Menu

2. Trauma MCQs

Practice Set 151 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 3001

Topic: Lower Extremity Trauma

A 35-year-old patient is undergoing a distal femoral osteotomy for a valgus deformity. The surgeon is aiming to restore normal joint orientation angles. Which of the following angles is the primary target for this specific correction, and what is its average target value?

. Medial Proximal Tibial Angle (MPTA); 87°
. Mechanical Lateral Distal Femoral Angle (mLDFA); 87°
. Mechanical Lateral Distal Tibial Angle (mLDTA); 89°
. Joint Line Convergence Angle (JLCA); 0°
. Lateral Proximal Femoral Angle (LPFA); 90°

Correct Answer & Explanation

. Mechanical Lateral Distal Femoral Angle (mLDFA); 87°

Explanation

Correct Answer: BThe primary target for a distal femoral osteotomy is the Mechanical Lateral Distal Femoral Angle (mLDFA), with an average target value of 87°. The table in the text lists 'mLDFA' as 'Crucial for distal femoral osteotomies' with an 'Average Target Value' of '87°'.Incorrect Options:A:MPTA is the primary target for high tibial osteotomies, not distal femoral.C:mLDTA is essential for supramalleolar corrections, not distal femoral.D:JLCA measures ligamentous laxity or cartilage loss, not a primary target for bone correction itself, though it's an important assessment.E:LPFA defines the relationship of the hip joint to the proximal femoral axis, not the distal femur.

Question 3002

Topic: 2. Trauma

A surgeon is performing a high tibial osteotomy. After creating the osteotomy, the surgeon notices that the bone does not yield easily to the osteotome twist, despite having made multiple drill holes. What is the most appropriate next step, according to the surgical pearls, and why?

. Apply more aggressive hammering to the osteotome to force the bone to separate, as this indicates a strong bone.
. Switch to a high-speed oscillating saw to complete the cut, as the drill hole technique is proving insufficient.
. Remove the osteotome and use the drill to connect any missed spots, as there is likely a remaining cortical bone bridge.
. Increase the rotational force on the osteotome significantly, as the twisting motion is designed to overcome resistance.
. Abandon the osteotomy at this level and move to a more distal site where the bone is less dense.

Correct Answer & Explanation

. Remove the osteotome and use the drill to connect any missed spots, as there is likely a remaining cortical bone bridge.

Explanation

Correct Answer: CThe most appropriate next step is to remove the osteotome and use the drill to connect any missed spots, as there is likely a remaining cortical bone bridge. The text's 'Surgical Pearls for Flawless Osteotomy Execution' explicitly states: 'Don't Force It: If the bone doesn't yield easily to the twist, there is a remaining cortical bone bridge. Remove the osteotome and use the drill to connect any missed spots.'Incorrect Options:A:Aggressive hammering is discouraged and can lead to uncontrolled fracture or comminution.B:Switching to a high-speed saw defeats the purpose of the multiple drill hole technique, which is to minimize thermal necrosis.D:While twisting is key, the pearl 'Don't Force It' indicates that excessive force is counterproductive and suggests a missed bone bridge rather than simply needing more force.E:Abandoning the osteotomy level without first ensuring the current attempt is complete is premature and may not be necessary if a simple bone bridge is the issue.

Question 3003

Topic: Lower Extremity Trauma

An 18-year-old male presents with bilateral genu varum. Standing long-leg radiographs reveal a Mechanical Axis Deviation (MAD) of 35 mm medial to the center of the knee. The mechanical Lateral Distal Femoral Angle (mLDFA) is measured at 87 degrees, and the Medial Proximal Tibial Angle (MPTA) is measured at 76 degrees. The Joint Line Convergence Angle (JLCA) is 1 degree. Where is the primary source of the deformity?

. Distal femur
. Proximal tibia
. Intra-articular (ligamentous laxity)
. Ankle joint
. Femoral neck

Correct Answer & Explanation

. Proximal tibia

Explanation

The normal mLDFA is 85-90 degrees (average 88) and normal MPTA is 85-90 degrees (average 87). The patient's MPTA is abnormally low (76 degrees), indicating proximal tibial varus is the primary driver of the medial MAD.

Question 3004

Topic: Lower Extremity Trauma

During Fixator-Assisted Nailing (FAN) for a distal tibial valgus deformity, the surgeon intends to use a blocking (Poller) screw to prevent the intramedullary nail from following the path of least resistance into the deformed metaphysis. To effectively guide the nail and correct the valgus, where should the blocking screw be placed in the distal segment?

. On the convex (medial) side of the planned nail path.
. On the concave (lateral) side of the planned nail path.
. Directly in the center of the medullary canal.
. Posterior to the nail to control sagittal alignment.
. Proximal to the osteotomy site only.

Correct Answer & Explanation

. On the concave (lateral) side of the planned nail path.

Explanation

Blocking screws should be placed on the concave side of the deformity (the wider side of the planned nail path) to narrow the metaphysis and force the nail towards the center of the bone. In a valgus deformity, the concavity is lateral, so the screw goes on the lateral side of the distal segment.

Question 3005

Topic: Lower Extremity Trauma

When evaluating sagittal plane deformities of the lower extremity using Paley's joint orientation angles, what is the normal expected Posterior Distal Femoral Angle (PDFA) referenced from the mechanical axis?

. 79 degrees
. 83 degrees
. 87 degrees
. 90 degrees
. 95 degrees

Correct Answer & Explanation

. 83 degrees

Explanation

The normal Posterior Distal Femoral Angle (PDFA) is 83 degrees. Deviations from this value indicate a sagittal plane deformity, such as a flexion or extension deformity of the distal femur.

Question 3006

Topic: Lower Extremity Trauma

A 40-year-old male presents with post-traumatic deformity. Standing radiographs show a lateral Mechanical Axis Deviation (MAD). Measurement of the mechanical Lateral Distal Femoral Angle (mLDFA) is 80 degrees, while the MPTA is 87 degrees. Based on Paley's normal parameters, what is the primary deformity?

. Femoral varus
. Femoral valgus
. Tibial varus
. Tibial valgus
. Femoral retroversion

Correct Answer & Explanation

. Femoral valgus

Explanation

The normal mLDFA is approximately 88 degrees. An mLDFA of 80 degrees indicates a reduced angle on the lateral side, meaning the distal femur is angled into valgus. A lateral MAD confirms a valgus overall alignment.

Question 3007

Topic: 2. Trauma

During the surgical approach for distraction osteogenesis, the surgeon performs a low-energy corticotomy rather than a standard osteotomy with a power saw. What is the primary biological rationale for this technique according to Ilizarov principles?

. To prevent angular deformity during the distraction phase.
. To preserve the periosteal and medullary blood supply crucial for osteogenesis.
. To decrease the risk of post-operative compartment syndrome.
. To allow immediate full weight-bearing post-operatively.
. To ensure perfectly orthogonal mechanical axes.

Correct Answer & Explanation

. To preserve the periosteal and medullary blood supply crucial for osteogenesis.

Explanation

A low-energy corticotomy (often using osteotomes and drill holes) minimizes thermal necrosis and preserves the medullary and periosteal blood vessels. This preservation of local biology is critical for forming healthy regenerate bone during distraction.

Question 3008

Topic: 2. Trauma

When performing Fixator-Assisted Plating (FAP) for a complex distal femoral deformity, what is the primary role of the temporary external fixator?

. To provide long-term weight-bearing stability.
. To dynamically distract the bone post-operatively.
. To dial in and hold the exact anatomical correction while the definitive plate is applied.
. To bypass the need for blocking screws during nailing.
. To compress the joint surface in intra-articular fractures.

Correct Answer & Explanation

. To dial in and hold the exact anatomical correction while the definitive plate is applied.

Explanation

In Fixator-Assisted Plating (FAP), a temporary external fixator is used intra-operatively to precisely correct the deformity and hold the limb in perfect alignment. Once alignment is achieved, a plate is definitively applied, and the fixator is removed.

Question 3009

Topic: 2. Trauma

When utilizing the Fixator-Assisted Nailing (FAN) technique for correcting a complex lower extremity deformity, what is the most critical step regarding the placement of the temporary half-pins?

. Pins must be placed exactly at the CORA to act as the ACA.
. Pins must be positioned outside the planned path of the intramedullary reamer and nail.
. Pins must be inserted exclusively in the metaphyseal bone to prevent diaphyseal stress risers.
. Pins must be left in place permanently alongside the nail to provide rotational stability.
. Pins must cross the osteotomy site to stabilize the fragments before reaming.

Correct Answer & Explanation

. Pins must be positioned outside the planned path of the intramedullary reamer and nail.

Explanation

In the FAN technique, the temporary external fixator maintains the correction while the intramedullary nail is inserted. The half-pins must be carefully planned and placed so they do not intersect or block the path of the reamer and the intramedullary nail.

Question 3010

Topic: 2. Trauma

You are treating a proximal third tibia fracture with a planned intramedullary nail and want to prevent the common valgus/procurvatum malalignment. Using the blocking (Poller) screw principle described in deformity correction, where should the blocking screws be placed in the proximal segment relative to the desired nail path?

. On the convex side of the anticipated deformity.
. On the concave side of the anticipated deformity.
. Directly through the center of the medullary canal.
. Exclusively in the distal segment.
. Parallel to the joint line regardless of the deformity plane.

Correct Answer & Explanation

. On the concave side of the anticipated deformity.

Explanation

Blocking screws should be placed on the concave side of the anticipated or existing deformity (which corresponds to the acute angle of the deformity). This effectively narrows the wide metaphyseal canal and guides the nail toward the center, forcing correction.

Question 3011

Topic: Lower Extremity Trauma

During preoperative planning for a sagittal plane tibial deformity, the Posterior Proximal Tibial Angle (PPTA) is measured. The normal anatomic PPTA is approximately 81 degrees. If a patient has a PPTA of 95 degrees, what type of deformity is present?

. Genu recurvatum (apex posterior deformity)
. Genu procurvatum (apex anterior deformity)
. Varus deformity
. Valgus deformity
. Normal alignment

Correct Answer & Explanation

. Genu recurvatum (apex posterior deformity)

Explanation

The normal PPTA is 81 degrees, reflecting the native posterior slope of the tibial plateau. A PPTA of 95 degrees indicates an abnormal anterior tilt of the plateau relative to the shaft, which corresponds to a recurvatum (apex posterior) deformity.

Question 3012

Topic: Lower Extremity Trauma

In the context of the Fixator-Assisted Nailing (FAN) technique, which of the following is an absolute contraindication to utilizing this method for deformity correction?

. Obesity (BMI > 35).
. Osteopenia.
. Active pin-tract infection from a prior external fixator in the path of the planned nail.
. A deformity magnitude greater than 15 degrees.
. Presence of a multi-apical deformity.

Correct Answer & Explanation

. Active pin-tract infection from a prior external fixator in the path of the planned nail.

Explanation

Active infection or a history of pin-tract infection directly in the planned path of the intramedullary nail is an absolute contraindication to FAN due to the unacceptably high risk of deep intramedullary sepsis.

Question 3013

Topic: 2. Trauma

A patient is undergoing Fixator-Assisted Plating (FAP) instead of FAN for a distal femoral valgus deformity. What is the primary biomechanical advantage of FAP over FAN in a very distal peri-articular deformity?

. FAP allows for immediate full weight-bearing.
. FAP provides superior control of the short metaphyseal segment without relying on intramedullary canal fit.
. FAP requires less soft tissue dissection than intramedullary nailing.
. FAP eliminates the need for temporary external fixation pins.
. FAP guarantees a faster bone healing index.

Correct Answer & Explanation

. FAP provides superior control of the short metaphyseal segment without relying on intramedullary canal fit.

Explanation

In very distal or proximal peri-articular deformities, the short metaphyseal segment may not provide enough purchase or correct canal length for an intramedullary nail. FAP uses locking plates which offer superior angular stability in short segments.

Question 3014

Topic: Lower Extremity Trauma

When calculating the magnitude of translation generated by applying Paley's Rule 2 (ACA at CORA, osteotomy distant from CORA), the amount of translation is mathematically dependent on which two factors?

. The bone healing index and the time to full weight-bearing.
. The diameter of the intramedullary nail and the width of the medullary canal.
. The magnitude of angular correction and the distance between the osteotomy and the CORA.
. The age of the patient and the bone density.
. The Joint Line Convergence Angle and the mechanical axis deviation.

Correct Answer & Explanation

. The magnitude of angular correction and the distance between the osteotomy and the CORA.

Explanation

The magnitude of iatrogenic translation at the osteotomy site in a Rule 2 correction is a geometric function of the angle of correction and the linear distance from the ACA (CORA) to the osteotomy site.

Question 3015

Topic: 2. Trauma

During a Fixator-Assisted Nailing (FAN) procedure for a proximal third tibia fracture with a valgus deformity, the surgeon plans to use Poller (blocking) screws to maintain alignment during reaming and nail insertion. Where is the most biomechanically advantageous position to place the blocking screw in the proximal segment?

. On the medial (convex) side of the deformity.
. On the lateral (concave) side of the deformity.
. Directly anterior to the intramedullary nail.
. Directly within the center of the medullary canal.
. Distal to the fracture site on the convex side.

Correct Answer & Explanation

. On the lateral (concave) side of the deformity.

Explanation

Blocking (Poller) screws should be placed on the concave side of the deformity (the lateral side in a valgus deformity). This effectively narrows the metaphyseal canal, forcing the reamer and nail toward the center and correcting the malalignment.

Question 3016

Topic: Lower Extremity Trauma

A 45-year-old patient presents with medial knee pain. Standing long-leg radiographs reveal a Mechanical Axis Deviation (MAD) of 35 mm medial to the midline. The Mechanical Proximal Tibial Angle (MPTA) is 87 degrees, the mechanical Lateral Distal Femoral Angle (mLDFA) is 96 degrees, and the Joint Line Convergence Angle (JLCA) is 1 degree. Where is the primary source of the patient's deformity?

. Proximal tibia (Varus)
. Proximal tibia (Valgus)
. Distal femur (Varus)
. Distal femur (Valgus)
. Intra-articular (Ligamentous laxity)

Correct Answer & Explanation

. Distal femur (Varus)

Explanation

The normal mLDFA is approximately 88 degrees. An mLDFA of 96 degrees indicates a distal femoral varus deformity. The MPTA (87 degrees) and JLCA (1 degree) are within normal limits.

Question 3017

Topic: Lower Extremity Trauma

A surgeon is evaluating a patient for a sagittal plane deformity of the proximal tibia prior to an osteotomy. What is the normal accepted range for the Posterior Proximal Tibial Angle (PPTA)?

. 65 to 70 degrees
. 77 to 84 degrees
. 85 to 90 degrees
. 91 to 95 degrees
. 96 to 102 degrees

Correct Answer & Explanation

. 77 to 84 degrees

Explanation

The normal PPTA ranges from 77 to 84 degrees, with an average of 81 degrees. It is used to assess the normal posterior slope of the tibial plateau in the sagittal plane.

Question 3018

Topic: 2. Trauma

During Fixator-Assisted Nailing (FAN) of a distal third femur fracture, the gastrocnemius muscle routinely pulls the distal segment into recurvatum (apex posterior angulation). To prevent this deformity during reaming and nailing, a Poller (blocking) screw should be strategically placed:

. Anterior to the expected nail path in the distal segment.
. Posterior to the expected nail path in the distal segment.
. Medial to the expected nail path in the proximal segment.
. Lateral to the expected nail path in the proximal segment.
. Directly through the fracture site.

Correct Answer & Explanation

. Posterior to the expected nail path in the distal segment.

Explanation

Recurvatum creates an apex posterior deformity, meaning the concave side is posterior. To guide the nail anteriorly and prevent recurvatum, the blocking screw must be placed posterior to the nail track in the distal segment.

Question 3019

Topic: 2. Trauma

A surgeon utilizes Fixator-Assisted Plating (FAP) for a complex distal tibia deformity. What is the primary procedural rationale for choosing FAP over traditional free-hand plating or pure external fixation?

. It eliminates the need for fluoroscopy during the procedure.
. It provides temporary multi-planar alignment stability while a minimally invasive locking plate is applied, avoiding prolonged external fixation.
. It allows for dynamic postoperative distraction osteogenesis using the plate.
. It relies solely on bone graft for structural integrity.
. It allows the use of un-locked standard plates in osteoporotic bone.

Correct Answer & Explanation

. It provides temporary multi-planar alignment stability while a minimally invasive locking plate is applied, avoiding prolonged external fixation.

Explanation

Fixator-Assisted Plating (FAP) uses a temporary external fixator to accurately dial in multi-planar correction. Once perfect alignment is confirmed, an internal plate is applied, sparing the patient months in an external frame.

Question 3020

Topic: 2. Trauma

A patient undergoes correction of a diaphyseal tibial malunion. The preoperative plan localizes the Center of Rotation of Angulation (CORA) at the mid-diaphysis. The surgeon performs the osteotomy precisely at the CORA and places the hinge of the external fixator at this exact same location. According to Paley's osteotomy rules, what is the expected biomechanical outcome of this correction?

. Pure translation without angulation
. Angulation combined with expected translation of the mechanical axis
. Pure angulation with complete collinear realignment of the mechanical axes
. Creation of a secondary uniapical deformity requiring a second osteotomy
. Angulation with a resultant oblique joint line orientation

Correct Answer & Explanation

. Pure angulation with complete collinear realignment of the mechanical axes

Explanation

According to Paley's Osteotomy Rule 1, when the osteotomy and the hinge are both located at the CORA, the mechanical axes will realign via pure angulation without translation.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page