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2. Trauma MCQs

Practice Set 636 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 12701

Topic: 2. Trauma
A 35-year-old male with an autosomal dominant form of osteopetrosis (Albers-Schönberg disease) sustains a displaced subtrochanteric femur fracture. During open reduction and internal fixation, which of the following intraoperative challenges is the surgeon most likely to encounter?
. Massive hemorrhage due to a highly vascularized medullary canal
. Inability to achieve adequate reduction due to profound soft tissue contractures
. Extreme difficulty in drilling the bone, with a high risk of drill bit breakage
. Immediate pull-out of screws due to severely osteopenic cancellous bone
. Rapid intraoperative formation of heterotopic ossification

Correct Answer & Explanation

. Extreme difficulty in drilling the bone, with a high risk of drill bit breakage

Explanation

In osteopetrosis, the bone is abnormally dense and hard, although mechanically brittle ('chalk-like'). Surgeons frequently encounter extreme difficulty when drilling, leading to drill bit breakage, heat necrosis, and difficult hardware placement.

Question 12702

Topic: Lower Extremity Trauma

Trichorhinophalangeal syndrome type 1 (TRPS1) is characterized by a specific triad of clinical findings. Which of the following radiographic features is the hallmark of this condition?

. Cone-shaped epiphyses of the phalanges
. Erlenmeyer flask deformity of the distal femur
. Rugger jersey spine
. Bone within a bone appearance
. Cotton wool appearance of the skull

Correct Answer & Explanation

. Cone-shaped epiphyses of the phalanges

Explanation

TRPS1 is classically associated with cone-shaped epiphyses of the phalanges, sparse hair, and a pear-shaped nose. The cone-shaped epiphyses often lead to premature fusion and brachydactyly.

Question 12703

Topic: 2. Trauma

A 28-year-old male with known autosomal dominant osteopetrosis requires open reduction and internal fixation for a displaced transverse femur fracture. Which of the following technical challenges is most characteristic during surgery for this patient?

. Severe intraoperative hemorrhage requiring massive transfusion
. Inability to achieve bone healing, requiring immediate bone grafting
. Increased surgical difficulty due to brittle bone and high risk of drill bit breakage
. Rapid hardware loosening within 48 hours due to osteopenia
. Requirement for specialized non-magnetic titanium implants due to iron overload

Correct Answer & Explanation

. Increased surgical difficulty due to brittle bone and high risk of drill bit breakage

Explanation

Bones in osteopetrosis, while dense and appearing strong on radiographs, are actually brittle and prone to 'chalk-stick' fractures. The extreme density makes surgical fixation extremely difficult, frequently causing drill bits to overheat or break.

Question 12704

Topic: 2. Trauma
A 35-year-old female with a history of recurrent fractures presents with progressive hearing loss and left-sided facial muscle weakness. Radiographs demonstrate diffuse osteosclerosis and loss of medullary canals. Which set of cranial nerves is most frequently affected by compressive neuropathies in this adult-onset condition?
. I, II, and III
. II, VII, and VIII
. III, IV, and VI
. V, IX, and X
. XI and XII

Correct Answer & Explanation

. II, VII, and VIII

Explanation

Adult osteopetrosis causes dense, brittle bone and narrowing of the cranial foramina. This frequently leads to compressive neuropathies of cranial nerves II (optic), VII (facial), and VIII (vestibulocochlear).

Question 12705

Topic: 2. Trauma

Which of the following features best distinguishes primary synovial chondromatosis from secondary synovial chondromatosis?

. Presence of intra-articular loose bodies
. Loose bodies of uniform size and shape
. Associated advanced osteoarthritis
. Predilection for the knee joint
. Calcification of the loose bodies

Correct Answer & Explanation

. Loose bodies of uniform size and shape

Explanation

Primary synovial chondromatosis typically presents with multiple loose bodies of uniform size due to synchronous synovial metaplasia. Secondary synovial chondromatosis (from trauma or osteoarthritis) features a few loose bodies of varying sizes alongside underlying degenerative joint disease.

Question 12706

Topic: Lower Extremity Trauma



During treatment of a complex tibial deformity with a hexapod circular external fixator, the surgeon notes a residual varus and procurvatum deformity after completing the initial correction schedule. What is the most appropriate next step to correct the residual deformity?

. Perform an acute adjustment in the clinic under sedation.
. Generate a new 'total residual' program using updated orthogonal radiographs.
. Remove the frame and convert to an intramedullary nail.
. Adjust only the anterior and medial struts empirically.
. Perform a closing wedge osteotomy.

Correct Answer & Explanation

. Generate a new 'total residual' program using updated orthogonal radiographs.

Explanation

The primary advantage of a hexapod circular frame is the ability to easily correct residual multiplanar deformities. The surgeon should obtain new orthogonal radiographs, re-measure the parameters, and enter them into the software to generate a precise residual correction schedule.

Question 12707

Topic: 2. Trauma

What is the primary advantage of the 'lengthening over a nail' (LON) technique compared to traditional Ilizarov lengthening?

. Increased amount of total lengthening achievable
. Decreased risk of deep infection
. Decreased external fixation index (EFI)
. Elimination of pin tract infections
. Lower risk of delayed consolidation

Correct Answer & Explanation

. Decreased external fixation index (EFI)

Explanation

Lengthening over a nail significantly reduces the time the external fixator must remain on the patient, thereby lowering the external fixation index. The fixator can be removed once the desired length is achieved, while the locked nail maintains length during consolidation.

Question 12708

Topic: 2. Trauma

A 6-year-old child weighing 25 kg sustains a completely displaced, isolated diaphyseal femur fracture. What is the standard of care for definitive surgical fixation?

. Rigid antegrade intramedullary nailing through the piriformis fossa
. Rigid antegrade intramedullary nailing through the greater trochanter
. Titanium elastic nails (TENs)
. Open reduction and dynamic compression plating
. External fixation

Correct Answer & Explanation

. Titanium elastic nails (TENs)

Explanation

For children aged 5-11 years with weight under 50 kg, flexible intramedullary nailing (TENs) is the preferred treatment for length-stable diaphyseal femur fractures. Rigid nailing in this age group carries an unacceptable risk of iatrogenic avascular necrosis of the femoral head.

Question 12709

Topic: 2. Trauma

A 10-year-old child is treated with eight-Plates (tension band constructs) for bilateral genu valgum. Eighteen months later, the deformity is fully corrected, and the hardware is removed. The parents should be counseled on which common post-removal phenomenon?

. Rebound growth causing recurrent valgus
. Sudden growth arrest leading to shortening
. Progression into a varus deformity
. Avascular necrosis of the distal femoral epiphysis
. Stress fracture at the screw holes

Correct Answer & Explanation

. Rebound growth causing recurrent valgus

Explanation

The "rebound phenomenon" frequently occurs after the removal of tension band plates for guided growth, especially in young children with significant remaining growth potential. For this reason, mild overcorrection is sometimes recommended.

Question 12710

Topic: Lower Extremity Trauma

During a femoral lengthening procedure utilizing the Lengthening Over a Nail (LON) technique, what is the primary advantage compared to lengthening with an external fixator alone?

. Reduced risk of deep intramedullary infection
. Decreased duration of external fixator wear
. Complete elimination of pin-tract infections
. Ability to use standard reamed nails in skeletally immature patients
. Better preservation of the endosteal blood supply

Correct Answer & Explanation

. Decreased duration of external fixator wear

Explanation

Lengthening over a nail (LON) allows the external fixator to be removed immediately once the desired length is achieved, with the intramedullary nail locked to maintain length during the consolidation phase. This drastically reduces the time the patient is burdened by the external frame.

Question 12711

Topic: 2. Trauma

A 7-year-old child presents with a 'gunstock' deformity of the right elbow following a supracondylar humerus fracture treated conservatively 2 years ago. The deformity is primarily caused by malunion in which plane?

. Coronal and horizontal rotation
. Sagittal only
. Axial translation only
. Sagittal and axial translation
. Pure coronal translation

Correct Answer & Explanation

. Coronal and horizontal rotation

Explanation

Cubitus varus (gunstock deformity) is a 3-dimensional malunion primarily caused by a failure to correct coronal tilt (varus) and horizontal rotation (internal rotation) of the distal fragment.

Question 12712

Topic: 2. Trauma

A 24-year-old male is undergoing femoral lengthening over a nail (LON) using a monoplanar external fixator. During the consolidation phase after achieving 4 cm of length, the fixator is removed prematurely before the intramedullary nail is proximally locked. What is the most likely complication?

. Rapid consolidation of the regenerate
. Acute axial collapse of the regenerate
. Deep periprosthetic joint infection
. Hypertrophic nonunion of the regenerate
. Stress fracture of the intramedullary nail

Correct Answer & Explanation

. Acute axial collapse of the regenerate

Explanation

In lengthening over a nail (LON), the external fixator controls length and rotation during the distraction phase. If the fixator is removed before the nail is properly locked with interlocking screws across the regenerate segment, the limb will acutely collapse axially.

Question 12713

Topic: 2. Trauma

A 28-year-old male sustains a closed midshaft humerus fracture following a motor vehicle collision. On secondary survey, the orthopedic surgeon notes a specific neurological deficit that is classically associated with this fracture pattern. Which of the following findings is most likely present?

. Inability to cross the fingers
. Numbness over the volar aspect of the index finger
. Inability to actively extend the wrist
. Weakness in thumb opposition
. Loss of active elbow flexion

Correct Answer & Explanation

. Inability to actively extend the wrist

Explanation

Correct Answer: Inability to actively extend the wristThe radial nerve courses in the spiral groove along the posterior aspect of the midshaft of the humerus, making it highly vulnerable to injury in midshaft humerus fractures (Holstein-Lewis fracture). Radial nerve palsy presents clinically with a 'wrist drop'—the inability to actively extend the wrist and digits—as well as numbness over the dorsal first web space.

Question 12714

Topic: 2. Trauma

A 24-year-old male is admitted after sustaining a comminuted tibial shaft fracture. Twelve hours post-injury, he complains of severe, escalating leg pain that is not relieved by intravenous opioids. Which of the following is considered the most reliable early clinical indicator of the condition requiring urgent surgical fasciotomy?

. Loss of palpable dorsalis pedis and posterior tibial pulses
. Pain with passive stretch of the toes
. Paresthesias in the first web space
. Motor paralysis of the anterior compartment musculature
. Capillary refill time greater than 3 seconds

Correct Answer & Explanation

. Pain with passive stretch of the toes

Explanation

Correct Answer: Pain with passive stretch of the toesThe patient is developing acute compartment syndrome, a surgical emergency requiring prompt fasciotomy. The most sensitive and reliable early clinical sign of compartment syndrome is pain out of proportion to the injury, specifically exacerbated by passive stretch of the muscles within the affected compartment (e.g., passive toe flexion/extension). Pulselessness and paralysis are late, ominous signs that indicate irreversible tissue ischemia.

Question 12715

Topic: 2. Trauma

A 6-year-old boy falls from monkey bars and sustains a widely displaced extension-type supracondylar humerus fracture. On examination, he is unable to flex his interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger. Which nerve is most likely injured, and what is the most feared vascular complication associated with this fracture pattern?

. Ulnar nerve; compartment syndrome of the forearm
. Radial nerve; brachial artery pseudoaneurysm
. Anterior interosseous nerve; Volkmann's ischemic contracture
. Posterior interosseous nerve; axillary artery thrombosis
. Median nerve (main trunk); deep vein thrombosis

Correct Answer & Explanation

. Anterior interosseous nerve; Volkmann's ischemic contracture

Explanation

Correct Answer: CThe anterior interosseous nerve (AIN), a branch of the median nerve, is the most commonly injured nerve in extension-type supracondylar humerus fractures. AIN palsy presents with the inability to flex the IP joint of the thumb (FPL) and the DIP joint of the index finger (FDP), resulting in an abnormal 'OK' sign. The most severe complication of a displaced supracondylar fracture is vascular compromise (brachial artery injury or severe swelling) leading to compartment syndrome of the forearm, which, if untreated, results in Volkmann's ischemic contracture.

Question 12716

Topic: 2. Trauma

A 25-year-old male sustains a closed, transverse midshaft humerus fracture in a motor vehicle collision. On examination, he is unable to actively extend his wrist or fingers, and he has decreased sensation over the dorsal first web space. Which of the following is the most appropriate initial management for this neurological deficit?

. Immediate surgical exploration and nerve repair
. Electromyography (EMG) and nerve conduction studies
. Observation and supportive care with a functional brace
. Urgent MRI of the humerus
. Corticosteroid injection into the spiral groove

Correct Answer & Explanation

. Observation and supportive care with a functional brace

Explanation

Correct Answer: CThe patient has a radial nerve palsy, which is the most common neurological injury associated with midshaft humerus fractures (especially Holstein-Lewis type fractures of the distal third). The vast majority of these are neuropraxias that will resolve spontaneously. The standard of care for a closed humerus fracture with a primary radial nerve palsy is observation and supportive care (e.g., functional bracing of the fracture, wrist splint to prevent contracture). Surgical exploration is generally reserved for open fractures, secondary palsies (occurring after reduction), or failure to recover after 3-6 months (confirmed by EMG).

Question 12717

Topic: 2. Trauma

A 30-year-old male sustains a comminuted tibial shaft fracture. Twelve hours post-admission, he complains of severe, unrelenting leg pain that is out of proportion to the injury and not relieved by intravenous opioids. On examination, the leg is tense, and passive stretch of the toes elicits excruciating pain. Pulses are palpable. What is the underlying pathophysiological mechanism driving this condition?

. Arterial vasospasm leading to distal ischemia
. Increased tissue pressure within a closed fascial space compromising microvascular perfusion
. Deep vein thrombosis causing venous outflow obstruction
. Direct mechanical compression of the tibial nerve by fracture fragments
. Systemic inflammatory response syndrome causing capillary leak

Correct Answer & Explanation

. Increased tissue pressure within a closed fascial space compromising microvascular perfusion

Explanation

Correct Answer: BThe patient is presenting with classic signs of acute compartment syndrome (pain out of proportion, pain with passive stretch, tense compartments). The underlying pathophysiology is an increase in interstitial tissue pressure within a non-yielding osteofascial compartment. When this pressure exceeds the capillary perfusion pressure, microvascular flow is compromised, leading to muscle and nerve ischemia. The presence of palpable pulses does not rule out compartment syndrome, as arterial pressure is much higher than capillary pressure; pulses are often maintained until late in the disease process. Urgent fasciotomy is required.

Question 12718

Topic: 2. Trauma

A 30-year-old male sustains a comminuted tibial shaft fracture. Twelve hours post-injury, he develops severe leg pain that is not relieved by intravenous opioids. Which of the following is the most sensitive early clinical indicator of the condition requiring urgent surgical intervention?

. Loss of distal pulses (dorsalis pedis and posterior tibial)
. Pallor and poikilothermia of the foot
. Pain with passive stretch of the toes
. Motor paralysis of the deep posterior compartment
. Paresthesias in the first web space

Correct Answer & Explanation

. Pain with passive stretch of the toes

Explanation

Correct Answer: Pain with passive stretch of the toesThe patient is developing acute compartment syndrome, a surgical emergency requiring prompt fasciotomy. The earliest and most sensitive clinical sign of compartment syndrome is pain out of proportion to the injury, specifically exacerbated by passive stretch of the muscles within the involved compartment (e.g., passive extension of the toes stretching the deep posterior or anterior compartments). Pulselessness and paralysis are late, often irreversible signs.

Question 12719

Topic: 2. Trauma

A 28-year-old male sustains a comminuted midshaft tibia fracture. Twelve hours post-injury, he develops severe, unrelenting leg pain out of proportion to the injury, which is exacerbated by passive stretch of the toes. What is the most appropriate definitive management?

. Elevation of the limb above heart level and ice application
. Administration of intravenous opioids and close observation
. Immediate emergent four-compartment fasciotomy
. Application of a long leg cast
. Intravenous administration of broad-spectrum antibiotics

Correct Answer & Explanation

. Immediate emergent four-compartment fasciotomy

Explanation

Correct Answer: Immediate emergent four-compartment fasciotomyThe patient's clinical presentation is classic for acute compartment syndrome, characterized by pain out of proportion, pain with passive stretch, paresthesias, pallor, paralysis, and pulselessness (the '6 Ps', though pulselessness is a late and unreliable sign). The definitive and urgent treatment is a surgical fasciotomy to release all four compartments of the lower leg to prevent irreversible ischemic muscle and nerve necrosis.

Question 12720

Topic: 2. Trauma

A 72-year-old female sustains a displaced intracapsular femoral neck fracture after a mechanical fall. She is scheduled for surgical intervention. The high risk of avascular necrosis (AVN) associated with this specific injury pattern is primarily due to the disruption of which of the following vascular structures?

. Artery of the ligamentum teres
. Medial femoral circumflex artery
. Lateral femoral circumflex artery
. Inferior gluteal artery
. Profunda femoris artery

Correct Answer & Explanation

. Medial femoral circumflex artery

Explanation

Correct Answer: BDisplaced intracapsular femoral neck fractures carry a high risk of avascular necrosis (AVN) of the femoral head and nonunion. The primary blood supply to the adult femoral head is derived from the medial femoral circumflex artery (MFCA), specifically its lateral epiphyseal branches, which course along the posterosuperior aspect of the femoral neck. Disruption or kinking of these vessels during fracture displacement leads to ischemia and subsequent AVN. The artery of the ligamentum teres provides a negligible blood supply to the adult femoral head.

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