Menu

Lower Extremity Trauma MCQs

Practice Set 21 of 34

This practice set contains high-yield board review questions covering key concepts in Lower Extremity Trauma. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 401

Topic: Lower Extremity Trauma

A 25-year-old sustains an external rotation ankle injury. On a standard AP mortise radiograph taken non-weight-bearing, which measurement threshold is most specifically indicative of syndesmotic instability?

. Tibiofibular overlap less than 1 mm
. Medial clear space greater than 2 mm
. Tibiofibular clear space greater than 5 mm
. Talar tilt greater than 5 degrees
. Lateral malleolar displacement greater than 2 mm

Correct Answer & Explanation

. Tibiofibular clear space greater than 5 mm

Explanation

A tibiofibular clear space of greater than 5 mm on an AP or mortise radiograph is widely considered abnormal and suggests a syndesmotic injury. The tibiofibular overlap can vary based on rotation, making the clear space a more reliable indicator.

Question 402

Topic: Lower Extremity Trauma

During a posteromedial approach to the tibia for open reduction and internal fixation of a Schatzker IV tibial plateau fracture, the dissection utilizes the interval between the medial head of the gastrocnemius and the pes anserinus. Which of the following structures is at greatest risk of iatrogenic injury during the superficial dissection?

. Common peroneal nerve
. Saphenous nerve
. Sural nerve
. Anterior tibial artery
. Medial superior genicular artery

Correct Answer & Explanation

. Saphenous nerve

Explanation

The posteromedial approach to the tibial plateau requires careful superficial dissection. The saphenous nerve and the great saphenous vein run superficially in this region and are at significant risk of injury during the surgical approach.

Question 403

Topic: Lower Extremity Trauma

A 45-year-old male sustains a high-energy Schatzker IV tibial plateau fracture featuring a displaced posteromedial shear fragment. Which surgical approach is most appropriate for direct visualization and buttress plating of this specific fragment?

. Anterolateral approach with submeniscal arthrotomy
. Direct medial approach
. Posteromedial approach between the pes anserinus and the medial head of the gastrocnemius
. Posterolateral approach with fibular osteotomy
. Anterior midline approach with tibial tubercle osteotomy

Correct Answer & Explanation

. Posteromedial approach between the pes anserinus and the medial head of the gastrocnemius

Explanation

The posteromedial approach interval is between the pes anserinus tendons anteriorly and the medial head of the gastrocnemius posteriorly. It allows direct access to posteromedial shear fragments for optimal anti-glide or buttress plating.

Question 404

Topic: Lower Extremity Trauma

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?

. Lateral head of the gastrocnemius
. Medial head of the gastrocnemius
. Semimembranosus
. Popliteus
. Soleus

Correct Answer & Explanation

. Medial head of the gastrocnemius

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 405

Topic: Lower Extremity Trauma

You are planning an eight-plate hemiepiphysiodesis for a 9-year-old girl with idiopathic genu valgum. To achieve the best mechanical advantage and minimize joint line distortion, where should the plates be placed?

. Medial proximal tibia and medial distal femur
. Lateral proximal tibia and lateral distal femur
. Medial distal femur only, strictly subperiosteal
. Anterior distal femur and anterior proximal tibia
. Lateral distal femur only

Correct Answer & Explanation

. Medial proximal tibia and medial distal femur

Explanation

For genu valgum (knock-knees), medial hemiepiphysiodesis tethers the faster-growing medial side, allowing the lateral physis to continue growing and correct the deformity. Addressing both the femur and tibia (if both contribute) limits joint line obliquity.

Question 406

Topic: Lower Extremity Trauma

A 42-year-old skier sustains a high-energy varus injury to the knee, resulting in a displaced medial tibial plateau fracture (Schatzker IV). Which of the following structures is at highest risk of iatrogenic injury during a standard posteromedial surgical approach to the proximal tibia?

. Common peroneal nerve
. Anterior tibial artery
. Saphenous nerve
. Popliteal artery
. Sural nerve

Correct Answer & Explanation

. Saphenous nerve

Explanation

The posteromedial approach to the tibia utilizes the interval between the medial gastrocnemius (retracted posteriorly/laterally) and the pes anserinus (retracted anteriorly). The saphenous nerve and great saphenous vein run superficially in this region and are at highest risk of iatrogenic injury during the superficial dissection.

Question 407

Topic: Lower Extremity Trauma

A 24-year-old skier presents with acute lateral ankle pain and a snapping sensation posterior to the fibula after an inversion and forced dorsiflexion injury. Radiographs reveal a "fleck sign" adjacent to the lateral malleolus. Injury to which anatomic structure is most strongly indicated by this radiographic finding?

. Superior peroneal retinaculum
. Inferior peroneal retinaculum
. Calcaneofibular ligament
. Anterior talofibular ligament
. Peroneus brevis tendon

Correct Answer & Explanation

. Superior peroneal retinaculum

Explanation

The "fleck sign" represents a bony avulsion from the posterolateral ridge of the fibula, which is the attachment site of the superior peroneal retinaculum (SPR). Injury to the SPR is the hallmark of peroneal tendon subluxation or dislocation.

Question 408

Topic: Lower Extremity Trauma

When evaluating a patient for a suspected syndesmotic injury on standard ankle radiographs, which of the following parameters is the most accurate radiographic indicator of syndesmosis widening on an AP view?

. Tibiofibular overlap less than 10 mm
. Tibiofibular clear space greater than 5 mm
. Medial clear space greater than 4 mm
. Talar tilt greater than 5 degrees
. Talocrural angle less than 75 degrees

Correct Answer & Explanation

. Tibiofibular clear space greater than 5 mm

Explanation

The tibiofibular clear space is measured 1 cm proximal to the joint line. A distance of >5 mm on the AP or mortise view is considered abnormal and is the most reliable radiographic indicator of syndesmotic injury. Tibiofibular overlap is highly dependent on rotation and is therefore less reliable.

Question 409

Topic: Lower Extremity Trauma

A 25-year-old soccer player sustains an external rotation ankle injury. Standard AP, mortise, and lateral radiographs are obtained to evaluate for a syndesmotic injury. Which of the following radiographic measurements is the most reliable and widely accepted indicator of syndesmotic widening?

. Tibiofibular overlap greater than 10 mm on the AP view
. Tibiofibular clear space greater than 5 mm measured 1 cm proximal to the joint line on the AP or mortise view
. A medial clear space less than 4 mm on the mortise view
. Talar tilt greater than 2 degrees on stress views
. Fibular shortening of less than 2 mm on the lateral view

Correct Answer & Explanation

. Tibiofibular clear space greater than 5 mm measured 1 cm proximal to the joint line on the AP or mortise view

Explanation

The tibiofibular clear space is the distance between the medial border of the fibula and the incisura fibularis of the tibia, typically measured 1 cm above the joint line. A clear space greater than 5 mm on either the AP or mortise view is abnormal and highly indicative of a syndesmotic injury. Tibiofibular overlap is highly dependent on rotation and is less reliable.

Question 410

Topic: Lower Extremity Trauma

A surgeon performs a medial opening-wedge high tibial osteotomy (HTO) to correct varus deformity in a patient with medial compartment osteoarthritis. The surgeon fails to release the distal superficial medial collateral ligament (sMCL) and inadvertently opens the osteotomy gap predominantly at the anterior cortex. What unintended sagittal plane deformity is most likely to result?

. Increased posterior tibial slope
. Decreased posterior tibial slope
. Increased anterior tibial slope
. Tibial recurvatum deformity
. Complete loss of normal tibial rotation

Correct Answer & Explanation

. Increased posterior tibial slope

Explanation

In a medial opening-wedge HTO, the tight posteromedial structures (specifically the sMCL) can act as a hinge. If the sMCL is not released, the osteotomy gap will preferentially open anteriorly. This anterior opening elevates the anterior tibial plateau relative to the posterior plateau, leading to an unintended increase in the posterior tibial slope. Releasing the sMCL and ensuring the gap is opened evenly (or slightly more posteromedially) prevents this.

Question 411

Topic: Lower Extremity Trauma

A 6-year-old child is evaluated for a painless 'snapping' and 'popping' of the lateral knee during flexion and extension. MRI reveals a complete Wrisberg variant of a discoid lateral meniscus. What is the primary anatomical deficiency in this specific variant?

. Absence of the meniscofemoral ligament of Wrisberg
. Absence of the posterior coronary (meniscotibial) ligaments
. Absence of the anterior horn attachment to the tibia
. Hypertrophy of the transverse meniscal ligament
. Anomalous insertion of the popliteus tendon into the meniscus

Correct Answer & Explanation

. Absence of the posterior coronary (meniscotibial) ligaments

Explanation

The Wrisberg variant of the discoid lateral meniscus lacks the normal posterior coronary ligament (meniscotibial) attachments to the tibial plateau. The posterior horn is only stabilized by the meniscofemoral ligament of Wrisberg, allowing hypermobility and resulting in the classic 'snapping knee' syndrome.

Question 412

Topic: Lower Extremity Trauma

A medial opening wedge high tibial osteotomy (HTO) is planned for a patient with medial compartment osteoarthritis and varus deformity. If not properly controlled during the procedure, what are the classic unintended effects on tibial slope and patellar height?

. Increased tibial slope and patella baja
. Increased tibial slope and patella alta
. Decreased tibial slope and patella baja
. Decreased tibial slope and patella alta
. No change in tibial slope and patella alta

Correct Answer & Explanation

. Increased tibial slope and patella alta

Explanation

Medial opening wedge HTO traditionally increases the posterior tibial slope (because the medial tibia is triangular and wider anteriorly, so a uniform wedge opens the anterior aspect more) and decreases patellar height (patella baja) relative to the joint line due to the elevation of the tibial plateau above the tibial tubercle.

Question 413

Topic: Lower Extremity Trauma

A 45-year-old active laborer presents with lateral compartment knee osteoarthritis and a mechanical valgus deformity of 16 degrees. Weight-bearing radiographs reveal the deformity is primarily driven by a mechanical axis deviation in the distal femur. Which of the following is the most appropriate surgical treatment?

. Medial opening wedge high tibial osteotomy
. Lateral closing wedge high tibial osteotomy
. Medial closing wedge distal femoral osteotomy
. Lateral opening wedge high tibial osteotomy
. Tibial tubercle osteotomy

Correct Answer & Explanation

. Medial closing wedge distal femoral osteotomy

Explanation

For severe valgus knee osteoarthritis (>12-15 degrees) originating from a distal femoral deformity, a distal femoral osteotomy (DFO) is indicated. A medial closing wedge or lateral opening wedge DFO corrects the mechanical axis. Tibial osteotomies are contraindicated for severe femoral-based valgus as they would induce an abnormal joint line obliquity.

Question 414

Topic: Lower Extremity Trauma

A 45-year-old male undergoes a medial opening-wedge high tibial osteotomy (HTO) for isolated medial compartment osteoarthritis and varus deformity. To optimize the long-term survivorship of the osteotomy and unload the medial compartment adequately, where should the postoperative weight-bearing line (WBL) be directed through the tibial plateau?

. 0% (medial edge of the tibial plateau)
. 30% of the plateau width from the medial edge
. 50% (neutral mechanical axis)
. 62.5% of the plateau width from the medial edge
. 80% of the plateau width from the medial edge

Correct Answer & Explanation

. 62.5% of the plateau width from the medial edge

Explanation

The optimal postoperative mechanical axis following a high tibial osteotomy for medial compartment OA intersects the tibial plateau at approximately 62% to 62.5% of its width from the medial edge. This corresponds to the Fujisawa point, which slightly overcorrects the varus deformity to adequately unload the medial compartment.

Question 415

Topic: Lower Extremity Trauma

During a posterior cruciate ligament-sacrificing total knee arthroplasty with anterior referencing, 8 mm of distal femur is resected. It is noted that the flexion gap is tight and the extension gap appears stable. What is the next most appropriate step in management?

. Cut more proximal tibia.
. Cut more distal femur.
. Cut both the proximal tibia and distal femur.
. Decrease the size of the femoral component.
. Decrease the tibial polyethylene insert thickness.

Correct Answer & Explanation

. Decrease the size of the femoral component.

Explanation

If the flexion gap is tight and the extension gap is correct, it is preferable to change only the flexion gap and leave the extension gap unchanged; therefore, the treatment of choice is to decrease the size of the femoral component. The smaller component will be smaller in both medial-lateral as well as anterior-posterior dimensions. A smaller anterior-posterior size will allow more space for the flexion gap without significantly affecting the extension gap. Decreasing the size of the tibial polyethylene insert thickness or cutting more proximal tibia will affect both the flexion and extension gaps. Cutting more distal femur will increase the extension gap and not change the flexion gap, making the described situation worse. Cutting both the proximal tibia and distal femur will increase both the flexion and extension gaps.

Question 416

Topic: Lower Extremity Trauma

Figure 43 shows an arthroscopic view of the posteromedial compartment of a patient's left knee using a 70-degree arthroscope placed through the intercondylar notch. The arrow is pointing to what structure?

Anatomy Board Review 2005: High-Yield MCQs (Set 4) - Figure 1

. Posterior horn of the medial meniscus
. Semimembranosus tendon
. Medial tibial plateau
. Medial head of the gastrocnemius tendon
. Medial plica

Correct Answer & Explanation

. Posterior horn of the medial meniscus

Explanation

Passing the 70-degree arthroscope through the intercondylar notch provides excellent visualization of the posteromedial corner of the knee. This view should be part of every knee arthroscopy because these structures are often not well visualized from the anterior portals. If this view is omitted, tears of the peripheral posterior horn of the medial meniscus can be overlooked. The arrow points to the peripheral aspect of the posterior horn of the medial meniscus. With an intact medial meniscus, the medial tibial plateau should not be seen from this view. The semimembranosus and gastrocnemius tendons are extra-articular and not visualized. Miller MD: Basic arthroscopic principles, in DeLee JC, Drez D Jr, Miller MD (eds): Orthopaedic Sports Medicine, ed 2. Philadelphia, PA, Saunders, 2003, pp 224-237.

Question 417

Topic: Lower Extremity Trauma

A 28-year-old man reports knee stiffness, swelling, and a constant ache that is worse with activity. Examination reveals an effusion, global tenderness, and warmth to the touch. Flexion is limited to 110 degrees. Figures 48a through 48d show sagittal T1-weighted, sagittal T2-weighted, axial T1-weighted fat-saturated gadolinium, and axial gradient echo MRI scans. Based on these findings, what is the most likely diagnosis?

. Infection
. Arthritis
. Synovial chondromatosis
. Pigmented villonodular synovitis (PVNS)
. Reactive synovitis

Correct Answer & Explanation

. Pigmented villonodular synovitis (PVNS)

Explanation

The MRI scans show multiple low-signal intensity lesions scattered throughout the knee, extending posteriorly inferior to the tibial plateau. The low-signal intensity on both the T1- and T2-weighted images, the modest vascularity noted on the gadolinium image, and the "blooming" noted on the gradient echo image (ferrous-laden tissue) are all strongly suggestive of diffuse PVNS. Whereas synovial chondromatosis can present as diffuse masses in the knee, they present as nodule masses that have low T1- and high T2-weighted signal characteristics. Resnick D (ed): Diagnosis of Bone and Joint Disorders. Philadelphia, PA, WB Saunders, 2002, pp 4241-4252.

Question 418

Topic: Lower Extremity Trauma

A 45-year-old male sustains a high-energy posterior bicondylar tibial plateau fracture (Schatzker VI). The surgeon plans a posteromedial approach to directly buttress the posteromedial shear fragment. During the superficial dissection of this approach, the internervous/intermuscular plane is typically developed between which two anatomical structures?

. Semitendinosus and semimembranosus
. Medial head of the gastrocnemius and the pes anserinus tendons
. Lateral head of the gastrocnemius and the soleus
. Tibialis posterior and the flexor digitorum longus
. Sartorius and gracilis

Correct Answer & Explanation

. Medial head of the gastrocnemius and the pes anserinus tendons

Explanation

The posteromedial approach to the tibial plateau is indicated for addressing posteromedial shear fragments. The surgical interval is developed between the pes anserinus tendons (sartorius, gracilis, semitendinosus) anteriorly and the medial head of the gastrocnemius posteriorly. Retracting the pes anteriorly and the medial gastrocnemius posteriorly protects the neurovascular structures in the popliteal fossa and provides direct access to the posteromedial corner of the proximal tibia.

Question 419

Topic: Lower Extremity Trauma



A 45-year-old male sustains a high-energy Schatzker IV tibial plateau fracture. Given the classic displacement pattern of this specific injury, which of the following is the most appropriate surgical approach and fixation strategy to properly neutralize the deforming forces?

. Anterolateral approach with a single lateral locking plate
. Posteromedial approach with a medial buttress (anti-glide) plate
. Direct midline anterior approach with dual locking plates
. Anterolateral approach with an anterior buttress plate
. Arthroscopic-assisted percutaneous lateral screw fixation

Correct Answer & Explanation

. Posteromedial approach with a medial buttress (anti-glide) plate

Explanation

A Schatzker IV fracture involves the medial tibial plateau and is typically the result of high-energy varus forces, often combined with an axial load. The primary deforming force drives the medial fragment into varus and posterior subluxation. The biomechanically sound treatment requires a posteromedial approach with a medial buttress (or anti-glide) plate to physically resist the varus and posterior displacement.

Question 420

Topic: Lower Extremity Trauma
A 45-year-old man sustains a high-energy knee injury in a motorcycle accident. Based on the Schatzker classification, a bicondylar tibial plateau fracture with complete dissociation of the metaphysis from the diaphysis is classified as:
. Schatzker III
. Schatzker IV
. Schatzker V
. Schatzker VI
. Schatzker II

Correct Answer & Explanation

. Schatzker VI

Explanation

A Schatzker VI fracture is defined by complete metaphyseal-diaphyseal dissociation, often accompanied by severe soft tissue injury. Schatzker V is a bicondylar fracture but maintains continuity between the articular segment and the diaphysis. Schatzker I-III involve the lateral plateau, and IV involves the medial plateau.

Test Yourself

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

On this Page