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1. General Principles & Basic Science MCQs

Practice Set 3 of 789

This practice set contains high-yield board review questions covering key concepts in 1. General Principles & Basic Science. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 41

Topic: 1. General Principles & Basic Science

Which of the following physical examination tests is most sensitive for diagnosing a syndesmotic ankle sprain?

. Anterior drawer test
. Talar tilt test
. External rotation stress test
. Squeeze test
. Cotton test

Correct Answer & Explanation

. External rotation stress test

Explanation

The external rotation stress test has the highest sensitivity for syndesmotic injury. The squeeze test has high specificity but low sensitivity.

Question 42

Topic: 1. General Principles & Basic Science

In a patient with an acute "turf toe" injury, the primary pathoanatomic disruption involves the:

. Dorsal capsule of the first metatarsophalangeal (MTP) joint
. Plantar plate and capsuloligamentous complex of the first MTP joint
. Extensor hallucis longus tendon
. Intermetatarsal ligament between the 1st and 2nd rays
. Abductor hallucis tendon insertion

Correct Answer & Explanation

. Plantar plate and capsuloligamentous complex of the first MTP joint

Explanation

Turf toe is a forced hyperextension injury of the first MTP joint. It results in a sprain or tear of the plantar plate and the associated plantar capsuloligamentous complex.

Question 43

Topic: 1. General Principles & Basic Science

The arterial blood supply to the meniscus of the knee in an adult is limited primarily to the:

. Inner one-third
. Middle one-third
. Peripheral 10% to 30%
. Entire meniscus via diffusion
. Anterior and posterior horns exclusively

Correct Answer & Explanation

. Peripheral 10% to 30%

Explanation

The adult meniscus is relatively avascular, receiving its blood supply from the medial and lateral geniculate arteries. These vessels only penetrate the peripheral 10% to 30%, often referred to as the "red-red" zone.

Question 44

Topic: 1. General Principles & Basic Science

The medial meniscus is injured more frequently than the lateral meniscus in the adult knee. This is primarily because the medial meniscus:

. Is thicker and completely avascular
. Is rigidly attached to the deep medial collateral ligament
. Lacks a posterior horn attachment to the tibia
. Is highly mobile compared to the lateral meniscus
. Bears a higher percentage of the patellofemoral load

Correct Answer & Explanation

. Is rigidly attached to the deep medial collateral ligament

Explanation

The medial meniscus has a firm attachment to the deep portion of the MCL and the joint capsule. This rigid fixation makes it less mobile and more susceptible to tearing from shearing forces than the lateral meniscus.

Question 45

Topic: Surgical Anatomy & Approaches

During hip arthroscopy, establishing the anterior portal places a specific neural structure at significant risk if placed incorrectly. Which nerve is most susceptible to direct injury during this step?

. Lateral femoral cutaneous nerve
. Femoral nerve
. Sciatic nerve
. Superior gluteal nerve
. Obturator nerve

Correct Answer & Explanation

. Lateral femoral cutaneous nerve

Explanation

The anterior portal is typically made lateral to the intersection of a sagittal line drawn distally from the ASIS and a transverse line from the greater trochanter. The lateral femoral cutaneous nerve (LFCN) is the primary structure at risk.

Question 46

Topic: 1. General Principles & Basic Science

For patients who sustain a knee dislocation, the role of clinical history, physical examination, and magnetic resonance imaging (MRI) is:

. Both physical examination and MRI are important, but physical examination is much more accurate.
. Neither physical examination or MRI is very accurate.
. Both physical examination and MRI are important, but MRI is more accurate.
. There is no role for MRI.
. C linical history is the more important than MRI.

Correct Answer & Explanation

. Both physical examination and MRI are important, but MRI is more accurate.

Explanation

In a study of 17 knee dislocations, the accuracy of clinical examination ranged from 53% to 82% correct compared to an accuracy of 85% to 100% with MRI. The limitations of clinical examination were mainly due to associated injuries.

Question 47

Topic: 1. General Principles & Basic Science

After high velocity knee dislocations, there is serious injury to the popliteal vessels in approximately what percentage of patients:

. 5%
. 10%
. 30%
. 75%
. More than 90%

Correct Answer & Explanation

. 30%

Explanation

After reviewing several series from 1963 to 1992, investigators found serious injury to the popliteal vessels in approximately 30% of cases and peroneal nerve injuries in 25% of cases. The incidence of arterial and nerve injury with lower velocity mechanisms (some athletic injuries) is lower.

Question 48

Topic: 1. General Principles & Basic Science

After high velocity knee dislocations, there is serious injury to the peroneal nerve in approximately what percentage of patients:

. Serious injury has not been reported.
. 5%
. 25%
. 75%
. More than 90%

Correct Answer & Explanation

. 25%

Explanation

After reviewing several series from 1963 to 1992, investigators found serious injury to the popliteal vessels in approximately 30% of cases and peroneal nerve injuries in 25% of cases. The incidence of arterial and nerve injury with lower velocity mechanisms (some athletic injuries) is lower.

Question 49

Topic: 1. General Principles & Basic Science

The strongest bundle in the posterior cruciate ligament is the:

. Anteromedial bundle
. Posteromedial bundle
. Anterolateral bundle
. Posterolateral bundle
. Both bands are of equal strength

Correct Answer & Explanation

. Anterolateral bundle

Explanation

The posterior cruciate ligament is made up of two bundles (anterolateral and posteromedial) that are named according to their origin on the femur and insertion on the tibia. The anterolateral bundle is the larger and stronger of the two bundles. The anterolateral bundle is tight in flexion, and the posteromedial bundle is tight in extension.

Question 50

Topic: 1. General Principles & Basic Science
In the posterior cruciate ligament the anterolateral bundle is tight in and the posteromedial bundle is tight in:
. Flexion, extension
. Extension, flexion
. Extension, extension
. Flexion, flexion
. Neither bundle tightens throughout the knee's range of motion.

Correct Answer & Explanation

. Flexion, extension

Explanation

The posterior cruciate ligament is made up of two bundles (anterolateral and posteromedial) that are named according to their origin on the femur and insertion on the tibia. The anterolateral bundle is the larger and stronger of the two bundles. The anterolateral bundle is tight in flexion, and the posteromedial bundle is tight in extension.

Question 51

Topic: 1. General Principles & Basic Science

In the posteromedial corner of the knee, which structure serves as the primary restraint to valgus stress and internal rotation when the knee is near full extension?

. Superficial medial collateral ligament
. Deep medial collateral ligament
. Posterior oblique ligament (POL)
. Semimembranosus tendon
. Oblique popliteal ligament

Correct Answer & Explanation

. Posterior oblique ligament (POL)

Explanation

The posterior oblique ligament (POL) is a primary stabilizer of the posteromedial corner. It heavily contributes to the restraint of valgus stress and internal tibial rotation, particularly when the knee is in full or near-full extension.

Question 52

Topic: Infection, Pharmacology & VTE
While femoral-sided Grade III MCL tears are typically managed nonoperatively when combined with an ACL tear, a tibial-sided Grade III MCL avulsion requires surgical repair. Why is operative intervention specifically indicated for this variant?
. It lacks blood supply compared to the femoral origin.
. The distal end of the superficial MCL can flip superficial to the pes anserinus.
. It invariably includes a medial meniscus root tear.
. It leads to rapid chondrolysis of the medial compartment.
. Tibial-sided tears cause isolated rotational instability.

Correct Answer & Explanation

. The distal end of the superficial MCL can flip superficial to the pes anserinus.

Explanation

In a tibial-sided Grade III MCL tear, the distal end of the superficial MCL can become entrapped outside the pes anserinus tendons, preventing healing. This creates a Stener-like lesion of the knee that requires surgical repair.

Question 53

Topic: 1. General Principles & Basic Science

Which of the following anatomical structures forms the primary static restraint to varus opening at 0 and 30 degrees of knee flexion?

. Popliteus tendon
. Popliteofibular ligament
. Fibular collateral ligament (LCL)
. Iliotibial band
. Biceps femoris tendon

Correct Answer & Explanation

. Fibular collateral ligament (LCL)

Explanation

The fibular collateral ligament (FCL/LCL) is the primary static restraint to varus gapping of the knee at both 0 and 30 degrees of flexion. The popliteus and popliteofibular ligament act as the primary restraints to external rotation.

Question 54

Topic: Infection, Pharmacology & VTE

The superficial medial collateral ligament (sMCL) has distinct femoral and tibial attachments. Where is its primary distal (tibial) attachment located?

. 1 cm distal to the joint line deep to the pes anserinus
. 4 to 5 cm distal to the joint line deep to the pes anserinus
. On the medial meniscus
. On the adductor tubercle
. 2 cm proximal to the joint line

Correct Answer & Explanation

. 4 to 5 cm distal to the joint line deep to the pes anserinus

Explanation

The superficial MCL attaches 4 to 5 cm distal to the joint line on the anteromedial surface of the tibia, deep to the pes anserinus tendons. The deep MCL attaches much closer to the articular margins of the joint line.

Question 55

Topic: Infection, Pharmacology & VTE

A patient sustains a high-energy knee dislocation. On examination, there is a transverse skin furrow (dimple sign) over the medial joint line, and the knee cannot be closed-reduced. What structure is most likely interposing and preventing reduction?

. Medial meniscus
. Medial head of the gastrocnemius
. Medial collateral ligament and medial capsule
. Pes anserinus tendons
. Posterior cruciate ligament stump

Correct Answer & Explanation

. Medial collateral ligament and medial capsule

Explanation

The 'dimple sign' or 'pucker sign' occurs in an irreducible posterolateral knee dislocation when the medial joint capsule and medial collateral ligament buttonhole through the joint. An open reduction via a medial approach is urgently required to extricate these structures and achieve reduction.

Question 56

Topic: 1. General Principles & Basic Science

The posteromedial corner of the knee provides primary restraint against valgus forces in full extension and anteromedial rotatory instability. Which of the following structures is the most crucial static component of this complex?

. Superficial medial collateral ligament
. Posterior oblique ligament
. Semimembranosus tendon
. Medial patellofemoral ligament
. Coronary ligament

Correct Answer & Explanation

. Posterior oblique ligament

Explanation

The posterior oblique ligament (POL) is the primary stabilizer of the posteromedial corner, heavily restricting valgus in full extension and internal tibial rotation. It intimately blends with the semimembranosus tendon and posteromedial capsule.

Question 57

Topic: Biomechanics & Biomaterials

During normal knee kinematics, the popliteus muscle plays a vital role in initiating knee flexion from a fully extended position. What is its primary biomechanical action during this phase?

. External rotation of the tibia on the femur
. Internal rotation of the femur on the tibia in a closed chain
. External rotation of the femur on the tibia in a closed chain
. Anterior translation of the tibia
. Varus angulation of the tibia

Correct Answer & Explanation

. External rotation of the femur on the tibia in a closed chain

Explanation

To 'unlock' the fully extended knee during closed-chain kinematics (when the foot is planted), the popliteus muscle acts to externally rotate the femur on the fixed tibia. In an open-chain state, it internally rotates the tibia on the femur.

Question 58

Topic: 1. General Principles & Basic Science

Which of the following anatomic structures is considered the primary restraint to varus opening at 30 degrees of knee flexion?

. Popliteus tendon
. Popliteofibular ligament
. Fibular collateral ligament
. Iliotibial band
. Anterolateral ligament

Correct Answer & Explanation

. Fibular collateral ligament

Explanation

The fibular collateral ligament (LCL) is the primary restraint to varus stress at 5 and 25-30 degrees of knee flexion. The popliteus and popliteofibular ligament act as primary restraints to external rotation.

Question 59

Topic: 1. General Principles & Basic Science

The popliteofibular ligament (PFL) plays a crucial role in posterolateral knee stability. Which of the following best describes its primary anatomical origin and insertion?

. Originates from the popliteus musculotendinous junction and inserts on the posteromedial down-slope of the fibular styloid.
. Originates from the lateral femoral epicondyle and inserts on the anterior fibular head.
. Originates from the lateral meniscus and inserts on the fibular styloid.
. Originates from the posterior tibia and inserts on the fibular head.
. Originates from the medial femoral condyle and inserts on the posterior tibia.

Correct Answer & Explanation

. Originates from the popliteus musculotendinous junction and inserts on the posteromedial down-slope of the fibular styloid.

Explanation

The popliteofibular ligament (PFL) branches off the popliteus tendon at the musculotendinous junction and inserts firmly into the posteromedial aspect of the fibular styloid, acting as a major restraint to external rotation.

Question 60

Topic: 1. General Principles & Basic Science

Which of the following arteries provides the main vascular supply to the humeral head:

. Ascending branch of the posterior humeral circumflex artery
. Descending branch of the posterior humeral circumflex artery
. Ascending branch of the anterior humeral circumflex artery
. Descending branch of the anterior humeral circumflex artery
. Ascending intramedullary artery

Correct Answer & Explanation

. Ascending branch of the anterior humeral circumflex artery

Explanation

The ascending branch of the anterior humeral circumflex artery provides the main vascular supply to the humeral head. Disruption of this blood supply can result in osteonecrosis of the humeral head.

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