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 4501
Topic: 2. Trauma
A 40-year-old male undergoes intramedullary nailing of a comminuted femoral shaft fracture utilizing a fracture table. Postoperatively, he complains of perineal numbness and erectile dysfunction. What is the most likely etiology of this complication?
Correct Answer & Explanation
. Unrecognized unstable pelvic ring injury
Explanation
Pudendal nerve neuropraxia is a known complication of utilizing a fracture table for femoral nailing. It is caused by prolonged, excessive traction against a hard or poorly padded perineal post.
Question 4502
Topic: 2. Trauma
A 30-year-old man sustains a closed mid-distal humeral shaft fracture. His initial neurologic examination in the trauma bay is entirely normal. Following an attempt at closed reduction and application of a coaptation splint, he is noted to have a complete loss of wrist and finger extension. What is the most appropriate management?
Correct Answer & Explanation
. Observation and repeat examination in 1 week
Explanation
A secondary radial nerve palsy that develops strictly after a closed reduction attempt of a humeral shaft fracture is an absolute indication for immediate surgical exploration. This presentation suggests the nerve may have become entrapped within the fracture site during manipulation.
Question 4503
Topic: 2. Trauma
A 35-year-old man sustains a lateral compression (LC-1) pelvic ring injury involving a significantly displaced fracture through the sacral ala. On physical examination, he demonstrates weakness in ankle dorsiflexion and great toe extension. Which nerve root is most likely compromised by this specific fracture?
Correct Answer & Explanation
. L3
Explanation
The L5 nerve root courses directly over the anterior aspect of the sacral ala before joining the sacral plexus. Displaced fractures of the sacral ala can stretch or impale the L5 root, causing profound weakness in ankle and hallux dorsiflexion.
Question 4504
Topic: 2. Trauma
A 65-year-old woman sustains a 3-part proximal humerus fracture. Her pain prevents any active shoulder movement. To accurately assess the function of the axillary nerve in this acute setting, which examination finding is most reliable?
Correct Answer & Explanation
. Palpating the tone of the teres minor during attempted external rotation
Explanation
Because severe pain precludes reliable motor testing of the deltoid and teres minor in an acute proximal humerus fracture, evaluating sensation over the lateral deltoid (innervated by the superior lateral brachial cutaneous branch of the axillary nerve) is the most reliable clinical test.
Question 4505
Topic: 2. Trauma
A 25-year-old man sustains a Grade II open fracture of the middle third of the humerus. On initial evaluation, he has an absent brachioradialis reflex and is entirely unable to extend his wrist or fingers. What is the standard of care for the nerve injury in this specific scenario?
Correct Answer & Explanation
. Observation and delayed EMG at 6 weeks
Explanation
An open humerus fracture combined with a radial nerve palsy is an absolute indication for surgical exploration of the radial nerve. This is performed concurrently with the required surgical debridement and fracture stabilization.
Question 4506
Topic: 2. Trauma
A 22-year-old man sustains a low-velocity gunshot wound to the arm, resulting in a comminuted midshaft humerus fracture and a complete radial nerve palsy. Distal pulses are strong, and the limb is well-perfused. What is the most appropriate initial treatment strategy?
Correct Answer & Explanation
. Immediate open nerve exploration and ORIF of the humerus
Explanation
Radial nerve palsies associated with low-velocity gunshot wounds to the humerus are typically neuropraxias. The standard of care is non-operative management initially with observation. Surgical exploration is reserved for those failing to show clinical or EMG recovery by 3-4 months.
Question 4507
Topic: 2. Trauma
A patient sustained a fracture of the left acetabulum. A single axial CT scan from a two-dimensional study is shown in Figure 61. This fracture pattern is best classified as
Correct Answer & Explanation
. both column.
Explanation
A transverse fracture divides the innominate bone into two portions. The fracture plane is horizontal (or semihorizontal) through the acetabulum at a variable proximal distal level. The superior segment retains a portion of the acetabular roof and the lower ischiopubic segment, the intact obturator foramen. A sagittally oriented fracture line is typically seen on axial view assessment.
Question 4508
Topic: 2. Trauma
Which of the following factors is considered most important when assessing an ankle fracture for surgical treatment?
Correct Answer & Explanation
. Position of the talus in the mortise
Explanation
Although all of these factors may influence the decision to perform surgery, the most important is the position of the talus in the mortise. The goal of treatment of ankle fractures is to maintain the talus centered in the mortise. If it is in this position, the other factors do not enter into the decision to intervene surgically.
Question 4509
Topic: 2. Trauma
Which of the following long bone fracture patterns occurs after a pure bending force is exerted to the bone?
Correct Answer & Explanation
. Transverse
Explanation
A pure bending force produces a transverse fracture pattern. Spiral fractures are mainly rotational, oblique are uneven bending, segmental are four-point bending, and comminuted are either a high-speed torsion or crush mechanism.
Question 4510
Topic: 2. Trauma
A patient is scheduled for a TKA. Radiographs show a healed midshaft femur fracture with a 15-degree coronal plane varus deformity. If an intra-articular bone resection is performed strictly perpendicular to the mechanical axis of the femur to correct alignment, what is the most likely consequence?
Correct Answer & Explanation
. Need for excessive distal lateral femoral resection leading to lateral collateral ligament laxity
Explanation
In the presence of a diaphyseal femoral varus deformity, the mechanical axis deviates medially. To cut perpendicular to this mechanical axis intra-articularly, the surgeon must resect a larger amount of bone from the lateral distal femur. This leads to relative lateral collateral ligament laxity in extension.
Question 4511
Topic: 2. Trauma
A 65-year-old male with a B2 glenoid (posterior wear, retroversion of 20 degrees) is undergoing anatomic total shoulder arthroplasty. What is the maximum amount of retroversion correction that should be attempted with eccentric anterior reaming alone before unacceptably compromising glenoid vault bone stock?
Correct Answer & Explanation
. 15 degrees
Explanation
Eccentric reaming is typically limited to correcting up to 10-15 degrees of retroversion. Reaming beyond 15 degrees removes excessive subchondral bone, narrowing the glenoid vault and compromising the fixation of the glenoid component.
Question 4512
Topic: 2. Trauma
A 72-year-old female sustains a periprosthetic femur fracture around a cemented polished taper stem. Radiographs reveal a comminuted fracture around the tip of the stem. The stem is loose, and there is severe proximal femoral bone loss preventing adequate diaphyseal fixation. How is this classified and most appropriately managed?
Correct Answer & Explanation
. Vancouver B3; managed with revision to a modular fluted tapered stem or proximal femoral replacement
Explanation
A fracture around the stem tip with a loose stem and poor bone stock is a Vancouver B3 fracture. The standard of care is revision arthroplasty bypassing the fracture using a modular fluted tapered stem or a proximal femoral replacement (megaprosthesis) if the bone loss is too severe.
Question 4513
Topic: 2. Trauma
What is the primary advantage of two incisions compared to one for open reduction internal fixation of a both bones forearm fracture?
Correct Answer & Explanation
. Lower risk of synostosis
Explanation
Post-osteosynthetic synostosis is a known complication in both bone forearm fractures. The risk is increased in fractures of the proximal 1/3 of the ulna and radius. Other risk factors include severity of injury, head trauma, and polytrauma. Vince et al found synostosis was often associated with bone fragments or hardware in the interosseous space. Bauer et al found 1/65 cases treated utilizing the two-incision approach developed synostosis, while 5/12 cases in which the fractures were stabilized using a single incision developed synostoses. They recommended a two-incision approach to both bones ORIF.
Question 4514
Topic: 2. Trauma
A 25-year-old professional soccer player sustains a fracture at the metaphyseal-diaphyseal junction of the fifth metatarsal.
Given his athletic status, what is the recommended treatment to minimize nonunion risk and expedite return to play?
Correct Answer & Explanation
. Intramedullary screw fixation
Explanation
A fracture at the metaphyseal-diaphyseal junction of the fifth metatarsal is a true Jones fracture. This area represents a vascular watershed zone, predisposing the fracture to a high rate of delayed union or nonunion. In high-demand athletes, early intramedullary screw fixation is recommended to achieve the highest union rates and the fastest return to sport, compared to non-operative casting.
Question 4515
Topic: Pelvic & Acetabular Trauma
A 40-year-old female with systemic lupus erythematosus on chronic corticosteroids presents with progressive groin pain. MRI reveals a crescent sign in the anterosuperior aspect of the femoral head. According to the Ficat and Arlet classification of osteonecrosis, what stage does this radiographic finding represent?
Correct Answer & Explanation
. Stage III
Explanation
The Ficat and Arlet classification for osteonecrosis of the femoral head is as follows: Stage I has normal radiographs but abnormal MRI/bone scan; Stage II shows cystic/sclerotic changes on radiographs but a spherical head; Stage III is characterized by subchondral collapse, which is radiographically visible as the 'crescent sign'; Stage IV involves complete collapse of the femoral head with secondary degenerative changes in the acetabulum (joint space narrowing).
Question 4516
Topic: Lower Extremity Trauma
A 32-year-old male sustains a midfoot injury while playing football. Weight-bearing radiographs demonstrate a 3 mm diastasis between the medial and middle cuneiforms and a "fleck sign" in the first intermetatarsal space. Which ligament complex is primarily disrupted in this injury?
Correct Answer & Explanation
. Interosseous ligament connecting the medial cuneiform to the second metatarsal base
Explanation
The Lisfranc ligament is an oblique interosseous ligament that connects the lateral aspect of the medial cuneiform to the medial aspect of the base of the second metatarsal. It is the strongest and most critical ligament stabilizing the tarsometatarsal joint complex. The "fleck sign" is pathognomonic for a Lisfranc injury and represents a bony avulsion of this ligament, usually from the base of the second metatarsal.
Question 4517
Topic: 2. Trauma
A 35-year-old female sustains a high-energy knee dislocation. On examination in the emergency department, the foot is cool with diminished pulses. An ankle-brachial index (ABI) is 0.7. A subsequent CT angiogram confirms a complete popliteal artery occlusion. What is the most appropriate sequence of surgical intervention?
Correct Answer & Explanation
. Skeletal stabilization with a spanning external fixator, followed by vascular repair, then prophylactic fasciotomies
Explanation
In a knee dislocation with hard signs of vascular compromise (ABI < 0.9, absent pulses, confirmed occlusion), emergent restoration of blood flow is critical. The standard sequence is temporary skeletal stabilization (typically a spanning external fixator) to protect the vascular repair, followed immediately by vascular repair (or temporary shunting if ischemia time is critical), and finally prophylactic four-compartment fasciotomies to prevent compartment syndrome secondary to reperfusion injury. Performing ligament reconstruction in the acute ischemic/vascular repair setting is contraindicated.
Question 4518
Topic: 2. Trauma
A 32-year-old man sustains a completely displaced Pauwels type III femoral neck fracture in a motor vehicle accident. Which of the following fixation constructs provides the most biomechanically stable fixation against the dominant vertical shear forces present in this fracture pattern?
Correct Answer & Explanation
. Dynamic hip screw (sliding hip screw) with a derotation screw
Explanation
Pauwels III fractures (>50 degrees to horizontal) are characterized by high vertical shear forces. Fixed-angle constructs, such as a sliding hip screw (dynamic hip screw), provide superior biomechanical stability against vertical shear and varus collapse compared to multiple cancellous screws. A derotation screw is often added to control rotation during insertion and postoperatively.
Question 4519
Topic: Pelvic & Acetabular Trauma
According to the Young-Burgess classification, an anteroposterior compression type II (APC-II) pelvic ring injury is characterized by the disruption of the symphysis pubis and which of the following posterior structures?
Correct Answer & Explanation
. Disrupted anterior SI ligaments, intact posterior SI ligaments, and disrupted sacrotuberous/sacrospinous ligaments
Explanation
In an APC-II injury, there is widening of the symphysis pubis > 2.5 cm, with tearing of the anterior sacroiliac (SI) ligaments, sacrotuberous, and sacrospinous ligaments. The posterior SI ligaments remain intact, providing vertical stability but allowing rotational instability ('open book'). An APC-III injury involves disruption of both anterior and posterior SI ligaments.
Question 4520
Topic: 2. Trauma
A 40-year-old construction worker falls from a ladder and sustains an intra-articular calcaneus fracture. Based on the Sanders classification, a coronal CT image showing two articular fragments (one primary fracture line) through the posterior facet is classified as:
Correct Answer & Explanation
. Type II
Explanation
The Sanders classification is based on coronal CT images of the posterior facet. Type I: non-displaced. Type II: two articular fragments (one fracture line). Type III: three articular fragments (two lines). Type IV: four or more articular fragments (highly comminuted).
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