Menu

2. Trauma MCQs

Practice Set 236 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 4701

Topic: 2. Trauma

A 28-year-old male sustains an ipsilateral midshaft femur fracture and middle-third tibia fracture (Floating Knee, Fraser Type IIa). He is hemodynamically stable. What is the generally accepted optimal sequence and method of fixation to minimize complications?

. External fixation of both bones acutely
. Intramedullary nailing of the tibia followed by plating of the femur
. Intramedullary nailing of the femur followed by intramedullary nailing of the tibia
. Plating of both the femur and the tibia
. Skeletal traction of the femur and intramedullary nailing of the tibia

Correct Answer & Explanation

. Intramedullary nailing of the femur followed by intramedullary nailing of the tibia

Explanation

In a stable patient with a floating knee, definitive fixation is preferred. The standard sequence is intramedullary nailing of the femur first, which stabilizes the limb and facilitates positioning and reduction for subsequent intramedullary nailing of the tibia.

Question 4702

Topic: Lower Extremity Trauma

A 42-year-old man sustains a highly comminuted Schatzker VI tibial plateau fracture. During surgical approach and reduction, excessive traction is placed on the lateral tissues. Postoperatively, the patient has an inability to extend his great toe and loss of sensation over the first web space. Which specific nerve branch is most likely injured?

. Deep peroneal nerve
. Superficial peroneal nerve
. Tibial nerve
. Sural nerve
. Saphenous nerve

Correct Answer & Explanation

. Deep peroneal nerve

Explanation

The deep peroneal nerve innervates the extensor hallucis longus (great toe extension) and provides sensation to the first dorsal web space. It is vulnerable to traction injury or compression during lateral approaches to the proximal tibia.

Question 4703

Topic: 2. Trauma

A 35-year-old male sustains a high-energy trauma resulting in an isolated coronal shear fracture of the lateral femoral condyle (Hoffa fracture). Which of the following internal fixation constructs provides the most biomechanically stable fixation?

. Anterior-to-posterior (AP) lag screws
. Posterior-to-anterior (PA) lag screws
. Medial-to-lateral lag screws
. Lateral-to-medial lag screws
. Isolated tension band wiring

Correct Answer & Explanation

. Posterior-to-anterior (PA) lag screws

Explanation

Biomechanical studies have demonstrated that posterior-to-anterior (PA) lag screws provide superior stability and higher load to failure compared to AP screws for Hoffa fractures. This is due to the screw trajectory being more perpendicular to the primary fracture plane.

Question 4704

Topic: 2. Trauma

A 45-year-old female undergoes tension band wiring for a transverse patella fracture. According to the principles of tension band fixation, dynamic loading of the knee will convert tensile forces into compressive forces at which of the following locations?

. Anterior cortex during knee extension
. Posterior articular surface during knee flexion
. Anterior cortex during knee flexion
. Posterior articular surface during knee extension
. Equally across both cortices during extension

Correct Answer & Explanation

. Posterior articular surface during knee flexion

Explanation

The tension band is applied to the anterior surface of the patella to counteract tensile forces. During knee flexion, dynamic loading converts these tensile forces into compressive forces across the posterior articular surface, enhancing fracture stability.

Question 4705

Topic: Lower Extremity Trauma

A 40-year-old man presents with a Schatzker IV tibial plateau fracture featuring a displaced posteromedial fragment. The surgeon plans an open reduction and internal fixation via a posteromedial approach. Which anatomic interval is classically utilized for 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 anterior and extensor hallucis longus
. Between the biceps femoris and the iliotibial band

Correct Answer & Explanation

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

Explanation

The posteromedial approach to the tibial plateau typically exploits the interval between the medial head of the gastrocnemius (retracted laterally/posteriorly) and the pes anserinus (retracted medially/anteriorly). This allows direct access to buttress posteromedial shear fragments.

Question 4706

Topic: 2. Trauma

A 25-year-old male undergoes intramedullary nailing of a closed tibial shaft fracture. Postoperatively, he develops severe leg pain. His blood pressure is 110/70 mmHg. Intracompartmental pressure in the anterior compartment is measured at 45 mmHg. What is the calculated delta pressure and the most appropriate next step?

. Delta pressure 65 mmHg; elevate leg and observe
. Delta pressure 25 mmHg; immediate four-compartment fasciotomy
. Delta pressure 45 mmHg; immediate two-compartment fasciotomy
. Delta pressure 25 mmHg; administer IV fluids and reassess in 2 hours
. Delta pressure 65 mmHg; remove the intramedullary nail

Correct Answer & Explanation

. Delta pressure 25 mmHg; immediate four-compartment fasciotomy

Explanation

Delta pressure is calculated as Diastolic Blood Pressure minus Intracompartmental Pressure (70 - 45 = 25 mmHg). A delta pressure of 30 mmHg or less is strongly indicative of acute compartment syndrome, necessitating emergent four-compartment fasciotomy.

Question 4707

Topic: 2. Trauma

A 60-year-old female is treated with a lateral locking plate for a highly comminuted extra-articular distal femur fracture. To optimize secondary bone healing via callus formation, the surgeon aims to decrease the construct stiffness. Which of the following technical modifications will best achieve this?

. Using stainless steel instead of titanium
. Placing screws in every hole near the fracture site
. Increasing the working length by omitting screws immediately adjacent to the fracture
. Decreasing the overall plate length
. Using bicortical locking screws in the diaphyseal segment instead of unicortical screws

Correct Answer & Explanation

. Increasing the working length by omitting screws immediately adjacent to the fracture

Explanation

Increasing the working length (the distance between the two closest screws on either side of the fracture) decreases construct stiffness, allowing appropriate micromotion for secondary bone healing. Filling holes near the fracture makes the construct too stiff, risking hypertrophic nonunion.

Question 4708

Topic: 2. Trauma
Examination of a 41-year-old man who was thrown from a motorcycle reveals that both legs appear externally rotated and there is bruising in the perineal area. He has a blood pressure of 80/40 mm Hg, a pulse rate of 140/min, a respiratory rate of 25/min, and he appears confused. Following administration of 4 L of saline solution and 2 units of packed red blood cells, he has a blood pressure of 80/40 mm Hg, a pulse rate of 160/min, and a respiratory rate of 25/min. The abdominal assessment for intraperitoneal blood is negative. An AP radiograph shows an anteroposterior compression injury with 7 cm of symphysis diastasis but no posterior displacement in the sacroiliac joints. What is the next most appropriate step in management?
. Stabilization of the pelvis through noninvasive methods
. Additional crystalloid solution replacement
. External fixation in the operating room
. Angiographic embolization
. Continuing observation of vital signs

Correct Answer & Explanation

. Stabilization of the pelvis through noninvasive methods

Explanation

Because the patient has sustained a major high-energy injury to the pelvic ring, it can be assumed that there is serious bleeding or hemodynamic instability related to a pelvic vascular injury. The goal of intervention at this time is to assist in the resuscitative effort and to stop the bleeding. All attempts at providing fluid and blood are important, but without cessation of the bleeding, continued loss occurs and significant problems can ensue such as coagulopathy and multiple organ failure. Noninvasive methods of stabilizing the pelvic ring should be used to stop the bleeding. These methods include wrapping a sheet around the pelvis or using commercially available belts, vacuum beanbags, or pneumatic shock garments. This will provide time to prepare for arteriography and/or external fixation. The next step is debatable, but in view of negative findings for intra-abdominal blood, arteriography performed with the pelvis reduced using noninvasive methods would be ideal.

Question 4709

Topic: 2. Trauma

A 40-year-old man fell off of a ladder at work sustaining the injury shown in Figures A and B. On examination, his skin is intact, but the pulses in his foot are absent. Following closed reduction and splinting, what would be the next best step?

. Re-evaluate pulses
. Vascular surgery consultation
. CT angiogram
. Formal angiogram
. Surgical exploration and stabilizationCorrent answer: 1This patient sustained a posterior ankle fracture/dislocation. After closed reduction and splinting, the next best step should be to re-evaluate pulses.With any dislocation, an immediate closed reduction should be performed. Though the initial vascular examination was abnormal in this case, the dislocation is contributing to this finding. This unique ankle fracture is known as the hyperplantarflexion variant. It is composed of a posterior tibial lip fracture with posterolateral and posteromedial fracture fragments separated by a vertical fracture line.Gardner et al. review the hyperplantarflexion variant and found that the fracture of the posteromedial tibial rim was the main feature of this injury which is sustained by a hyperflexion mechanism. They also reported that posterior malleolus fractures are present in a majority of these injuries as well.On MRI they determined that the deltoid and posterior tibiofibular ligaments were intact in all cases. They conclude, when treating these fractures with ORIF of the posteromedial and posterior fragments with antiglide fixation, excellent results were obtained.Hinds et al. name the unique double cortical density at the inferomedial tibial metaphysis the "spur sign." They found the spur sign to be present in 79% of variant ankle fracture cases. They found the positive predictive value and negative predictive value to be 100% and 99%, respectively when this sign is present.Figures A and B demonstrate the hyperplantarflexion variant ankle fracture. Illustration A demonstrates the spur sign, as indicated by the red arrow.Incorrect Answers:

Correct Answer & Explanation

. Re-evaluate pulses

Explanation

OrthoCash 2020

Question 4710

Topic: Lower Extremity Trauma

making a cut toward the ball. He felt a pop and his leg gave way. During physical examination, as the knee is moved from full extension into flexion with an internal rotation and valgus force, you notice a “clunk” within the knee. What is the most likely biomechanical basis for the “clunk”?

. In extension with internal rotation/valgus force, the medial tibial plateau is subluxated; with flexion, the medial tibial plateau reduces
. In extension with internal rotation/valgus force, the medial tibial plateau is reduced; with flexion, the medial tibial plateau subluxates
. In extension with internal rotation/valgus force, the lateral tibial plateau is reduced; with flexion, the lateral plateau subluxates
. In extension with internal rotation/valgus force, the lateral tibial plateau is subluxated; with flexion, the lateral plateau reduces

Correct Answer & Explanation

. In extension with internal rotation/valgus force, the medial tibial plateau is subluxated; with flexion, the medial tibial plateau reduces

Explanation

DISCUSSIONThis patient sustained an isolated anterior cruciate ligament (ACL) injury based upon the mechanism described and examination findings. The finding that produces the “clunk” is the pivot-shift maneuver, which is positive in a knee with an incompetent ACL. With an ACL-deficient knee in full extension and internal rotation, the lateral tibial plateau subluxates anteriorly. As the knee is flexed, the lateral tibial plateau slides posteriorly into a reduced position, causing an audible clunk. Response 4 correctly describes the pathomechanics that result in the audible clunk heard during the pivot-shift maneuver. Responses 1 and 2 are incorrect because they describe the medial tibial plateau, which is not part of the pathomechanics of the pivot shift. Response 3 is incorrect because in extension, the lateral tibial plateau is subluxated, not reduced.

Question 4711

Topic: 2. Trauma
He is a nonsmoker with medical comorbidities of hypertension and hypercholesterolemia that is well controlled with medicine and diet. Capillary refill and sensation are intact distally and the patient is able to move his toes with mild discomfort. Serosanguinous fracture blisters are present laterally, and the foot is swollen and red. What is the most appropriate management?
. Short leg cast for 6 weeks
. Splinting with early range of motion at 3 weeks
. Immediate open reduction and internal fixation through a medial approach
. Delayed open reduction and internal fixation
. Fusion

Correct Answer & Explanation

. Delayed open reduction and internal fixation

Explanation

Whereas a patient age of older than 50 years used to be a contraindication for open reduction and internal fixation of displaced intra-articular calcaneal fractures, new data suggest that the presence of associated medical comorbidities that affect wound healing such as smoking, diabetes mellitus, and peripheral vascular disease are more relevant to postoperative functional outcome. Surgical treatment of Sanders II and III displaced intra-articular calcaneal fractures with initial Bohler angles of > 15 degrees results in better outcomes as compared to nonsurgical management. Indications for primary fusion might include Sanders IV fractures in which articular congruity or Bohler angles cannot be restored. Given the condition of the soft tissues at presentation, delayed fixation is recommended.

Question 4712

Topic: 2. Trauma
A 10-year-old girl has a midshaft both-bone forearm fracture. After attempted closed reduction, alignment consists of bayonet apposition, 10° of malrotation, and 8° of volar angulation. Management should now consist of
. open reduction and plating of the radius to restore the radial bow.
. open reduction of the ulna and plating.
. closed reduction and nailing of the bones with flexible nails.
. a long arm cast and follow-up of alignment in 5 days.
. a short arm cast for 6 weeks.

Correct Answer & Explanation

. a long arm cast and follow-up of alignment in 5 days.

Explanation

Acceptable alignment in both-bone forearm fractures is related to age and location. In children younger than age 9 years, angulations of 15° and malrotation of 45° are acceptable. In children older than age 9 years, acceptable alignment is 10° of angulation and 30° of malrotation. Bayonet apposition is acceptable provided that the angular and rotational reductions are held within these guidelines. A long arm cast provides better control of deforming forces than a short arm cast.

Question 4713

Topic: 2. Trauma
A 35-year-old male is brought to the trauma bay after a high-speed motorcycle collision. He has a mechanically unstable anterior-posterior compression (APC) type III pelvic ring injury and remains hemodynamically unstable despite initial fluid resuscitation. What is the most common anatomical source of his massive pelvic hemorrhage?
. Superior gluteal artery
. Obturator artery
. Presacral venous plexus
. Internal pudendal artery
. External iliac vein

Correct Answer & Explanation

. Presacral venous plexus

Explanation

While arterial bleeding (e.g., from the internal pudendal, obturator, or superior gluteal arteries) can occur and be life-threatening, the vast majority (up to 80-90%) of pelvic hemorrhage in high-energy ring disruptions arises from the disrupted presacral venous plexus and bleeding from fractured cancellous bone surfaces.

Question 4714

Topic: 2. Trauma

A 45-year-old male sustains a Schatzker IV tibial plateau fracture. The surgeon elects to use a posteromedial surgical approach. Which of the following represents the correct intermuscular interval for this approach?

. Between the medial head of the gastrocnemius and the popliteus
. Between the pes anserinus and the medial head of the gastrocnemius
. Between the semimembranosus and the semitendinosus
. Between the soleus and the tibialis posterior
. Between the sartorius and the gracilis

Correct Answer & Explanation

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

Explanation

The posteromedial approach to the proximal tibia is frequently used to buttress medial plateau fractures (Schatzker IV). The standard superficial internervous/intermuscular interval is between the pes anserinus tendons (anteriorly) and the medial head of the gastrocnemius (posteriorly). The gastrocnemius is retracted posteriorly and laterally to protect the popliteal neurovascular bundle.

Question 4715

Topic: 2. Trauma
A 28-year-old female sustains a Pauwels type III (vertical) femoral neck fracture. Which of the following internal fixation constructs provides the greatest biomechanical stability against vertical shear forces?
. Three parallel cancellous screws in an inverted triangle configuration
. Three parallel cancellous screws in an upright triangle configuration
. A sliding hip screw combined with a derotation screw
. A standard cephalomedullary nail with a single lag screw
. Two parallel fully threaded cortical screws

Correct Answer & Explanation

. A sliding hip screw combined with a derotation screw

Explanation

Vertical femoral neck fractures (Pauwels III, angle >50 degrees) experience very high shear forces, leading to high rates of varus collapse and nonunion when treated with standard parallel cancellous screws. Biomechanical studies have consistently demonstrated that a fixed-angle construct, specifically a sliding hip screw supplemented with a derotation screw, provides significantly superior resistance to vertical shear forces.

Question 4716

Topic: 2. Trauma

A 25-year-old male sustains a closed comminuted tibial shaft fracture. The orthopedic surgeon is evaluating the patient for acute compartment syndrome using continuous intra-compartmental pressure monitoring. Which of the following correctly defines the 'delta P' threshold commonly used to indicate the absolute need for a fasciotomy?

. Mean arterial pressure minus compartment pressure < 30 mmHg
. Systolic blood pressure minus compartment pressure < 30 mmHg
. Diastolic blood pressure minus compartment pressure < 30 mmHg
. Systolic blood pressure minus diastolic blood pressure < 30 mmHg
. Compartment pressure minus central venous pressure < 30 mmHg

Correct Answer & Explanation

. Diastolic blood pressure minus compartment pressure < 30 mmHg

Explanation

Acute compartment syndrome is defined by inadequate tissue perfusion due to elevated intracompartmental pressure. The 'delta P' is calculated as the diastolic blood pressure minus the compartment pressure. A delta P of less than 30 mmHg is considered the critical threshold for tissue ischemia and is an absolute indication for emergency fasciotomy.

Question 4717

Topic: 2. Trauma

A 45-year-old female sustains a high-energy distal femur fracture following a motor vehicle accident. The CT scan reveals a 'Hoffa' fragment. Which of the following best describes this specific fracture pattern?

. A sagittal plane fracture of the medial femoral condyle
. An intra-articular coronal plane fracture of the lateral femoral condyle
. A transverse metaphyseal fracture of the distal femur
. An avulsion fracture of the medial collateral ligament origin
. An osteochondral sheer defect of the femoral trochlea

Correct Answer & Explanation

. A sagittal plane fracture of the medial femoral condyle

Explanation

A Hoffa fracture (AO/OTA 33-B3) is defined as an intra-articular coronal plane fracture of the distal femoral condyle. It most commonly involves the lateral condyle. Because it lies in the coronal plane, it is often radiographically occult on standard AP radiographs and is best visualized on a true lateral radiograph or CT scan. It requires AP or PA interfragmentary screw fixation for stable reconstruction.

Question 4718

Topic: 2. Trauma
A 28-year-old male sustains a high-energy Pauwels type III vertical femoral neck fracture. Which of the following fixation constructs provides the greatest biomechanical stability for this fracture pattern?
. Three parallel cancellous screws
. Sliding hip screw with a derotational screw
. Bipolar hemiarthroplasty
. Total hip arthroplasty
. Cephalomedullary nail

Correct Answer & Explanation

. Sliding hip screw with a derotational screw

Explanation

Pauwels type III fractures are highly unstable due to significant vertical shear forces. A sliding hip screw with a derotational cancellous screw provides superior biomechanical stability against vertical shear compared to three parallel screws.

Question 4719

Topic: 2. Trauma
A 28-year-old male sustains a vertically oriented (Pauwels III) femoral neck fracture. What is the primary biomechanical advantage of utilizing a sliding hip screw with an anti-rotation screw compared to three parallel cannulated screws for this specific fracture pattern?
. Prevention of varus collapse by resisting high vertical shear forces
. Greater control of anterior-posterior translational forces
. Decreased risk of osteonecrosis of the femoral head
. Elimination of the need for an open capsulotomy
. Preservation of the lateral epiphyseal vascular supply

Correct Answer & Explanation

. Prevention of varus collapse by resisting high vertical shear forces

Explanation

Pauwels III fractures have a high vertical shear angle that predisposes the fracture to varus collapse. A fixed-angle length-stable device, such as a sliding hip screw, resists these massive shear forces significantly better than parallel cannulated screws.

Question 4720

Topic: 2. Trauma
A 28-year-old male sustains a vertically oriented, Pauwels type III femoral neck fracture. When treating this injury with an inverted triangle configuration of cancellous screws, what biomechanical disadvantage makes this fixation prone to failure?
. Inadequate resistance to axial compression forces
. Increased risk of implant cut-out in dense young bone
. Poor resistance to vertical shear forces
. Excessive rotational instability at the fracture site
. High incidence of avascular necrosis due to reaming

Correct Answer & Explanation

. Poor resistance to vertical shear forces

Explanation

Pauwels type III fractures are highly vertical and experience significant shear forces rather than compressive forces. Standard cancellous screws offer poor resistance to these vertical shear forces, often necessitating fixed-angle devices like a sliding hip screw or cephalomedullary nail.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page