluids and elevation of the extremity
. Serial compartment pressure measurements
. CT angiogram to assess vascular compromise

Correct Answer & Explanation

. Immediate operative exploration and fasciotomy

Explanation

The patient presents with classic signs and symptoms of acute compartment syndrome: severe pain disproportionate to the injury, swelling, tense compartment, pain with passive stretch (dorsiflexion), and neurological deficits (weakness, diminished sensation). While pulses may still be palpable, the presence of neurologic compromise and a tense compartment in the setting of a high-energy injury warrants immediate operative exploration and fasciotomy to prevent irreversible muscle and nerve damage. Delay can lead to Volkmann's ischemic contracture. Compartment pressure measurements can confirm the diagnosis but should not delay surgery if clinical signs are clear.

Question 9788

Topic: 2. Trauma

A 30-year-old male sustains a proximal humerus fracture (AO/OTA 11-B2) with a displaced greater tuberosity fragment and impaction of the articular surface. He is a smoker. What is the most significant risk factor for avascular necrosis (AVN) of the humeral head in this specific fracture pattern?

. Age of the patient
. Smoking status
. Displacement of the greater tuberosity fragment
. Degree of metaphyseal comminution
. Disruption of the medial calcar blood supply

Correct Answer & Explanation

. Disruption of the medial calcar blood supply

Explanation

In proximal humerus fractures, the most significant anatomical factor contributing to avascular necrosis (AVN) of the humeral head is the disruption of the medial calcar blood supply, specifically the ascending branch of the anterior humeral circumflex artery and its arcade. This artery provides the dominant blood supply to the humeral head. Fracture patterns that severely compromise this supply (e.g., 3- and 4-part fractures with significant displacement or angulation) are at highest risk. While smoking and age are general risk factors, the specific vascular disruption is paramount for this fracture. Greater tuberosity displacement itself does not directly correlate as strongly with AVN as the calcar blood supply.

Question 9789

Topic: 2. Trauma

A 25-year-old male sustains a closed, isolated mid-shaft clavicle fracture. He is active and desires the quickest return to sports. Radiographs show 100% displacement and 2 cm of shortening. What is the most appropriate management strategy?

. Sling immobilization for 6 weeks, then physical therapy
. Figure-of-eight brace, then physical therapy
. Open reduction internal fixation with plate and screws
. Intramedullary nailing of the clavicle
. Non-weight-bearing restriction for 3 months

Correct Answer & Explanation

. Open reduction internal fixation with plate and screws

Explanation

While many mid-shaft clavicle fractures can be treated non-operatively, significant displacement (>100%), shortening (>1.5-2 cm), or comminution in an active patient, especially those desiring the quickest return to function, are increasingly considered indications for surgical intervention. Open reduction internal fixation with a plate and screws offers more reliable anatomical reduction, faster time to union, and earlier return to activity compared to non-operative management for these specific fracture patterns. Sling immobilization is for minimally displaced fractures. Intramedullary nailing is an option but plate fixation is more common for mid-shaft. Non-weight-bearing is not the primary determinant of outcome here.

Question 9790

Topic: 2. Trauma

A 75-year-old female sustains a Colles fracture of her distal radius. She has known osteoporosis. Which of the following is the most appropriate initial management for this closed, non-articular, dorsally displaced fracture with good bone quality for reduction?

. Immediate surgical open reduction and internal fixation
. Closed reduction and sugar tong splint immobilization
. External fixation
. Casting in pronation, ulnar deviation, and volar flexion
. Observation with pain management

Correct Answer & Explanation

. Closed reduction and sugar tong splint immobilization

Explanation

A Colles fracture, characterized by dorsal displacement and often dorsal angulation, is typically treated with closed reduction and casting or splinting. For a non-articular, dorsally displaced fracture with good bone quality, a closed reduction followed by immobilization in a sugar tong splint or volar forearm cast is the standard initial management. The immobilization typically positions the wrist in slight flexion, ulnar deviation, and pronation to maintain reduction. Surgical options are reserved for unstable fractures or those that cannot be adequately reduced or maintained non-operatively. Observation alone is inappropriate for a displaced fracture.

Question 9791

Topic: 2. Trauma

Which of the following is considered the most reliable indicator of successful revascularization following fasciotomy for compartment syndrome?

. Return of distal pulses
. Resolution of pain
. Resolution of tenseness in the compartments
. Improved motor function
. Normalized intracompartmental pressures

Correct Answer & Explanation

. Normalized intracompartmental pressures

Explanation

While return of pulses, resolution of pain, and decreased compartment tenseness are positive clinical signs, normalized intracompartmental pressures are the most objective and reliable indicator that decompression has been successful and tissue perfusion has been restored adequately within the compartments. Motor function and sensory changes recover more slowly and are not immediate indicators of revascularization.

Question 9792

Topic: 2. Trauma

A 45-year-old male sustains a closed, mid-shaft humeral fracture after a fall. Radiographs show a transverse fracture with 15 degrees of varus angulation and 1 cm shortening. He has intact neurovascular status. Which of the following is the most appropriate initial treatment?

. Open reduction and internal fixation with a compression plate
. Intramedullary nailing
. Functional bracing (e.g., Sarmiento brace) after initial coaptation splinting
. Hanging cast for 6-8 weeks
. External fixation

Correct Answer & Explanation

. Functional bracing (e.g., Sarmiento brace) after initial coaptation splinting

Explanation

For most closed, stable humeral shaft fractures, non-operative management with a functional brace (such as a Sarmiento brace) is the gold standard, achieving union rates over 90%. Initial immobilization in a coaptation splint or U-splint helps reduce pain and stabilize the fracture before fitting a functional brace once swelling subsides. Acceptable alignment includes up to 20 degrees of angulation in any plane and up to 3 cm of shortening. The given angulation and shortening fall within these acceptable limits. Operative management is typically reserved for specific indications.

Question 9793

Topic: 2. Trauma

A 28-year-old active duty military recruit presents with a spiral fracture of the distal third of the humerus, sustained during a training exercise. Radiographs confirm the fracture, and he has a complete radial nerve palsy on presentation (wrist drop, inability to extend MCPs of fingers/thumb, sensory loss in radial distribution). What is the most appropriate management strategy?

. Immediate surgical exploration of the radial nerve and ORIF
. Non-operative management with a functional brace and observation of radial nerve recovery
. CT angiogram to rule out vascular injury
. EMG/NCS immediately to confirm nerve injury type
. Intramedullary nailing without nerve exploration

Correct Answer & Explanation

. Non-operative management with a functional brace and observation of radial nerve recovery

Explanation

In the setting of a closed humeral shaft fracture with a radial nerve palsy occurring at the time of injury (primary palsy) and no other absolute indications for surgery (e.g., open fracture, vascular injury), non-operative management of the fracture with observation of the nerve is the preferred approach. The vast majority (up to 90%) of these palsies are neurapraxias or axonotmesis and recover spontaneously, typically within 3-6 months. Surgical exploration of the nerve is indicated if the nerve palsy is iatrogenic (after reduction or surgery), incomplete but worsening, or fails to show signs of recovery within 3-4 months. Immediate exploration of the nerve in primary closed injuries without other surgical indications is generally not recommended as it does not improve outcomes and subjects the patient to surgical risks.

Question 9794

Topic: 2. Trauma

Which of the following fracture patterns is generally considered an absolute indication for operative management of a humeral shaft fracture?

. Transverse mid-shaft fracture with 10 degrees valgus angulation
. Spiral fracture of the distal third with 2 cm shortening
. Segmental humeral shaft fracture in a polytrauma patient
. Oblique fracture with associated radial nerve palsy (primary injury)
. Comminuted fracture in an elderly, low-demand patient

Correct Answer & Explanation

. Segmental humeral shaft fracture in a polytrauma patient

Explanation

A segmental humeral shaft fracture in a polytrauma patient (specifically, a 'floating elbow' or other associated severe injuries requiring early mobilization) is a strong indication for operative stabilization. This allows for earlier mobilization, easier nursing care, and can prevent complications associated with prolonged immobilization in a complex trauma patient. Other absolute indications include open fractures, vascular injury requiring repair, compartment syndrome, irreducible fractures, ipsilateral forearm fractures (floating elbow), pathological fractures, and fractures requiring surgical exposure for nerve or vessel repair. The other options generally fall within the realm of non-operative management or relative indications, depending on patient factors.

Question 9795

Topic: 2. Trauma

A 70-year-old female presents with a displaced, comminuted mid-shaft humeral fracture after a simple fall. She has significant osteopenia. She lives alone and is otherwise healthy. What is the most appropriate treatment option that offers the best balance of stability and return to function in this patient?

. Functional bracing
. Hanging cast
. Minimally invasive plate osteosynthesis (MIPO)
. Antegrade intramedullary nailing
. External fixation

Correct Answer & Explanation

. Antegrade intramedullary nailing

Explanation

While functional bracing is often the first-line for many humeral shaft fractures, a displaced, comminuted fracture in an osteoporotic bone may struggle to heal with non-operative methods due to poor bone quality and instability, leading to higher rates of nonunion or malunion. Intramedullary nailing (IMN), particularly antegrade, is a good option for comminuted fractures, especially in osteoporotic bone, as it provides good biomechanical stability, is load-sharing, and is less disruptive to the soft tissues than conventional ORIF. MIPO is also an option but IMN is often preferred for more comminuted patterns, particularly in osteopenic bone where screw purchase for plates might be compromised. Functional bracing is prone to failure in this specific scenario, and a hanging cast provides less control over rotation and alignment compared to bracing or surgery. External fixation is generally reserved for open fractures with significant soft tissue compromise or as a temporary measure.

Question 9796

Topic: 2. Trauma

Regarding intramedullary nailing for humeral shaft fractures, which of the following is a recognized disadvantage?

. Increased risk of radial nerve injury compared to plating
. Higher rates of nonunion for mid-shaft fractures
. Limited use in pathological fractures
. Potential for shoulder pain and restricted motion (e.g., impingement) with antegrade nails
. Inferior stability for spiral fractures compared to plates

Correct Answer & Explanation

. Potential for shoulder pain and restricted motion (e.g., impingement) with antegrade nails

Explanation

Antegrade intramedullary nailing for humeral shaft fractures is known to carry a risk of shoulder pain and restricted motion, particularly impingement, due to hardware prominence at the entry site (rotator cuff injury). This is a well-documented complication that can significantly impact patient function. While IMNs are generally associated with good union rates, they can have higher rates of delayed union or nonunion in specific scenarios (e.g., transverse fractures treated with flexible nails or in certain designs). Radial nerve injury is more commonly associated with plate fixation due to direct exposure, though it can occur with IMN. IMNs are actually excellent for pathological fractures due to their load-sharing capabilities and minimal soft tissue disruption. IMNs provide good stability for most fracture types, including spiral fractures, though their rotational control can be slightly less than a perfectly contoured plate.

Question 9797

Topic: 2. Trauma

What is the most common reason for failure of non-operative management of humeral shaft fractures?

. Radial nerve palsy
. Vascular injury
. Infection
. Nonunion or malunion
. Development of compartment syndrome

Correct Answer & Explanation

. Nonunion or malunion

Explanation

The most common reason for failure of non-operative management of humeral shaft fractures is nonunion or symptomatic malunion. While non-operative treatment boasts high union rates (>90-95%), failure to achieve union or union in an unacceptable alignment (symptomatic malunion) typically necessitates conversion to operative treatment. Radial nerve palsy is a common association but usually recovers and doesn't constitute a 'failure' of fracture healing. Vascular injury and compartment syndrome are acute complications and rare with closed humeral shaft fractures, especially after initial management. Infection is a risk of operative management, not non-operative.

Question 9798

Topic: 2. Trauma

A 32-year-old construction worker presents with a comminuted mid-shaft humeral fracture. He is highly motivated to return to work quickly. Which surgical fixation method is generally preferred to allow for early functional rehabilitation and high union rates in this patient?

. Hanging cast
. Functional bracing
. Intramedullary nailing
. External fixation
. Lag screw fixation only

Correct Answer & Explanation

. Intramedullary nailing

Explanation

For a comminuted mid-shaft humeral fracture in a young, active, and high-demand patient who desires early return to work, intramedullary nailing is often favored. IMNs offer a load-sharing construct, allowing for early functional rehabilitation and weight-bearing through the arm. They also have minimal soft tissue stripping compared to plating, which can theoretically improve healing. While plating can also provide stable fixation, IMNs are generally considered superior for comminuted mid-shaft fractures in terms of load sharing and allowing for earlier protected motion. Functional bracing is less reliable for comminuted fractures, and a hanging cast is inadequate for early functional recovery. External fixation is reserved for specific indications (e.g., open fractures, severe soft tissue injury). Lag screw fixation alone is insufficient for a comminuted fracture.

Question 9799

Topic: 2. Trauma

Which of the following describes an acceptable radiographic outcome for a closed humeral shaft fracture treated non-operatively?

. 25 degrees of varus angulation
. 35 degrees of sagittal angulation (anterior/posterior)
. 4 cm of shortening
. 25 degrees of internal rotation malunion
. 2 cm of shortening and 15 degrees of varus angulation

Correct Answer & Explanation

. 2 cm of shortening and 15 degrees of varus angulation

Explanation

Acceptable radiographic outcomes for closed humeral shaft fractures treated non-operatively include up to 20 degrees of angulation in any plane (varus/valgus, anterior/posterior) and up to 3 cm of shortening. Rotational malunion is generally well-tolerated and difficult to assess accurately on plain radiographs. Therefore, 2 cm of shortening and 15 degrees of varus angulation fall within these acceptable limits. Options A, B, and C exceed the generally accepted thresholds for angulation or shortening, and option D implies rotational assessment which is less critical and harder to quantify radiographically for functional outcome.

Question 9800

Topic: 2. Trauma
A 60-year-old obese female with diabetes and a history of chronic alcoholism presents with an open Gustilo-Anderson Type IIIA transverse humeral shaft fracture. What is the most appropriate initial management?
. Immediate closed reduction and functional bracing
. Thorough irrigation and debridement, followed by external fixation
. Thorough irrigation and debridement, followed by immediate intramedullary nailing
. Thorough irrigation and debridement, followed by immediate plate fixation
. Broad-spectrum antibiotics and observation for 24 hours

Correct Answer & Explanation

. Thorough irrigation and debridement, followed by external fixation

Explanation

Open fractures, particularly Gustilo-Anderson Type IIIA, require urgent surgical debridement and irrigation to prevent infection. Given the open nature and significant soft tissue injury (Type IIIA implies extensive contamination and/or soft tissue loss), external fixation is generally the preferred initial stabilization method. It allows for wound inspection, repeat debridements, and manages potential soft tissue swelling and contamination effectively, while deferring definitive internal fixation until the soft tissue envelope is healthy and the risk of infection is minimized. Immediate internal fixation (plating or nailing) in a Type IIIA open fracture carries a high risk of deep infection, especially in a patient with comorbidities like diabetes and alcoholism.

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