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 4941
Topic: 2. Trauma
A 45-year-old smoker is undergoing ORIF of a displaced intra-articular calcaneus fracture via an extensile lateral approach. To minimize the risk of wound necrosis, the full-thickness flap is elevated subperiosteally. Which vascular structure serves as the primary blood supply to the apex of this flap?
Correct Answer & Explanation
. Lateral calcaneal artery
Explanation
The extensile lateral approach relies on a full-thickness flap whose corner is critically supplied by the lateral calcaneal artery, a terminal branch of the peroneal artery. Subperiosteal elevation and avoiding forceful retraction are essential to prevent ischemic flap necrosis.
Question 4942
Topic: 2. Trauma
Six weeks following open reduction and internal fixation of a displaced talar neck fracture, an AP radiograph of the ankle demonstrates a distinct subchondral radiolucent band in the talar dome. What does this radiographic finding indicate?
Correct Answer & Explanation
. Revascularization and viability of the talar body
Explanation
The Hawkins sign is a subchondral radiolucent band in the talar dome typically seen 6-8 weeks post-injury, indicating active subchondral bone resorption due to hyperemia. This is a highly reliable indicator of intact vascularity to the talar body, effectively ruling out avascular necrosis.
Question 4943
Topic: Pelvic & Acetabular Trauma
When evaluating an acetabular fracture utilizing the standard Judet radiographic series, which structural components of the acetabulum are best visualized in profile on the obturator oblique view?
Correct Answer & Explanation
. Anterior column and posterior wall
Explanation
The obturator oblique view of the pelvis profiles the anterior column and the posterior wall of the acetabulum. Conversely, the iliac oblique view profiles the posterior column and the anterior wall.
Question 4944
Topic: 2. Trauma
A 30-year-old male sustains a vertically oriented (Pauwels Type III) femoral neck fracture. Biomechanically, which fixation construct provides the most stable construct against the high shear forces inherent to this specific fracture pattern?
Correct Answer & Explanation
. Dynamic hip screw (DHS) with a derotation screw
Explanation
Pauwels Type III femoral neck fractures have a high vertical angle, subjecting the fracture to significant shear forces and a high risk of varus collapse. A fixed-angle device, such as a Dynamic Hip Screw (DHS), provides superior biomechanical resistance to these shear forces compared to parallel cancellous screws.
Question 4945
Topic: 2. Trauma
A 38-year-old male presents with an ipsilateral midshaft clavicle fracture and a highly displaced scapular neck fracture (a 'floating shoulder'). According to current literature, which surgical approach is recommended to best restore the superior suspensory shoulder complex (SSSC)?
Correct Answer & Explanation
. Open reduction and internal fixation of both the clavicle and the scapula
Explanation
In a true 'floating shoulder' characterized by significant displacement of both the clavicle and the scapular neck, fixation of both fractures is recommended. While isolated clavicle fixation was historically performed, it does not reliably correct severe scapular neck displacement or restore the SSSC.
Question 4946
Topic: 2. Trauma
In the underlying pathophysiology of acute compartment syndrome following a severe lower extremity crush injury, which physiological event occurs first as intracompartmental pressure begins to rise?
Correct Answer & Explanation
. Venous outflow obstruction
Explanation
As intracompartmental pressure rises, the thin-walled venous and lymphatic vessels are compressed first, resulting in venous outflow obstruction. This leads to vascular congestion, increased capillary hydrostatic pressure, and a vicious cycle of further tissue edema before eventual arterial occlusion.
Question 4947
Topic: 2. Trauma
A 22-year-old male presents with a scaphoid waist fracture. Avascular necrosis of the proximal pole is a known complication. Which of the following describes the primary arterial supply to the scaphoid?
Correct Answer & Explanation
. Dorsal branches of the radial artery entering distally
Explanation
The primary blood supply to the scaphoid comes from the dorsal carpal branch of the radial artery, which enters the scaphoid distally (in the region of the distal pole and dorsal ridge) and flows retrogradely to supply the proximal pole. Because of this retrograde blood supply, fractures at the scaphoid waist or proximal pole disrupt the vascularity to the proximal fragment, significantly increasing the risk of avascular necrosis and nonunion.
Question 4948
Topic: 2. Trauma
A 35-year-old male sustains an intra-articular calcaneus fracture after falling from a ladder. A coronal CT scan is obtained. At the level showing the widest portion of the posterior facet, there are two distinct primary fracture lines crossing the posterior facet, dividing it into three articular fragments. According to the Sanders classification, what type of fracture is this?
Correct Answer & Explanation
. Type I
Explanation
The Sanders classification for intra-articular calcaneus fractures is based on the number of fracture lines through the posterior facet on a coronal CT scan. Type I is non-displaced. Type II has one fracture line (two articular fragments). Type III has two fracture lines (three articular fragments). Type IV is highly comminuted with more than three fracture lines (four or more articular fragments).
Question 4949
Topic: Upper Extremity Trauma
A 42-year-old bodybuilder feels a pop in his posterior elbow during a heavy bench press. Examination reveals a palpable gap and loss of active elbow extension against gravity. Surgical repair of the distal triceps tendon is planned. Based on biomechanical studies, which repair construct provides the highest load to failure and restores the largest anatomic footprint?
Correct Answer & Explanation
. Cruciate repair using transosseous tunnels in a double-row equivalent
Explanation
Biomechanical studies have shown that a cruciate double-row or anatomic transosseous cruciate repair technique provides the highest load to failure, minimizes gap formation, and optimally restores the broad anatomic footprint of the distal triceps tendon on the olecranon, compared to single-row suture anchor repairs or simple transosseous knots.
Question 4950
Topic: 2. Trauma
When performing tibial lengthening over an intramedullary nail (LON) compared to classic Ilizarov circular frame lengthening alone, LON provides which of the following primary advantages?
Correct Answer & Explanation
. Decreased total duration of external fixation
Explanation
Lengthening over a nail (LON) allows the external fixator to be removed immediately after the distraction phase, relying on the locked nail to support the regenerate during consolidation. This significantly decreases the time spent in the external fixator, improving patient comfort.
Question 4951
Topic: 2. Trauma
A patient sustains a traumatic elbow subluxation resulting in an anteromedial facet fracture of the coronoid. This specific fracture pattern is highly predictive of an associated injury to which of the following ligamentous structures?
Correct Answer & Explanation
. Lateral collateral ligament complex
Explanation
Anteromedial facet fractures of the coronoid result from varus posteromedial rotatory instability. The mechanism involves varus stress that tears the lateral collateral ligament (LCL) complex, followed by posteromedial subluxation that shears the anteromedial coronoid facet.
Question 4952
Topic: Lower Extremity Trauma
You are planning an eight-plate hemiepiphysiodesis for a 9-year-old girl with idiopathic genu valgum. To achieve the best mechanical advantage and minimize joint line distortion, where should the plates be placed?
Correct Answer & Explanation
. Medial proximal tibia and medial distal femur
Explanation
For genu valgum (knock-knees), medial hemiepiphysiodesis tethers the faster-growing medial side, allowing the lateral physis to continue growing and correct the deformity. Addressing both the femur and tibia (if both contribute) limits joint line obliquity.
Question 4953
Topic: 2. Trauma
A 68-year-old female presents with vague thigh pain for 3 months. She has a history of osteoporosis and has been on alendronate for 8 years. Radiographs demonstrate an incomplete transverse fracture of the lateral cortex of the femoral shaft. According to the 2013 American Society for Bone and Mineral Research (ASBMR) criteria, which of the following is considered a 'Major' criterion required for the diagnosis of an atypical femur fracture (AFF)?
Correct Answer & Explanation
. Transverse or short oblique configuration
Explanation
The ASBMR 2013 revised criteria for an atypical femur fracture require that all 5 major criteria be present. These include: 1) Location along the femur from just distal to the lesser trochanter to just proximal to the supracondylar flare; 2) Minimal or no trauma; 3) Transverse or short oblique configuration; 4) Complete fractures extending through both cortices or incomplete fractures involving only the lateral cortex; and 5) Noncomminuted or minimally comminuted. Prodromal pain, delayed healing, and bilateral fractures are 'Minor' criteria.
Question 4954
Topic: Pelvic & Acetabular Trauma
A 45-year-old male sustains a closed pelvic ring injury in a high-speed motor vehicle collision. Physical examination reveals a large, fluctuant, soft tissue swelling over the greater trochanter with overlying skin ecchymosis. Aspiration yields serosanguinous fluid. Which of the following accurately characterizes the pathophysiology of this specific lesion?
Correct Answer & Explanation
. Separation of the subcutaneous tissue from the underlying fascia filled with hemolymphatic fluid
Explanation
The clinical presentation describes a Morel-Lavallรฉe lesion, which is a closed degloving injury. It is characterized by the traumatic separation of the subcutaneous fat and skin from the underlying deep fascia. This creates a potential space that fills with blood, lymph, and necrotic fat (hemolymphatic fluid). If unrecognized or improperly treated, it carries a high risk of soft tissue necrosis and deep infection.
Question 4955
Topic: 2. Trauma
A 35-year-old male is admitted with a highly comminuted, closed tibial shaft fracture following a crush injury. Six hours post-injury, he complains of severe leg pain out of proportion to the injury. His blood pressure is 105/75 mmHg. Intracompartmental pressure (ICP) monitoring is performed. Which of the following pressure relationships strongly supports the diagnosis of acute compartment syndrome and the need for immediate fasciotomy?
Correct Answer & Explanation
. Diastolic blood pressure minus ICP < 30 mmHg
Explanation
The most reliable indicator for acute compartment syndrome is the delta pressure (ฮP), calculated as the diastolic blood pressure minus the intracompartmental pressure (ICP). A delta pressure of less than 30 mmHg accurately indicates inadequate tissue perfusion and is a strong indication for immediate four-compartment fasciotomy. Absolute pressure readings can be misleading due to variations in systemic blood pressure.
Question 4956
Topic: 2. Trauma
In the evaluation of a displaced proximal humerus fracture, maintaining the viability of the humeral head relies predominantly on the integrity of the intra-osseous circulation and capsular attachments. According to the Hertel radiographic criteria, which of the following fracture characteristics is the most reliable predictor of subsequent avascular necrosis (AVN) of the humeral head?
Correct Answer & Explanation
. Medial calcar hinge disruption > 2 mm
Explanation
Hertel et al. described highly predictive radiographic criteria for ischemia and AVN in proximal humerus fractures. The best predictors are: 1) a medial calcar hinge disruption > 2 mm, 2) a short calcar length (medial metaphyseal head extension attached to the articular segment) of < 8 mm, and 3) an anatomic neck fracture. Therefore, a disrupted medial hinge > 2 mm strongly portends AVN.
Question 4957
Topic: 2. Trauma
A 25-year-old male sustains a displaced, highly vertical (Pauwels type III) femoral neck fracture in a motor vehicle collision. Open reduction and internal fixation is planned. Biomechanically, what is the primary rationale for utilizing a fixed-angle device (e.g., sliding hip screw with an anti-rotation screw) rather than multiple parallel cancellous screws for this specific fracture pattern?
Correct Answer & Explanation
. Increased resistance to the inherently high vertical shear forces
Explanation
Pauwels type III femoral neck fractures have a highly vertical fracture line (angle > 50 degrees to the horizontal), which subjects the fracture site to massive vertical shear forces and varus stress rather than compressive forces. Multiple parallel cancellous screws often fail to resist these shear forces in vertical patterns in young adults. A fixed-angle device, such as a sliding hip screw, provides significantly greater biomechanical resistance to vertical shear and varus collapse.
Question 4958
Topic: 2. Trauma
A 30-year-old male sustains a low-velocity civilian gunshot wound to the right thigh, resulting in a comminuted midshaft femur fracture. The entry and exit wounds are approximately 1 cm each, with no expanding hematoma, and distal pulses are palpable and symmetric. According to current orthopaedic trauma guidelines, what is the most appropriate initial management of the soft tissues and fracture?
Correct Answer & Explanation
. Superficial local wound care, tetanus prophylaxis, intravenous antibiotics, and intramedullary nailing
Explanation
Low-velocity handgun injuries resulting in femur fractures without neurovascular compromise or massive contamination do not typically require formal surgical debridement of the bullet tract. The standard of care involves superficial local wound care, administration of tetanus prophylaxis and intravenous antibiotics, and stabilization of the fracture, most commonly with antegrade intramedullary nailing.
Question 4959
Topic: Pelvic & Acetabular Trauma
An unstable 35-year-old male is brought to the trauma bay following a high-speed motorcycle collision. His blood pressure is 80/40 mmHg. An anteroposterior pelvic radiograph reveals an APC-III pelvic ring injury (open book pelvis). A circumferential pelvic binder is ordered. To maximize the biomechanical reduction of the pelvic volume, the binder should be centered precisely over which of the following anatomical landmarks?
Correct Answer & Explanation
. The greater trochanters
Explanation
To effectively reduce pelvic volume and provide hemostasis in an 'open book' (APC) pelvic ring injury, a pelvic binder or sheet must be centered directly over the greater trochanters. This directs the compressive force through the femoral heads and into the acetabula, effectively closing the anterior diastasis at the pubic symphysis and reducing the posterior sacroiliac joints. Placing the binder higher (e.g., iliac crests) can actually flare the true pelvis and exacerbate the deformity.
Question 4960
Topic: Upper Extremity Trauma
A 29-year-old mountain biker falls directly onto the point of his shoulder. Radiographs reveal an acromioclavicular (AC) joint dislocation. He is diagnosed with a Rockwood Type V injury. Which of the following best describes the specific anatomical disruption and radiographic appearance that defines a Type V injury?
Correct Answer & Explanation
. Complete rupture of AC and CC ligaments with 25-100% superior displacement of the clavicle relative to the acromion
Explanation
The Rockwood classification of AC joint injuries is based on the degree and direction of distal clavicle displacement. Type I is a sprain; Type II involves AC rupture and CC sprain; Type III is complete rupture of AC and CC ligaments with 25-100% superior displacement. Type IV is posterior displacement into or through the trapezius. Type V is severe superior displacement (>100% and up to 300%) due to disruption of the AC ligaments, CC ligaments, and the deltotrapezial fascial attachments.
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