Menu

2. Trauma MCQs

Practice Set 251 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 5001

Topic: 2. Trauma

When evaluating the adequacy of fixation for an intertrochanteric femur fracture treated with a sliding hip screw (SHS), the Tip-Apex Distance (TAD) is measured on postoperative radiographs. Maintaining a TAD of less than 25 mm primarily decreases the risk of which complication?

. Fracture nonunion
. Avascular necrosis of the femoral head
. Lag screw cut-out
. Peri-implant femoral shaft fracture
. Deep surgical site infection

Correct Answer & Explanation

. Lag screw cut-out

Explanation

Baumgaertner et al. demonstrated that a Tip-Apex Distance (TAD) greater than 25 mm is the strongest predictive factor for lag screw cut-out in the treatment of intertrochanteric fractures. A TAD < 25 mm is universally recommended.

Question 5002

Topic: 2. Trauma
A 28-year-old male sustains a vertical shear femoral neck fracture (Pauwels type III). What is the biomechanical rationale for using a sliding hip screw (SHS) with a derotation screw rather than multiple parallel cancellous screws?
. It prevents avascular necrosis by preserving capsular vessels.
. It provides superior resistance to vertical shear forces.
. It allows for dynamic dynamization of the femoral shaft.
. It avoids the need for an open reduction.
. It requires less cortical bone removal.

Correct Answer & Explanation

. It provides superior resistance to vertical shear forces.

Explanation

Pauwels III fractures (angle > 50 degrees) are highly unstable due to significant vertical shear forces. A fixed-angle construct like a sliding hip screw (SHS) with a derotation screw provides far greater biomechanical stability against shear forces than multiple parallel cancellous screws, leading to lower failure rates in vertical fracture patterns.

Question 5003

Topic: 2. Trauma

During intramedullary nailing of a closed, isolated subtrochanteric femur fracture in a 30-year-old male, what is the typical deformity of the proximal fragment induced by the surrounding musculature?

. Flexed, abducted, and internally rotated
. Flexed, adducted, and externally rotated
. Extended, abducted, and externally rotated
. Flexed, abducted, and externally rotated
. Extended, adducted, and internally rotated

Correct Answer & Explanation

. Flexed, abducted, and externally rotated

Explanation

In subtrochanteric fractures, the proximal fragment is typically flexed (by the iliopsoas), abducted (by the gluteus medius and minimus), and externally rotated (by the short external rotators). Recognizing this deforming force is crucial for achieving accurate reduction prior to nail passage.

Question 5004

Topic: 2. Trauma

A 22-year-old male sustains a posterior hip dislocation and a posterior wall acetabular fracture. The hip is reduced in the emergency department. Which of the following CT findings is an absolute indication for operative fixation of the posterior wall?

. Involvement of > 50% of the posterior wall articular surface
. Involvement of 10% of the posterior wall articular surface
. Associated anterior column non-displaced fracture
. Associated superior pubic ramus fracture
. Absence of marginal impaction

Correct Answer & Explanation

. Involvement of > 50% of the posterior wall articular surface

Explanation

A posterior wall fracture involving > 50% of the articular surface renders the hip uniformly unstable and is an absolute indication for open reduction and internal fixation. Fractures < 20% are typically stable, while those between 20% and 50% often require dynamic stress testing to determine stability.

Question 5005

Topic: 2. Trauma

A 70-year-old female sustains a periprosthetic distal femur fracture (Su Type 3) proximal to a posterior-stabilized (PS) total knee arthroplasty. The femoral component is well-fixed, but the fracture is highly comminuted with a very short distal segment. What is the most appropriate fixation method?

. Hinged knee brace and restricted weight-bearing
. Retrograde intramedullary nail through the intercondylar notch
. Lateral locked plating spanning the fracture
. Immediate distal femoral replacement
. Revision to a stemmed constrained condylar knee

Correct Answer & Explanation

. Lateral locked plating spanning the fracture

Explanation

Su Type 3 fractures occur very distal to the superior pole of the femoral component. The presence of a posterior-stabilized (PS) box typically precludes the use of a retrograde intramedullary nail. For a well-fixed component with comminution, lateral locked plating (often using minimally invasive techniques) is the standard of care to achieve stable fixation.

Question 5006

Topic: 2. Trauma

When comparing a cephalomedullary nail to a sliding hip screw (SHS) for the treatment of an unstable reverse oblique intertrochanteric fracture (OTA 31-A3), what is the primary biomechanical advantage of the intramedullary nail?

. It allows greater fracture impaction along the femoral neck.
. It provides a shorter lever arm and transfers stress to the femoral shaft.
. It completely preserves the lateral femoral wall from surgical trauma.
. It relies purely on the lag screw for rotational control.
. It inherently prevents valgus collapse of the proximal fragment.

Correct Answer & Explanation

. It provides a shorter lever arm and transfers stress to the femoral shaft.

Explanation

Reverse oblique fractures (OTA 31-A3) disrupt the lateral wall and have a tendency for medial displacement of the femoral shaft. Intramedullary devices (cephalomedullary nails) are biomechanically superior because they reside closer to the mechanical axis, providing a shorter lever arm for deforming forces and acting as an intramedullary buttress against medial displacement.

Question 5007

Topic: 2. Trauma

A 25-year-old male with an isolated, displaced transverse patella fracture undergoes tension band wiring (TBW). For the tension band construct to function optimally, where must the wires be placed relative to the patella?

. On the articular surface to compress the cartilage
. On the anterior surface (tension side) of the patella
. Through the exact central longitudinal axis of the patella
. Circumferentially around the equator of the patella
. In a figure-of-8 pattern purely within the retinaculum

Correct Answer & Explanation

. On the anterior surface (tension side) of the patella

Explanation

The tension band principle relies on placing the implant on the tension side of the bone. In the patella, flexion creates tension anteriorly and compression posteriorly (articular side). Wires placed on the anterior surface convert the tensile forces generated during knee flexion into compressive forces at the articular surface.

Question 5008

Topic: 2. Trauma

A 50-year-old female undergoes reamed intramedullary nailing for a closed tibial shaft fracture. On postoperative day 1, she complains of severe, out-of-proportion leg pain, paresthesias in the first web space of the foot, and severe pain with passive toe flexion. Which fascial compartment of the leg is most likely experiencing elevated pressure?

. Anterior compartment
. Lateral compartment
. Superficial posterior compartment
. Deep posterior compartment
. Tibialis posterior compartment

Correct Answer & Explanation

. Anterior compartment

Explanation

The patient's symptoms localize to the anterior compartment, which contains the deep peroneal nerve (sensation to the 1st web space) and the extensor hallucis longus and extensor digitorum longus (pain with passive toe flexion). The anterior compartment is the most commonly involved compartment in acute compartment syndrome of the leg.

Question 5009

Topic: Pelvic & Acetabular Trauma

A 45-year-old male sustains a posterior dislocation of the right hip. Closed reduction is performed urgently in the emergency department. Post-reduction CT scan reveals a concentrically reduced hip, but shows a 4 mm intra-articular osteochondral fragment lodged within the weight-bearing dome of the acetabulum. What is the most appropriate next step in management?

. Skeletal traction for 6 weeks
. Operative intervention for fragment removal and joint debridement
. Immediate weight-bearing as tolerated
. MRI of the hip to assess the labrum before deciding on surgery
. Repeat closed reduction in the operating room

Correct Answer & Explanation

. Operative intervention for fragment removal and joint debridement

Explanation

A retained intra-articular fragment within the joint space, especially in the weight-bearing zone, will rapidly lead to third-body wear, cartilage destruction, and post-traumatic arthritis. It is an absolute indication for operative intervention (via arthroscopy, arthrotomy, or surgical dislocation) for removal.

Question 5010

Topic: 2. Trauma

In the management of a 'floating knee' injury (ipsilateral diaphyseal fractures of the femur and tibia) in a hemodynamically stable polytrauma patient, which sequence of operative fixation is generally recommended?

. Tibia first, followed by the femur
. Femur first, followed by the tibia
. Simultaneous fixation using a single midline incision
. External fixation of the tibia, followed by intramedullary nailing of the femur
. Plating of the fibula first, followed by intramedullary nailing of the femur

Correct Answer & Explanation

. Femur first, followed by the tibia

Explanation

The general consensus for a floating knee is to stabilize the femur first. This converts a complex, multidirectional instability into a simpler scenario, allows easier manipulation and positioning of the leg for subsequent tibial nailing, and addresses the larger source of bleeding and potential fat emboli sooner.

Question 5011

Topic: 2. Trauma

A 55-year-old male sustains a Schatzker II (split-depression) lateral tibial plateau fracture. Which of the following describes the most mechanically sound surgical sequence for restoring joint congruity and stability during open reduction and internal fixation?

. Plate application -> elevation of joint -> bone grafting -> lag screw
. Elevation of joint -> bone grafting -> lag screw -> plate application
. Bone grafting -> plate application -> elevation of joint
. Lag screw -> plate application -> elevation of joint
. Plate application -> lag screw -> elevation of joint -> bone grafting

Correct Answer & Explanation

. Elevation of joint -> bone grafting -> lag screw -> plate application

Explanation

The standard surgical sequence for a Schatzker II fracture is: 1) open the lateral split to access the depression, 2) elevate the depressed articular segment to restore joint congruity, 3) pack the metaphyseal void with bone graft/substitute to support the elevation, 4) compress the lateral split with lag screws, and 5) apply a lateral buttress plate.

Question 5012

Topic: 2. Trauma

A 35-year-old female presents with a highly comminuted patella fracture. Operative fixation with an anterior locking plate and screws is chosen over traditional tension band wiring. Which of the following is an advantage of anterior plating for highly comminuted patella fractures?

. It requires significantly less soft tissue dissection.
. It relies entirely on the dynamic tension band principle.
. It provides fixed-angle rigid fixation independent of anterior cortical support, allowing early range of motion.
. It guarantees a lower rate of symptomatic hardware requiring removal.
. It is biomechanically superior to tension band wiring in simple transverse two-part fractures.

Correct Answer & Explanation

. It provides fixed-angle rigid fixation independent of anterior cortical support, allowing early range of motion.

Explanation

In highly comminuted patella fractures, the anterior cortex is often deficient, making the tension band principle impossible to achieve (as it requires anterior cortical apposition to convert tension to compression). Anterior locking plates provide a rigid, fixed-angle construct that bridges the comminution, allowing for stable fixation and early range of motion even without intact anterior bone.

Question 5013

Topic: 2. Trauma
A 74-year-old female sustains a distal femur fracture above a posterior-stabilized (PS) total knee arthroplasty. Radiographs reveal a comminuted fracture 5 cm above the anterior flange, and the femoral component remains well-fixed. Which of the following statements regarding fixation is true?
. Retrograde intramedullary nailing is strictly contraindicated due to the posterior-stabilized box.
. A lateral locking plate provides superior biomechanical stability compared to a retrograde intramedullary nail for all distal femur fractures.
. Retrograde nailing may be performed through the intercondylar notch if the specific PS box design permits.
. Distal femoral replacement is indicated for all periprosthetic fractures above a posterior-stabilized knee.
. Dual plating is mandatory to prevent varus collapse in osteoporotic bone.

Correct Answer & Explanation

. Retrograde nailing may be performed through the intercondylar notch if the specific PS box design permits.

Explanation

In Lewis-Rorabeck Type II fractures (well-fixed component), fixation is indicated. Retrograde intramedullary nailing (RIMN) is possible through many PS boxes if the intercondylar notch of the implant accommodates the nail diameter. It is not strictly contraindicated if the specific implant design allows. Distal femoral replacement is reserved for loose components (Type III) or unfixable bone.

Question 5014

Topic: 2. Trauma

A 45-year-old male is involved in a high-speed motor vehicle collision. An AP pelvis radiograph demonstrates an acetabular fracture with a pathognomonic 'spur sign'. Which of the following Letournel fracture patterns is most likely present?

. Transverse fracture
. T-type fracture
. Anterior column posterior hemitransverse fracture
. Both-column fracture
. Posterior wall fracture

Correct Answer & Explanation

. Both-column fracture

Explanation

The 'spur sign' is pathognomonic for a both-column fracture of the acetabulum. It represents the intact posterior ilium that remains attached to the axial skeleton, projecting posterior and superior to the displaced articular segment, best seen on the obturator oblique radiograph.

Question 5015

Topic: 2. Trauma

In displaced intracapsular femoral neck fractures, osteonecrosis of the femoral head is a major concern. Which of the following vessels provides the primary blood supply to the weight-bearing dome of the femoral head in an adult?

. Artery of the ligamentum teres
. Inferior gluteal artery
. Lateral femoral circumflex artery
. Medial femoral circumflex artery
. First perforating branch of the profunda femoris

Correct Answer & Explanation

. Medial femoral circumflex artery

Explanation

The medial femoral circumflex artery (MFCA) is the predominant blood supply to the femoral head in adults. Specifically, its lateral epiphyseal artery branch supplies the weight-bearing superolateral aspect of the head. It is at high risk of disruption in displaced femoral neck fractures.

Question 5016

Topic: 2. Trauma

A 40-year-old male sustains a subtrochanteric femur fracture. During closed reduction, the proximal fragment is noted to be flexed, abducted, and externally rotated. Which muscle is primarily responsible for the flexion deformity of the proximal fragment?

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

Correct Answer & Explanation

. Iliopsoas

Explanation

In subtrochanteric fractures, the proximal fragment is notoriously difficult to control. It is flexed by the iliopsoas (attaching to the lesser trochanter), abducted by the gluteus medius and minimus (greater trochanter), and externally rotated by the short external rotators.

Question 5017

Topic: 2. Trauma

A 32-year-old female sustains a coronal plane fracture of the lateral femoral condyle (Hoffa fracture) extending into the intercondylar notch. To optimize biomechanical stability, in which direction should the lag screws ideally be directed during open reduction and internal fixation?

. Lateral to Medial
. Medial to Lateral
. Anterior to Posterior
. Posterior to Anterior
. Inferior to Superior

Correct Answer & Explanation

. Posterior to Anterior

Explanation

Hoffa fractures are coronal plane fractures of the distal femoral condyles. Biomechanical studies have demonstrated that posterior-to-anterior (PA) directed lag screws provide significantly stronger fixation and greater resistance to shear forces compared to anterior-to-posterior (AP) directed screws.

Question 5018

Topic: 2. Trauma

A 65-year-old osteoporotic female falls from standing and sustains a lateral compression type 1 (LC-1) pelvic ring injury, consisting of a unilateral superior and inferior pubic ramus fracture with an ipsilateral sacral ala impaction fracture. She is hemodynamically stable but has severe pain with mobilization. What is the currently accepted indication for operative fixation of her pelvic ring?

. All LC-1 fractures require surgical fixation.
. Failure to mobilize due to intractable pain despite optimal non-operative management.
. Presence of an ipsilateral sacral ala fracture regardless of displacement.
. More than 5 mm of displacement of the pubic rami.
. Involvement of the S2 foramina.

Correct Answer & Explanation

. Failure to mobilize due to intractable pain despite optimal non-operative management.

Explanation

Most LC-1 fractures are mechanically stable and treated non-operatively with weight-bearing as tolerated. However, operative fixation (e.g., percutaneous pelvic fixation) is indicated in patients who fail non-operative management, specifically those who cannot mobilize due to intractable mechanical pain, to prevent complications of immobility.

Question 5019

Topic: 2. Trauma

A 45-year-old male undergoes open reduction and internal fixation of a displaced transverse patella fracture using an anterior tension band wiring construct. The principle of the tension band in this application relies on which of the following biomechanical conversions?

. Converting shear forces into distraction forces during extension
. Converting tension forces on the anterior cortex into compression forces at the articular surface during knee flexion
. Converting compression forces on the anterior cortex into tension forces at the articular surface during knee flexion
. Neutralizing torsional forces applied by the quadriceps tendon
. Providing absolute stability through static compression alone

Correct Answer & Explanation

. Converting tension forces on the anterior cortex into compression forces at the articular surface during knee flexion

Explanation

The tension band principle relies on applying a tension band (wire) on the tension side of a bone. In the patella, the anterior surface experiences tension during knee flexion. The anterior wire converts these anterior distraction/tension forces into dynamic compression forces at the articular surface, promoting stability and primary bone healing.

Question 5020

Topic: Lower Extremity Trauma

A 42-year-old skier sustains a high-energy varus injury to the knee, resulting in a displaced medial tibial plateau fracture (Schatzker IV). Which of the following structures is at highest risk of iatrogenic injury during a standard posteromedial surgical approach to the proximal tibia?

. Common peroneal nerve
. Anterior tibial artery
. Saphenous nerve
. Popliteal artery
. Sural nerve

Correct Answer & Explanation

. Saphenous nerve

Explanation

The posteromedial approach to the tibia utilizes the interval between the medial gastrocnemius (retracted posteriorly/laterally) and the pes anserinus (retracted anteriorly). The saphenous nerve and great saphenous vein run superficially in this region and are at highest risk of iatrogenic injury during the superficial dissection.

Test Yourself

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

On this Page