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 11261
Topic: 2. Trauma
In injured tissues, ischemia begins when the tissue pressure within the compartment comes within mm Hg of the diastolic pressure.
Correct Answer & Explanation
. 10
Explanation
Normal tissues have adequate tissue perfusion with increases in compartment pressure to within 10 mm Hg of the diastolic pressure. In damaged tissue (eg, tibia fracture), perfusion can be impaired when the diastolic pressure reaches within 20 mm Hg of the diastolic pressure.One should remember that hypotensive patients with extremity injuries are prone to compartment syndromes. Correct Answer: 20
Question 11262
Topic: 2. Trauma
A 35-year-old male sustains the fracture seen in Figures A and B. Which of the following substances has been shown to result in the least radiographic subsidence when combined with open reduction and internal fixation?
Correct Answer & Explanation
. Cancellous allograft bone chips
Explanation
Figures A and B show a plateau fracture with a lateral split and depression of the articular surface. In treating tibial plateau fractures, calcium phosphate has been shown to have the least amount of articular subsidence on follow-up examinations due to its high compressive strength.The study by Lobenhoffer et al noted improved radiographic outcomes and earlier weightbearing with usage of calcium phosphate cement. Welch and Zhang reproduced tibial plateau fractures in goats and compared cancellous autograft to calcium phosphate cement augmentation. At 24 hours, four of five specimens treated with autograft had subsidence of the fragment. Only two specimens from limbs treated with cement showed minimal subsidence; the remaining were congruent.Yetkinlerโs study compared cement to no cement treatment in a model of depressed plateau fractures. Calcium phosphate cement of high compressivestrength provided equivalent or better stability than conventional open reductionand internal fixation with either auto/allograft bone which had both a lower compressive strength and reduced mechanical stability.
Question 11263
Topic: 2. Trauma
A 25-year-old laborer sustains a transverse fracture of the proximal 25% of the scaphoid. CT reconstructions reveal a 1-mm fracture gap. What is the most appropriate treatment?
Correct Answer & Explanation
. Internal fixation of the fracture with a compression screw
Explanation
A higher risk of nonunion and the need for prolonged immobilization is seen after nonsurgical management of proximal pole fractures of the scaphoid. Because of the relatively poor blood supply of the proximal pole, surgical treatment with a compression screw is advocated for fractures of the proximal third of the scaphoid.
Question 11264
Topic: 2. Trauma
Figures 11a and 11b show the radiographs of the open fracture of a 46-year-old man who injured his elbow on his nondominant arm in a motorcycle crash. On the day of injury, he underwent irrigation and debridement of the fracture. He was also treated with antibiotics. Which of the following definitive treatment methods will most likely lead to the best functional outcome?
Correct Answer & Explanation
. Open reduction and plate fixation
Explanation
For displaced intra-articular fractures of the olecranon, open reduction and internal fixation (ORIF) with plate fixation is generally preferred to restore articular congruity and provide stable fixation, especially in active patients. Tension band wiring is typically reserved for simple transverse fractures.
Question 11265
Topic: 2. Trauma
A 22-year-old male sustains the injury seen in Figures A and B as the result of a motor vehicle collision. He subsequently undergoes the procedure shown in Figures C and D with a 12 millimeter nail. When would full weight-bearing be allowed after surgery?
Correct Answer & Explanation
. Immediately
Explanation
Comminuted femoral shaft fractures treated with statically locked intramedullary nails of appropriate diameter can be treated with immediate weight-bearing, with little risk of nail/screw breakage or deformity. Immediate range of motion and weight-bearing can be extremely beneficial to short-term patient outcomes, especially in polytrauma patients.Brumback et al.(1988) reviewed 133 dynamically locked femoral nails and report that 10.5% lost fixation and/or reduction postoperatively. They recommend reviewing high-quality radiographs to determine fracture characteristics, and note that dynamic fixation only be considered for transverse fracture patterns.Brumback et al.(1988) performed a prospective series of 97 patients with statically locked femoral nails, and they report that 98% of these went on to successful union without additional procedures, and the 2% with nonunions were successfully treated with later conversion to dynamic interlocking. They also found that no implant failure or deformity occurred with early walking or weight-bearing.Brumback et al.(1999) reviewed the biomechanics of immediate weightbearing after statically locked intramedullary nails are used in a segmental femur model, and they found that it would be safe. They then looked at immediate weight-bearing of these fractures after statically locked nail insertion in a series of 35 patients, and found no loss of reduction or implant failure with immediate weight-bearing.Figures A and B show a comminuted, segmental femoral shaft fracture, while Figures C and D show the immediate postoperative radiographs of this patient after intramedullary nailing.Incorrect Answers:Answers 2-5: Delay in weight-bearing is not required for this injury pattern, if treated with an appropriate diameter statically locked intramedullary nail.
Question 11266
Topic: 2. Trauma
Figures 34a through 34c are the radiographs and MR image of a 15-year-old, right-hand-dominant boy who was playing ice hockey and was checked into the boards. He had immediate anterior right shoulder pain and was unable to return to play. He was seen in the emergency department, and radiograph findings reportedly were normal. A sling is placed and he is seen in the office 3 days later. An examination reveals forward flexion of 90 degrees, abduction of 50 degrees, and external rotation of 0 degrees; all are painful. Belly-press test findings also are painful and abnormal. What is the most likely diagnosis?
Correct Answer & Explanation
. Lesser tuberosity fracture
Explanation
Apophyseal injuries of the lesser tuberosity are rare. If missed, these injuries can have devastating implications for return to normal function. The subscapularis tendon inserts on the lesser tuberosity, and injury to this structure is diagnosed with an examination and direct imaging. Delay in diagnosis is not uncommon. There is no evidence of acromioclavicular separation on radiographs. The coracoid and proximal humerus have a normal appearance for a 15-year-old with an unfused apophysis, and there is no irregularity or widening.
Question 11267
Topic: 2. Trauma
When performing a shoulder hemiarthroplasty for an unreconstructable proximal humerus fracture, the relationship of the repaired greater tuberosity to the prosthetic humeral head should be
Correct Answer & Explanation
. 6 mm to 8 mm superior to the top of the humeral head.
Explanation
DISCUSSIONThe greater tuberosity lies anatomically 6 mm to 8 mm inferior to the top of the humeral head. Normal proximal humeral anatomy must be recreated when performing a hemiarthroplasty for fracture so as to minimize the complications associated with the greater tuberosity and maximize functional outcomes. Tuberosity malunion and nonunion are considered the most common reasons for poor clinical outcomes following this procedure. Placing the tuberosity too proximal can lead to issues with impingement during shoulder abduction, and placement too distal can increase the tension on the rotator cuff as it courses over theprosthetic humeral head.
Question 11268
Topic: Pelvic & Acetabular Trauma
A 35-year-old male is brought to the trauma bay after a motorcycle accident. His blood pressure is 80/40 mmHg and heart rate is 130 bpm. A radiograph of the pelvis is obtained as part of the primary survey. Assuming an Anteroposterior Compression Type III (APC III) pattern is confirmed with complete disruption of the anterior and posterior pelvic rings, what is the most likely anatomic source of life-threatening arterial hemorrhage in this specific injury pattern?
Correct Answer & Explanation
. Internal pudendal artery
Explanation
In pelvic ring injuries, the vascular injury pattern closely correlates with the mechanism of injury. Anteroposterior compression (APC) injuries typically result in an increase in pelvic volume and stretch or tear anterior vascular structures, most commonly the internal pudendal or obturator arteries. Conversely, vertical shear or severe posterior ring disruptions are more closely associated with injuries to the superior gluteal artery.
Question 11269
Topic: 2. Trauma
A 24-year-old male sustains a humerus shaft fracture and presents with an associated radial nerve palsy. According to Seddon's classification of nerve injury, which term describes a nerve injury in which the axon and its myelin sheath are disrupted, causing Wallerian degeneration, but the endoneurium, perineurium, and epineurium remain structurally intact?
Correct Answer & Explanation
. Neuropraxia
Explanation
According to Seddon's classification: Neuropraxia is a transient conduction block without axonal disruption; recovery is rapid and complete. Axonotmesis involves disruption of the axon and myelin sheath, leading to distal Wallerian degeneration, but the supporting connective tissue frameworks (endoneurium, perineurium, epineurium) remain intact, allowing for axonal regeneration at about 1 mm/day. Neurotmesis is a complete transection of the nerve including all connective tissue layers, requiring surgical repair for recovery.
Question 11270
Topic: 2. Trauma
A 28-year-old male is admitted after a high-energy closed midshaft tibia fracture. Twelve hours post-injury, he complains of intractable leg pain that is not relieved by escalating doses of opioids. Pain is severely exacerbated by passive extension of the great toe. Intracompartmental pressure (ICP) monitoring is initiated. A fasciotomy is universally indicated when the 'Delta P' (difference between diastolic blood pressure and ICP) falls below what critical threshold?
Correct Answer & Explanation
. 10 mmHg
Explanation
Acute compartment syndrome is a surgical emergency characterized by tissue perfusion pressures falling below that required for cellular viability. While absolute compartment pressures (e.g., >30-40 mmHg) have been used historically, the current gold standard is the 'Delta P' concept introduced by McQueen. A Delta P (Diastolic Blood Pressure minus Intracompartmental Pressure) of less than 30 mmHg is highly predictive of compartment syndrome and represents an absolute indication for emergent four-compartment fasciotomy.
Question 11271
Topic: 2. Trauma
A 13-year-old male presents with chronic, dull anterior knee pain. Anteroposterior radiographs demonstrate a radiolucent line separating a bony fragment from the main body of the patella. According to the Saupe classification, which anatomic location represents the most common variant (Type III) of a bipartite patella?
Correct Answer & Explanation
. Superolateral pole
Explanation
A bipartite patella results from failure of secondary ossification centers to fuse with the main body of the patella. The Saupe classification categorizes them by location: Type I is at the inferior pole (~5%), Type II is at the lateral margin (~20%), and Type III is at the superolateral pole. Type III is by far the most common, accounting for approximately 75% of all bipartite patellas.
Question 11272
Topic: Upper Extremity Trauma
An 18-year-old elite baseball pitcher experiences a sudden 'pop' in his medial elbow during a fast pitch, followed by severe pain and an inability to continue throwing. An MRI confirms a complete rupture of the primary restraint to valgus stress. During ulnar collateral ligament (UCL) reconstruction, the surgeon must replicate the exact anatomic footprints of the anterior bundle. Which of the following describes the accurate native attachments of the anterior bundle of the UCL?
Correct Answer & Explanation
. From the lateral epicondyle to the annular ligament
Explanation
The medial ulnar collateral ligament (UCL) consists of anterior, posterior, and transverse bundles. The anterior bundle is the primary restraint to valgus stress at the elbow during the late cocking and early acceleration phases of throwing. Its anatomical footprint originates on the anteroinferior, undersurface of the medial epicondyle (slightly posterior to the axis of rotation) and inserts distally on the sublime tubercle, which is located on the medial aspect of the coronoid process of the ulna.
Question 11273
Topic: Pelvic & Acetabular Trauma
A 45-year-old male is involved in a motor vehicle collision. He is hemodynamically stable. An AP pelvis radiograph demonstrates symphysis pubis widening of 3.2 cm and widening of the anterior sacroiliac (SI) joints, but the posterior SI ligaments appear functionally intact. According to the Young-Burgess classification, what is the most likely injury pattern and best definitive treatment?
The clinical description of a symphysis pubis widening greater than 2.5 cm with disrupted anterior SI ligaments but intact posterior SI ligaments describes an Anteroposterior Compression (APC) Type II injury. In a hemodynamically stable patient, definitive treatment for an APC II injury typically requires anterior stabilization, most commonly via symphyseal plating, to restore the anterior tension band. APC III injuries involve complete posterior disruption and require both anterior and posterior fixation.
Question 11274
Topic: Lower Extremity Trauma
A 32-year-old male sustains a high-energy trauma to his left knee. Radiographs and CT scans reveal a bicondylar tibial plateau fracture with a transverse fracture line separating the metaphysis from the diaphysis. What is the correct Schatzker classification for this injury?
Correct Answer & Explanation
. Schatzker VI
Explanation
The Schatzker classification is widely used for tibial plateau fractures. Schatzker I, II, and III are lateral plateau fractures (split, split-depression, pure depression). Schatzker IV involves the medial plateau. Schatzker V is a bicondylar fracture where the metaphysis remains in continuity with the diaphysis. Schatzker VI is defined by metaphyseal-diaphyseal dissociation (complete separation of the joint block from the shaft), typically due to high-energy trauma.
Question 11275
Topic: 2. Trauma
The scaphoid bone is notorious for a high rate of avascular necrosis following a fracture due to its unique retrograde blood supply. Which of the following accurately describes the primary entry point and flow direction of the major intraosseous blood supply to the scaphoid?
Correct Answer & Explanation
. Enters the palmar-distal pole and flows proximally
Explanation
Approximately 70-80% of the scaphoid's blood supply is derived from the radial artery via branches that enter the scaphoid at the dorsal ridge, which is located distally. The intraosseous vascular flow is therefore retrograde, moving from distal to proximal. This anatomical reality means that fractures through the waist or proximal pole highly jeopardize the vascularity of the proximal fragment, significantly increasing the risk of delayed union, nonunion, and avascular necrosis.
Question 11276
Topic: 2. Trauma
A 78-year-old male falls from a standing height and sustains a fracture located at the junction of the base of the dens (odontoid process) and the body of C2, with 2 mm of posterior displacement. Based on the Anderson and D'Alonzo classification, what type of fracture is this, and what is its characteristic clinical challenge?
Correct Answer & Explanation
. Type II; high risk of nonunion due to watershed blood supply and biomechanical instability
Explanation
An Anderson and D'Alonzo Type II odontoid fracture occurs at the base of the dens (the junction of the dens and the body of C2). It is the most common type of odontoid fracture. It poses a significant clinical challenge because it has a notoriously high rate of nonunion, especially in the elderly, due to a watershed blood supply in this region, limited cancellous bone contact, and difficult biomechanical stabilization. Type I is an apical avulsion, and Type III extends into the cancellous body of C2 (which generally heals well).
Question 11277
Topic: 2. Trauma
A 35-year-old female sustains a high-energy trauma resulting in an intra-articular distal femur fracture. CT imaging reveals a coronal plane fracture of the lateral femoral condyle (Hoffa fracture). Which of the following represents the optimal surgical approach and fixation strategy for this specific fragment?
Correct Answer & Explanation
. Lateral approach with anterior-to-posterior lag screws
Explanation
Hoffa fractures are coronal plane fractures of the femoral condyle. They are optimally addressed via a lateral (or anterolateral) arthrotomy to directly visualize the articular surface, stabilized with lag screws placed in an anterior-to-posterior direction, often supplemented with an anti-glide plate.
Question 11278
Topic: 2. Trauma
A 28-year-old male is admitted with a highly comminuted tibial shaft fracture. He complains of pain out of proportion to the injury. Which of the following physiological thresholds is the most accurate and absolute indication for performing a fasciotomy for acute compartment syndrome?
Correct Answer & Explanation
. Absolute compartment pressure > 20 mmHg
Explanation
A delta pressure (defined as Diastolic Blood Pressure minus Compartment Pressure) of less than 30 mmHg is the most reliable and validated threshold for diagnosing acute compartment syndrome. Relying on absolute pressures alone can lead to unnecessary fasciotomies or missed diagnoses depending on systemic blood pressure.
Question 11279
Topic: 2. Trauma
A 40-year-old male arrives in the trauma bay in hemorrhagic shock following a crush injury. Radiographs show a widened symphysis pubis and disrupted posterior sacroiliac ligaments (APC-III). When applying a circumferential pelvic binder to stabilize the pelvis, over which anatomic landmarks must the binder be centered?
Correct Answer & Explanation
. Greater trochanters
Explanation
A pelvic binder must be centered directly over the greater trochanters to effectively close the pelvic ring volume and stabilize an 'open book' fracture pattern. Misplacing the binder proximally over the iliac crests is ineffective and can paradoxically widen the true pelvis.
Question 11280
Topic: 2. Trauma
A 35-year-old male sustains a closed tibia fracture and is admitted for observation. Several hours later, he complains of severe pain out of proportion to the injury. Which of the following clinical parameters is the most reliable objective indicator for emergent fasciotomy?
Correct Answer & Explanation
. Absolute compartment pressure of 25 mmHg
Explanation
A Delta P (diastolic blood pressure minus compartment pressure) of 30 mmHg or less is widely considered the threshold for diagnosing acute compartment syndrome and mandates emergent fasciotomy. Loss of pulses is a late and unreliable sign of compartment syndrome.
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