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Knee Sports MCQs

Practice Set 39 of 102

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

Question 761

Topic: Knee Sports
A 16-year-old female presents with recurrent lateral patellar instability and is scheduled for medial patellofemoral ligament (MPFL) reconstruction. To restore normal kinematics, the femoral tunnel must be placed at the anatomic MPFL footprint (Schöttle's point). Where is this landmark located radiographically on a strict lateral view?
. 1 mm anterior to the posterior femoral cortical line and 2.5 mm distal to Blumensaat's line
. 1 mm posterior to the posterior femoral cortical line and 2.5 mm proximal to Blumensaat's line
. 5 mm anterior to the posterior femoral cortical line and 5 mm proximal to Blumensaat's line
. On the posterior femoral cortical line, at the level of the adductor tubercle
. 5 mm distal to Blumensaat's line and 5 mm anterior to the posterior femoral cortical line

Correct Answer & Explanation

. 1 mm anterior to the posterior femoral cortical line and 2.5 mm distal to Blumensaat's line

Explanation

Schöttle's point defines the radiographic femoral footprint of the MPFL on a strict lateral X-ray. It is located 1 mm anterior to the posterior femoral cortical extension line, 2.5 mm distal to the posterior border of Blumensaat's line, and proximal to the posterior aspect of the medial femoral condyle.

Question 762

Topic: Knee Sports

A 22-year-old sustains a longitudinal tear in the red-white zone of the medial meniscus. Which vessel provides the primary vascular supply to the peripheral capillary plexus of the medial meniscus?

. Middle genicular artery
. Inferior medial genicular artery
. Superior lateral genicular artery
. Descending genicular artery
. Anterior tibial recurrent artery

Correct Answer & Explanation

. Inferior medial genicular artery

Explanation

The menisci receive their primary blood supply from the medial and lateral genicular arteries. Specifically, the inferior and superior medial genicular arteries form the perimeniscal capillary plexus supplying the peripheral 10-30% (red zone) of the medial meniscus. The middle genicular artery supplies the cruciate ligaments (ACL/PCL).

Question 763

Topic: Knee Sports

During a posterior cruciate ligament (PCL) reconstruction, the surgeon aims to anatomically reconstruct the anterolateral (AL) bundle. What is the primary biomechanical function of the AL bundle?

. Tightest in extension; resists posterior translation
. Tightest in flexion; resists posterior translation
. Tightest in flexion; resists external rotation
. Tightest in extension; resists anterior translation
. Tightest in mid-flexion; resists varus angulation

Correct Answer & Explanation

. Tightest in flexion; resists posterior translation

Explanation

The PCL consists of the larger anterolateral (AL) bundle and the smaller posteromedial (PM) bundle. The AL bundle is tightest in flexion and is the primary restraint to posterior tibial translation. The PM bundle is tightest in extension.

Question 764

Topic: Knee Sports

A patient demonstrates increased external rotation on the dial test at 30 degrees of knee flexion, but symmetrical external rotation at 90 degrees compared to the contralateral normal knee. Which structures are most likely injured?

. Isolated posterior cruciate ligament (PCL)
. Isolated posterolateral corner (PLC)
. Combined PCL and PLC
. Isolated anterior cruciate ligament (ACL)
. Combined ACL and medial collateral ligament (MCL)

Correct Answer & Explanation

. Isolated posterolateral corner (PLC)

Explanation

The dial test evaluates for posterolateral corner (PLC) and PCL injuries. Increased external rotation (>10 degrees compared to the normal side) only at 30 degrees of flexion indicates an isolated PLC injury (specifically the popliteus complex and fibular collateral ligament). If increased external rotation is present at both 30 and 90 degrees, it indicates a combined PLC and PCL injury.

Question 765

Topic: Knee Sports

On MRI, which finding has the highest specificity for indicating instability of an osteochondritis dissecans (OCD) lesion in a skeletally mature patient?

. Subchondral bone marrow edema
. Thickening of the overlying articular cartilage
. Low T1 signal in the fragment
. Subchondral cyst formation
. High T2 signal line surrounding the fragment

Correct Answer & Explanation

. High T2 signal line surrounding the fragment

Explanation

A high T2-weighted signal line surrounding the OCD fragment indicates that synovial fluid has tracked behind the fragment into the subchondral bone, which strongly indicates lesion instability and a breach of the overlying articular cartilage. This is an indication for surgical stabilization in a skeletally mature patient.

Question 766

Topic: Knee Sports
During reconstruction of the Medial Patellofemoral Ligament (MPFL) for recurrent patellar instability, non-anatomic femoral tunnel placement is a common cause of failure. If the femoral tunnel is placed too proximal to the anatomic footprint (Schöttle's point), what biomechanical consequence will occur during knee range of motion?
. The graft will be tight in extension and loose in flexion
. The graft will be tight in flexion and loose in extension
. The graft will be uniformly loose throughout motion
. The graft will cause obligatory external rotation of the tibia
. The graft will cause isolated lateral patellar tilt

Correct Answer & Explanation

. The graft will be tight in flexion and loose in extension

Explanation

If the MPFL femoral tunnel is placed too proximally, the distance between the patellar attachment and the femoral attachment increases as the knee flexes. This results in an anisometry where the graft is excessively tight in flexion (causing increased medial patellofemoral contact pressures and loss of flexion) and loose in extension (failing to prevent lateral dislocation).

Question 767

Topic: Knee Sports

Following a microfracture procedure for a 1.5 cm^2 symptomatic full-thickness chondral defect on the medial femoral condyle, what type of cartilage primarily fills the defect, and what is its major collagen component?

. Hyaline cartilage; Type II collagen
. Fibrocartilage; Type I collagen
. Fibrocartilage; Type II collagen
. Hyaline cartilage; Type I collagen
. Elastic cartilage; Type II collagen

Correct Answer & Explanation

. Fibrocartilage; Type I collagen

Explanation

Marrow stimulation techniques, such as microfracture, result in the formation of a 'super clot' that organizes into fibrocartilage. Fibrocartilage is primarily composed of Type I collagen, which is biomechanically inferior to the Type II collagen found in native hyaline cartilage.

Question 768

Topic: Knee Sports

Six months following a bone-patellar tendon-bone anterior cruciate ligament (ACL) reconstruction, a patient complains of a palpable clunk and pain at the anterior knee, along with a 15-degree lack of full terminal extension. MRI reveals a nodular mass in the intercondylar notch anterior to the ACL graft. What is the most likely diagnosis?

. Arthrofibrosis of the suprapatellar pouch
. Patellar tendon rupture
. Cyclops lesion (localized anterior arthrofibrosis)
. Ganglion cyst of the PCL
. Displaced meniscal root tear

Correct Answer & Explanation

. Cyclops lesion (localized anterior arthrofibrosis)

Explanation

A Cyclops lesion is a form of localized anterior arthrofibrosis consisting of a fibrovascular nodule that forms anterior to the ACL graft in the intercondylar notch. It acts as a mechanical block, classically causing an anterior clunk, pain, and loss of terminal extension.

Question 769

Topic: Knee Sports

A 24-year-old athlete sustains a direct blow to the anteromedial tibia. Physical examination reveals an abnormal Dial test with 15 degrees of increased external tibial rotation at 30 degrees of knee flexion, but symmetric rotation at 90 degrees compared to the uninjured side. This finding is highly specific for an isolated injury to which of the following structures?

. Posterior cruciate ligament (PCL)
. Anterior cruciate ligament (ACL)
. Posterolateral corner (PLC)
. Combined PCL and PLC
. Medial collateral ligament (MCL)

Correct Answer & Explanation

. Posterolateral corner (PLC)

Explanation

The Dial test evaluates for external rotation asymmetry. The posterolateral corner (PLC) is the primary restraint to external rotation at 30 degrees of flexion. At 90 degrees of flexion, the posterior cruciate ligament (PCL) becomes the primary restraint. Therefore, an increase of >10 degrees of external rotation at 30 degrees but not at 90 degrees indicates an isolated PLC injury. If rotation is increased at both 30 and 90 degrees, it indicates a combined PCL and PLC injury.

Question 770

Topic: Knee Sports
When drilling the femoral tunnel during a medial patellofemoral ligament (MPFL) reconstruction, identifying Schöttle's point is critical to ensure near-isometric graft behavior. On a strict lateral radiograph, where is this point located?
. 1 mm anterior to the posterior femoral cortex extension line, 2.5 mm distal to the posterior origin of the medial femoral condyle, and proximal to Blumensaat's line
. 1 mm posterior to the posterior femoral cortex extension line, 2.5 mm proximal to the posterior origin of the medial femoral condyle, and distal to Blumensaat's line
. 5 mm anterior to the posterior femoral cortex extension line and centered precisely on Blumensaat's line
. Directly on the adductor tubercle
. Directly on the medial epicondyle

Correct Answer & Explanation

. 1 mm posterior to the posterior femoral cortex extension line, 2.5 mm proximal to the posterior origin of the medial femoral condyle, and distal to Blumensaat's line

Explanation

Schöttle's point marks the radiographic femoral origin of the MPFL. It is located 1 mm anterior to a line extending the posterior femoral cortex, 2.5 mm distal to the posterior origin of the medial femoral condyle, and distinctly proximal to the level of the posterior aspect of Blumensaat's line. Placing the graft here avoids anisometry and abnormal patellofemoral tracking.

Question 771

Topic: Knee Sports
Histological evaluation of the repair tissue one year following marrow stimulation (microfracture) for a full-thickness chondral defect of the medial femoral condyle will demonstrate a matrix composed predominantly of which type of collagen?
. Type I
. Type II
. Type III
. Type IX
. Type X

Correct Answer & Explanation

. Type I

Explanation

Marrow stimulation techniques like microfracture rely on releasing marrow elements to form a 'superclot' over the cartilage defect. The resulting repair tissue differentiates into fibrocartilage, which is predominantly composed of Type I collagen. This tissue is mechanically inferior and less durable than native hyaline cartilage, which is predominantly Type II collagen.

Question 772

Topic: Knee Sports

The anterior cruciate ligament (ACL) is composed of distinct anteromedial (AM) and posterolateral (PL) bundles. Which of the following statements regarding their biomechanical behavior is most accurate?

. The AM bundle is tightest in extension and controls rotatory stability
. The PL bundle is tightest in deep flexion and controls anterior translation
. The AM bundle is tightest in flexion and serves as the primary restraint to anterior tibial translation at 90 degrees
. The PL bundle is equally taut throughout the entire range of motion
. Both bundles are maximally lax in flexion and maximally taut in extension

Correct Answer & Explanation

. The AM bundle is tightest in flexion and serves as the primary restraint to anterior tibial translation at 90 degrees

Explanation

The anteromedial (AM) bundle of the ACL is tight in flexion and is the primary restraint to anterior tibial translation at 90 degrees of knee flexion. Conversely, the posterolateral (PL) bundle is tight in extension and is primarily responsible for providing rotatory stability to the knee.

Question 773

Topic: Knee Sports

A 10-year-old skeletally immature male presents with lateral knee pain. Radiographs show a 15 mm osteochondritis dissecans (OCD) lesion on the lateral aspect of the medial femoral condyle. The physes are widely open. MRI reveals intact overlying cartilage with no high T2 signal fluid behind the lesion. What is the most appropriate initial management?

. Arthroscopic drilling of the lesion to promote revascularization
. Arthroscopic microfracture of the defect
. Osteochondral autograft transfer (OATS)
. Activity modification and restricted weight-bearing
. Internal fixation with bioabsorbable screws

Correct Answer & Explanation

. Activity modification and restricted weight-bearing

Explanation

Juvenile Osteochondritis Dissecans (JOCD) in a patient with widely open physes and a stable lesion (no fluid behind the lesion on T2 MRI, intact cartilage) has a very high rate of spontaneous healing. The standard initial treatment is conservative management, which consists of activity modification, protected weight-bearing, and potential immobilization. Surgery is reserved for unstable lesions or failure of prolonged conservative treatment.

Question 774

Topic: Knee Sports
A 24-year-old male presents with an acute knee dislocation (KD III-M) with complete tears of the ACL, PCL, and MCL. Vascular status is intact. When considering reconstruction versus repair of the MCL in this multi-ligament setting, what does the current evidence suggest regarding surgical management?
. Early direct repair of the MCL yields superior clinical outcomes to reconstruction
. Delayed reconstruction of all ligaments yields the best ultimate range of motion
. Acute/subacute reconstruction of the MCL provides superior stability compared to direct repair in the setting of multiligamentous injury
. ACL and PCL should be reconstructed immediately while MCL is managed non-operatively
. External fixation is mandatory prior to any ligamentous intervention

Correct Answer & Explanation

. Acute/subacute reconstruction of the MCL provides superior stability compared to direct repair in the setting of multiligamentous injury

Explanation

In multiligament knee injuries, recent literature (e.g., Stannard et al.) demonstrates that MCL reconstruction has significantly lower failure rates and provides superior stability compared to direct primary repair, especially for severe grade III tears in the setting of a multi-ligament injured knee.

Question 775

Topic: Knee Sports

During clinical examination of a knee, the dial test is performed at both 30 degrees and 90 degrees of flexion. An increase in external rotation of 15 degrees at 30 degrees of flexion, but NO increase in external rotation at 90 degrees of flexion, indicates injury to which of the following structures?

. Posterior cruciate ligament only
. Posterolateral corner only
. Both PCL and PLC
. Anterior cruciate ligament only
. Medial collateral ligament

Correct Answer & Explanation

. Posterolateral corner only

Explanation

The dial test measures external rotation. Asymmetry of >10-15 degrees compared to the contralateral side is considered positive. A positive test at 30 degrees but normal at 90 degrees indicates an isolated posterolateral corner (PLC) injury. If the test is positive at both 30 and 90 degrees, it indicates a combined PCL and PLC injury.

Question 776

Topic: Knee Sports

The Medial Patellofemoral Ligament (MPFL) is the primary restraint to lateral patellar translation. At what degree of knee flexion does the MPFL provide the greatest relative contribution to preventing lateral patellar displacement?

. 0 to 30 degrees
. 45 to 60 degrees
. 60 to 90 degrees
. 90 to 120 degrees
. Beyond 120 degrees

Correct Answer & Explanation

. 0 to 30 degrees

Explanation

The MPFL is the primary soft tissue restraint to lateral patellar displacement, contributing 50-60% of the restraining force at 0-30 degrees of knee flexion. As the knee flexes past 30 degrees, the patella engages the trochlear groove, and bony architecture becomes the primary stabilizer.

Question 777

Topic: Knee Sports
Matrix-induced autologous chondrocyte implantation (MACI) involves harvesting chondrocytes, expanding them in vitro, and seeding them onto a membrane prior to implantation. Which type of collagen primarily constitutes the membrane used in current FDA-approved MACI implants?
. Type I and III collagen (porcine derived)
. Type II collagen (bovine derived)
. Type IV collagen (human derived)
. Type VI collagen (synthetic)
. Type X collagen (equine derived)

Correct Answer & Explanation

. Type I and III collagen (porcine derived)

Explanation

The MACI implant utilizes a resorbable, porcine-derived type I and III collagen membrane. Autologous human chondrocytes are cultured and seeded onto this membrane before it is implanted into the cartilage defect.

Question 778

Topic: Knee Sports

When drilling the femoral tunnel during Anterior Cruciate Ligament (ACL) reconstruction, positioning the tunnel too vertically (at the 12 o'clock position in the intercondylar notch) rather than lower (at the 10 o'clock or 2 o'clock position) results in which of the following biomechanical outcomes?

. Restores rotational stability but fails to restore anterior-posterior stability
. Restores anterior-posterior stability but fails to restore rotational stability
. Restores both anterior-posterior and rotational stability
. Causes impingement with the PCL in deep flexion
. Decreases the risk of a positive Lachman test postoperatively

Correct Answer & Explanation

. Restores anterior-posterior stability but fails to restore rotational stability

Explanation

A vertical femoral tunnel (e.g., 12 o'clock position) poorly controls rotational instability. While it acts strictly in the sagittal plane and may correct the Lachman test (AP stability), it fails to control the pivot shift (rotational stability). A more anatomic, lower position on the lateral notch wall is necessary to restore both.

Question 779

Topic: Knee Sports

A 50-year-old female experiences a 'pop' in the back of her knee while squatting. An MRI demonstrates a complete radial tear of the posterior horn of the medial meniscus exactly at its root attachment. Biomechanically, an un-repaired medial meniscus posterior root tear is equivalent to which of the following?

. A functional partial meniscectomy
. A functional total meniscectomy
. Normal knee biomechanics if the anterior horn is intact
. An isolated tear of the meniscofemoral ligament of Wrisberg
. An isolated anterior cruciate ligament deficiency

Correct Answer & Explanation

. A functional total meniscectomy

Explanation

A posterior root tear of the medial meniscus completely disrupts the hoop stresses of the meniscus, causing it to extrude. Biomechanical studies have shown that an un-repaired root tear leads to peak contact pressures and contact areas that are biomechanically equivalent to a total meniscectomy, rapidly accelerating the development of osteoarthritis.

Question 780

Topic: Knee Sports

The microfracture technique for cartilage restoration works by penetrating the subchondral bone plate to release marrow elements. The resulting repair tissue is predominantly characterized by which of the following?

. Type II collagen rich hyaline cartilage
. Type I collagen rich fibrocartilage
. Type I collagen rich hyaline cartilage
. Type IX collagen rich fibrocartilage
. Type X collagen rich woven bone

Correct Answer & Explanation

. Type I collagen rich fibrocartilage

Explanation

Microfracture stimulates marrow elements to form a 'super clot', leading to the formation of fibrocartilage repair tissue. Fibrocartilage is mechanically inferior to normal hyaline articular cartilage and is composed primarily of Type I collagen, unlike native articular cartilage which is primarily Type II collagen.

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