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2. Trauma MCQs

Practice Set 135 of 640

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 2681

Topic: 2. Trauma

At the beginning of an oral board case, the examiner hands you an imaging study. Which of the following opening statements demonstrates the most structured and professional viva technique?

. This is a broken femur; I would proceed to the operating room for nailing.
. I am looking at an AP and lateral radiograph of the right lower extremity of a skeletally mature individual demonstrating a comminuted midshaft femur fracture.
. Can I get a CT scan to see this fracture better?
. This patient obviously needs an intramedullary nail due to the visible displacement.
. The fracture is located in the diaphysis and seems to be in multiple pieces.

Correct Answer & Explanation

. I am looking at an AP and lateral radiograph of the right lower extremity of a skeletally mature individual demonstrating a comminuted midshaft femur fracture.

Explanation

A structured X-ray read should systematically state the modality, views, body part, skeletal maturity, and specific pathology. This establishes control, buys time to think, and shows the examiner a disciplined approach to clinical evaluation.

Question 2682

Topic: 2. Trauma

During the case review portion of your oral exam, an examiner points out a severe malunion in a distal radius fracture you treated non-operatively. What is the most defensible and professional way to handle this line of questioning?

. Blame the patient's non-compliance for the loss of reduction.
. Acknowledge the poor outcome, discuss the biomechanical reasons it occurred, and explain how you have changed your indications for surgery.
. State that the literature supports non-operative treatment regardless of the radiographic outcome.
. Suggest that the emergency department physician applied a poor initial splint.
. Refuse to discuss the case further as it is an isolated bad outcome.

Correct Answer & Explanation

. Acknowledge the poor outcome, discuss the biomechanical reasons it occurred, and explain how you have changed your indications for surgery.

Explanation

Examiners use the case list to test a candidate's insight and ability to learn from complications. Taking ownership of a bad outcome and articulating a specific change in future practice demonstrates the safety and maturity required of a board-certified surgeon.

Question 2683

Topic: 2. Trauma

A 30-year-old male is brought to the trauma bay following a high-speed motor vehicle collision. He has a hemodynamically unstable anterior-posterior compression (APC) pelvic ring injury. You order the placement of a non-invasive pelvic binder. Over which anatomical landmark should the binder be centered for maximum efficacy?

. Iliac crests.
. Greater trochanters.
. Anterior superior iliac spines.
. Umbilicus.
. Symphysis pubis.

Correct Answer & Explanation

. Greater trochanters.

Explanation

To effectively reduce pelvic volume and stabilize the pelvic ring, a pelvic binder or sheet must be centered directly over the greater trochanters. Placing it higher over the iliac crests is less mechanically effective and can worsen certain fracture patterns.

Question 2684

Topic: Pelvic & Acetabular Trauma

A 45-year-old male presents after a motorcycle collision with an anteroposterior compression (APC) type II pelvic ring injury. His hemodynamics are stable. What is the primary anatomic indication for surgical fixation of the anterior ring in this specific injury pattern?

. Symphyseal diastasis greater than 2.5 cm
. Presence of a concurrent Denis zone 1 sacral fracture
. Prevention of long-term erectile dysfunction
. Presence of a posterior urethral tear
. Associated L5 nerve root injury

Correct Answer & Explanation

. Symphyseal diastasis greater than 2.5 cm

Explanation

A symphyseal diastasis > 2.5 cm indicates disruption of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments, leading to rotational instability. Surgical fixation is indicated to restore pelvic ring stability and anatomy.

Question 2685

Topic: 2. Trauma

During an ABOS Part II oral exam, the examiner questions your decision-making regarding a case of deep postoperative infection following an open tibia fracture. You realize you missed a critical early sign of infection in your clinical narrative. What is the most appropriate tactic to address this during the viva?

. Defend the original decision to demonstrate surgical confidence
. Explain that the nursing staff failed to document the clinical sign
. Acknowledge the oversight, accept responsibility, and explain how it altered your future practice
. Quickly pivot the conversation to the eventual successful union of the fracture
. Request to skip the current case and move to the next patient

Correct Answer & Explanation

. Acknowledge the oversight, accept responsibility, and explain how it altered your future practice

Explanation

In oral board examinations, displaying insight, acknowledging complications, and demonstrating a capacity to learn from errors are critical for passing. Defensiveness, avoiding the question, or blaming others are major red flags.

Question 2686

Topic: 2. Trauma

A 24-year-old male presents with radial-sided wrist pain 6 months after a fall. Radiographs reveal a scaphoid waist fracture with cystic changes and sclerosis at the fracture margins. MRI confirms the proximal pole is well-vascularized. What is the most appropriate surgical treatment?

. Cast immobilization for an additional 12 weeks
. Proximal row carpectomy
. Open reduction internal fixation with non-vascularized bone graft
. Open reduction internal fixation with a vascularized bone graft
. Four-corner arthrodesis

Correct Answer & Explanation

. Open reduction internal fixation with non-vascularized bone graft

Explanation

For a scaphoid nonunion without avascular necrosis (AVN), ORIF with a non-vascularized bone graft (e.g., from the iliac crest or distal radius) is the standard treatment. Vascularized grafts are typically reserved for nonunions complicated by AVN.

Question 2687

Topic: 2. Trauma

In an oral board exam setting, you are presented with a radiograph of a highly comminuted distal femur fracture in a polytrauma patient. What is the most appropriate first step in verbalizing your response to maximize your score?

. Immediately recommend a retrograde intramedullary nail to show decisiveness
. Classify the fracture using the AO/OTA alphanumeric system
. Provide a systematic description of the patient demographics, the imaging modality, and the key radiographic findings
. Ask the examiner for the patient's Glasgow Coma Scale (GCS) score before describing the film
. Outline the surgical approach and patient positioning

Correct Answer & Explanation

. Provide a systematic description of the patient demographics, the imaging modality, and the key radiographic findings

Explanation

Examiners look for a safe, structured, and systematic approach. Before classifying or treating, you must accurately describe the basic clinical scenario and radiographic findings to demonstrate sound observational skills and fundamental knowledge.

Question 2688

Topic: 2. Trauma

During a trauma viva, the examiner suggests treating a displaced both-bone forearm fracture in a healthy 30-year-old laborer with a long arm cast, a clearly outdated and suboptimal method. What is the candidate's most appropriate response?

. Agree with the examiner to avoid any confrontation.
. Laugh and tell the examiner that no one has done that in 20 years.
. Respectfully disagree, stating that current evidence supports ORIF to restore radial bow and pronosupination.
. Agree, but state you would switch to a functional brace at 2 weeks.
. Tell the examiner that conservative management is malpractice.

Correct Answer & Explanation

. Respectfully disagree, stating that current evidence supports ORIF to restore radial bow and pronosupination.

Explanation

Examiners often play 'devil's advocate' by suggesting suboptimal or outdated treatments to test a candidate's conviction and knowledge. The candidate must politely but firmly defend the standard of care based on current evidence.

Question 2689

Topic: 2. Trauma

During an oral exam, an examiner strongly questions your choice of operative fixation for a midshaft clavicle fracture, asking, 'Why not treat this non-operatively?' What is the most appropriate viva tactic to employ?

. Yield immediately and change your answer to non-operative management.
. Defend your choice by citing the higher nonunion rate in displaced fractures while acknowledging non-operative management is also a standard option.
. Argue aggressively that non-operative treatment is obsolete in modern orthopedics.
. State you only operate because you are a surgeon and it is what you are trained to do.
. Ask the examiner what they would do in their own practice.

Correct Answer & Explanation

. Defend your choice by citing the higher nonunion rate in displaced fractures while acknowledging non-operative management is also a standard option.

Explanation

Examiners test your ability to defend your clinical reasoning. Acknowledging controversy while defending your choice with evidence demonstrates safety, maturity, and a balanced perspective.

Question 2690

Topic: 2. Trauma
A 30-year-old male sustains a vertically displaced femoral neck fracture (Pauwels III) in a motorcycle crash. What is the most appropriate biomechanical fixation construct to minimize shear forces?
. Three parallel cancellous screws
. Sliding hip screw (SHS) with a derotational screw
. Hemiarthroplasty
. Total hip arthroplasty
. Cephalomedullary nail

Correct Answer & Explanation

. Sliding hip screw (SHS) with a derotational screw

Explanation

Young adult Pauwels III fractures have high vertical shear forces. A sliding hip screw with a derotational screw provides superior biomechanical stability compared to parallel cancellous screws.

Question 2691

Topic: 2. Trauma
A 35-year-old construction worker sustains a Gustilo-Anderson Type IIIB open tibia fracture. According to current evidence, what is the most critical factor in reducing his immediate infection risk?
. Immediate application of an external fixator
. Time to systemic antibiotic administration
. Time to definitive soft tissue coverage within 24 hours
. Use of a reamed intramedullary nail instead of unreamed
. Addition of local antibiotic beads at 1 week

Correct Answer & Explanation

. Time to systemic antibiotic administration

Explanation

The earliest possible administration of systemic antibiotics is the single most critical factor in reducing infection rates in open fractures. Debridement timing is secondary to early antibiotic administration.

Question 2692

Topic: Lower Extremity Trauma

A 45-year-old active laborer presents with medial knee pain. Radiographs reveal isolated medial compartment osteoarthritis and a mechanical axis that passes through the medial compartment. When planning a valgus-producing high tibial osteotomy (HTO), where should the target mechanical axis ideally pass?

. Through the center of the knee joint (50% of tibial width)
. Through the lateral compartment at 62% of the tibial width from medial to lateral
. Through the medial compartment at 40% of the tibial width from medial to lateral
. Through the lateral compartment at 80% of the tibial width
. Directly through the lateral tibial spine

Correct Answer & Explanation

. Through the lateral compartment at 62% of the tibial width from medial to lateral

Explanation

In a valgus-producing HTO for medial compartment OA, the target mechanical axis is typically shifted to the lateral compartment, approximately 62% of the tibial plateau width from medial to lateral (Fujisawa point). This effectively unloads the diseased medial compartment.

Question 2693

Topic: Lower Extremity Trauma

During revision TKA, the surgeon encounters an isolated tight extension gap with a well-balanced flexion gap. Assuming the components are currently optimally sized, which of the following is the most appropriate surgical action?

. Resect more distal femur
. Increase the posterior slope of the tibial baseplate
. Upsize the femoral component
. Downsize the tibial polyethylene insert
. Release the posterior capsule from the femur

Correct Answer & Explanation

. Release the posterior capsule from the femur

Explanation

A tight extension gap with a balanced flexion gap is addressed by releasing the posterior capsule or resecting more distal femur. Since resecting more bone elevates the joint line, posterior capsular release is often the preferred initial step.

Question 2694

Topic: Lower Extremity Trauma

A 30-year-old female presents with a progressive genu valgum deformity. Preoperative planning reveals a Mechanical Lateral Distal Femoral Angle (mLDFA) of 95 degrees. All other joint orientation angles (MPTA, JLCA, LDTA) are within normal limits. Based on these findings, where is the primary anatomical location of the deformity?

. Proximal tibia
. Distal tibia
. Proximal femur
. Distal femur
. Intra-articular (knee joint)

Correct Answer & Explanation

. Distal femur

Explanation

Correct Answer: DThe Mechanical Lateral Distal Femoral Angle (mLDFA) is the lateral angle formed between the mechanical axis of the femur and the distal femoral joint line. Its normal value range is 85° to 90° (average 87°). A mLDFA of 95 degrees indicates that the distal femur is in valgus (an angle greater than 90 degrees for mLDFA signifies valgus, while an angle less than 85 degrees signifies varus). Since all other joint orientation angles are normal, the primary deformity is isolated to the distal femur.Options A, B, and C are incorrect because the MPTA, LDTA, and mLPFA (respectively) would be abnormal if the deformity were located in those segments. Option E is incorrect because a normal JLCA (Joint Line Convergence Angle) suggests no significant intra-articular pathology or ligamentous laxity contributing to the angular deformity.

Question 2695

Topic: Lower Extremity Trauma

A resident is preparing to evaluate a patient for a lower extremity deformity correction using Paley's methodology. The first crucial step is to measure the Mechanical Axis Deviation (MAD). Which of the following accurately describes the correct technique for measuring MAD?

. Drawing a line from the anterior superior iliac spine to the medial malleolus on a supine AP radiograph.
. Drawing a line from the center of the femoral head to the center of the talar dome on a standing, full-length, weight-bearing anteroposterior radiograph.
. Measuring the angle between the femoral shaft axis and the tibial shaft axis on a non-weight-bearing lateral radiograph.
. Drawing a line from the greater trochanter to the lateral malleolus on a supine AP radiograph.
. Measuring the distance between the medial femoral condyle and the medial tibial plateau on a knee MRI.

Correct Answer & Explanation

. Drawing a line from the center of the femoral head to the center of the talar dome on a standing, full-length, weight-bearing anteroposterior radiograph.

Explanation

Correct Answer: BAs explicitly stated in the teaching case, 'How to Measure the MAD: The patient must be positioned for a standing, full-length, weight-bearing anteroposterior (AP) radiograph (often called a teleoroentgenogram). A straight line is drawn from the exact center of the femoral head to the exact center of the talar dome in the ankle. This line represents the mechanical axis (or weight-bearing line) of the lower limb.'Option A is incorrect because MAD requires a standing, weight-bearing film and connects the femoral head to the talar dome, not the ASIS to the medial malleolus. Option C describes an angular measurement on a lateral view, not the MAD. Option D is incorrect as it uses different anatomical landmarks and a supine film. Option E describes a measurement from an MRI, which is not the standard method for determining global mechanical axis deviation on a radiograph.

Question 2696

Topic: 2. Trauma

A 68-year-old male presents with severe bilateral knee pain and a 'bow-legged' appearance. Full-length standing radiographs confirm a significant varus deformity in both lower extremities, with the mechanical axis passing 20 mm medial to the knee center bilaterally. According to Paley's principles, while the Mechanical Axis Deviation (MAD) perfectly quantifies the magnitude of this overall malalignment, what crucial information does the MAD alone NOT provide?

. The patient's functional limitations and pain level.
. The specific location (femur, tibia, or knee joint) of the deformity causing the malalignment.
. The presence of associated meniscal tears or cartilage defects.
. The patient's bone mineral density and risk of fracture.
. The optimal surgical hardware for correction (e.g., plate vs. external fixator).

Correct Answer & Explanation

. The specific location (femur, tibia, or knee joint) of the deformity causing the malalignment.

Explanation

Correct Answer: BThe teaching case clearly states: 'While the MAD perfectly quantifies themagnitudeof the overall malalignment, it is only a screening tool. It does not tell you thesourceof the deformity. The structural problem could be localized in the femur, the tibia, the knee joint itself (due to ligamentous laxity or bony changes).' Therefore, while MAD tells us the extent of the varus, it doesn't pinpoint whether the deformity originates in the distal femur, proximal tibia, or is a combined issue.Options A, C, D, and E are all important clinical considerations but are not directly related to the specific limitation of MAD as a diagnostic tool for identifying the anatomical source of the angular deformity. MAD is a geometric measurement of global alignment, not a comprehensive diagnostic tool for all associated pathologies or treatment planning specifics.

Question 2697

Topic: Lower Extremity Trauma

A 38-year-old male presents with chronic right knee pain and a progressive varus deformity. On weight-bearing full-length radiographs, the mechanical axis line of the lower extremity passes 20 mm medial to the center of the knee joint. Based on Paley's principles, what is the most accurate interpretation of this finding?

. The patient has a physiologic varus alignment within normal limits.
. The deformity is primarily located in the distal femur, requiring a distal femoral osteotomy.
. The patient has a clinically significant varus deformity, leading to medial compartment overload.
. The deformity is primarily located in the proximal tibia, requiring a proximal tibial osteotomy.
. The mechanical axis deviation indicates a valgus deformity requiring lateral compartment decompression.

Correct Answer & Explanation

. The patient has a clinically significant varus deformity, leading to medial compartment overload.

Explanation

Correct Answer: CThe Mechanical Axis Deviation (MAD) is defined as the perpendicular distance from the mechanical axis line (femoral head to ankle plafond) to the center of the knee joint. A normal MAD passes slightly medial to the knee's center, typically by 8 mm (± 7 mm). In this patient, the mechanical axis passes 20 mm medial to the knee center. This value significantly exceeds the normal range, indicating a clinically significant varus or 'bow-legged' deformity. This medial deviation of the mechanical axis results in excessive load bearing on the medial compartment of the knee, predisposing to medial meniscus degeneration and unicompartmental osteoarthritis.Option A is incorrectbecause 20 mm medial deviation is well outside the normal physiologic range of 8 mm (± 7 mm).Options B and D are incorrectbecause while an abnormal MAD indicates a deformity, it does not, by itself, pinpoint the exact anatomic source (distal femur vs. proximal tibia). Further joint orientation angle assessment (e.g., mLDFA, MPTA) is required to localize the deformity.Option E is incorrectbecause a medial deviation of the mechanical axis indicates a varus deformity, not a valgus deformity. A valgus deformity would present with the mechanical axis passing lateral to the knee center.

Question 2698

Topic: Lower Extremity Trauma

A 55-year-old female presents with left knee pain and a valgus deformity. Preoperative weight-bearing radiographs reveal a Mechanical Lateral Distal Femoral Angle (mLDFA) of 95° and a Medial Proximal Tibial Angle (MPTA) of 88°. All other joint orientation angles are within normal limits. Based on Paley's principles, where is the primary apex of the deformity located?

. Proximal tibia
. Distal tibia
. Proximal femur
. Distal femur
. Intra-articular (Joint Line Convergence Angle)

Correct Answer & Explanation

. Distal femur

Explanation

Correct Answer: DThe text states that the mLDFA (Mechanical Lateral Distal Femoral Angle) has a normal range of 85°-90°. An angle >90° indicates distal femoral valgus. In this patient, the mLDFA is 95°, which is significantly greater than 90°, indicating a valgus deformity originating in the distal femur. The MPTA (Medial Proximal Tibial Angle) has a normal range of 85°-90°. This patient's MPTA of 88° falls within the normal range, ruling out a primary deformity in the proximal tibia. Since all other angles are normal, the primary apex of the deformity is localized to the distal femur.Option A is incorrectbecause the MPTA is within the normal range.Option B is incorrectas the mLDTA (Mechanical Lateral Distal Tibial Angle) is not mentioned as abnormal.Option C is incorrectas the LPFA (Lateral Proximal Femoral Angle) is not mentioned as abnormal.Option E is incorrectas the JLCA (Joint Line Convergence Angle) is not mentioned as elevated, which would suggest intra-articular pathology.

Question 2699

Topic: 2. Trauma

During the preoperative planning for a tibial deformity correction, the surgeon is selecting the appropriate ring diameter for the circular external fixator. The widest part of the patient's calf measures 12 cm. According to the 'Two-Fingerbreadth Rule' and accounting for potential postoperative edema, what is the most appropriate ring diameter to select?

. 12 cm
. 14 cm
. 16 cm
. 18 cm
. 20 cm

Correct Answer & Explanation

. 18 cm

Explanation

Correct Answer: DThe text states: 'The optimal ring diameter is large enough to allow for two finger's-breadth (approximately 2-3 cm) of clearance circumferentially between the patient's skin and the inner border of the ring.' This measurement must be taken at the widest part of the limb and account for postoperative edema. Two fingerbreadths on each side would mean approximately 2-3 cm of clearance on the medial side and 2-3 cm on the lateral side, totaling 4-6 cm added to the limb diameter. For a 12 cm calf, adding 4-6 cm would result in a required ring diameter of 16-18 cm. A 18 cm ring provides adequate clearance (3 cm on each side), allowing for swelling and preventing skin impingement.Option A (12 cm) is incorrectas it provides no clearance and would lead to immediate skin impingement.Option B (14 cm) is incorrectas it provides only 1 cm of clearance on each side, which is insufficient and risks pressure sores and infection.Option C (16 cm) is incorrectas it provides 2 cm of clearance on each side, which might be borderline, especially with significant swelling. While 16cm is within the 16-18cm range, 18cm is 'more generous over bulky muscle compartments' as advised.Option E (20 cm) is incorrectbecause while it provides ample clearance (4 cm on each side), it might be 'too large,' which 'exponentially decreases the stiffness of the construct,' increasing the risk of delayed union or nonunion.

Question 2700

Topic: Lower Extremity Trauma

A surgeon is applying a circular external fixator for a tibial deformity correction. The following diagram illustrates the desired placement of the reference rings:

Based on the principles of tibial frame application, what is the critical requirement for the placement of the proximal and distal reference rings?

. They must be placed at the exact level of the CORA to ensure pure angular correction.
. They must be applied perfectly parallel to their respective joint lines to restore normal joint orientation angles.
. They must be positioned to maximize the distance between them, regardless of joint line orientation.
. The proximal ring must be perpendicular to the tibial shaft, and the distal ring parallel to the ankle joint.
. Their placement is arbitrary as long as sufficient bone is captured by wires and half-pins.

Correct Answer & Explanation

. They must be applied perfectly parallel to their respective joint lines to restore normal joint orientation angles.

Explanation

Correct Answer: BThe text, in the 'Tibial Frame Application' section, explicitly states: 'As this diagram illustrates, the reference rings must be applied perfectly parallel to their respective joint lines: ... This ring must be applied perfectly parallel to the knee joint line. ... This ring must be applied perfectly parallel to the ankle joint line.' It further explains, 'By securing these two rings parallel to the joints, the surgeon guarantees that when the connecting rods are made parallel (straightening the frame during the correction phase), the joint orientation angles (MPTA and mLDTA) will be automatically restored to their normal values.'Option A is incorrectbecause while the CORA is critical for hinge placement, the reference rings themselves are positioned relative to the joint lines, not necessarily at the CORA.Option C is incorrectbecause while maximizing the lever arm is important for stability, it must be balanced with respecting joint line parallelism and avoiding neurovascular structures.Option D is incorrectbecause both proximal and distal reference rings must be parallel to their respective joint lines, not perpendicular to the shaft.Option E is incorrectbecause ring placement is highly specific and follows strict anatomic and biomechanical rules, it is not arbitrary.

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