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2. Trauma MCQs

Practice Set 440 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 8781

Topic: 2. Trauma
A 15-year-old male basketball player lands forcefully and avulses his tibial tubercle (Ogden Type III fracture) with intra-articular extension. He undergoes surgical fixation. Which complication is most uniquely concerning in the immediate post-injury period for this specific fracture pattern?
. Popliteal artery occlusion
. Patella baja
. Genu recurvatum
. Compartment syndrome of the leg
. Premature physeal closure with angular deformity

Correct Answer & Explanation

. Compartment syndrome of the leg

Explanation

Tibial tubercle avulsion fractures carry a high risk of anterior compartment syndrome due to bleeding from the anterior tibial recurrent artery, which frequently tears during the injury.

Question 8782

Topic: 2. Trauma

A 32-year-old male falls from a height. Radiographs and CT scan (Figure 2) show an acetabular fracture involving both the anterior and posterior columns. The spur sign is present on the obturator oblique radiograph. Which fracture pattern is this?

. Transverse fracture
. T-type fracture
. Associated both-column fracture
. Anterior column posterior hemitransverse fracture
. Posterior column fracture

Correct Answer & Explanation

. Associated both-column fracture

Explanation

The spur sign is pathognomonic for an associated both-column fracture of the acetabulum. It represents the intact ilium attached to the axial skeleton protruding posteriorly to the displaced articular segment.

Question 8783

Topic: 2. Trauma

In the biomechanical analysis of the hip joint during single-leg stance, if the abductor lever arm is shortened (e.g., due to severe medialization of the femoral shaft or trochanteric nonunion), how does this affect the joint reaction force?

. It decreases the joint reaction force
. It does not alter the joint reaction force
. It increases the joint reaction force by requiring greater abductor muscle force
. It decreases the body weight lever arm
. It shifts the center of gravity laterally

Correct Answer & Explanation

. It increases the joint reaction force by requiring greater abductor muscle force

Explanation

The joint reaction force is heavily influenced by the abductor muscle force. If the abductor lever arm is shortened, the abductors must generate significantly more force to maintain a level pelvis against the body weight moment, thereby greatly increasing the joint reaction force.

Question 8784

Topic: Pelvic & Acetabular Trauma

A 24-year-old female with residual dysplasia of the hip presents with groin pain.

Radiographs demonstrate a closed triradiate cartilage, a center-edge (CE) angle of 12 degrees, and an anteriorly deficient acetabulum. She is scheduled for a Bernese periacetabular osteotomy (PAO). Which of the following is the primary advantage of the PAO over a standard Salter osteotomy in this patient?

. It hinges on the pubic symphysis to maintain pelvic volume
. It preserves the posterior column, maintaining immediate pelvic ring stability
. It relies on an open triradiate cartilage to achieve correction
. It is performed strictly through a minimally invasive posterior approach
. It inherently lengthens the operated limb by at least 2 cm

Correct Answer & Explanation

. It preserves the posterior column, maintaining immediate pelvic ring stability

Explanation

The Bernese periacetabular osteotomy (PAO) is indicated for skeletally mature hips and preserves the posterior column of the hemipelvis. This structural preservation allows for immediate postoperative pelvic stability and permits extensive, multi-planar correction of the acetabulum.

Question 8785

Topic: 2. Trauma

A 78-year-old female sustains a highly unstable intertrochanteric femur fracture with subtrochanteric extension and loss of the posteromedial cortex. She is treated with a cephalomedullary nail. Which of the following technical factors is most critical in minimizing the risk of lag screw cut-out?

. Placing the lag screw in the superior-anterior quadrant of the femoral head
. Achieving a tip-apex distance (TAD) of less than 25 mm
. Reaming the femoral canal at least 2 mm larger than the nail diameter
. Utilizing a long nail instead of a short nail
. Routinely utilizing a supplementary trochanteric stabilizing plate

Correct Answer & Explanation

. Achieving a tip-apex distance (TAD) of less than 25 mm

Explanation

The tip-apex distance (TAD), described by Baumgaertner, is the most highly predictive radiographic factor for lag screw cut-out in the fixation of intertrochanteric fractures. A TAD of less than 25 mm ensures central and deep placement of the lag screw within the femoral head.

Question 8786

Topic: 2. Trauma

Figure 13 shows an AP radiograph of an 80-year-old female who sustained a mechanical fall. She has a reverse obliquity intertrochanteric fracture. Which device provides the most biomechanically stable fixation for this specific fracture pattern?

. Dynamic hip screw (DHS)
. Multiple cannulated screws
. Proximal femoral locking plate
. Long cephalomedullary nail
. Hemiarthroplasty

Correct Answer & Explanation

. Long cephalomedullary nail

Explanation

Reverse obliquity and subtrochanteric extension patterns are inherently unstable because the femoral shaft tends to displace medially. A cephalomedullary nail provides optimal load-sharing biomechanics and prevents medial translation, making it superior to a sliding hip screw for this pattern.

Question 8787

Topic: Pelvic & Acetabular Trauma



A 40-year-old woman with severe developmental dysplasia of the hip (Crowe Type IV) is undergoing THA. The femoral head is entirely superior to the true acetabulum. Placing the cup in the true acetabulum will most likely require which concurrent procedure?

. Greater trochanteric advancement
. Subtrochanteric shortening osteotomy
. Isolated adductor tenotomy
. Iliopsoas fractional lengthening only
. Pelvic support osteotomy

Correct Answer & Explanation

. Subtrochanteric shortening osteotomy

Explanation

In Crowe IV dysplasia, restoring the anatomic hip center requires significant distal translation of the femur. A subtrochanteric shortening osteotomy is typically necessary to safely reduce the hip without causing sciatic nerve stretch injury.

Question 8788

Topic: Pelvic & Acetabular Trauma

A 24-year-old male hockey player presents with gradual onset of deep groin pain exacerbated by hip flexion and internal rotation. Radiographs reveal an alpha angle of 65 degrees and normal acetabular coverage. Which of the following pathologic mechanisms is most likely responsible for his symptoms?

. Shear forces causing anterosuperior labral detachment and chondral delamination
. Contrecoup cartilage injury in the posteroinferior acetabulum
. Pincer impingement causing circumferential labral ossification
. Dysplastic subluxation causing labral hypertrophy
. Ischiofemoral impingement causing quadratus femoris edema

Correct Answer & Explanation

. Shear forces causing anterosuperior labral detachment and chondral delamination

Explanation

Cam impingement is characterized by an abnormal femoral head-neck junction (high alpha angle) that forcefully enters the acetabulum during flexion. This creates tremendous shear forces that lead to anterosuperior chondral delamination and inside-out labral tears.

Question 8789

Topic: 2. Trauma
A 30-year-old man sustains a completely displaced, high-angle (Pauwels Type III) femoral neck fracture. He is medically stable. What fixation method provides the most biomechanically stable construct to resist the high shear forces inherent in this fracture pattern?
. Three parallel cancellous screws
. Sliding hip screw with an anti-rotation screw
. Dynamic condylar screw
. Cephalomedullary nail
. Multiple Knowles pins

Correct Answer & Explanation

. Sliding hip screw with an anti-rotation screw

Explanation

Pauwels Type III fractures have a vertical fracture line (angle >50 degrees) subjected to high shear forces. A fixed-angle device, such as a sliding hip screw combined with a derotational screw, provides superior biomechanical stability compared to multiple parallel cancellous screws.

Question 8790

Topic: 2. Trauma
A 28-year-old man sustains a highly vertical (Pauwels type III) basicervical femoral neck fracture following a motor vehicle collision. Which of the following internal fixation constructs provides the highest biomechanical stability against vertical shear forces?
. Three parallel cancellous screws placed in an inverted triangle
. A dynamic hip screw (sliding hip screw) with a derotation screw
. Three parallel cancellous screws placed in a standard triangle
. Two crossed partially threaded cancellous screws
. An intramedullary piriformis-entry nail

Correct Answer & Explanation

. A dynamic hip screw (sliding hip screw) with a derotation screw

Explanation

Vertical femoral neck fractures (Pauwels III) in young adults experience high shear forces leading to varus collapse. A fixed-angle device, such as a sliding hip screw with a derotation screw, provides superior biomechanical stability against vertical shear compared to multiple cancellous screws.

Question 8791

Topic: Pelvic & Acetabular Trauma
A 40-year-old male sustains a pelvic ring injury. Radiographs show a widened pubic symphysis of 3.5 cm and disruption of the anterior sacroiliac ligaments with intact posterior sacroiliac ligaments. What type of injury is this according to the Young and Burgess classification?
. APC I
. APC II
. APC III
. LC I
. VS

Correct Answer & Explanation

. APC II

Explanation

An APC II injury involves symphyseal widening >2.5 cm and disruption of the anterior SI ligaments but with intact posterior SI ligaments, causing rotational instability while maintaining vertical stability.

Question 8792

Topic: 2. Trauma
A 30-year-old male sustains a vertically oriented (Pauwels type III) femoral neck fracture. Which of the following fixation constructs is biomechanically optimal to resist the high shear forces in this fracture pattern?
. Three parallel cancellous lag screws in an inverted triangle
. A sliding hip screw (DHS) with a derotational screw
. Two parallel cancellous screws
. Bipolar hemiarthroplasty
. Cemented total hip arthroplasty

Correct Answer & Explanation

. A sliding hip screw (DHS) with a derotational screw

Explanation

Pauwels type III fractures are subject to significant shear forces. A fixed-angle device such as a sliding hip screw (often supplemented with a derotational screw) provides superior biomechanical stability against varus collapse compared to multiple cancellous screws alone.

Question 8793

Topic: 2. Trauma
A 30-year-old sustains a displaced, vertical (Pauwels type III) femoral neck fracture. Biomechanical studies indicate which of the following fixation constructs provides the greatest stability for this fracture pattern?
. Three parallel cancellous screws
. Dynamic hip screw (DHS) with an anti-rotation screw
. Cephalomedullary nail
. Two parallel cancellous screws
. Cannulated screws placed in an inverted triangle

Correct Answer & Explanation

. Dynamic hip screw (DHS) with an anti-rotation screw

Explanation

Pauwels type III fractures have a high degree of vertical shear. A fixed-angle device such as a dynamic hip screw (DHS) supplemented with an anti-rotation screw provides superior biomechanical stability compared to multiple cancellous screws.

Question 8794

Topic: Pelvic & Acetabular Trauma



A 70-year-old man requires a revision THA. Preoperative evaluation of the pelvis reveals severe bone loss with a complete dissociation of the superior and inferior halves of the hemipelvis. Which of the following constructs is most appropriate to achieve durable fixation in this scenario?

. Jumbo multi-hole hemispherical cup alone
. Impaction bone grafting with a cemented polyethylene cup
. Cup-cage construct or custom triflange acetabular component
. Standard porous-coated cup with adjunctive anterior column plating
. Bipolar hemiarthroplasty articulating with the remaining native bone

Correct Answer & Explanation

. Cup-cage construct or custom triflange acetabular component

Explanation

The scenario describes a pelvic discontinuity. Achieving stability requires bridging the defect to unite the superior and inferior segments. This is best accomplished using highly porous metal augments with a cup-cage construct, a custom triflange, or a pelvic distraction technique.

Question 8795

Topic: 2. Trauma

A surgeon is evaluating a 70-year-old patient with an un-displaced subcapital femoral neck fracture. To maximize fracture stability and reduce the risk of nonunion and avascular necrosis during cannulated screw fixation, which mechanical configuration of the screws is optimal?

. Parallel screws spread closely together in the center of the femoral neck
. Three parallel screws arranged in an inverted triangle with the inferior screw resting on the calcar
. Three crossing screws converging at the apex of the femoral head
. Four screws placed along the anterior cortex
. Two parallel screws placed superiorly to act as a tension band

Correct Answer & Explanation

. Three parallel screws arranged in an inverted triangle with the inferior screw resting on the calcar

Explanation

For internal fixation of femoral neck fractures, three parallel screws in an inverted triangle configuration provide the most biomechanical stability. The inferior screw must sit adjacent to the dense bone of the calcar to resist inferior displacement and varus collapse.

Question 8796

Topic: Pelvic & Acetabular Trauma

A 24-year-old male hockey player presents with anterior groin pain exacerbated by hip flexion and internal rotation. Radiographs reveal a pistol-grip deformity and an alpha angle of 70 degrees. Which of the following best describes the pathomechanics of his condition?

. Linear contact between the aspheric femoral head-neck junction and acetabular rim causing labral and cartilage shear
. Repetitive microtrauma to the ligamentum teres causing instability
. Increased femoral anteversion leading to posterior rim overload
. Global acetabular overcoverage causing a pincer impingement
. Dysplastic shallow acetabulum leading to edge loading

Correct Answer & Explanation

. Linear contact between the aspheric femoral head-neck junction and acetabular rim causing labral and cartilage shear

Explanation

Cam impingement features an aspherical femoral head that forcefully enters the acetabulum during flexion. This creates outside-in shear forces that cause labral separation and adjacent chondral delamination from the acetabular rim.

Question 8797

Topic: Pelvic & Acetabular Trauma

A 35-year-old man presents with a hemodynamically unstable pelvic ring injury following a motorcycle collision. A pelvic binder is applied. To optimally reduce the pelvic volume in an anteroposterior compression (APC) injury, over which anatomic structure should the pelvic binder be centered?

. Iliac crests
. Anterior superior iliac spines
. Greater trochanters
. Pubic symphysis
. Sacral ala

Correct Answer & Explanation

. Greater trochanters

Explanation

Pelvic binders should be centered over the greater trochanters to effectively close the pelvic ring and reduce pelvic volume in APC-type injuries. Placement over the iliac crests is less effective and may cause paradoxical opening of the pelvic floor.

Question 8798

Topic: 2. Trauma

Following a high-energy closed tibial shaft fracture, a 28-year-old patient develops severe pain out of proportion to the injury. On examination, he has pain with passive extension of the great toe. Which muscle compartment of the leg is most likely affected based on this specific clinical finding?

. Anterior
. Lateral
. Superficial posterior
. Deep posterior
. Peroneal

Correct Answer & Explanation

. Deep posterior

Explanation

Pain with passive extension of the great toe stretches the flexor hallucis longus, which is located in the deep posterior compartment. The anterior compartment would present with pain on passive plantarflexion of the toes.

Question 8799

Topic: 2. Trauma
A 25-year-old man sustains a completely displaced, vertically oriented (Pauwels type III) femoral neck fracture. Which of the following fixation constructs provides the most biomechanically stable construct to resist shear forces in this specific fracture pattern?
. Three parallel cancellous lag screws
. Dynamic hip screw with an anti-rotation screw
. Cephalomedullary nail
. Multiple fully threaded cortical screws
. Hemiarthroplasty

Correct Answer & Explanation

. Dynamic hip screw with an anti-rotation screw

Explanation

For high-shear vertically oriented (Pauwels type III) femoral neck fractures in young adults, a fixed-angle device such as a dynamic hip screw (with a derotation screw) provides superior biomechanical stability against vertical shear forces compared to multiple cancellous screws.

Question 8800

Topic: 2. Trauma

A 45-year-old woman sustains a complex bicondylar tibial plateau fracture with a large, displaced posteromedial fragment. Which surgical approach provides the most direct access for buttress plating of the posteromedial fragment?

. Anterolateral approach
. Medial parapatellar approach
. Posteromedial approach
. Direct posterior approach
. Lateral approach with fibular osteotomy

Correct Answer & Explanation

. Posteromedial approach

Explanation

A posteromedial approach (often via a medial gastrocnemius interval) provides direct access to the posteromedial tibial plateau, allowing for optimal placement of an anti-glide or buttress plate. This is essential to prevent varus collapse.

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