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 2581
Topic: Pelvic & Acetabular Trauma
A 25-year-old male unrestrained passenger is involved in a head-on motor vehicle collision. His knees strike the dashboard. In the emergency department, his right leg is severely painful and completely immobile. Which of the following postures is classic for an unreduced posterior hip dislocation?
Correct Answer & Explanation
. Hip flexed, adducted, and internally rotated
Explanation
A posterior hip dislocation typically presents with the affected limb shortened, flexed, adducted, and internally rotated. This occurs because the femoral head rests posterior and superior to the acetabulum, putting tension on the anterior hip capsule and Y-ligament.
Question 2582
Topic: 2. Trauma
A 24-year-old male presents with a displaced femoral neck fracture (Pauwels type III). What is the primary biomechanical advantage of using a dynamic hip screw (DHS) with a derotational screw compared to three parallel cannulated screws for this injury?
Correct Answer & Explanation
. Superior resistance to vertical shear forces
Explanation
Pauwels type III femoral neck fractures are vertically oriented and subjected to high shear forces. A sliding hip screw (DHS) with a derotational screw provides superior biomechanical resistance to these vertical shear forces compared to multiple cancellous screws.
Question 2583
Topic: 2. Trauma
A 45-year-old male sustains a high-energy Schatzker IV tibial plateau fracture (medial plateau). An MRI is obtained to evaluate soft tissue injuries. Which of the following ligamentous structures is most commonly injured in association with this specific fracture pattern?
Schatzker IV (medial tibial plateau) fractures typically occur from high-energy varus forces. This mechanism places extreme tension on the lateral-sided structures, leading to a high incidence of lateral collateral ligament (LCL) and posterolateral corner injuries.
Question 2584
Topic: Pelvic & Acetabular Trauma
A 35-year-old male presents with a hypotensive (BP 75/40 mmHg) pelvic ring injury after a crush injury. The FAST exam is negative. A pelvic binder is applied, but he remains persistently hypotensive (BP 80/45 mmHg) after 2 liters of crystalloid. The institution lacks immediate interventional radiology capabilities. What is the most appropriate next step in management?
Correct Answer & Explanation
. Preperitoneal pelvic packing
Explanation
In a hemodynamically unstable patient with a pelvic ring injury and negative FAST who fails to respond to a pelvic binder and volume resuscitation, retroperitoneal venous or cancellous bone bleeding is likely. Preperitoneal pelvic packing is the most appropriate and immediate lifesaving intervention, especially when angiography is unavailable.
Question 2585
Topic: 2. Trauma
A 30-year-old male falls from a height. Radiographs
demonstrate a comminuted intra-articular distal femur fracture. CT scan reveals an associated coronal plane fracture of the lateral femoral condyle. What surgical approach provides the most direct and extensile access for anatomic reduction and fixation of this specific articular fragment?
Correct Answer & Explanation
. Swashbuckler (extended lateral) approach
Explanation
The Swashbuckler approach, an extended lateral approach that elevates the vastus lateralis from the lateral intermuscular septum, provides excellent, highly extensile exposure of the distal femoral articular surface. This is particularly critical for visualizing and reducing complex intra-articular fractures involving coronal plane (Hoffa) fragments.
Question 2586
Topic: 2. Trauma
A 25-year-old competitive long-distance runner presents with bilateral lower leg pain, tightness, and paresthesias during running, resolving with rest. Intracompartmental pressure monitoring confirms Chronic Exertional Compartment Syndrome. Which of the following best describes the primary pathophysiological mechanism leading to his symptoms?
Correct Answer: CThe correct answer is C. Chronic Exertional Compartment Syndrome (CECS) is characterized by pathologically non-compliant fascial envelopes that fail to accommodate the transient increase in muscle volume (up to 20%) during vigorous exercise. This leads to a precipitous rise in intracompartmental pressure, compromising microvascular perfusion and causing ischemic pain and nerve compression.Option A describes acute compartment syndrome, which is typically traumatic and irreversible without immediate intervention. Option B describes Popliteal Artery Entrapment Syndrome, a vascular pathology involving dynamic arterial occlusion. Option D describes a tibial stress fracture, an osseous injury. Option E describes Medial Tibial Stress Syndrome, which involves diffuse inflammation along the posteromedial tibia, not primarily a fascial compliance issue.
Question 2587
Topic: 2. Trauma
Following a provocative exercise test, the patient's right anterior compartment pressures were recorded as: Resting 18 mm Hg, 1-minute post 45 mm Hg, 5-minute post 32 mm Hg. Based on the Pedowitz criteria, which of these readings alone would be sufficient to confirm the diagnosis of Chronic Exertional Compartment Syndrome in this compartment?
Correct Answer & Explanation
. All three readings (Resting, 1-minute post, and 5-minute post) are individually sufficient.
Explanation
Correct Answer: DThe correct answer is D. The Pedowitz criteria for diagnosing Chronic Exertional Compartment Syndrome state that one or more of the following pressure thresholds must be met: 1) A pre-exercise resting pressure greater than or equal to 15 mm Hg; 2) A one-minute post-exercise pressure greater than or equal to 30 mm Hg; 3) A five-minute post-exercise pressure greater than or equal to 20 mm Hg.In this patient's right anterior compartment, all three readings individually meet these criteria: Resting (18 mm Hg ≥ 15 mm Hg), 1-minute post (45 mm Hg ≥ 30 mm Hg), and 5-minute post (32 mm Hg ≥ 20 mm Hg). Therefore, any one of these readings would be sufficient for diagnosis.
Question 2588
Topic: 2. Trauma
A 25-year-old competitive long-distance runner presents with exertional lower leg pain. During the diagnostic workup, the orthopedic surgeon performs a focused vascular examination post-exercise. The preservation of strong dorsalis pedis and posterior tibial pulses post-exertion is a critical finding that helps differentiate Chronic Exertional Compartment Syndrome from which of the following conditions?
Correct Answer & Explanation
. Popliteal Artery Entrapment Syndrome
Explanation
Correct Answer: CThe correct answer is C. Popliteal Artery Entrapment Syndrome (PAES) is a critical vascular differential diagnosis for exertional leg pain. In PAES, the popliteal artery is dynamically compressed, typically by the medial head of the gastrocnemius, during active plantarflexion or exercise. This leads to claudication-like symptoms and, importantly, diminished or absent pedal pulses (dorsalis pedis and posterior tibial) during or immediately after exercise. Chronic Exertional Compartment Syndrome primarily affects the microcirculation and capillary beds, and major arterial inflow is rarely compromised, thus distal pulses typically remain palpable post-exertion.Options A, B, and D are musculoskeletal or neurological conditions that do not typically present with diminished distal pulses. Option E, Deep Vein Thrombosis, is a venous pathology and while it can cause leg pain and swelling, it is not typically exertional and does not cause diminished arterial pulses.
Question 2589
Topic: 2. Trauma
During the planned bilateral anterolateral fasciotomy for the patient, a single longitudinal incision was made approximately two centimeters lateral to the tibial crest. As the surgeon performed subcutaneous dissection and undermined tissues, meticulous care was taken to identify and protect a specific nerve that typically pierces the deep fascia of the lateral compartment to become subcutaneous. Which nerve is the surgeon most critically trying to identify and protect in this approach?
Correct Answer & Explanation
. Superficial peroneal nerve
Explanation
Correct Answer: CThe correct answer is C. The superficial peroneal nerve is the most critical nerve to identify and protect during an anterolateral fasciotomy. It typically pierces the deep fascia of the lateral compartment to become subcutaneous approximately 10-12 cm proximal to the lateral malleolus, often within the surgical field for a single-incision anterolateral approach. Injury to this nerve can result in permanent numbness over the dorsum of the foot and potentially neuropathic pain.The deep peroneal nerve is located deeper within the anterior compartment and is generally protected by the muscle bellies during this approach, though care must be taken during the fascial release. The sural nerve is located more posteriorly and laterally, typically not in the primary field of an anterolateral approach. The saphenous nerve is a sensory branch of the femoral nerve, located medially. The tibial nerve is in the posterior compartment.
Question 2590
Topic: 2. Trauma
Prior to intracompartmental pressure monitoring, the patient underwent standard weight-bearing radiographs and a resting MRI of the lower extremities, both of which were unremarkable. While resting MRI is often normal in Chronic Exertional Compartment Syndrome, which of the following advanced imaging findings, if obtained post-exercise, would be most suggestive of the condition?
Correct Answer & Explanation
. T2 hyperintensity within the affected compartments, reflecting increased extracellular fluid and edema.
Explanation
Correct Answer: DThe correct answer is D. While resting MRI is often normal in Chronic Exertional Compartment Syndrome (CECS), advanced imaging protocols utilizing post-exercise T2-weighted mapping can be highly suggestive of the condition. T2 hyperintensity within the affected compartments post-exercise reflects increased extracellular fluid and edema resulting from the compromised microcirculation and fluid extravasation, which is characteristic of CECS.Option A suggests a stress fracture or periostitis. Option B suggests a stress fracture or Medial Tibial Stress Syndrome. Option C suggests Popliteal Artery Entrapment Syndrome. Option E suggests Deep Vein Thrombosis. None of these are primary findings for CECS, and the case explicitly states resting MRI was unremarkable, ruling out early stress fractures or MTSS.
Question 2591
Topic: 2. Trauma
Given the patient's status as a high-demand competitive runner and the failure of conservative treatment, a bilateral anterolateral fasciectomy was performed. The decision to perform a partial fasciectomy (excision of a 1-2 cm strip of fascia) rather than a simple fasciotomy was primarily based on which of the following considerations?
Correct Answer & Explanation
. To significantly reduce the risk of fascial re-approximation and recurrent compartmental hypertension.
Explanation
Correct Answer: CThe correct answer is C. For high-demand competitive athletes, a partial fasciectomy (excision of a 1-2 cm strip of fascia) is often preferred over a simple fasciotomy. The primary rationale is to significantly reduce the risk of fascial re-approximation and subsequent recurrent compartmental hypertension. Simple fasciotomies, especially in the robust anterior compartment fascia, carry a higher risk of incomplete release or fascial scarring and re-tethering, leading to recurrence rates that can approach 15-20% in elite athletes. Excising a strip of fascia creates a larger, more permanent defect, minimizing this risk.Option A is incorrect; a fasciectomy typically requires a slightly larger incision than a minimally invasive fasciotomy. Option B is incorrect; nerve injury risk is related to meticulous dissection, not the extent of fascial excision. Option D is incorrect; nerve identification is a separate step. Option E is incorrect; hematoma prevention is achieved through meticulous hemostasis, not the type of fascial release.
Question 2592
Topic: 2. Trauma
The patient's symptoms of bursting pain, tightness, and paresthesias in specific muscle compartments, with insidious onset during exercise at a predictable time/distance and complete resolution within 30 minutes of rest, are highly characteristic of Chronic Exertional Compartment Syndrome. Which of the following clinical presentations would be most indicative of Medial Tibial Stress Syndrome (MTSS) rather than CECS?
Correct Answer & Explanation
. Diffuse, dull ache along the posteromedial border of the tibia, pain early in exercise, potentially improving during activity, and worsening post-exercise.
Explanation
Correct Answer: CThe correct answer is C. Medial Tibial Stress Syndrome (MTSS) typically presents as a diffuse, dull ache along the posteromedial border of the distal third of the tibia. A key differentiating feature from CECS is its onset and offset characteristics: pain often occurs early in exercise, may warm up and improve during the activity, and then returns or worsens post-exercise, often with a prolonged ache at rest. Palpation reveals diffuse tenderness along the tibial crest, rather than tense muscle compartments.Option A describes Popliteal Artery Entrapment Syndrome. Option B describes a Tibial Stress Fracture. Option D describes Superficial Peroneal Nerve Entrapment. Option E describes a more severe or persistent neurological deficit not typical of CECS's transient nature, or potentially a different neurological pathology. The case specifically highlights the differences in the comparative analysis table.
Question 2593
Topic: 2. Trauma
A 22-year-old collegiate distance runner complains of bilateral lower leg pain that begins reliably after 3 miles of running and resolves after 20 minutes of rest. Suspecting chronic exertional compartment syndrome, compartment pressures are measured. Which of the following measurements meets the diagnostic criteria for this condition?
Correct Answer & Explanation
. 5-minute post-exercise pressure of 22 mm Hg
Explanation
The Pedowitz criteria for chronic exertional compartment syndrome include a pre-exercise pressure >=15 mm Hg, a 1-minute post-exercise pressure >=30 mm Hg, or a 5-minute post-exercise pressure >=20 mm Hg.
Question 2594
Topic: 2. Trauma
A 19-year-old female soccer player is diagnosed with chronic exertional compartment syndrome. She notes transient numbness on the dorsum of her foot, particularly in the first web space, after matches. Which compartment is most likely affected?
Correct Answer & Explanation
. Anterior compartment
Explanation
The anterior compartment is most commonly affected in CECS. Compression of the deep peroneal nerve within this compartment can cause paresthesias in the first dorsal web space.
Question 2595
Topic: 2. Trauma
A 28-year-old military recruit presents with chronic exertional compartment syndrome isolated to the deep posterior compartment of the leg. During fasciotomy, which of the following structures must be carefully protected to avoid causing plantar foot paresthesias?
Correct Answer & Explanation
. Tibial nerve
Explanation
The tibial nerve runs within the deep posterior compartment of the leg. Injury during deep posterior fasciotomy can result in numbness or paresthesias over the plantar aspect of the foot.
Question 2596
Topic: 2. Trauma
A 25-year-old runner undergoes a fasciotomy for chronic exertional compartment syndrome of the lateral compartment. Postoperatively, she complains of numbness over the dorsum of her foot, excluding the first web space, but has full motor function. Which nerve was most likely injured during the surgical approach?
Correct Answer & Explanation
. Superficial peroneal nerve
Explanation
The superficial peroneal nerve exits the lateral compartment fascia in the distal third of the leg. It is at high risk of iatrogenic injury during lateral compartment fasciotomy, leading to dorsal foot numbness.
Question 2597
Topic: 2. Trauma
A 22-year-old collegiate runner presents with bilateral anterior leg pain that occurs 15 minutes into a run and resolves after 30 minutes of rest. Intracompartmental pressure testing is performed. According to the modified Pedowitz criteria, which of the following measurements confirms the diagnosis of Chronic Exertional Compartment Syndrome (CECS)?
Correct Answer & Explanation
. 1 minute post-exercise pressure ≥ 30 mmHg
Explanation
The modified Pedowitz criteria for diagnosing CECS require one or more of the following: resting pressure ≥ 15 mmHg, 1 minute post-exercise pressure ≥ 30 mmHg, or 5 minutes post-exercise pressure ≥ 20 mmHg. A 1-minute post-exercise pressure of 30 mmHg or greater is highly diagnostic.
Question 2598
Topic: 2. Trauma
A 25-year-old female undergoes a two-incision fasciotomy for anterior and lateral Chronic Exertional Compartment Syndrome. Postoperatively, she reports numbness over the dorsum of her foot, though sensation in the first web space remains intact. Which nerve was most likely iatrogenically injured during the procedure?
Correct Answer & Explanation
. Superficial peroneal nerve
Explanation
The superficial peroneal nerve provides sensation to the dorsum of the foot (sparing the first web space) and is at high risk of injury during lateral and anterior compartment fasciotomies as it exits the fascia approximately 10-12 cm proximal to the lateral malleolus.
Question 2599
Topic: 2. Trauma
A 20-year-old cross-country runner is diagnosed with anterior Chronic Exertional Compartment Syndrome. She strongly wishes to avoid surgical fasciotomy. Which of the following gait modifications is most likely to reduce her symptoms?
Correct Answer & Explanation
. Transitioning from a rearfoot (heel) strike to a forefoot strike
Explanation
Transitioning to a forefoot strike reduces the eccentric load on the tibialis anterior muscle during the initial contact phase of running. This modification has been shown to significantly lower anterior compartment pressures and alleviate CECS symptoms.
Question 2600
Topic: 2. Trauma
A 24-year-old soldier presents with exertional calf pain that forces him to stop running. Pre- and post-exercise intracompartmental pressures are within normal limits. Physical examination reveals diminished pedal pulses specifically during active ankle plantarflexion against resistance. What is the most likely diagnosis?
Correct Answer & Explanation
. Popliteal artery entrapment syndrome
Explanation
Popliteal artery entrapment syndrome (PAES) often mimics CECS but is characterized by vascular claudication. The pathognomonic sign is a decrease or loss of pedal pulses with active plantarflexion, which compresses the popliteal artery against an anomalous medial head of the gastrocnemius.
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