OITE & AAOS Orthopedic Board Review MCQs: Part 53

Question 1

A 65-year-old male presents with profound upper extremity weakness and mild lower extremity weakness after a hyperextension injury to his cervical spine. He has no cortical sensory loss but complains of burning pain in his hands. According to recent literature evaluating acute central cord syndrome without frank mechanical instability, what is the optimal timing and role of surgical decompression?

Explanation

Historically, acute central cord syndrome was managed non-operatively or with delayed surgery to allow cord edema to subside. However, recent studies and subset analyses of trials (such as STASCIS) have shown that early surgical decompression (within 24 hours) in patients with acute central cord syndrome and focal compression is safe and yields significantly improved ASIA motor scores and functional outcomes compared to delayed surgery or conservative care.

Question 2

A radiograph of the pelvis in a trauma patient shows a fracture involving the right acetabulum. Analysis of the standardized radiographic lines reveals that the iliopectineal line is disrupted, but the ilioischial line remains completely intact. The anterior rim of the acetabulum is also fractured. Which Letournel fracture pattern does this most likely represent?

Explanation

According to the Letournel and Judet classification of acetabular fractures, disruption of the iliopectineal line on an AP radiograph indicates an anterior column or anterior wall fracture. Because the ilioischial line (which defines the posterior column) is intact, this is an isolated anterior column fracture. Transverse and both column fractures would disrupt both lines.

Question 3

A 34-year-old male sustains a Hawkins Type III talar neck fracture following a motor vehicle collision. Which of the following is the predominant blood supply to the talar body that is most consistently disrupted in this fracture pattern?

Explanation

The artery of the tarsal canal, a branch of the posterior tibial artery, is the predominant blood supply to the body of the talus. It forms an anastomotic sling with the artery of the tarsal sinus (from the dorsalis pedis/anterior tibial artery). In a Hawkins Type III fracture (talar neck fracture with subtalar and tibiotalar dislocation), the artery of the tarsal canal, artery of the tarsal sinus, and often the deltoid branches are all disrupted, leading to a near 100% rate of avascular necrosis.

Question 4

A 45-year-old female sustains a Schatzker IV tibial plateau fracture with a large, displaced posteromedial fragment. Biomechanically, what is the most appropriate internal fixation strategy to address the posteromedial fragment?

Explanation

Schatzker IV fractures involve the medial tibial plateau. A classic variant includes a coronal fracture line creating a posteromedial fragment. This fragment is subjected to significant shear forces during weight-bearing and knee flexion. Biomechanically, it is best neutralized with a posteromedial buttress plate placed directly at the apex of the fracture, preventing apex-posterior and medial subluxation of the medial femoral condyle.

Question 5

A 25-year-old male sustains a Type IIA odontoid fracture (transverse fracture comminuted at the base) following a high-speed collision. Which of the following conditions represents an absolute contraindication to anterior odontoid screw fixation?

Explanation

Anterior odontoid screw fixation requires an intact transverse atlantal ligament to maintain C1-C2 stability after the dens is fixed. If the transverse ligament is ruptured, the C1 ring can still translate anteriorly on C2 even if the odontoid fracture heals, leading to persistent atlantoaxial instability. Therefore, an associated transverse ligament rupture is an absolute contraindication to anterior screw fixation; a posterior C1-C2 instrumented fusion is required.

Question 6

When evaluating a comminuted intra-articular calcaneus fracture to determine surgical strategy, the Sanders classification is utilized based on computed tomography (CT) imaging. Which anatomical structure determines the primary classification lines in this system?

Explanation

The Sanders classification is based on the coronal CT section that displays the widest aspect of the posterior facet of the calcaneus. The posterior facet is divided into three columns by two lines, creating potential for 4 pieces (A, B, C, and the sustentacular fragment). The number and location of fracture lines through the posterior facet dictate the Sanders type (I through IV).

Question 7

A 28-year-old male sustains a vertically oriented femoral neck fracture (Pauwels Type III). What is the primary biomechanical advantage of utilizing a sliding hip screw (SHS) with a derotational screw over three parallel cannulated cancellous screws (CCS) for this specific fracture pattern?

Explanation

Pauwels Type III femoral neck fractures have a vertical fracture line (angle > 50 degrees to the horizontal), resulting in very high vertical shear forces that predispose to varus collapse and nonunion. Biomechanical studies have demonstrated that a fixed-angle construct like a sliding hip screw (SHS) provides significantly greater resistance to vertical shear forces compared to three parallel cannulated screws.

Question 8

A 35-year-old female presents with severe elbow pain after falling onto an outstretched hand. The lateral elbow radiograph demonstrates a 'double-arc sign.' What does this classic radiographic finding indicate regarding the distal humerus fracture pattern?

Explanation

The 'double-arc sign' on a lateral radiograph of the elbow is pathognomonic for a capitellum fracture that extends medially to include a significant portion of the trochlea (McKee modification Type IV). The two arcs represent the subchondral bone of the capitellum and the lateral ridge of the trochlea. Identifying this requires adequate surgical approach and fixation of both articular segments.

Question 9

A 40-year-old male falls from a height of 10 feet, sustaining an L1 burst fracture. He is neurologically intact on presentation. A subsequent MRI demonstrates an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is his total score and the generally recommended management?

Explanation

The TLICS system assigns points based on three categories: injury morphology, neurologic status, and integrity of the posterior ligamentous complex (PLC). Burst fracture morphology = 2 points. Neurologically intact = 0 points. Intact PLC = 0 points. Total score = 2. A score of 3 or less is an indication for non-operative management, a score of 4 is equivocal, and 5 or more indicates operative intervention.

Question 10

A 25-year-old male is admitted with a highly comminuted, closed tibial shaft fracture. Hours later, he complains of severe leg pain out of proportion to the injury. Compartment pressures are measured. Which of the following threshold formulas is considered the most reliable indicator for diagnosing acute compartment syndrome and proceeding with fasciotomy?

Explanation

The delta pressure (Delta P) calculation is the most accurate criteria for diagnosing acute compartment syndrome. It is defined as the Diastolic Blood Pressure minus the intracompartmental pressure. A Delta P of less than 30 mmHg indicates inadequate capillary perfusion to the muscle and is an absolute indication for emergent fasciotomy.

Question 11

A 22-year-old collegiate athlete sustains a purely ligamentous Lisfranc injury. Based on level I prospective randomized literature comparing primary arthrodesis versus open reduction and internal fixation (ORIF) for this specific injury type, what is a documented advantage of primary arthrodesis?

Explanation

Multiple studies (e.g., Ly and Coetzee, JBJS Am 2006) have demonstrated that for purely ligamentous Lisfranc injuries, primary arthrodesis of the medial 2 or 3 rays yields better functional outcomes (higher AOFAS scores) and significantly lower rates of secondary procedures compared to ORIF. Patients treated with ORIF often require hardware removal and later salvage arthrodesis due to post-traumatic arthritis.

Question 12

A 30-year-old female is brought to the emergency department after a motor vehicle collision. She is awake, fully alert, and cooperative. Examination reveals an isolated C6 motor weakness. Radiographs demonstrate a unilateral C5-C6 facet dislocation. What is the most appropriate next step in her management?

Explanation

In an awake, alert, and cooperative patient with a cervical facet dislocation, rapid closed reduction with cranial traction is indicated and considered safe. Continuous clinical neurologic monitoring is essential. MRI is not required prior to closed reduction in this specific clinical scenario, as delayed reduction increases the risk of permanent neurologic deficit. MRI prior to reduction is required if the patient is obtunded or fails closed reduction.

Question 13

A 24-year-old male presents with a symptomatic proximal pole scaphoid nonunion 8 months after a fall. MRI shows early signs of avascular necrosis in the proximal pole, but there is no evidence of carpal collapse (SNAC wrist). Based on the retrograde blood supply to the scaphoid, which of the following is an established pedicled vascularized bone graft used to address this specific pathology?

Explanation

The 1,2 intercompartmental supraretinacular artery (1,2 ICSRA) pedicled vascularized bone graft (Zaidemberg graft) is harvested from the dorsal distal radius. It is particularly useful for proximal pole scaphoid nonunions with avascular necrosis where carpal geometry is maintained. The scaphoid receives its primary blood supply from retrograde branches of the radial artery entering distally, making proximal pole fractures highly susceptible to AVN.

Question 14

A 29-year-old male sustains a low-velocity civilian gunshot wound to the right thigh, resulting in a comminuted midshaft femur fracture. The entrance and exit wounds are 5 mm and clean. He has palpable distal pulses, a normal sensorimotor exam, and an ankle-brachial index of 1.0. What is the most appropriate definitive management?

Explanation

Low-velocity civilian gunshot wounds with associated long bone fractures, clean wounds, and no evidence of vascular compromise do not require formal open irrigation and debridement of the bullet tract. They can be safely treated with local wound care, appropriate tetanus prophylaxis, prophylactic antibiotics, and standard internal fixation (e.g., intramedullary nailing of the femur), with infection rates comparable to closed fractures.

Question 15

In the surgical treatment of a complex tibial pilon fracture, the articular surface of the distal tibia is frequently split into three primary fragments. The anterolateral fragment (often referred to as the Chaput fragment) is tethered primarily by which of the following ligaments?

Explanation

In a classical pilon fracture, the three main articular fragments are the medial (tethered by the deltoid ligament), the posterior or Volkmann fragment (tethered by the posterior inferior tibiofibular ligament - PITFL), and the anterolateral or Chaput fragment (tethered by the anterior inferior tibiofibular ligament - AITFL).

Question 16

A 28-year-old male sustains a highly displaced U-shaped sacral fracture (spinopelvic dissociation) following a 30-foot fall. Decompression and lumbopelvic fixation are planned. Given the typical fracture pattern involving a transverse fracture line through the sacrum, which of the following neurologic deficits is most frequently seen?

Explanation

A U-shaped sacral fracture is the classic pattern of spinopelvic dissociation, characterized by bilateral vertical sacral fractures connected by a transverse fracture line. This transverse line typically crosses through the upper sacral segments (S1, S2, or S3). Because the sacral nerve roots (S2-S4) control sphincter function, bowel and bladder dysfunction are highly characteristic and devastating complications of this fracture.

Question 17

Historical orthopedic literature long taught that a specific artery provided the vast majority of the blood supply to the humeral head. However, more recent quantitative anatomical studies have redefined this. Which artery is now recognized as providing the predominant blood supply to the humeral head?

Explanation

Historically, the arcuate artery (a continuation of the ascending branch of the anterior circumflex humeral artery) was thought to supply the majority of the humeral head. However, Hettrich et al. (JBJS Am 2010) demonstrated via quantitative assessment that the posterior circumflex humeral artery actually provides the predominant blood supply (approximately 64%) to the humeral head.

Question 18

A 45-year-old male sustains an acetabular fracture in a motor vehicle accident. The obturator oblique radiograph demonstrates a classic 'spur sign.' Which of the following Letournel fracture patterns is unequivocally indicated by this radiographic finding?

Explanation

The 'spur sign' is a pathognomonic radiographic finding seen on the obturator oblique view of the pelvis. It represents the intact strut of iliac bone attached to the sacroiliac joint, sitting above the displaced acetabular columns. Its presence indicates that all articular segments of the acetabulum are detached from the intact axial skeleton, defining an Associated Both Column fracture.

Question 19

A 72-year-old female with a history of a cementless total hip arthroplasty presents with thigh pain after a ground-level fall. Radiographs demonstrate a fracture around the tip of the femoral stem. The stem is visibly loose and has subsided 5 mm compared to previous films, but the proximal femur maintains excellent circumferential bone stock. According to the Vancouver classification, what is the fracture type and the recommended standard of care?

Explanation

The Vancouver classification guides treatment for periprosthetic femur fractures. A fracture around the stem (Type B) with a loose stem but good proximal bone stock is a Vancouver B2 fracture. The standard of care is revision arthroplasty using a long stem (often extensively porous-coated or fluted tapered) to bypass the fracture and achieve stable fixation in the intact distal bone.

Question 20

A 12-year-old boy, who was wearing only a lap-belt in the back seat of a car during a high-speed collision, presents with severe mid-back pain. Radiographs demonstrate a flexion-distraction injury (Chance fracture) at the L2 level. Which of the following concomitant injuries is classically associated with this mechanism and must be rigorously ruled out?

Explanation

A Chance fracture is a flexion-distraction injury of the spine, classically seen in patients restrained by a lap-belt during a sudden deceleration. The fulcrum of flexion is anterior to the spine (at the abdominal wall), causing severe distraction forces across the posterior and middle columns. This specific mechanism is highly associated with concomitant intra-abdominal injuries, most notably bowel rupture or other hollow viscus injuries (seen in up to 40-50% of cases).

Question 21

An 82-year-old male sustains a hyperextension injury to his cervical spine after a fall. Examination reveals 2/5 motor strength in his bilateral upper extremities and 4/5 motor strength in his lower extremities. Proprioception and pain sensation are intact but diminished. What is the most likely prognosis for his motor recovery?

Explanation

This patient has Central Cord Syndrome, characterized by upper extremity weakness that is disproportionately greater than lower extremity weakness. The typical sequence of neurological recovery is lower extremity function first (most regain ambulation), followed by bowel and bladder control, then proximal upper extremity function, and lastly (often incompletely) fine intrinsic hand dexterity.

Question 22

A 45-year-old male sustains a Schatzker IV tibial plateau fracture with a large, displaced posteromedial fragment. Which surgical approach and fixation strategy is biomechanically optimal for this specific fragment?

Explanation

Posteromedial fragments in tibial plateau fractures represent a coronal shear injury. They tend to displace distally and posteriorly. Biomechanically, these fragments require direct visualization via a posteromedial approach and fixation with an anti-glide (buttress) plate at the apex of the fracture to effectively resist vertical shear forces. Lateral locked plates typically do not adequately capture or buttress this fragment.

Question 23

A 25-year-old male sustains a highly vertical (Pauwels Type III) femoral neck fracture. Which of the following fixation constructs provides the highest biomechanical stability against vertical shear forces for this fracture pattern?

Explanation

Pauwels Type III fractures (>50 degrees) are highly unstable due to significant vertical shear forces. Multiple parallel cancellous screws are primarily designed to resist compressive forces and often fail in shear. A fixed-angle device, such as a Dynamic Hip Screw (DHS), provides superior biomechanical resistance to vertical shear. A supplemental derotational cancellous screw is typically added to control rotational instability.

Question 24

An 85-year-old female presents with a Type II odontoid fracture displaced 3 mm posteriorly after a ground-level fall. She has significant medical comorbidities. She is neurologically intact. What is the most appropriate initial management?

Explanation

In elderly patients (especially those >80 years old) with Type II odontoid fractures, halo vest immobilization is associated with high morbidity and mortality (up to 40%). Surgical intervention carries significant perioperative risks. Current evidence supports rigid cervical collar immobilization as the initial treatment of choice; although the nonunion rate is high, fibrous nonunions are typically stable and asymptomatic in this demographic.

Question 25

Six weeks after sustaining a displaced talar neck fracture treated with open reduction and internal fixation, an AP radiograph of the ankle demonstrates a subchondral radiolucent band in the dome of the talus. What does this radiographic finding indicate?

Explanation

The subchondral radiolucency in the talar dome, visible on an AP radiograph 6 to 8 weeks after a talar neck fracture, is known as the Hawkins sign. It represents subchondral osteopenia secondary to hyperemia from disuse. The presence of hyperemia proves that the talar body has an intact blood supply, making the subsequent development of avascular necrosis (AVN) highly unlikely.

Question 26

A hemodynamically unstable 35-year-old male is brought to the trauma bay following a high-speed motorcycle crash. Pelvic radiographs show a severely widened symphysis pubis and bilateral sacroiliac joint disruption (APC-III). A pelvic binder is to be applied. To effectively maximize reduction of the pelvic volume, at what anatomic level should the binder be centered?

Explanation

To effectively reduce pelvic volume in an open-book (Anteroposterior Compression) pelvic ring injury, a pelvic binder or sheet must be centered directly over the greater trochanters. Placing the binder too proximally over the iliac crests is a common error that can paradoxically widen the pelvic outlet or fail to adequately close the symphyseal diastasis.

Question 27

A 55-year-old female treated with a volar locking plate for a distal radius fracture 6 months ago presents with the sudden inability to actively flex the interphalangeal joint of her thumb. What is the most likely underlying technical cause of this complication?

Explanation

The sudden inability to flex the thumb IP joint post-volar plating strongly suggests a rupture of the flexor pollicis longus (FPL) tendon. The most common iatrogenic cause is placing the volar plate too far distally, beyond the watershed line (the volar margin of the distal radius articular surface). Prominent hardware in this area causes attrition, fraying, and eventual rupture of the overlying FPL tendon.

Question 28

A 30-year-old male falls from a roof and sustains a T12 burst fracture. He is neurologically intact with no focal deficits. An MRI is obtained, which demonstrates an intact posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is his total score and recommended treatment?

Explanation

The TLICS score is calculated based on three categories: injury morphology, neurologic status, and posterior ligamentous complex (PLC) integrity. A burst fracture morphology receives 2 points. Intact neurologic status receives 0 points. An intact PLC receives 0 points. The total score is 2. A TLICS score of less than 4 implies non-operative management is recommended.

Question 29

A 28-year-old male sustains a closed, middle-third transverse humeral shaft fracture after a wrestling injury. In the emergency department, he is noted to have a complete absence of wrist and finger extension. What is the most appropriate management regarding his nerve deficit?

Explanation

An acute radial nerve palsy associated with a closed humeral shaft fracture is typically a neuropraxia (or axonotmesis) and has a high rate of spontaneous recovery (up to 90%). The standard of care is functional bracing of the humerus and clinical observation. Surgical exploration is generally reserved for open fractures, penetrating trauma, palsy occurring only after a reduction maneuver, or failure of clinical/EMG recovery after 3-6 months.

Question 30

A 40-year-old male sustains an isolated coronal shear fracture of the lateral femoral condyle (Hoffa fracture). Which of the following describes the ideal biomechanical screw fixation trajectory to achieve compression across this specific fracture pattern?

Explanation

Hoffa fractures are coronal plane shear fractures of the femoral condyles. Biomechanically, placing lag screws from posterior to anterior (PA) directs the compressive forces perpendicular to the fracture line and articular surface, which provides superior stability against shear compared to anterior-to-posterior (AP) screws. However, due to surgical exposure challenges, AP screws (often supplemented with an anti-glide plate) are frequently used in practice.

Question 31

A 24-year-old male suffers a severe crush injury to his right calf. The leg is tensely swollen, and he complains of pain out of proportion to the injury. Compartment pressures are measured. At what delta P (systemic diastolic blood pressure minus compartment pressure) is a four-compartment fasciotomy unequivocally indicated?

Explanation

Acute compartment syndrome is primarily a clinical diagnosis. When pressure measurements are utilized (such as in an unexaminable or equivocal patient), a delta P (Diastolic Blood Pressure - Compartment Pressure) of less than 30 mm Hg is the widely accepted threshold for surgical decompression via fasciotomy. This accounts for the fact that tissue perfusion pressure relies on systemic diastolic blood pressure.

Question 32

A 42-year-old male arrives at the trauma bay intubated and sedated following a severe motor vehicle collision. A CT scan of the cervical spine reveals a bilateral C5-C6 facet dislocation. What is the most appropriate next step in management?

Explanation

In an unexaminable patient (e.g., intubated, sedated, or altered mental status) with a cervical facet dislocation, an MRI of the cervical spine must be obtained prior to any reduction attempts. This is crucial to evaluate for an extruded cervical disc herniation. If a disc is present behind the vertebral body, an anterior approach to remove the disc must be performed before reduction to prevent iatrogenic spinal cord transection.

Question 33

A 21-year-old male falls on an outstretched hand and sustains a fracture of the proximal pole of the scaphoid. The high rate of avascular necrosis and nonunion associated with this specific fracture location is primarily due to the dominant arterial supply entering the scaphoid at which of the following locations?

Explanation

The scaphoid receives 70-80% of its blood supply from branches of the radial artery that enter the bone distally along the dorsal ridge at the waist. The blood then flows in a retrograde fashion to supply the proximal pole. Because of this retrograde perfusion, fractures at the proximal pole disrupt the blood supply, leading to a high incidence of avascular necrosis.

Question 34

A 29-year-old male sustains a low-velocity gunshot wound to the right thigh, resulting in a comminuted midshaft femur fracture. Distal pulses are palpable and biphasic on Doppler. There is no expanding hematoma. What is the standard of care regarding antibiotic prophylaxis and definitive fracture management?

Explanation

Low-velocity gunshot wounds causing long bone fractures are generally treated as Gustilo-Anderson Type I open fractures. Current evidence dictates that 24 hours of a first-generation cephalosporin (e.g., cefazolin) provides adequate prophylaxis. Standard treatment is prompt reamed intramedullary nailing, which yields excellent union rates and functional outcomes comparable to closed fractures.

Question 35

A 26-year-old professional rugby player sustains a hyperplantarflexion injury to his midfoot. Weight-bearing radiographs demonstrate a 3 mm diastasis between the base of the first and second metatarsals. The primary stabilizing ligament of this articulation originates on the lateral aspect of the medial cuneiform and inserts on which of the following structures?

Explanation

The Lisfranc ligament is an incredibly strong interosseous ligament that is the primary stabilizer of the tarsometatarsal joint complex. It originates from the lateral surface of the medial cuneiform and inserts distally and laterally onto the medial aspect of the base of the second metatarsal.

Question 36

A 33-year-old male sustains a C6 spinal cord injury. On examination, he has 0/5 motor function below the C6 myotome. However, he has preserved pinprick and light touch sensation in the S4-S5 dermatomes, and deep anal pressure is intact. Voluntary anal contraction is absent. How is this injury classified on the ASIA Impairment Scale?

Explanation

The American Spinal Injury Association (ASIA) Impairment Scale evaluates the completeness of a spinal cord injury. ASIA B signifies a sensory incomplete but motor complete injury. The patient has sensory preservation below the neurological level of injury, importantly including the sacral segments S4-S5, but has no motor function preserved more than 3 levels below the motor level, and lacks voluntary anal contraction.

Question 37

A 38-year-old female presents with an isolated coronal shear fracture of the capitellum without involvement of the trochlea or posterior comminution (Bryan-Morrey Type I). Which surgical approach is generally most appropriate for open reduction and internal fixation of this fracture?

Explanation

The extended lateral approach (utilizing either the Kocher interval between the ECU and anconeus, or the Kaplan interval between the ECRL and EDC) provides direct and excellent visualization of the anterior articular surface of the capitellum and lateral column. It is the workhorse approach for Bryan-Morrey Type I (isolated capitellum) and Type IV (coronal shear) fractures. Olecranon osteotomies are typically reserved for complex, bicolumnar distal humerus fractures.

Question 38

A 32-year-old male sustains a Gustilo-Anderson Type IIIB open tibia fracture in the middle third of the diaphysis. Following initial aggressive debridement and external fixation, there remains a 5x5 cm soft tissue defect with exposed tibial cortex devoid of periosteum. Which of the following is the most classic and appropriate soft tissue coverage option for this specific defect?

Explanation

Local soft tissue coverage for the tibia is classically divided by thirds. Defects in the proximal third are typically covered by a medial or lateral gastrocnemius rotational flap. Defects in the middle third are optimally covered by a soleus rotational flap. Defects in the distal third generally require free tissue transfer (e.g., ALT or latissimus dorsi) or a reverse sural artery flap.

Question 39

A 7-year-old boy falls on an outstretched hand and presents to the ER. Radiographs demonstrate a fracture of the proximal third of the ulna with an anterior dislocation of the radial head. According to the Bado classification system, what type of Monteggia fracture pattern does this represent?

Explanation

The Bado classification categorizes Monteggia fractures (proximal ulnar fracture with radial head dislocation) based on the direction of the radial head displacement. Type I involves anterior dislocation of the radial head (with anterior angulation of the ulnar fracture) and is the most common type. Type II is posterior, Type III is lateral, and Type IV involves fractures of both the radius and ulna shafts with anterior radial head dislocation.

Question 40

A 25-year-old female is involved in a high-speed motor vehicle collision while wearing only a lap seatbelt. She sustains a severe flexion-distraction injury (Chance fracture) at the L2 vertebral level. This specific spinal fracture pattern is most frequently associated with concomitant injuries to which of the following organ systems?

Explanation

Chance fractures are flexion-distraction injuries of the spine classically caused by acute hyperflexion over a fulcrum, such as a lap-only seatbelt in a motor vehicle collision. The severe compressive and shearing forces transmitted through the abdomen place intra-abdominal contents at high risk. Gastrointestinal injuries, particularly hollow viscus perforations or mesenteric tears, occur in up to 40-50% of patients with a Chance fracture.

Question 41

The majority of the blood supply to the body of the talus is provided by which of the following vessels?

Explanation

The artery of the tarsal canal, a branch of the posterior tibial artery, provides the dominant blood supply to the talar body. It enters the neck and supplies the majority of the middle and lateral portions of the talar body. The artery of the sinus tarsi provides collateral supply, but is not the dominant contributor.

Question 42

In the surgical management of a 'terrible triad' injury of the elbow, which of the following sequences represents the generally accepted standard protocol for reconstruction?

Explanation

The standard surgical sequence for a terrible triad injury (elbow dislocation, radial head fracture, coronoid fracture) is: 1. Fixation or replacement of the radial head. 2. Fixation of the coronoid (or anterior capsule). 3. Repair of the lateral collateral ligament (LCL) complex. MCL repair or external fixation is reserved for cases of residual instability after the primary lateral protocol is complete.

Question 43

A 68-year-old male presents with a central cord syndrome following a hyperextension injury to his cervical spine. Which of the following best describes the expected typical progression of his neurologic recovery?

Explanation

In Central Cord Syndrome, the classic pattern of motor recovery occurs in a specific sequence: lower extremity recovery usually occurs first, followed by bowel/bladder function, then proximal upper extremity, and finally distal upper extremity (hand/fine motor function). Distal upper extremity function often remains the most permanently impaired.

Question 44

A 55-year-old male with a known history of ankylosing spondylitis presents to the emergency department after a low-energy ground-level fall. He complains of moderate neck pain but is neurologically intact. Initial cross-table lateral cervical spine radiographs reveal an ossified anterior longitudinal ligament with a widened C5-C6 disc space. What is the most appropriate next step in management?

Explanation

Patients with ankylosing spondylitis are highly susceptible to unstable spinal fractures even from minor trauma, and these injuries are often highly unstable. Due to the altered biomechanics of the ankylosed spine, there is a high incidence of non-contiguous secondary fractures (up to 20%). Therefore, the standard of care is to obtain a CT scan of the entire spine (cervical, thoracic, and lumbar) to rule out additional fractures.

Question 45

Which of the following radiographic parameters is considered an established indication for operative intervention in the management of a displaced extra-articular scapular body/neck fracture?

Explanation

Surgical indications for extra-articular scapular neck and body fractures include a glenopolar angle (GPA) of < 22 degrees (normal is 30-45 degrees), medial-lateral displacement > 20 mm, and angulation > 45 degrees. A severely decreased GPA alters the resting length and vectors of the rotator cuff, leading to poor functional outcomes if treated nonoperatively.

Question 46

When utilizing a posteromedial approach for the fixation of a Schatzker IV tibial plateau fracture, the main surgical window is established by utilizing the interval between the medial border of the tibia (pes anserinus) anteriorly and which of the following structures posteriorly?

Explanation

The standard posteromedial approach to the tibial plateau utilizes the plane between the pes anserinus (anteriorly/medially) and the medial head of the gastrocnemius (posteriorly). Retracting the medial head of the gastrocnemius laterally and posteriorly exposes the posteromedial aspect of the proximal tibia and protects the neurovascular bundle.

Question 47

In the setting of a volar shear fracture of the distal radius (volar Barton's fracture), failure to adequately reduce and stabilize the volar lunate facet fragment most commonly leads to volar carpal subluxation. This occurs due to the direct attachment of which critical ligament to this specific bony fragment?

Explanation

The short radiolunate ligament originates from the volar lunate facet of the distal radius and inserts onto the lunate. It is critical for stabilizing the lunate and the entire carpus. If the volar lunate facet fragment is not surgically stabilized (e.g., with a buttress plate), the short radiolunate ligament pulls the carpus volarly, resulting in volar carpal subluxation.

Question 48

A 12-year-old male sustains a Chance fracture of L2 while wearing a lap belt during a high-speed motor vehicle collision. Which of the following concomitant injuries is most statistically likely to be found in this patient?

Explanation

Chance fractures are flexion-distraction injuries commonly associated with lap belt use in motor vehicle accidents, particularly in the pediatric population. They carry a very high association (up to 40-50%) with intra-abdominal hollow viscus injuries, most notably small bowel perforations or mesenteric avulsions, due to the corresponding severe localized compression of the abdominal contents against the spine.

Question 49

During an anterior (ilioinguinal or modified Stoppa) approach to the acetabulum, severe, life-threatening hemorrhage can occur from the 'corona mortis'. This structure represents an anastomosis between which two vascular systems?

Explanation

The corona mortis (crown of death) is an anatomical variant representing an arterial or venous anastomosis between the external iliac (or its branch, the inferior epigastric) system and the obturator system. It is located on the posterior aspect of the superior pubic ramus, typically 5 to 6 cm lateral to the pubic symphysis, and is highly vulnerable during anterior pelvic ring and acetabular exposures.

Question 50

A 28-year-old male sustains a vertically oriented (Pauwels Type III) femoral neck fracture. Based on biomechanical studies, which of the following internal fixation constructs provides the greatest stability against the high vertical shear forces inherent to this fracture pattern?

Explanation

Pauwels Type III femoral neck fractures have a fracture angle greater than 50 degrees from the horizontal, leading to extremely high vertical shear forces at the fracture site. Biomechanical studies demonstrate that a fixed-angle device, such as a sliding hip screw (DHS), combined with an anti-rotation cancellous screw provides superior resistance to vertical shear compared to multiple parallel cancellous screws alone.

Question 51

A 35-year-old male sustains a closed, isolated transverse fracture of the middle third of the humeral shaft resulting from a direct blow. On initial examination in the emergency department, he is unable to extend his wrist or digits. The skin is intact and distal pulses are palpable. What is the most appropriate management regarding his radial nerve palsy?

Explanation

A primary radial nerve palsy in the setting of a closed humeral shaft fracture (without vascular compromise) is generally a neuropraxia and has a spontaneous recovery rate of >70-90%. The standard of care is non-operative management with a functional brace and clinical observation. Immediate exploration is reserved for open fractures, associated vascular injuries requiring repair, penetrating trauma, or secondary palsies that develop after closed reduction.

Question 52

A 30-year-old male sustains a fall from a height. Radiographs and CT show an L1 burst fracture. His neurologic examination is completely normal. MRI reveals a complete disruption of the posterior ligamentous complex (PLC). According to the Thoracolumbar Injury Classification and Severity (TLICS) score, what is his total score and the recommended treatment?

Explanation

The TLICS score is calculated based on three categories: 1) Morphology: Burst fracture = 2 points. 2) Neurologic status: Intact = 0 points. 3) Posterior ligamentous complex (PLC) integrity: Disrupted = 3 points. Total score = 2 + 0 + 3 = 5. A TLICS score of > 4 indicates instability, and operative intervention is strictly recommended.

Question 53

In the management of Lisfranc injuries, prospective randomized trials have demonstrated that primary arthrodesis provides superior functional outcomes and lower reoperation rates compared to open reduction and internal fixation (ORIF) for which specific subset of patients?

Explanation

Multiple landmark studies (e.g., Ly and Coetzee) have shown that for purely ligamentous Lisfranc injuries, primary arthrodesis of the medial column (1st, 2nd, and 3rd TMT joints) yields significantly better functional outcomes and lower rates of secondary surgeries (for hardware removal or salvage arthrodesis due to post-traumatic arthritis) compared to ORIF. The 4th and 5th TMT joints should remain mobile.

Question 54

During an extensile lateral approach for open reduction and internal fixation of a displaced intra-articular calcaneus fracture, a full-thickness soft tissue flap must be carefully elevated directly off the periosteum. Which of the following arteries is the primary blood supply to this large, delicate lateral flap?

Explanation

The lateral calcaneal artery, which is a terminal branch of the peroneal artery, supplies the angiosome of the lateral hindfoot. During an extensile lateral approach to the calcaneus, a full-thickness 'no-touch' flap containing the sural nerve, peroneal tendons, and the lateral calcaneal artery must be elevated subperiosteally to preserve its blood supply and minimize the high risk of wound necrosis.

Question 55

A 42-year-old female presents to the emergency department after a motor vehicle collision. She is awake, alert, and fully cooperative. She has a right-sided C6 radiculopathy but no long tract signs (no myelopathy). Lateral cervical radiographs reveal a unilateral jumped facet at C5-C6 with 25% anterior translation. What is the most appropriate next step in management?

Explanation

According to current spinal trauma guidelines, an awake, alert, and cooperative patient with a cervical facet dislocation can safely undergo immediate closed reduction via skeletal traction with serial neurologic examinations. MRI prior to reduction is not required and may unnecessarily delay spinal cord/nerve root decompression. MRI is mandated prior to reduction ONLY if the patient is unexaminable (e.g., comatose) or fails closed reduction.

Question 56

When evaluating a severely traumatized lower limb using the Mangled Extremity Severity Score (MESS), which of the following variables uniquely doubles its allocated point value if a specific time threshold is exceeded?

Explanation

The MESS score evaluates four criteria: Skeletal/soft-tissue injury, Limb ischemia, Shock, and Age. The points allocated for Limb Ischemia are specifically doubled if the ischemia time exceeds 6 hours, recognizing the exponential increase in the risk of irreversible muscle necrosis and ultimate amputation following prolonged anoxia.

Question 57

According to the Hertel criteria, which of the following radiographic parameters is the most reliable predictor of subsequent avascular necrosis (AVN) following a proximal humerus fracture?

Explanation

Hertel et al. identified specific radiographic criteria highly predictive of humeral head ischemia and subsequent AVN. The most significant predictors include an anatomic neck fracture pattern, a short calcar segment (metaphyseal head extension less than 8 mm), and disruption of the medial hinge (> 2 mm displacement). A metaphyseal head extension < 8 mm was shown to have a very high positive predictive value for ischemia.

Question 58

A 45-year-old male is undergoing open reduction and internal fixation of a severe tibial pilon fracture using an anterolateral approach to the distal tibia. During the superficial surgical dissection, which neural structure is most directly at risk and must be identified and protected?

Explanation

The anterolateral approach to the distal tibia/pilon frequently utilizes the interval between the fibula and tibia (between peroneus tertius and extensor digitorum longus). The superficial peroneal nerve pierces the deep fascia in the distal third of the leg and its terminal branches cross directly over the anterolateral surgical field, putting them at significant risk of iatrogenic injury during the superficial dissection.

Question 59

An 82-year-old female with multiple medical comorbidities including severe COPD and ischemic heart disease sustains a Type II odontoid fracture with 2 mm of posterior displacement after a mechanical fall. She is neurologically intact. Which of the following is the most appropriate initial management strategy?

Explanation

In elderly patients (>80 years) with significant medical comorbidities, the treatment of Type II odontoid fractures must balance fracture healing with the severe morbidity and mortality of interventions. Halo immobilization in the elderly carries a mortality rate approaching 20-30% due to respiratory complications and falls. Operative fixation also carries high perioperative risks. Current evidence strongly supports that immobilization in a rigid cervical collar is the most appropriate initial treatment. Although the nonunion rate is higher, the majority are stable fibrous nonunions that remain clinically asymptomatic.

Question 60

A 24-year-old male with bilateral femoral shaft fractures develops severe hypoxia, tachycardia, and a non-blanching rash on his axillae and chest 36 hours after injury. According to Gurd's criteria for the diagnosis of Fat Embolism Syndrome, which of the following clinical findings represents one of the 'major' criteria?

Explanation

Gurd's diagnostic criteria for Fat Embolism Syndrome (FES) include major and minor criteria. The three major criteria are: 1) Respiratory insufficiency (hypoxemia), 2) Cerebral involvement (neurologic dysfunction/confusion), and 3) Petechial rash (typically on the axillae, chest, conjunctiva, or palate). Tachycardia, fever, retinal changes, and drops in hemoglobin/platelets are considered minor criteria.

Question 61

A 24-year-old female presents after a high-speed motor vehicle collision. She was wearing a lap-only seatbelt. Imaging reveals a flexion-distraction injury (Chance fracture) at L2. She is neurologically intact. Which of the following is the most commonly associated concomitant injury in this patient population?

Explanation

Chance fractures are flexion-distraction injuries commonly associated with lap seatbelts. Up to 50% of these patients have concomitant intra-abdominal injuries, with hollow viscus (especially small bowel) perforations being the most common.

Question 62

A 45-year-old male sustains a closed posteromedial tibial plateau fracture after falling from a ladder. Which of the following surgical approaches and patient positionings provides the most optimal access for direct reduction and buttress plating of this specific fracture fragment?

Explanation

Posteromedial tibial plateau fractures exhibit a vertically oriented shear fragment. A prone position with a posteromedial approach allows direct visualization, perpendicular lag screw placement, and optimal anti-glide buttress plating.

Question 63

A 35-year-old female undergoes surgery for a 'terrible triad' elbow injury. Following radial head arthroplasty, lateral collateral ligament (LCL) repair, and non-operative management of a Type 1 coronoid tip fracture, the elbow readily subluxates posteriorly at 30 degrees of extension. What is the most appropriate next step?

Explanation

According to standard surgical algorithms for terrible triad injuries, if the elbow remains unstable after addressing the coronoid, radial head, and LCL, the next indicated step is either MCL repair or application of a hinged external fixator.

Question 64

A 72-year-old male sustains a Type II odontoid fracture following a ground-level fall. Nonoperative management with a rigid cervical collar is being considered. Which of the following radiographic parameters is the most significant predictor of nonunion for this fracture pattern?

Explanation

Risk factors for nonunion of Type II odontoid fractures include initial displacement greater than 5 mm, angulation greater than 10 degrees, age > 65 years, and delayed treatment. A displacement > 5 mm drastically decreases the likelihood of union with conservative management.

Question 65

A 45-year-old male sustains a high-energy Moore Type I (coronal split) fracture of the medial tibial plateau. A posteromedial surgical approach is chosen for buttress plating. Which of the following describes the correct anatomic interval for this surgical approach?

Explanation

The posteromedial approach to the tibial plateau utilizes the interval between the medial head of the gastrocnemius (retracted posteriorly/laterally) and the pes anserinus (retracted anteriorly/medially). This allows direct visualization and buttress plating of posteromedial shear fragments.

Question 66

A 24-year-old male presents with a displaced fracture of the proximal pole of the scaphoid. He is counseled on the high risk of avascular necrosis. The tenuous blood supply to the proximal pole is predominantly provided by retrograde flow from which of the following vessels?

Explanation

The major blood supply to the scaphoid is from the dorsal carpal branch of the radial artery, which enters the dorsal ridge and supplies the proximal 80% of the scaphoid via retrograde blood flow. This retrograde supply explains the high risk of AVN in proximal pole fractures.

Question 67

A 35-year-old female sustains a "terrible triad" injury of the elbow. Operative intervention is planned to restore stability. According to standard biomechanical principles and established protocols, what is the most appropriate sequence of surgical reconstruction?

Explanation

The standard surgical algorithm for a terrible triad injury proceeds from deep to superficial and inside to outside. The typical sequence is fixing the coronoid first, followed by the radial head (fixation or replacement), and finally repairing the LUCL.

Question 68

A 68-year-old male with long-standing ankylosing spondylitis presents to the emergency department complaining of new-onset lower cervical pain after a minor bump in his car. Initial standard radiographs of the cervical spine show classic bridging syndesmophytes but no obvious fracture. Neurological exam is intact. What is the most appropriate next step in management?

Explanation

Patients with ankylosing spondylitis are highly susceptible to highly unstable, transdiscal or chalk-stick fractures of the spine even from minor trauma. Standard radiographs are notoriously inadequate for ruling out fractures in this population; a CT scan is mandatory.

Question 69

An 80-year-old female falls onto her hip and sustains a severe acetabular fracture. Anteroposterior and Judet oblique pelvic radiographs demonstrate a pathognomonic "spur sign." This radiographic finding definitively indicates which of the following Letournel fracture patterns?

Explanation

The "spur sign" is seen on the obturator oblique view and is pathognomonic for a both-column acetabular fracture. It represents the uninjured superior portion of the iliac wing, from which the entire articular surface has been disconnected and medially displaced.

Question 70

A 28-year-old male polytrauma patient arrives with bilateral femur fractures, pulmonary contusions, and a closed head injury. The decision is being made between Early Total Care (ETC) and Damage Control Orthopedics (DCO). Which of the following physiologic parameters is an accepted absolute indication for DCO?

Explanation

Damage Control Orthopedics (DCO) is indicated in the presence of the "lethal triad" or severe physiologic exhaustion. Accepted criteria for DCO include a base deficit > 8 mEq/L, pH < 7.24, core temperature < 35 degrees C, and coagulopathy.

Question 71

During open reduction and internal fixation of a volar shear distal radius fracture, the surgeon notes that the critical volar ulnar corner (lunate facet fragment) escapes the standard volar plate. Failure to capture this fragment puts the patient at risk for volar carpal subluxation due to the attachment of which critical ligament?

Explanation

The short radiolunate ligament firmly attaches the lunate to the volar ulnar corner of the distal radius (lunate facet). If this fragment is not rigidly stabilized, the radiocarpal joint can subluxate volarly.

Question 72

A 32-year-old male sustains an APC-III pelvic ring injury. Despite external pelvic binding and aggressive fluid resuscitation, he remains hypotensive. Pre-peritoneal pelvic packing is initiated. During the approach, the surgeon must be cautious of the "corona mortis." This vascular structure represents an anastomosis between which two vascular systems?

Explanation

The corona mortis is a vascular anastomosis between the external iliac (or deep inferior epigastric) vessels and the obturator vessels. It crosses the superior pubic ramus and is highly susceptible to injury in pelvic ring disruptions and anterior surgical approaches.

Question 73

A 22-year-old male sustains a comminuted fracture of the tibial diaphysis. Overnight, he complains of severe pain out of proportion to the injury. The clinical suspicion for acute compartment syndrome is high, and intracompartmental pressures are measured. Which of the following calculations strictly defines the accepted threshold (Delta P) for diagnosing compartment syndrome?

Explanation

The Delta P is the most reliable objective measure for diagnosing compartment syndrome. It is calculated as the diastolic blood pressure minus the intracompartmental pressure. A Delta P of less than 30 mmHg is an indication for emergent fasciotomies.

Question 74

A 38-year-old male sustains a high-energy Pauwels Type III (vertical) femoral neck fracture. A fixed-angle sliding hip screw (SHS) with a derotational screw is chosen over multiple parallel cancellous screws. What is the primary biomechanical rationale for this choice?

Explanation

Pauwels Type III femoral neck fractures have a high vertically oriented fracture line, making them highly subjected to vertical shear forces. A fixed-angle device, such as a sliding hip screw, provides superior biomechanical resistance to vertical shear compared to parallel cancellous screws.

Question 75

A 26-year-old male sustains a midfoot injury during a rugby tackle. On physical examination, plantar ecchymosis is present. Radiographs demonstrate subtle widening between the 1st and 2nd metatarsal bases. The primary ligament ruptured in this injury pattern connects which two osseous structures?

Explanation

Plantar ecchymosis is highly suggestive of a Lisfranc injury. The Lisfranc ligament is an interosseous ligament that connects the lateral aspect of the medial cuneiform to the medial aspect of the base of the second metatarsal.

Question 76

A 40-year-old female is brought in after an MVC with an obviously deformed knee. Radiographs reveal a complete anterior knee dislocation (KD-III). After closed reduction, she has palpable dorsalis pedis and posterior tibial pulses with brisk capillary refill. The Ankle-Brachial Index (ABI) is measured at 0.85. What is the mandatory next step in management?

Explanation

In knee dislocations, an ABI < 0.9 is highly sensitive for a clinically significant vascular injury, even in the presence of palpable pulses (which can be present via collaterals or intimal flaps). This finding mandates advanced vascular imaging with a CT angiogram.

Question 77

A 45-year-old male sustains an L1 thoracolumbar burst fracture. He is neurologically intact. When calculating the Thoracolumbar Injury Classification and Severity (TLICS) score to determine operative vs nonoperative management, which of the following MRI findings would add the most points and independently push the total score towards surgical intervention?

Explanation

In the TLICS system, disruption of the posterior ligamentous complex (PLC) is assigned 3 points. When combined with a burst morphology (2 points), the score becomes 5, which strongly favors surgical intervention (score > 4). Canal stenosis without neurologic deficit does not independently add points in TLICS.

Question 78

A 29-year-old male undergoes open reduction and internal fixation for a Galeazzi fracture (distal one-third radial shaft fracture). Following anatomic and rigid fixation of the radius, the distal radioulnar joint (DRUJ) remains highly unstable to dorsal translation of the ulna. The surgeon decides to temporarily pin the DRUJ. In what position is the forearm most commonly pinned to maximize DRUJ stability?

Explanation

Following a Galeazzi fracture, if the DRUJ remains unstable after radius fixation, it is typically due to a massive TFCC tear. The position of maximal stability for the DRUJ is supination, as the intact volar radioulnar ligaments become taught, reducing the dorsal subluxation of the ulna.

Question 79

A 65-year-old female sustains a 3-part proximal humerus fracture. The surgeon is evaluating the risk of avascular necrosis (AVN) of the humeral head to decide between ORIF and arthroplasty. According to Hertel's criteria, which of the following findings is the most reliable predictor of humeral head ischemia?

Explanation

Hertel's criteria describe predictors of humeral head ischemia in proximal humerus fractures. The most significant predictors include a short metaphyseal head extension (<8 mm), disruption of the medial hinge (>2 mm displacement), and an anatomic neck fracture pattern.

Orthopedic Surgery Board Review MCQs: Arthroplasty, Trauma & Spine Part 255

Orthopedic Surgery Board Review MCQs: Trauma, Extremity & Spine | Part 53

Key Takeaway

Orthopedic Surgery Board Review MCQs: Trauma, Extremity & Spine | Part 53

Chapter Index