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2. Trauma MCQs

Practice Set 219 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 4361

Topic: 2. Trauma
A 45-year-old male sustains a lateral compression type II (LC-II) pelvic ring injury in a motor vehicle collision. According to the Young-Burgess classification, which of the following is the hallmark posterior ring injury associated with this specific pattern?
. Complete disruption of the posterior sacroiliac ligaments
. Sacral ala impaction fracture with anterior sacroiliac ligament disruption
. Crescent fracture of the posterior ilium
. Bilateral superior and inferior pubic rami fractures
. Avulsion fracture of the ischial spine

Correct Answer & Explanation

. Crescent fracture of the posterior ilium

Explanation

The Young-Burgess classification divides lateral compression (LC) injuries into three types. LC-I involves a sacral compression fracture on the side of impact. LC-II is characterized by the continuation of the lateral compressive force resulting in a crescent fracture (fracture-dislocation of the sacroiliac joint involving the posterior ilium). LC-III involves a 'windswept' pelvis, with an LC-I or LC-II injury on the ipsilateral side and an external rotation (APC-type) injury on the contralateral side.

Question 4362

Topic: 2. Trauma

A 30-year-old female is evaluated for a high-energy distal femur fracture. Computed tomography reveals an isolated coronal plane fracture of the lateral femoral condyle. What is the AO classification for this fracture, and what is the preferred surgical approach for optimal articular reduction?

. AO type 33-B3; Anterolateral approach
. AO type 33-C1; Medial parapatellar approach
. AO type 33-A1; Subvastus approach
. AO type 33-B1; Direct lateral approach
. AO type 33-B3; Direct posterior approach

Correct Answer & Explanation

. AO type 33-B3; Anterolateral approach

Explanation

A coronal plane fracture of the femoral condyle is a Hoffa fracture, classified as AO 33-B3. It most commonly involves the lateral condyle. An anterolateral approach (or lateral arthrotomy) is preferred for lateral Hoffa fractures as it allows direct visualization of the articular surface for anatomic reduction prior to placement of anterior-to-posterior (or posterior-to-anterior) headless compression screws.

Question 4363

Topic: 2. Trauma

A 34-year-old male sustains a talar neck fracture. Radiographs taken 8 weeks postoperatively demonstrate a subchondral radiolucent band in the dome of the talus on the AP ankle view. What is the physiological and prognostic significance of this radiographic finding (Hawkins sign)?

. It represents avascular necrosis of the talar body
. It indicates impending nonunion of the talar neck
. It confirms intact vascularity and active revascularization of the talar body
. It suggests an indolent infection of the subtalar joint
. It is an early sign of post-traumatic subtalar osteoarthritis

Correct Answer & Explanation

. It represents avascular necrosis of the talar body

Explanation

The Hawkins sign is characterized by a subchondral radiolucent band in the talar dome on an AP mortise view typically seen 6 to 8 weeks after a talar neck fracture. It represents subchondral osteopenia secondary to active hyperemia and bone resorption. The presence of this sign is a highly reliable indicator that the talar body has sufficient blood supply and is undergoing revascularization, effectively ruling out total avascular necrosis.

Question 4364

Topic: 2. Trauma

A 40-year-old male is admitted with a high-energy Schatzker VI tibial plateau fracture. Twelve hours later, he complains of severe, escalating leg pain unrelieved by opioids. Passive stretch of his great toe elicits excruciating pain. Which of the following pressure measurements provides the most reliable indication for performing an emergency four-compartment fasciotomy?

. An absolute compartment pressure greater than 20 mmHg
. A differential pressure (Delta P) between diastolic blood pressure and compartment pressure of less than 30 mmHg
. A differential pressure (Delta P) between systolic blood pressure and compartment pressure of less than 45 mmHg
. An absolute compartment pressure greater than 25 mmHg isolated to the anterior compartment
. A differential pressure (Delta P) between mean arterial pressure (MAP) and compartment pressure of less than 10 mmHg

Correct Answer & Explanation

. An absolute compartment pressure greater than 20 mmHg

Explanation

The diagnosis of acute compartment syndrome relies heavily on clinical suspicion and continuous pressure monitoring in equivocal cases. The most reliable threshold for intervention is a Delta P (Diastolic Blood Pressure minus Compartment Pressure) of less than 30 mmHg. Relying solely on absolute compartment pressures (e.g., > 30 mmHg) can lead to unnecessary fasciotomies, particularly in hypertensive patients.

Question 4365

Topic: Upper Extremity Trauma

A 20-year-old collegiate baseball pitcher experiences chronic posteromedial elbow pain during the deceleration phase of throwing. He has a 15-degree flexion contracture. Radiographs show prominent osteophytes on the posteromedial olecranon. The surgeon plans an arthroscopic posteromedial olecranon resection for valgus extension overload. What complication is directly associated with resecting more than 3 mm of the posteromedial olecranon?

. Ulnar collateral ligament (UCL) insufficiency
. Radial nerve palsy
. Heterotopic ossification of the brachialis muscle
. Complete triceps tendon rupture
. Capitellar osteochondritis dissecans

Correct Answer & Explanation

. Ulnar collateral ligament (UCL) insufficiency

Explanation

In valgus extension overload, repetitive impingement of the olecranon into the olecranon fossa causes posteromedial osteophytes. The posteromedial olecranon is an important secondary bony stabilizer to valgus stress. Resecting excessive bone (typically defined as > 2 to 3 mm) from the posteromedial olecranon unmasks underlying Ulnar Collateral Ligament (UCL) insufficiency and transfers excessive valgus stress to the anterior band of the UCL, leading to medial instability.

Question 4366

Topic: 2. Trauma

A 28-year-old male sustains a midshaft clavicle fracture during a cycling accident. He is a high-level manual laborer. Which of the following radiographic parameters is widely accepted as a strong relative indication for primary open reduction and internal fixation rather than conservative management?

. 100% displacement with 2 cm of shortening
. A single butterfly fragment with 5 mm of translation
. An associated non-displaced scapular body fracture
. 10 degrees of superior angulation
. Fracture extension into the medial third of the clavicle

Correct Answer & Explanation

. 100% displacement with 2 cm of shortening

Explanation

Absolute indications for operative fixation of clavicle fractures include open fractures, neurovascular compromise, and severe skin tenting threatening to progress to an open fracture. Relative indications, especially in active patients, include 100% displacement (no cortical contact) combined with significant shortening (typically defined as > 1.5 to 2.0 cm), as these are associated with higher rates of nonunion, malunion, and decreased shoulder strength if treated non-operatively.

Question 4367

Topic: 2. Trauma

A 65-year-old male sustains a subtrochanteric fracture of the femur. On plain radiographs, the proximal fragment is noted to be severely displaced in a predictable pattern of flexion, abduction, and external rotation. Which specific muscle group is the primary deforming force responsible for the abduction of the proximal fragment?

. Iliopsoas
. Gluteus maximus
. Gluteus medius and minimus
. Short external rotators
. Adductor longus

Correct Answer & Explanation

. Iliopsoas

Explanation

In a subtrochanteric femur fracture, the proximal fragment is subjected to distinct muscular deforming forces. The iliopsoas (attaching to the lesser trochanter) causes flexion. The short external rotators (piriformis, gemelli, obturator internus) cause external rotation. The abductors, primarily the gluteus medius and minimus (attaching to the greater trochanter), pull the proximal fragment into profound abduction. The adductors cause the distal fragment to translate medially.

Question 4368

Topic: 2. Trauma

A 24-year-old male is evaluated in the trauma bay following a severe motorcycle accident resulting in a complete fracture-dislocation at T6. He is hypotensive (BP 80/40), bradycardic (HR 50), and has warm, well-perfused extremities. He has absent motor and sensory function below the umbilicus and an absent bulbocavernosus reflex. Which of the following pathophysiological mechanisms is primarily responsible for his acute hemodynamic instability?

. Loss of sympathetic vasomotor tone due to disruption of descending autonomic pathways
. Massive retroperitoneal hemorrhage from an occult pelvic ring injury
. Cardiac contusion causing immediate right ventricular pump failure
. Systemic inflammatory response syndrome (SIRS) from polytrauma
. Transient loss of somatic spinal reflexes

Correct Answer & Explanation

. Loss of sympathetic vasomotor tone due to disruption of descending autonomic pathways

Explanation

The patient is exhibiting signs of neurogenic shock, which is characterized by hypotension, bradycardia, and warm, flushed extremities. It is caused by the sudden loss of sympathetic vasomotor tone and unopposed vagal parasympathetic tone after a cervical or high thoracic (above T6) spinal cord injury. This differs from spinal shock, which refers to the transient loss of somatic reflex activity (e.g., absent bulbocavernosus reflex) below the level of the injury, regardless of hemodynamic status.

Question 4369

Topic: 2. Trauma
A 35-year-old male sustains an Anterior-Posterior Compression (APC) type III pelvic ring injury following a motorcycle collision. A retrograde cystogram demonstrates an isolated extraperitoneal bladder rupture. The orthopedic team plans to perform an open reduction and internal fixation (ORIF) of the pubic symphysis with a plate. What is the recommended management for the concomitant extraperitoneal bladder rupture?
. Nonoperative management with a Foley catheter for 14 days following the orthopedic fixation
. Placement of a suprapubic catheter only, prior to orthopedic fixation
. Surgical repair of the bladder rupture concurrently with the anterior pelvic ring fixation
. Delaying orthopedic fixation until the bladder heals with 3 weeks of catheter decompression
. Percutaneous pelvic drainage and external fixation instead of internal fixation

Correct Answer & Explanation

. Surgical repair of the bladder rupture concurrently with the anterior pelvic ring fixation

Explanation

Standard management for an isolated extraperitoneal bladder rupture is nonoperative treatment with Foley catheter drainage. However, an absolute indication for operative repair of an extraperitoneal bladder rupture is when the patient is concurrently undergoing open reduction and internal fixation of the anterior pelvic ring. Repairing the bladder reduces the risk of hardware contamination and deep pelvic infection by sealing off the source of urine leakage from the orthopedic surgical bed.

Question 4370

Topic: 2. Trauma

A 65-year-old female presents with atraumatic thigh pain and a subsequent radiograph showing a noncomminuted subtrochanteric femur fracture. To correctly diagnose an Atypical Femur Fracture (AFF) according to the 2013 American Society for Bone and Mineral Research (ASBMR) task force criteria, certain major criteria must be met. Which of the following is considered a major criterion for an AFF?

. Transverse or short oblique fracture line
. Bilateral prodromal pain in the groin or thigh
. Bilateral radiographic findings of incomplete cortical fissuring
. Delayed healing or nonunion
. Concurrent use of bisphosphonates for greater than 3 years

Correct Answer & Explanation

. Transverse or short oblique fracture line

Explanation

The 2013 ASBMR criteria for Atypical Femur Fractures dictate that at least four of five major criteria must be present. These are: 1) associated with minimal or no trauma; 2) fracture line originates at the lateral cortex and is transverse in orientation (may become short oblique as it progresses medially); 3) complete fractures extend through both cortices and may be associated with a medial spike; incomplete fractures involve only the lateral cortex; 4) noncomminuted or minimally comminuted; 5) localized periosteal or endosteal thickening of the lateral cortex (beaking or flaring) at the fracture site. Bilateral findings, prodromal pain, delayed healing, and bisphosphonate use are all MINOR criteria.

Question 4371

Topic: 2. Trauma

During retrograde intramedullary nailing of a supracondylar distal femur fracture (AO/OTA 33A), the fracture tends to fall into a characteristic deformity. To prevent the most common angular malalignment, a blocking (Poller) screw should be strategically placed. Which of the following is the characteristic deformity, and what is the primary deforming muscle force responsible?

. Apex anterior and valgus; Quadriceps mechanism
. Apex posterior and varus; Gastrocnemius and adductor magnus
. Apex anterior and varus; Hamstrings
. Apex posterior and valgus; Biceps femoris
. Translational shortening; Sartorius

Correct Answer & Explanation

. Apex anterior and valgus; Quadriceps mechanism

Explanation

Distal femur fractures typically fall into an apex posterior (extension) and varus deformity. The apex posterior angulation is caused by the pull of the gastrocnemius heads on the distal articular fragment. The varus angulation is primarily driven by the adductor magnus pulling the distal femur medially, while the unsupported lateral cortex collapses. To combat varus using blocking (Poller) screws, the screw should be placed on the concavity of the deformity (medial side of the distal fragment) to force the nail laterally and correctly align the mechanical axis.

Question 4372

Topic: 2. Trauma

You are assessing a 32-year-old male with a comminuted midshaft tibia fracture for suspected acute compartment syndrome. Clinical signs are equivocal, and you decide to obtain intra-compartmental pressure measurements. To obtain the highest and most accurate peak pressure representative of the zone of injury, where should the transducer needle be placed?

. In the deep posterior compartment, exactly at the fracture site
. In the anterior compartment, exactly at the fracture site
. In the anterior compartment, within 5 cm of the fracture site
. In the lateral compartment, 10 cm distal to the fracture site
. In the superficial posterior compartment, at the most proximal aspect of the tibia

Correct Answer & Explanation

. In the deep posterior compartment, exactly at the fracture site

Explanation

Intracompartmental pressures in the setting of acute compartment syndrome following a tibia fracture are not uniform throughout the compartment. Research has shown that the highest pressure is usually located in the anterior compartment, specifically within 5 cm of the fracture site. Measurements taken further away (e.g., >5 cm) will yield progressively lower and potentially falsely reassuring pressures. Inserting the needle directly into the fracture hematoma itself may yield inaccurate pressure readings.

Question 4373

Topic: 2. Trauma

A 28-year-old male involved in a high-speed motor vehicle collision sustains a severe closed traction injury to his right upper extremity. Radiographs reveal marked lateral displacement of the scapula with an intact acromioclavicular joint, characteristic of scapulothoracic dissociation. What concomitant injury represents the most significant determinant of long-term functional outcome for his right arm?

. Subclavian artery intimal tear
. Complete acromioclavicular joint disruption
. Clavicle diaphyseal fracture
. Complete brachial plexus avulsion
. Fracture of the coracoid process

Correct Answer & Explanation

. Subclavian artery intimal tear

Explanation

Scapulothoracic dissociation is a high-energy trauma characterized by complete disruption of the scapulothoracic articulation, essentially an internal amputation of the upper extremity. It involves massive soft tissue damage, subclavian/axillary vessel rupture, and brachial plexus injury. While vascular injuries are life-threatening and require emergent repair, the ultimate long-term functional outcome and limb viability are almost entirely dictated by the neurologic status. A complete brachial plexus avulsion is frequent and portends a devastating functional outcome, often resulting in an insensate, flail limb that may ultimately require early amputation.

Question 4374

Topic: 2. Trauma
A 28-year-old male sustains a vertically oriented, Pauwels type III femoral neck fracture. To minimize the risk of shear-induced displacement and varus collapse, which of the following internal fixation constructs is biomechanically superior?
. Three parallel cannulated screws in an inverted triangle
. A sliding hip screw with an anti-rotation screw
. Two parallel 7.3 mm cannulated screws
. Dynamic condylar screw
. Multiple smooth Steinmann pins

Correct Answer & Explanation

. A sliding hip screw with an anti-rotation screw

Explanation

A sliding hip screw (SHS) with a derotational screw provides a fixed-angle construct that is biomechanically superior to parallel cannulated screws in resisting the high vertical shear forces seen in Pauwels type III femoral neck fractures.

Question 4375

Topic: Lower Extremity Trauma

A 42-year-old male sustains a high-energy Schatzker type IV tibial plateau fracture with significant posteromedial articular depression. A posteromedial approach is planned. What is the primary internervous/intermuscular interval utilized in this approach?

. Between the medial head of the gastrocnemius and the pes anserinus
. Between the lateral head of the gastrocnemius and the soleus
. Between the semimembranosus and semitendinosus
. Between the tibialis posterior and flexor digitorum longus
. Between the popliteus and the soleus

Correct Answer & Explanation

. Between the medial head of the gastrocnemius and the pes anserinus

Explanation

The posteromedial approach to the tibial plateau utilizes the interval between the medial head of the gastrocnemius (tibial nerve) and the pes anserinus tendons (femoral/sciatic nerve branches), allowing direct access to the posteromedial articular fragment.

Question 4376

Topic: 2. Trauma

A 30-year-old male falls from a height of 20 feet. He is hemodynamically stable but has a severely comminuted, U-shaped sacral fracture with spinopelvic dissociation and bilateral lower extremity weakness. What is the classic plain radiographic finding associated with this injury?

. The "teardrop" sign on an AP view
. The "paradoxical inlet" view of the upper sacrum on a standard AP pelvis radiograph
. Widening of the pubic symphysis > 2.5 cm
. Superior migration of the entire intact pelvic ring
. A completely obliterated obturator foramen bilaterally

Correct Answer & Explanation

. The "teardrop" sign on an AP view

Explanation

In spinopelvic dissociation (U-type sacral fractures), the upper sacral segment often flexes forward due to the pull of gravity and the lack of pelvic continuity. This creates a "paradoxical inlet" appearance of the sacrum on a standard AP radiograph.

Question 4377

Topic: 2. Trauma
Which of the following types of displaced posterior pelvic disruptions must undergo anatomic reduction and internal fixation to ensure the best clinical outcome?
. Sacral fracture through the foramen
. Sacral fracture through the ala
. Sacroiliac joint dislocation
. Reverse fracture-dislocation of the sacroiliac joint through the ilium
. Iliac wing fracture

Correct Answer & Explanation

. Sacroiliac joint dislocation

Explanation

DISCUSSION: Although all of the above displaced injuries require reduction, the sacroiliac joint dislocation is a ligamentous injury. Without fixation, healing is unlikely and the result will be a painful dislocation. Both Holdsworth and Tile showed that the sacroiliac joint must be reduced anatomically and stabilized. The injuries through bone will unite fairly rapidly and, if reduced and stabilized with traction or external fixation, will generally result in an acceptable outcome unless modified by other associated problems such as neurologic injury. REFERENCES: Tile M: Fractures of the Pelvis and the Acetabulum. Baltimore, MD, Williams and Wilkins, 1995. Holdsworth FW: Dislocation and fracture dislocation of the pelvis. J Bone Joint Surg Br 1948;30:461-465. Henderson RC: The long-term results of nonoperatively treated major pelvic disruptions. J Orthop Trauma 1989;3:41-47.

Question 4378

Topic: 2. Trauma
Figure 5 shows the radiograph of a 10-year-old girl who reports chronic shoulder pain after her gymnastics classes. Examination reveals pain on internal and external rotation but no instability. What is the most likely diagnosis?
. Acromial fracture
. Humeral stress fracture
. Acromioclavicular joint separation
. Fracture of the surgical neck of the scapula
. Triceps avulsion fracture

Correct Answer & Explanation

. Humeral stress fracture

Explanation

DISCUSSION: The patient has a very wide humeral growth plate, indicating the presence of a proximal humeral stress fracture, an uncommon diagnosis in gymnasts. Gymnasts are prone to stress fractures of the scaphoid, distal radius, elbow, and clavicle. Proximal humeral stress fractures are more commonly seen in those participating in racket or throwing sports. Stress fractures can lead to growth arrest or inhibition, particularly in the distal radius. The radiograph shows normal findings for the acromion, acromioclavicular joint, scapula, and triceps origin. REFERENCES: Fallon KE, Fricker PA: Stress fracture of the clavicle in a young female gymnast. Br J Sports Med 2001;35:448-449. Sinha AK, Kaeding CC, Wadley GM: Upper extremity stress fractures in athletes: Clinical features of 44 cases. Clin J Sports Med 1999;9:199-202. Caine D, Howe W, Ross W, Bergman G: Does repetitive physical loading inhibit radial growth in female gymnasts? Clin J Sports Med 1997;7:302-308. Chan D, Aldridge MJ, Maffulli N, Davies AM: Chronic stress injuries of the elbow in young gymnasts. Br J Radiol 1991;64:1113-1118.

Question 4379

Topic: 2. Trauma
A 19-year-old woman fell onto her nondominant hand 6 weeks ago. Radiographs are shown in Figures 37a and 37b. A decision has been made to treat this fracture surgically. What is the best approach to treat this fracture?
. Percutaneous pinning of the fracture with Kirschner wires
. Open reduction and pinning with Kirschner wires
. Arthroscopic in situ compression screw fixation
. Reduction and compression screw fixation via a volar approach
. Reduction and compression screw fixation via a dorsal approach

Correct Answer & Explanation

. Reduction and compression screw fixation via a dorsal approach

Explanation

DISCUSSION: Displaced fractures of the scaphoid are best treated with compression screw fixation. Proximal third fractures (as in this patient) are optimally approached via a dorsal approach to ensure proper reduction and compression. Fractures of the scaphoid waist can be approached either by a volar or a dorsal approach. Kirschner wire fixation is limited to proximal pole fractures that are too small to accommodate the trailing head of a compression screw. REFERENCES: Retting ME, Raskin KB: Retrograde compression screw fixation of acute proximal pole fractures. J Hand Surg Am 1999;24:1206-1210. Filan SK, Herbert TJ: Herbert screw fixation of scaphoid fractures. J Bone Joint Surg Br 1996;78:519-529.

Question 4380

Topic: Lower Extremity Trauma
A 28-year-old man reports knee stiffness, swelling, and a constant ache that is worse with activity. Examination reveals an effusion, global tenderness, and warmth to the touch. Flexion is limited to 110 degrees. Figures 48a through 48d show sagittal T1-weighted, sagittal T2-weighted, axial T1-weighted fat-saturated gadolinium, and axial gradient echo MRI scans. Based on these findings, what is the most likely diagnosis?
. Infection
. Arthritis
. Synovial chondromatosis
. Pigmented villonodular synovitis (PVNS)
. Reactive synovitis

Correct Answer & Explanation

. Pigmented villonodular synovitis (PVNS)

Explanation

DISCUSSION: The MRI scans show multiple low-signal intensity lesions scattered throughout the knee, extending posteriorly inferior to the tibial plateau. The low-signal intensity on both the T1- and T2-weighted images, the modest vascularity noted on the gadolinium image, and the โ€œbloomingโ€ noted on the gradient echo image (ferrous-laden tissue) are all strongly suggestive of diffuse PVNS. Whereas synovial chondromatosis can present as diffuse masses in the knee, they present as nodule masses that have low T1- and high T2-weighted signal characteristics. REFERENCES: Resnick D (ed): Diagnosis of Bone and Joint Disorders. Philadelphia, PA, WB Saunders, 2002, pp 4241-4252. Sanders TG, Parsons TW: Radiographic imaging of musculoskeletal neoplasia. Cancer Control 2001;8:1-11.

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