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2. Trauma MCQs

Practice Set 254 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 5061

Topic: Pelvic & Acetabular Trauma

According to the Young-Burgess classification, an Anteroposterior Compression Type II (APC-II) pelvic ring injury opens the symphysis greater than 2.5 cm. Which ligaments remain intact in this injury, preventing complete vertical instability of the hemipelvis?

. Anterior sacroiliac ligaments
. Posterior sacroiliac ligaments
. Sacrotuberous ligaments
. Sacrospinous ligaments
. Iliolumbar ligaments

Correct Answer & Explanation

. Posterior sacroiliac ligaments

Explanation

An APC-II injury ('open book' pelvis) is characterized by disruption of the pubic symphysis, anterior sacroiliac (SI) ligaments, sacrospinous ligaments, and sacrotuberous ligaments. The posterior SI ligaments, which are the strongest ligaments in the body, remain intact. Thus, the pelvis is rotationally unstable but vertically stable.

Question 5062

Topic: 2. Trauma

A 28-year-old male develops acute compartment syndrome following a tibial plateau fracture. A dual-incision four-compartment fasciotomy is performed. Through the medial incision, the soleus is detached from the posterior tibia. Which compartment is directly accessed by this specific step?

. Superficial posterior
. Deep posterior
. Anterior
. Lateral
. Medial

Correct Answer & Explanation

. Medial

Explanation

In a two-incision fasciotomy of the lower leg, the medial incision is used to release the superficial and deep posterior compartments. After incising the fascia over the gastrocnemius-soleus complex to release the superficial posterior compartment, the soleus bridge must be detached from the posterior aspect of the tibia to expose and release the fascia covering the deep posterior compartment (tibialis posterior, FDL, FHL).

Question 5063

Topic: 2. Trauma

In a subtrochanteric femur fracture, the proximal fragment typically assumes a characteristic deformed position due to uninhibited muscle forces. Which muscle group is primarily responsible for the external rotation of the proximal fragment?

. Gluteus medius
. Iliopsoas
. Short external rotators
. Tensor fasciae latae
. Adductor longus

Correct Answer & Explanation

. Iliopsoas

Explanation

The classic deformity of the proximal fragment in a subtrochanteric fracture includes flexion (driven by the iliopsoas), abduction (driven by the gluteus medius and minimus), and external rotation (driven by the short external rotators, including the piriformis, gemelli, and obturator internus).

Question 5064

Topic: 2. Trauma

A 30-year-old male fell from a height, sustaining a displaced talar neck fracture treated with open reduction and internal fixation. At 8 weeks postoperatively, an AP radiograph of the ankle demonstrates a subchondral radiolucent band in the talar dome. What does this radiographic finding indicate?

. Developing avascular necrosis of the talar body
. Impending hardware failure
. Intact vascularity to the talar body
. Early signs of osteomyelitis
. Atrophic nonunion of the talar neck

Correct Answer & Explanation

. Intact vascularity to the talar body

Explanation

The described finding is Hawkins sign, a subchondral radiolucent band seen 6-8 weeks post-injury. It represents subchondral atrophy from disuse and local hyperemia, indicating intact vascularity and predicting the absence of avascular necrosis.

Question 5065

Topic: 2. Trauma

A 45-year-old man sustains a high-energy supracondylar femur fracture. A CT scan reveals an intra-articular coronal plane fracture of the lateral femoral condyle. What is the optimal internal fixation strategy for this specific articular fragment?

. Anterior-to-posterior lag screws
. Posterior-to-anterior lag screws
. Distal-to-proximal lag screws
. Medial-to-lateral lag screws
. Excision of the fragment and meniscal repair

Correct Answer & Explanation

. Anterior-to-posterior lag screws

Explanation

A coronal shear fracture of the femoral condyle is known as a Hoffa fracture. It is optimally treated with anterior-to-posterior lag screws placed perpendicular to the fracture plane to achieve anatomic reduction and absolute stability.

Question 5066

Topic: 2. Trauma

A 32-year-old male presents with a comminuted midshaft tibia fracture and reports severe leg pain out of proportion to the injury. His blood pressure is 110/70 mmHg. Intracompartmental pressure monitoring is performed. At what specific pressure threshold is a four-compartment fasciotomy definitively indicated?

. Absolute compartment pressure > 20 mmHg
. Delta P (Diastolic BP - Compartment Pressure) < 30 mmHg
. Delta P (Mean Arterial Pressure - Compartment Pressure) < 30 mmHg
. Delta P (Systolic BP - Compartment Pressure) < 40 mmHg
. Absolute compartment pressure > 15 mmHg

Correct Answer & Explanation

. Delta P (Diastolic BP - Compartment Pressure) < 30 mmHg

Explanation

The most reliable threshold for diagnosing acute compartment syndrome and indicating fasciotomy is a Delta P (diastolic blood pressure minus intracompartmental pressure) of less than 30 mmHg.

Question 5067

Topic: 2. Trauma

A 65-year-old woman undergoes locked plating for a 3-part proximal humerus fracture. The surgeon ensures the placement of an inferomedial calcar screw. What is the primary biomechanical purpose of this specific screw?

. Prevents greater tuberosity escape
. Resists varus collapse of the humeral head
. Decreases the risk of axillary nerve entrapment
. Prevents anterior subluxation of the humeral head
. Stimulates endosteal blood supply to the surgical neck

Correct Answer & Explanation

. Resists varus collapse of the humeral head

Explanation

Inferomedial calcar screws provide critical medial column support in proximal humerus locking plates. This support strongly resists the deforming forces that lead to varus collapse of the humeral head and subsequent intra-articular screw cut-out.

Question 5068

Topic: 2. Trauma
A 35-year-old male is brought to the trauma bay with an anterior-posterior compression (APC) III pelvic ring injury following a crush accident. He is hemodynamically unstable despite a pelvic binder and fluid resuscitation. What is the most common anatomic source of massive hemorrhage in this fracture pattern?
. Presacral venous plexus
. Superior gluteal artery
. Internal pudendal artery
. Obturator artery
. Corona mortis

Correct Answer & Explanation

. Presacral venous plexus

Explanation

Up to 80% of pelvic bleeding in blunt trauma is venous, originating primarily from the presacral venous plexus and fractured cancellous bone. Arterial bleeding is less common but more frequently associated with severe lateral compression or high-energy shear injuries.

Question 5069

Topic: 2. Trauma

A 42-year-old female sustains a Schatzker IV tibial plateau fracture with a large posteromedial shear fragment. What is the optimal surgical approach and internal fixation strategy?

. Anterolateral approach with a locked plate
. Posteromedial approach with an anti-glide plate
. Dual medial and lateral plates via a single anterior midline incision
. External fixation spanning the knee joint without internal fixation
. Medial approach with anterior-to-posterior lag screws only

Correct Answer & Explanation

. Posteromedial approach with an anti-glide plate

Explanation

A Schatzker IV fracture involving a posteromedial shear fragment requires rigid buttress fixation applied from posterior to anterior. A posteromedial approach allows optimal placement of an anti-glide plate to neutralize these specific vertical shear forces.

Question 5070

Topic: 2. Trauma

A 30-year-old motorcyclist sustains a Hoffa fracture (coronal plane fracture of the lateral femoral condyle). What is the most biomechanically sound fixation strategy for this fracture pattern?

. Lateral locking plate alone without lag screws
. Anterior-to-posterior lag screws with an optional lateral neutralization plate
. Posterior-to-anterior lag screws alone
. Antegrade intramedullary nailing
. Bridge plating without lag screws

Correct Answer & Explanation

. Anterior-to-posterior lag screws with an optional lateral neutralization plate

Explanation

A Hoffa fracture is a coronal shear fracture that requires rigid interfragmentary compression. This is best achieved with anterior-to-posterior (or posterior-to-anterior) lag screws, often supplemented with a lateral buttress or neutralization plate to counteract vertical shear.

Question 5071

Topic: 2. Trauma

A 7-year-old boy falls onto an outstretched hand, sustaining a Bado type I Monteggia fracture-dislocation. The radial head is dislocated in which direction, and which nerve is at the highest risk of injury?

. Anteriorly; Posterior interosseous nerve (PIN)
. Posteriorly; Anterior interosseous nerve (AIN)
. Laterally; Ulnar nerve
. Anteriorly; Median nerve
. Posteriorly; Posterior interosseous nerve (PIN)

Correct Answer & Explanation

. Anteriorly; Posterior interosseous nerve (PIN)

Explanation

A Bado type I Monteggia fracture is characterized by an anterior dislocation of the radial head and an apex anterior fracture of the ulnar diaphysis. The posterior interosseous nerve (PIN) wraps around the radial neck and is the most commonly injured nerve in this pattern.

Question 5072

Topic: 2. Trauma

A 30-year-old male presents with a closed tibial shaft fracture. His blood pressure is 110/65 mmHg. Intracompartmental pressure testing reveals an anterior compartment pressure of 45 mmHg. What is the most appropriate next step in management?

. Application of a long leg cast and serial examinations
. Observation with strict elevation above the heart level
. Immediate four-compartment fasciotomy
. Single-incision fasciotomy of the anterior compartment only
. External fixation without soft tissue decompression

Correct Answer & Explanation

. Immediate four-compartment fasciotomy

Explanation

A Delta P (Diastolic BP minus compartment pressure) of less than 30 mmHg (65 - 45 = 20 mmHg) is highly indicative of acute compartment syndrome. The definitive treatment is an emergent four-compartment fasciotomy.

Question 5073

Topic: 2. Trauma
A 28-year-old male sustains a Pauwels type III vertical femoral neck fracture. Which of the following fixation constructs provides the greatest biomechanical stability against shear forces for this specific fracture pattern?
. Three parallel cancellous lag screws in an inverted triangle
. Sliding hip screw (SHS) with an anti-rotation screw
. Fully threaded screws without washers
. Non-locking trochanteric entry intramedullary nail
. Bipolar hemiarthroplasty

Correct Answer & Explanation

. Sliding hip screw (SHS) with an anti-rotation screw

Explanation

Pauwels type III fractures are highly vertical and subject to significant shear forces. A fixed-angle device, such as a sliding hip screw combined with a derotational screw, provides superior biomechanical stability compared to multiple cancellous screws.

Question 5074

Topic: 2. Trauma
A 35-year-old male involved in a crush injury presents with an anteroposterior compression (APC) type III pelvic fracture. He has blood at the urethral meatus and a high-riding prostate on rectal exam. What is the most appropriate next step in the urologic management of this patient?
. Blind insertion of a Foley catheter
. Immediate suprapubic catheter placement in the trauma bay
. Retrograde urethrogram (RUG)
. CT cystogram
. Cystoscopy

Correct Answer & Explanation

. Retrograde urethrogram (RUG)

Explanation

Blood at the meatus and a high-riding prostate are classic signs of urethral injury associated with pelvic ring disruptions. A retrograde urethrogram (RUG) must be performed to evaluate urethral integrity before any attempt at catheterization.

Question 5075

Topic: 2. Trauma

A 24-year-old male sustains a closed, distal-third spiral humeral shaft fracture (Holstein-Lewis type). His initial examination shows an intact radial nerve. Following closed reduction and placement of a coaptation splint, he develops a complete radial nerve palsy. What is the most appropriate next step in management?

. Observe for 3 months with serial EMG
. Immediate surgical exploration and nerve release
. Switch to a functional fracture brace
. Prescribe a wrist extension splint and re-evaluate in 6 weeks
. Administer a short course of high-dose oral corticosteroids

Correct Answer & Explanation

. Immediate surgical exploration and nerve release

Explanation

A secondary radial nerve palsy occurring after closed reduction of a humeral shaft fracture, particularly a Holstein-Lewis variant, indicates possible entrapment of the nerve in the fracture site. This is an absolute indication for immediate surgical exploration.

Question 5076

Topic: 2. Trauma

A 29-year-old male is involved in a motorcycle collision, sustaining an ipsilateral closed midshaft femur fracture and a closed midshaft tibia fracture (floating knee). To minimize the risk of systemic complications such as ARDS, what is the most appropriate timing and method of surgical management?

. External fixation of both fractures within 24 hours followed by delayed nailing
. Early total care with intramedullary nailing of both fractures within 24 hours if hemodynamically stable
. Intramedullary nailing of the femur and non-operative cast management of the tibia
. Plate fixation of the femur and external fixation of the tibia
. Delayed intramedullary nailing of both fractures at 7-10 days

Correct Answer & Explanation

. Early total care with intramedullary nailing of both fractures within 24 hours if hemodynamically stable

Explanation

In a hemodynamically stable patient with a floating knee, early total care with reamed intramedullary nailing of major long bone fractures within 24 hours minimizes the risk of ARDS and systemic inflammatory response.

Question 5077

Topic: 2. Trauma

A 65-year-old female presents with a displaced supracondylar distal femur fracture proximal to a well-fixed total knee arthroplasty with a closed-box posterior-stabilized femoral design. What is the preferred surgical treatment?

. Revision of the femoral component to a distal femoral replacement
. Retrograde intramedullary nailing
. Anterolateral plating
. Distal femoral locking plate fixation via a lateral approach
. Long leg casting

Correct Answer & Explanation

. Distal femoral locking plate fixation via a lateral approach

Explanation

A closed-box posterior-stabilized TKA femoral component prevents the passage of a retrograde intramedullary nail. Therefore, a lateral distal femoral locking plate is the optimal fixation method for this periprosthetic fracture.

Question 5078

Topic: 2. Trauma
A 12-year-old boy sustains open comminuted midshaft tibial and fibular fractures while playing indoor soccer. The wound is grossly clean and measures 7 cm with some periosteal stripping. Antibiotics and tetanus toxoid are administered immediately in the emergency department. Following irrigation and debridement of the wound in the operating room, treatment should include:
. A long leg cast
. A reamed nail
. An unreamed nail
. An external fixator
. Plates and screws

Correct Answer & Explanation

. An external fixator

Explanation

Open fractures in children have similar rates of short-term complications such as compartment syndrome, vascular injury, and nerve injury when compared to adult fractures. Primary wound closure should be used for Gustilo and Anderson type 1 or uncomplicated type 2 fractures after surgical debridement. Skeletal stabilization may consist of external fixation, flexible nails, or casting with or without supplementary pin fixation. For an open comminuted midshaft fracture, external fixation is the treatment of choice. Reamed intramedullary nailing is contraindicated in children with an open physis. Plate fixation has a high complication rate in severe open fractures.

Question 5079

Topic: 2. Trauma

A 28-year-old male presents with persistent wrist pain 18 months after a scaphoid waist fracture. Imaging reveals a proximal pole nonunion with avascular necrosis (AVN) of the proximal fragment, which measures 4 mm. A previous attempt at fixation with a Herbert screw and non-vascularized bone graft failed. There is no evidence of radiocarpal arthritis. Which of the following is the most appropriate surgical treatment to maximize the chance of union?

. 1,2 Intercompartmental supraretinacular artery (ICSRA) pedicled bone graft
. Proximal row carpectomy
. Free vascularized medial femoral condyle (MFC) bone graft
. Scaphoid excision and four-corner fusion
. Radial shortening osteotomy

Correct Answer & Explanation

. Free vascularized medial femoral condyle (MFC) bone graft

Explanation

For scaphoid nonunions with AVN of the proximal pole, especially those that have failed prior surgery and possess a very small proximal fragment, a free vascularized bone graft from the medial femoral condyle (MFC) is the gold standard. The MFC graft provides robust, highly vascularized structural bone and has demonstrated higher union rates in this specific, difficult clinical scenario compared to pedicled distal radius grafts like the 1,2 ICSRA.

Question 5080

Topic: 2. Trauma

The tenuous blood supply to the proximal pole of the scaphoid is a primary factor in its high rate of nonunion following fracture. The predominant blood supply to the scaphoid enters at which anatomical location?

. Volar tubercle via the superficial palmar arch
. Scapholunate ligament insertion
. Distal articular surface via the radioscaphocapitate ligament
. Dorsal ridge via the dorsal carpal branch of the radial artery
. Proximal pole directly from the anterior interosseous artery

Correct Answer & Explanation

. Dorsal ridge via the dorsal carpal branch of the radial artery

Explanation

The primary blood supply to the scaphoid (accounting for 70-80% of its vascularity) enters via the dorsal ridge, which is located on the dorsal aspect of the scaphoid waist. These vessels originate from the dorsal carpal branch of the radial artery and flow in a retrograde direction to supply the proximal pole. Because of this retrograde flow, fractures at the scaphoid waist or proximal pole disrupt the blood supply to the proximal fragment, leading to ischemia and nonunion.

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