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 4401
Topic: 2. Trauma
When performing a decompressive fasciotomy for acute compartment syndrome of the foot, the surgeon intentionally opens the medial compartment. Which of the following muscles is located exclusively within this specific compartment?
Correct Answer & Explanation
. Adductor hallucis
Explanation
The medial compartment of the foot contains the abductor hallucis and the flexor hallucis brevis muscles. The superficial (central) compartment contains the flexor digitorum brevis. The adductor compartment contains the adductor hallucis. The calcaneal compartment contains the quadratus plantae.
Question 4402
Topic: 2. Trauma
A 22-year-old collegiate basketball player sustains a fracture of the fifth metatarsal at the metaphyseal-diaphyseal junction extending into the intermetatarsal facet. What is the most appropriate management to ensure optimal outcome and return to play?
Correct Answer & Explanation
. Hard-soled shoe weight-bearing as tolerated
Explanation
This describes a Zone 2 (Jones) fracture. In high-level or competitive athletes, acute intramedullary screw fixation is recommended. It significantly reduces the risk of nonunion and allows for an earlier return to sport compared to non-operative management, which carries a high rate of delayed union or nonunion due to the watershed blood supply in this zone.
Question 4403
Topic: 2. Trauma
A 20-year-old track athlete is diagnosed with a mid-body tarsal navicular stress fracture. Non-operative management is chosen. Why is this specific anatomical location at high risk for delayed union or nonunion?
Correct Answer & Explanation
. It is subjected to constant tensile forces from the tibialis posterior
Explanation
The tarsal navicular receives its blood supply from branches of the dorsalis pedis and medial plantar arteries forming a network on its dorsal and plantar surfaces. Microangiographic studies show that the central third of the navicular body is a watershed area and is relatively avascular. This renders stress fractures in this central region highly prone to delayed union or nonunion.
Question 4404
Topic: 2. Trauma
A 35-year-old male sustains a severe crush injury to the foot from heavy machinery. Clinical examination demonstrates tense swelling and excruciating pain with passive toe extension, raising strong clinical suspicion for compartment syndrome. How many distinct fascial compartments are generally recognized in the foot?
Correct Answer & Explanation
. 4
Explanation
There are 9 recognized fascial compartments in the foot: the medial, lateral, superficial, and calcaneal compartments, four interosseous compartments, and the adductor compartment. Fasciotomies are typically performed via a dual dorsal incision approach or a single extensive medial incision, depending on the injury pattern and surgeon preference.
Question 4405
Topic: 2. Trauma
A 25-year-old skier sustains an inversion injury to the ankle. Examination reveals tenderness over the posterior margin of the distal fibula. Radiographs show a small cortical avulsion fracture from the lateral ridge of the distal fibula (Fleck sign). What is the most likely diagnosis?
Correct Answer & Explanation
. Anterior talofibular ligament avulsion
Explanation
The 'fleck sign' at the posterior margin of the lateral malleolus on an AP or mortise radiograph represents a bony avulsion of the superior peroneal retinaculum (SPR). This radiographic finding is pathognomonic for a peroneal tendon subluxation or dislocation.
Question 4406
Topic: 2. Trauma
In the operative management of a trimalleolar ankle fracture, what constitutes a widely accepted modern indication for direct internal fixation of the posterior malleolus?
Correct Answer & Explanation
. Any posterior malleolus fracture regardless of fragment size
Explanation
Traditionally, posterior malleolar fragments were fixed only if they involved >25-33% of the articular surface. Modern indications have expanded, recognizing the importance of the posterior malleolus in syndesmotic stability (via the PITFL). Current indications include fragments involving >25% of the articular surface, persistent posterior subluxation of the talus, persistent displacement or step-off of the fragment after fibular reduction, or concomitant syndesmotic instability where fixing the fragment securely restores the PITFL.
Question 4407
Topic: 2. Trauma
According to the Lauge-Hansen classification of ankle fractures, a Supination-External Rotation (SER) type IV fracture classically involves disruption of the deltoid ligament or a transverse fracture of the medial malleolus. What represents the very first stage (Stage I) of injury in the SER sequence?
Correct Answer & Explanation
. Rupture of the anterior inferior tibiofibular ligament (AITFL)
Explanation
The Lauge-Hansen Supination-External Rotation (SER) sequence is the most common ankle fracture pattern and progresses in four distinct stages: Stage I: Rupture of the anterior inferior tibiofibular ligament (AITFL); Stage II: Spiral or oblique fracture of the distal fibula; Stage III: Rupture of the posterior inferior tibiofibular ligament (PITFL) or avulsion fracture of the posterior malleolus; Stage IV: Rupture of the deltoid ligament or transverse avulsion fracture of the medial malleolus.
Question 4408
Topic: 2. Trauma
A 38-year-old female presents with a closed spiral fracture of the distal third of the tibial shaft following a skiing fall. Initial anteroposterior and lateral radiographs of the tibia demonstrate the diaphyseal fracture but are otherwise unremarkable. What is the most appropriate next step in radiographic evaluation to rule out a commonly associated, yet frequently missed, injury?
Correct Answer & Explanation
. Anteroposterior and lateral radiographs of the knee
Explanation
Spiral distal third tibia fractures have a high association (up to 50-90%) with occult posterior malleolar fractures. A CT scan of the ankle is highly recommended in this fracture pattern to identify and characterize intra-articular extension.
Question 4409
Topic: 2. Trauma
A 27-year-old male sustains a Hawkins II talar neck fracture and undergoes urgent open reduction and internal fixation. At the 8-week postoperative visit, an anteroposterior radiograph of the ankle demonstrates a subchondral radiolucent band across the talar dome. What does this radiographic finding indicate?
Correct Answer & Explanation
. Impending avascular necrosis of the talar body
Explanation
A subchondral radiolucent band on the talar dome is known as the Hawkins sign. It represents subchondral atrophy secondary to hyperemia and disuse, indicating that the vascular supply to the talar body remains intact.
Question 4410
Topic: 2. Trauma
A 32-year-old male sustains a severe ankle fracture-dislocation. Closed reduction in the emergency department is unsuccessful despite adequate sedation and muscle relaxation. Post-reduction radiographs reveal that the distal fibula remains entrapped posterior to the posterior tubercle of the distal tibia. Which of the following best describes this specific injury pattern?
Correct Answer & Explanation
. Tillaux fracture
Explanation
A Bosworth fracture-dislocation is characterized by the proximal fragment of the fractured fibula becoming locked behind the posterior tubercle of the tibia. This irreducible pattern invariably requires open reduction.
Question 4411
Topic: 2. Trauma
A 21-year-old collegiate track athlete presents with insidious onset dorsal midfoot pain. A CT scan confirms a stress fracture of the tarsal navicular. Which specific region of the navicular is at the highest risk for delayed union or nonunion due to its inherently poor vascularity?
Correct Answer & Explanation
. Dorsal lip
Explanation
The central third of the tarsal navicular constitutes a vascular watershed area between the branches of the dorsalis pedis and medial plantar arteries. This tenuous blood supply makes stress fractures in this zone prone to nonunion.
Question 4412
Topic: 2. Trauma
A 68-year-old diabetic female with a history of peripheral neuropathy sustains a closed avulsion fracture of the calcaneal tuberosity following a fall. The posterior skin over the heel is severely blanched and tented by the fracture fragment. What is the most appropriate initial management?
Correct Answer & Explanation
. Application of a short leg cast in maximal equinus
Explanation
Displaced calcaneal tuberosity avulsion fractures that cause skin tenting and blanching are orthopedic emergencies. Urgent surgical reduction and fixation are required to relieve pressure and prevent devastating posterior heel skin necrosis.
Question 4413
Topic: Lower Extremity Trauma
A 28-year-old soccer player experiences sudden lateral ankle pain accompanied by a popping sensation during a rapid cutting maneuver. Physical examination reveals subluxation of the peroneal tendons anterior to the lateral malleolus with resisted eversion. Insufficiency of which of the following structures is most likely responsible?
Correct Answer & Explanation
. Inferior peroneal retinaculum
Explanation
The superior peroneal retinaculum (SPR) is the primary restraint preventing anterior subluxation of the peroneal tendons over the lateral malleolus. Injury to the SPR or its fibular attachment ('fleck sign') is the hallmark of peroneal tendon dislocation.
Question 4414
Topic: 2. Trauma
A 30-year-old construction worker sustains a severe crush injury to the foot from a falling steel beam. Acute compartment syndrome of the foot is suspected. Anatomically, how many distinct fascial compartments are generally recognized within the foot?
Correct Answer & Explanation
. 3
Explanation
There are 9 commonly recognized fascial compartments in the foot: medial, lateral, superficial central, deep central, calcaneal, and four interosseous compartments. All must be carefully released if full foot compartment syndrome is confirmed.
Question 4415
Topic: 2. Trauma
A 20-year-old elite basketball player sustains a fracture of the fifth metatarsal at the metaphyseal-diaphyseal junction, with the fracture line extending into the fourth-fifth intermetatarsal facet. To minimize the risk of nonunion and expedite return to play, what is the most appropriate definitive management?
Correct Answer & Explanation
. Non-weight-bearing short leg cast for 6 weeks
Explanation
This describes a true Jones fracture (Zone 2). In elite athletes, operative treatment with an intramedullary screw is recommended to decrease the time to union, lower the nonunion rate, and accelerate return to sport.
Question 4416
Topic: 2. Trauma
During an extensile lateral approach for a displaced intra-articular calcaneus fracture, the surgeon must be careful to protect the primary vascular supply to the lateral soft tissue flap. Which artery provides this primary supply?
Correct Answer & Explanation
. Lateral calcaneal artery
Explanation
The lateral calcaneal artery provides the primary blood supply to the lateral extensile flap used in calcaneus fracture fixation. Careful full-thickness subperiosteal dissection is required to protect this vessel and minimize the risk of wound edge necrosis.
Question 4417
Topic: 2. Trauma
A 32-year-old female presents with an isolated lateral malleolus fracture. A gravity stress radiograph demonstrates a medial clear space of 6 mm. This finding is indicative of a complete disruption of which of the following structures?
Correct Answer & Explanation
. Anterior inferior tibiofibular ligament
Explanation
A medial clear space of greater than 4 to 5 mm on a gravity stress or weight-bearing radiograph indicates a complete disruption of the deep deltoid ligament. This converts an isolated lateral malleolus fracture into an unstable bimalleolar-equivalent injury requiring operative fixation.
Question 4418
Topic: 2. Trauma
A 21-year-old collegiate basketball player sustains a fracture at the metaphyseal-diaphyseal junction of the fifth metatarsal base. What is the most appropriate management to minimize the risk of nonunion and allow early return to sport?
Correct Answer & Explanation
. Non-weight bearing in a short leg cast for 6 weeks
Explanation
Intramedullary screw fixation is the gold standard for acute Jones fractures in elite athletes. This approach provides rigid stabilization of the watershed vascular zone, minimizing nonunion risk and allowing for an accelerated return to competitive sports.
Question 4419
Topic: 2. Trauma
A 22-year-old man falls 30 feet from a roof, landing on his buttocks. He complains of severe sacral pain, perineal numbness, and inability to void. Radiographs and CT demonstrate a transverse sacral fracture at the S2 level connecting bilateral longitudinal sacral fractures. Which of the following terms best describes this fracture pattern, and what is the primary neurovascular concern?
A transverse fracture through the upper sacrum (typically S1 or S2) connecting bilateral longitudinal transforaminal fractures represents a 'U-type' or 'H-type' sacral fracture. This results in spinopelvic dissociation, separating the upper spine/central sacrum from the pelvis. Because the fracture passes transversely through the sacral canal, there is a very high incidence of neurologic injury, specifically cauda equina syndrome, leading to bowel, bladder, and sexual dysfunction, as well as perineal numbness.
Question 4420
Topic: Pelvic & Acetabular Trauma
A 35-year-old male is involved in a motorcycle accident. Radiographs reveal an anteroposterior compression (APC) type II pelvic ring injury. Which of the following posterior pelvic ligamentous structures is characteristically disrupted in this specific injury pattern?
Correct Answer & Explanation
. Anterior sacroiliac, sacrotuberous, and sacrospinous ligaments
Explanation
APC II injuries involve symphyseal diastasis and disruption of the anterior sacroiliac (SI) ligaments, as well as the sacrotuberous and sacrospinous ligaments. The critical distinction is that the strong posterior SI ligaments remain intact, providing vertical stability but allowing rotational instability (the 'open book' pelvic injury). APC III involves disruption of both anterior and posterior SI ligaments, resulting in both rotational and vertical instability.
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