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2. Trauma MCQs

Practice Set 589 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 11761

Topic: 2. Trauma

In the management of a large segmental bone defect in the tibia resulting from an open fracture, which type of bone graft is generally considered superior due to its osteoinductive, osteoconductive, and osteogenic properties?

. Demineralized bone matrix (DBM).
. Allograft cortical strut.
. Autogenous iliac crest bone graft (ICBG).
. Ceramic bone graft substitute.
. Bone marrow aspirate concentrate (BMAC).

Correct Answer & Explanation

. Autogenous iliac crest bone graft (ICBG).

Explanation

Autogenous iliac crest bone graft (ICBG) is considered the 'gold standard' for bone grafting due to its osteoinductive (growth factors), osteoconductive (scaffold), and osteogenic (live osteocytes and progenitor cells) properties. It also carries no risk of disease transmission or immune rejection. Allografts (cortical struts) provide osteoconduction and structural support but lack osteogenic cells and have limited osteoinductive potential. DBM and ceramic substitutes are primarily osteoconductive with some osteoinductive properties but lack osteogenic cells. BMAC provides osteogenic cells but generally needs a scaffold.

Question 11762

Topic: 2. Trauma

Which of the following statements most accurately describes the biomechanical principle of a 'tension band' construct, commonly used in patellar or olecranon fractures?

. It converts tensile forces on one side of the bone into compressive forces on the fracture site.
. It provides absolute stability through lag screw effect.
. It is a load-sharing device that allows immediate full weight-bearing.
. It acts as a buttress to prevent axial collapse.
. It provides rotational stability but not axial stability.

Correct Answer & Explanation

. It converts tensile forces on one side of the bone into compressive forces on the fracture site.

Explanation

A tension band construct (e.g., using K-wires and a figure-of-eight wire loop) is designed to convert tensile forces, which typically cause gapping on the convex side of a fracture (e.g., anterior patella during knee flexion), into compressive forces at the fracture site. This dynamic compression promotes fracture healing and allows for early range of motion. It provides relative stability, not absolute stability via lag screw. It's a load-sharing construct but not for immediate full weight-bearing on weight-bearing bones. Buttress plates prevent axial collapse. Tension bands provide some rotational stability but their primary role is converting tension to compression.

Question 11763

Topic: 2. Trauma
A 30-year-old male sustains an 'open book' pelvic fracture (APC Type II) with diastasis of the pubic symphysis and disruption of the anterior sacroiliac ligaments. He is hemodynamically stable. What is the most appropriate definitive management strategy?
. Non-operative management with bed rest.
. Anterior internal fixation of the pubic symphysis.
. Posterior sacroiliac screw fixation.
. External fixation of the pelvis.
. Anterior and posterior internal fixation.

Correct Answer & Explanation

. Anterior internal fixation of the pubic symphysis.

Explanation

An APC Type II pelvic fracture involves disruption of the pubic symphysis and partial tearing of the posterior ligamentous complex (anterior sacroiliac ligaments). In a hemodynamically stable patient, the primary goal of definitive fixation is to restore pelvic ring stability and prevent chronic pain or deformity. For APC Type II fractures, anterior internal fixation of the pubic symphysis (e.g., with a plate) is typically sufficient, as the posterior ligaments are only partially disrupted. Posterior fixation (sacroiliac screws) is usually reserved for APC Type III fractures with complete posterior ligamentous disruption. External fixation can be used as a temporizing measure but is generally not definitive for this pattern unless there are severe soft tissue issues. Bed rest is not definitive for unstable fractures.

Question 11764

Topic: 2. Trauma

Which of the following is NOT a component of the Essex-Lopresti classification system for calcaneus fractures?

. Tongue-type fracture.
. Joint depression-type fracture.
. Posterior facet involvement.
. Non-articular fracture.
. Sustentacular fracture.

Correct Answer & Explanation

. Tongue-type fracture.

Explanation

The Essex-Lopresti classification specifically describes intra-articular calcaneus fractures, categorizing them based on the primary fracture lines and displacement patterns. It identifies two main types: 'tongue-type' and 'joint depression-type.' Both involve the posterior facet. Non-articular fractures are outside this classification system's primary focus. A sustentacular fracture is a specific extra-articular fracture often caused by inversion, and while it is a calcaneus fracture, it is not part of the Essex-Lopresti classification, which focuses on the more complex intra-articular patterns affecting the posterior facet.

Question 11765

Topic: Pelvic & Acetabular Trauma
A 30-year-old male presents to the emergency department after a high-speed motor vehicle accident. He is hemodynamically unstable, with a blood pressure of 80/40 mmHg and heart rate of 130 bpm. Pelvic X-ray shows a symphyseal diastasis of 5 cm and bilateral sacroiliac joint disruption. Which type of pelvic fracture does this best represent?
. Lateral Compression Type I (LC-I)
. Lateral Compression Type II (LC-II)
. Anterior-Posterior Compression Type I (APC-I)
. Anterior-Posterior Compression Type III (APC-III)
. Vertical Shear (VS)

Correct Answer & Explanation

. Anterior-Posterior Compression Type III (APC-III)

Explanation

This patient's injury pattern with symphyseal diastasis and bilateral sacroiliac joint disruption, combined with hemodynamic instability, is characteristic of an Anterior-Posterior Compression Type III (APC-III) pelvic fracture. This involves complete disruption of the posterior ligamentous complex (including sacrospinous, sacrotuberous, and anterior/posterior SI ligaments), leading to significant pelvic instability and a high risk of life-threatening hemorrhage. APC-I has symphyseal widening but intact posterior ligaments. LC types involve lateral compression with different degrees of rotation. Vertical Shear involves vertical displacement with complete disruption.

Question 11766

Topic: 2. Trauma

Which of the following is a contraindication to retrograde intramedullary nailing for a distal femur fracture?

. Prior total knee arthroplasty (TKA).
. Articular extension of the fracture into the knee joint.
. Obesity.
. Associated femoral neck fracture.
. Open fracture (Gustilo Type I).

Correct Answer & Explanation

. Articular extension of the fracture into the knee joint.

Explanation

Retrograde intramedullary nailing involves inserting the nail through the intercondylar notch of the knee and advancing it proximally. Significant articular extension of a distal femur fracture into the knee joint is a contraindication as it compromises the ability to obtain and maintain an anatomical articular reduction, risks damage to the articular cartilage during nail insertion, and may not provide adequate fixation for the articular fragments. While a prior TKA might make entry difficult, it's often possible through a notch or via one of the femoral component pegs. Obesity and Gustilo Type I open fractures are not contraindications. An associated ipsilateral femoral neck fracture would indicate an ipsilateral femoral shaft fracture, which is often managed with a long antegrade nail, but a distal femur can also be nailed retrograde.

Question 11767

Topic: 2. Trauma

A 55-year-old male sustains a comminuted fracture of the femoral shaft. His contralateral leg has an open tibia fracture. What is the preferred method for temporary stabilization of the femoral shaft fracture in the setting of polytrauma, especially if definitive fixation needs to be delayed?

. Skeletal traction.
. External fixation.
. Spica cast.
. Plate osteosynthesis.
. Splinting with a long-leg splint.

Correct Answer & Explanation

. External fixation.

Explanation

In the setting of polytrauma, especially with an associated open fracture, external fixation is often the preferred method for temporary stabilization of a femoral shaft fracture. It provides rapid and effective stabilization, facilitates wound care for associated open injuries, and allows for patient transport and resuscitation without the risks of prolonged skeletal traction or definitive internal fixation in an unstable patient. Skeletal traction is an option but less versatile. Spica casts are rarely used for adult femoral fractures due to patient discomfort and lack of stability. Plate osteosynthesis is definitive fixation. Splinting is insufficient for femoral shaft fractures.

Question 11768

Topic: 2. Trauma

Which of the following describes a 'stress shielding' effect as a complication of fracture fixation?

. Inadequate load transfer to the bone, leading to osteopenia beneath the implant.
. Excessive loading of the implant, leading to implant failure.
. Increased bone density around the fracture site due to excessive stress.
. Delayed union caused by micromotion at the fracture site.
. Bone resorption at the screw-bone interface.

Correct Answer & Explanation

. Inadequate load transfer to the bone, leading to osteopenia beneath the implant.

Explanation

Stress shielding occurs when an implant carries too much of the load, preventing the underlying bone from experiencing normal physiological stresses. According to Wolff's Law, bone adapts to the loads placed upon it. When bone is 'shielded' from stress, it can lead to bone atrophy or osteopenia beneath the implant, weakening the bone and potentially contributing to refracture after implant removal or other long-term complications. Excessive loading of the implant leads to failure. Increased bone density due to stress is a normal response to loading. Delayed union is due to insufficient stability or biology, not stress shielding per se. Bone resorption at the screw-bone interface can be due to micromotion or infection.

Question 11769

Topic: 2. Trauma

A 70-year-old female sustains an unstable intertrochanteric hip fracture. She is medically optimized. Which of the following implants is generally considered the most biomechanically stable for this fracture pattern?

. Dynamic Hip Screw (DHS).
. Cannulated cancellous screws.
. Trochanteric intramedullary nail.
. Long-leg cast.
. Bipolar hemiarthroplasty.

Correct Answer & Explanation

. Trochanteric intramedullary nail.

Explanation

For unstable intertrochanteric hip fractures (e.g., reverse obliquity, subtrochanteric extension, or highly comminuted), a trochanteric intramedullary nail is generally preferred over a Dynamic Hip Screw (DHS). IMN provides a more load-sharing construct, especially on the medial side, and is more resistant to varus collapse and cut-out, which are common failure modes in unstable patterns treated with a DHS. Cannulated screws are for femoral neck fractures. Long-leg casts are not used. Hemiarthroplasty might be considered for very specific cases but not the primary fixation choice for an unstable intertrochanteric fracture.

Question 11770

Topic: 2. Trauma
Which of the following Gustilo-Anderson classifications of open fractures carries the highest risk of infection and typically requires a free flap for definitive soft tissue coverage?
. Type I
. Type II
. Type IIIA
. Type IIIB
. Type IIIC

Correct Answer & Explanation

. Type IIIB

Explanation

The Gustilo-Anderson classification categorizes open fractures based on wound size, soft tissue damage, and contamination. Type IIIB involves extensive soft tissue loss, periosteal stripping, and often requires rotational or free flap coverage for definitive soft tissue reconstruction. It carries a high risk of infection and nonunion. Type I and II have smaller wounds and less soft tissue damage. Type IIIA has significant soft tissue damage but usually allows for local coverage. Type IIIC includes an associated arterial injury requiring repair, making it limb-threatening but IIIB is specifically defined by the need for advanced soft tissue coverage.

Question 11771

Topic: 2. Trauma

A 25-year-old male sustains a high-energy injury resulting in an ankle fracture and a compartment syndrome requiring fasciotomy. Which of the following is NOT an appropriate measure to prevent heterotopic ossification (HO)?

. Indomethacin post-operatively.
. Early range of motion.
. Local radiation therapy.
. Prophylactic antibiotics.
. Aggressive wound care and debridement.

Correct Answer & Explanation

. Prophylactic antibiotics.

Explanation

Prophylactic antibiotics are crucial for preventing infection in open fractures or after surgical procedures but have no role in preventing heterotopic ossification (HO). HO is abnormal bone formation in soft tissues and is typically prevented by NSAIDs (like indomethacin) or low-dose local radiation therapy. Early range of motion, aggressive wound care, and debridement are important for overall recovery but are not direct preventative measures for HO. Compartment syndrome requiring fasciotomy is a known risk factor for HO, especially in the thigh and pelvis, but can occur elsewhere.

Question 11772

Topic: 2. Trauma

What is the primary role of an articular block in the reconstruction of a comminuted tibial plateau fracture with significant articular depression?

. To provide definitive fixation for the entire fracture.
. To prevent collapse of the articular segment during bone grafting and plate application.
. To allow for early weight-bearing.
. To serve as a temporary reduction aid prior to external fixation.
. To restore fibular length.

Correct Answer & Explanation

. To prevent collapse of the articular segment during bone grafting and plate application.

Explanation

In comminuted tibial plateau fractures with articular depression, an 'articular block' involves temporarily supporting or reducing the depressed articular fragments, often with K-wires or provisional screws, before elevating the depressed fragments and filling the metaphyseal void with bone graft. This technique prevents the articular segment from collapsing during the subsequent steps of bone grafting and definitive plate application, ensuring anatomical reduction and maintenance of the joint surface. It is a crucial step in joint reconstruction, not for definitive fixation, early weight-bearing, or fibular length.

Question 11773

Topic: 2. Trauma

Which of the following fractures is most susceptible to delayed union or nonunion due to its inherent poor vascularity and biomechanical environment?

. Femoral shaft fracture.
. Distal radius fracture.
. Tibial shaft fracture (middle-distal third).
. Humeral shaft fracture.
. Intertrochanteric hip fracture.

Correct Answer & Explanation

. Tibial shaft fracture (middle-distal third).

Explanation

Tibial shaft fractures, particularly in the middle to distal third, have the highest reported rates of delayed union and nonunion among long bone fractures. This is primarily due to the tibia's relatively poor soft tissue envelope (especially anteriorly), segmented blood supply, and significant cortical bone without much cancellous bone for rapid healing. The mechanical environment is also often challenging due to high stresses. Other fractures listed generally have better vascularity or a more favorable biomechanical environment for healing.

Question 11774

Topic: 2. Trauma

A 25-year-old male presents with a spiral fracture of the middle third of the tibia and fibula. Which imaging modality is most critical for pre-operative planning, especially concerning the fracture pattern and rotational alignment?

. Standard AP and lateral X-rays of the tibia/fibula.
. CT scan of the tibia/fibula.
. MRI of the tibia/fibula.
. Long-leg standing X-rays.
. Angiography.

Correct Answer & Explanation

. CT scan of the tibia/fibula.

Explanation

While standard AP and lateral X-rays are essential for initial diagnosis, a CT scan of the tibia/fibula is invaluable for pre-operative planning, especially for comminuted or complex spiral fractures. It provides detailed information about the fracture pattern, fragment comminution, and critically, aids in assessing and restoring rotational alignment. Rotational malunion is a common complication of tibial shaft fractures, and CT can help quantify this pre-operatively. MRI is better for soft tissue. Long-leg standing X-rays are for alignment assessment after healing. Angiography is for vascular injury.

Question 11775

Topic: 2. Trauma
A 20-year-old male presents with a Type I open fracture of the distal tibia. After initial debridement, what is the most appropriate primary antibiotic regimen?
. Clindamycin.
. Vancomycin.
. Cefazolin.
. Ciprofloxacin and clindamycin.
. Amoxicillin-clavulanate.

Correct Answer & Explanation

. Cefazolin.

Explanation

For Gustilo-Anderson Type I open fractures, the primary concern is usually Gram-positive organisms (e.g., Staphylococcus aureus). Therefore, a first-generation cephalosporin like cefazolin is the most appropriate initial empirical antibiotic. Vancomycin is reserved for patients with penicillin allergy or high suspicion of MRSA. Clindamycin is for anaerobic or specific Gram-positive coverage. Ciprofloxacin adds Gram-negative coverage, typically reserved for Type II and III fractures. Amoxicillin-clavulanate has broader coverage but is not the first-line for this specific injury type.

Question 11776

Topic: 2. Trauma

Which of the following is a common complication specifically associated with non-operative treatment of a displaced, unstable ankle fracture (e.g., Weber B with medial clear space widening)?

. Avascular necrosis of the talus.
. Compartment syndrome.
. Malunion leading to post-traumatic arthritis.
. Deep vein thrombosis (DVT).
. Peroneal nerve palsy.

Correct Answer & Explanation

. Malunion leading to post-traumatic arthritis.

Explanation

Displaced and unstable ankle fractures, particularly those involving syndesmotic instability (medial clear space widening), require anatomical reduction and stable fixation. Non-operative treatment of such fractures typically results in malunion, leading to persistent instability, abnormal joint mechanics, and a high likelihood of early onset post-traumatic arthritis. AVN of the talus is rare. Compartment syndrome and DVT are general complications of trauma and immobilization, not specific to non-operative treatment outcomes in the same way. Peroneal nerve palsy is a nerve injury, not a direct result of malunion.

Question 11777

Topic: 2. Trauma

In the management of an open pelvic fracture, what is the initial priority?

. Definitive external fixation of the pelvic ring.
. Primary closure of the perineal wound.
. Control of hemorrhage and diversion of the fecal stream if a rectal injury is present.
. Immediate CT angiography to identify bleeding.
. Application of a pelvic binder.

Correct Answer & Explanation

. Control of hemorrhage and diversion of the fecal stream if a rectal injury is present.

Explanation

Open pelvic fractures are severe injuries with high mortality. The initial priority is to control hemorrhage (often with a pelvic binder, then angioembolization or external fixation) and manage any associated open wound. If there is a perineal or rectal injury causing an open wound to the pelvis, diversion of the fecal stream (e.g., colostomy) and aggressive debridement are critical to prevent severe infection and sepsis. Primary wound closure is contraindicated due to high infection risk. While imaging is important, it should not delay life-saving interventions.

Question 11778

Topic: 2. Trauma

A 35-year-old male sustains a high-energy distal tibia fracture that is intra-articular (pilon). Which aspect of the surgical planning is most crucial to prevent long-term post-traumatic arthritis?

. Achieving stable fixation with a bridge plate.
. Restoring fibular length and alignment.
. Obtaining an anatomical reduction of the articular surface.
. Early weight-bearing to stimulate bone healing.
. Minimizing surgical incision size.

Correct Answer & Explanation

. Obtaining an anatomical reduction of the articular surface.

Explanation

For any intra-articular fracture, especially a pilon fracture, the most crucial aspect of surgical planning and execution is achieving an anatomical reduction of the articular surface. Any step-off or gap in the joint surface, even a few millimeters, dramatically increases the risk and severity of post-traumatic arthritis. While stable fixation (often with a bridge plate) and restoring fibular length are important components of the overall reconstruction, they are secondary to the primary goal of articular congruity. Early weight-bearing is contraindicated, and minimizing incision size is part of a minimally invasive technique but not the primary determinant of long-term articular health.

Question 11779

Topic: 2. Trauma

Which of the following is a potential complication of prolonged skeletal traction for a femoral shaft fracture, particularly in an elderly patient?

. Delayed union.
. Fat embolism.
. Knee stiffness.
. Vascular injury.
. Peroneal nerve palsy.

Correct Answer & Explanation

. Knee stiffness.

Explanation

Prolonged skeletal traction, especially in the elderly, can lead to significant knee stiffness and quadriceps muscle contracture, making rehabilitation difficult. While delayed union can occur with any fracture management, it's not specific to traction. Fat embolism is an acute complication of the fracture itself and initial management, not typically specific to prolonged traction. Vascular injury and peroneal nerve palsy are rare with proper traction setup. Knee stiffness is a very common and well-recognized complication of prolonged immobilization in traction.

Question 11780

Topic: 2. Trauma
A 38-year-old male presents after a rollover MVC. He is hypotensive and has a significantly widened pubic symphysis and disruption of the sacroiliac joints bilaterally on pelvic X-ray (APC III). His hemodynamic status is improving after initial fluid resuscitation and application of a pelvic binder. What is the most appropriate next step for definitive pelvic stabilization?
. Immediate external fixation of the anterior pelvic ring.
. Application of skeletal traction.
. Percutaneous iliosacral screw fixation.
. Open reduction and internal fixation (ORIF) of the pubic symphysis.
. Immediate angiography and embolization.

Correct Answer & Explanation

. Percutaneous iliosacral screw fixation.

Explanation

An APC III (Anteroposterior Compression Type III, or 'open book' fracture with posterior disruption) involves both anterior and posterior pelvic ring instability. While a pelvic binder provides initial temporary stability and reduces the volume, definitive stabilization is required. Given the posterior instability (sacroiliac joint disruption), percutaneous iliosacral screw fixation is often the preferred method for stabilizing the posterior ring, which is crucial for overall pelvic stability. Anterior external fixation is important, but often used as a temporary measure or in conjunction with posterior fixation. Angiography is indicated for ongoing hemodynamic instability despite mechanical stabilization. ORIF of the pubic symphysis might be considered for isolated symphysis diastasis but not for APC III. Skeletal traction is generally not used for pelvic ring fractures.

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