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Knee Sports MCQs

Practice Set 83 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 1641

Topic: Knee Sports

Compared to the medial collateral ligament (MCL), the anterior cruciate ligament (ACL) demonstrates a poor healing capacity after complete rupture. This difference in healing potential is primarily attributed to:

. The ACL's intrinsic vascular supply being significantly poorer than the MCL's.
. The ACL being an intra-articular ligament, exposed to synovial fluid that inhibits fibrin clot formation.
. The MCL having a greater proportion of Type I collagen compared to the ACL.
. The ACL's inability to recruit sufficient mesenchymal stem cells to the injury site.
. The MCL being subjected to lower tensile forces compared to the ACL.

Correct Answer & Explanation

. The ACL being an intra-articular ligament, exposed to synovial fluid that inhibits fibrin clot formation.

Explanation

The poor healing of the ACL is primarily due to its intra-articular location. Synovial fluid contains high levels of proteases that quickly degrade the hematoma and fibrin clot necessary for initiating the healing cascade, preventing the formation of a robust scaffold for repair cells. This 'washout' effect is a major contributor to its inability to heal. While vascularity can play a role, the ACL does have some blood supply, and its poorer healing is more dominantly attributed to the synovial fluid environment. The MCL, being extra-articular, forms a stable hematoma and has a more organized healing response. Type I collagen is dominant in both. Stem cell recruitment is impaired but is a consequence of the disrupted healing environment. Tensile forces contribute to re-rupture but not necessarily the initial failure to heal.

Question 1642

Topic: Knee Sports
The healing of a ruptured anterior cruciate ligament (ACL) in the knee is notoriously poor, often leading to non-union or a functionally inferior scar. This outcome, when compared to the robust healing seen in the medial collateral ligament (MCL), is best explained by:
. The ACL's intra-articular location and lack of a distinct synovial sheath.
. Lower collagen type III to type I ratio in the ACL scar compared to MCL.
. The higher vascularity of the ACL compared to the MCL.
. The different biomechanical loading profiles, with ACL experiencing more shear forces.
. The inherent differences in the resident fibroblast populations, specifically their regenerative capacity.

Correct Answer & Explanation

. The ACL's intra-articular location and lack of a distinct synovial sheath.

Explanation

The poor healing capacity of the ACL is primarily attributed to its intra-articular location. Unlike extra-articular ligaments like the MCL, the ACL is bathed in synovial fluid. While synovial fluid provides nutrition, it also dilutes and washes away critical components (e.g., fibrin clot, growth factors, inflammatory cells) necessary for effective primary healing. The lack of a distinct synovial sheath that can contain and organize the healing response further contributes to this. Option A is correct. Option B is incorrect; a robust scar often has a higher initial Type III collagen which is later remodeled to Type I. Option C is incorrect; the ACL actually has relatively poor vascularity, which contributes to poor healing, but the intra-articular environment is a more critical factor for its specific challenges. Option D describes loading but isn't the primary biological reason for the difference in healing potential. Option E is plausible but less definitively established as the primary distinguishing factor than the intra-articular environment and synovial fluid effects.

Question 1643

Topic: Knee Sports

During an anatomic anterior cruciate ligament (ACL) reconstruction, the surgeon specifically addresses both the anteromedial (AM) and posterolateral (PL) bundles.

Which of the following best describes the biomechanical role and tension pattern of the PL bundle?

. It is tight in flexion and primarily controls anteroposterior translation.
. It is tight in extension and primarily controls rotatory stability.
. It is tight in flexion and primarily controls rotatory stability.
. It is tight in extension and primarily controls anteroposterior translation.
. It remains isometric throughout the entire range of motion.

Correct Answer & Explanation

. It is tight in extension and primarily controls rotatory stability.

Explanation

The ACL consists of the Anteromedial (AM) and Posterolateral (PL) bundles. The AM bundle tightens in flexion and is the primary restraint to anterior tibial translation. The PL bundle tightens in extension and is the primary restraint to rotatory loads (e.g., pivot shift). Thus, the PL bundle is most critical for rotatory stability near extension.

Question 1644

Topic: Knee Sports

The posterior cruciate ligament (PCL) consists of two distinct bundles: the anterolateral (AL) and the posteromedial (PM). Which of the following statements accurately describes the tension pattern of these bundles?

. The AL bundle is tight in flexion, and the PM bundle is tight in extension.
. The AL bundle is tight in extension, and the PM bundle is tight in flexion.
. Both bundles are tightest in full extension.
. Both bundles are tightest in 90 degrees of flexion.
. The PM bundle is isometric, while the AL bundle tightens in extension.

Correct Answer & Explanation

. The AL bundle is tight in flexion, and the PM bundle is tight in extension.

Explanation

The PCL has two main bundles. The Anterolateral (AL) bundle is larger and stronger; it is tight in flexion and lax in extension. The Posteromedial (PM) bundle is smaller; it is tight in extension and lax in flexion.

Question 1645

Topic: Knee Sports
A 16-year-old female undergoes medial patellofemoral ligament (MPFL) reconstruction for recurrent patellar instability. Intraoperative fluoroscopy is used to determine the anatomic femoral attachment site (Schöttle's point). Which of the following radiographic landmarks correctly identifies this location on a strict lateral radiograph?
. 2 mm anterior to the posterior cortex line, 5 mm distal to the medial epicondyle, and on Blumensaat's line
. 1 mm anterior to the posterior cortex line, 2.5 mm distal to the posterior origin of the medial femoral condyle, and proximal to Blumensaat's line
. 5 mm posterior to the posterior cortex line, exactly on Blumensaat's line
. Directly over the adductor tubercle, 10 mm proximal to the medial epicondyle
. 1 mm posterior to the posterior cortex line, 5 mm proximal to the medial epicondyle, and distal to Blumensaat's line

Correct Answer & Explanation

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

Explanation

Schöttle's point is the radiographic landmark for the femoral origin of the MPFL. On a strict lateral radiograph, it is found 1 mm anterior to a line extending from the posterior femoral cortex, 2.5 mm distal to the posterior articular border of the medial femoral condyle, and proximal to the posterior projection of Blumensaat's line.

Question 1646

Topic: Knee Sports

During surgical reconstruction of the posterolateral corner (PLC) of the knee, anatomic placement of the fibular collateral ligament (FCL) and popliteus tendon (PT) grafts is critical.

What is the precise anatomical relationship of the femoral footprint of the popliteus tendon relative to the FCL femoral footprint?

. Popliteus originates 18.5 mm anterior and inferior (distal) to the FCL
. Popliteus originates 10 mm posterior and superior (proximal) to the FCL
. Popliteus originates 18.5 mm posterior and inferior (distal) to the FCL
. Popliteus originates directly medial to the FCL within the same footprint
. Popliteus originates 10 mm anterior and superior (proximal) to the FCL

Correct Answer & Explanation

. Popliteus originates 18.5 mm anterior and inferior (distal) to the FCL

Explanation

The anatomic footprint of the popliteus tendon (PT) on the lateral femoral condyle is located approximately 18.5 mm anterior and inferior (distal) to the footprint of the fibular collateral ligament (FCL). Recognizing this relationship is essential to restore proper biomechanics during anatomic PLC reconstruction.

Question 1647

Topic: Knee Sports

During posterior cruciate ligament (PCL) reconstruction, understanding bundle biomechanics is essential.

Which of the following best describes the function and tensioning pattern of the native PCL bundles?

. The anterolateral bundle is the primary restraint to posterior translation in extension and is lax in flexion
. The posteromedial bundle is the primary restraint to posterior translation at 90 degrees of flexion
. The anterolateral bundle is the primary restraint to posterior translation at 90 degrees of flexion and tightens in flexion
. The posteromedial bundle is the primary restraint to internal rotation at 30 degrees of flexion
. Both bundles are equally tensioned throughout the entire arc of motion

Correct Answer & Explanation

. The anterolateral bundle is the primary restraint to posterior translation at 90 degrees of flexion and tightens in flexion

Explanation

The PCL consists of the larger anterolateral (AL) bundle and the smaller posteromedial (PM) bundle. The AL bundle is lax in extension and becomes tight in flexion, acting as the primary restraint to posterior tibial translation at 90 degrees of knee flexion. Conversely, the PM bundle is tight in extension and lax in flexion.

Question 1648

Topic: Knee Sports

A 15-year-old male presents with chronic knee pain. MRI reveals a stable Osteochondritis Dissecans (OCD) lesion of the knee. Which of the following anatomic locations is the classic and most common site for an OCD lesion in the knee?

. Lateral aspect of the medial femoral condyle
. Medial aspect of the medial femoral condyle
. Central weight-bearing surface of the lateral femoral condyle
. Posterior aspect of the lateral tibial plateau
. Inferior pole of the patella

Correct Answer & Explanation

. Lateral aspect of the medial femoral condyle

Explanation

The classic and most common location for an osteochondritis dissecans (OCD) lesion in the knee is the lateral aspect of the medial femoral condyle (often remembered by the mnemonic 'LAME': Lateral Aspect Medial Epicondyle/Condyle). It accounts for approximately 70-80% of knee OCD lesions.

Question 1649

Topic: Knee Sports

A 45-year-old male sustains a posterior root tear of the medial meniscus.

Biomechanically, if this injury is left untreated, it alters knee contact pressures and kinematics most similarly to which of the following conditions?

. An ACL deficient knee
. A complete medial meniscectomy
. A longitudinal bucket-handle tear
. A radial tear of the anterior horn
. An isolated medial collateral ligament (MCL) rupture

Correct Answer & Explanation

. A complete medial meniscectomy

Explanation

The meniscal roots are essential for anchoring the meniscus and converting axial loads into circumferential 'hoop' stresses. A complete radial tear at the posterior root completely disrupts this ability to contain hoop stresses, causing the meniscus to extrude. Biomechanical studies have shown that the contact pressures in a knee with a medial meniscus root tear are nearly identical to those of a knee that has undergone a complete medial meniscectomy.

Question 1650

Topic: Knee Sports

The anterior cruciate ligament (ACL) is composed of the anteromedial (AM) and posterolateral (PL) bundles. During which knee position is the PL bundle most tight?

. Full extension
. 30 degrees of flexion
. 60 degrees of flexion
. 90 degrees of flexion
. 120 degrees of flexion

Correct Answer & Explanation

. Full extension

Explanation

The posterolateral (PL) bundle of the ACL is tightest in full extension and primarily controls rotatory stability. The anteromedial (AM) bundle is tightest in flexion and primarily controls anterior translation.

Question 1651

Topic: Knee Sports

A 22-year-old soccer player sustains a twisting injury to his knee. He reports immediate pain, swelling, and a 'pop.' On examination, there is a positive Lachman test and pivot shift test. Which of the following associated injuries is most commonly missed on initial MRI or requires arthroscopic evaluation for definitive diagnosis?

. Medial collateral ligament tear
. Lateral meniscus tear
. Articular cartilage injury
. Posterior cruciate ligament tear
. Posterolateral corner injury

Correct Answer & Explanation

. Articular cartilage injury

Explanation

While MCL tears and meniscal tears (especially lateral) are common with ACL injuries, significant articular cartilage injuries (osteochondral fractures or chondral delamination) are frequently associated with acute ACL ruptures due to the valgus-external rotation or internal rotation impaction mechanisms. These can be difficult to fully appreciate on initial MRI and may only be definitively diagnosed during arthroscopy, often contributing to long-term issues if not addressed. PCL and PLC injuries are distinct and usually evident.

Question 1652

Topic: Knee Sports

Which of the following ligaments is the primary static stabilizer preventing anterior translation of the tibia on the femur?

. Posterior cruciate ligament
. Medial collateral ligament
. Lateral collateral ligament
. Anterior cruciate ligament
. Meniscofemoral ligament

Correct Answer & Explanation

. Anterior cruciate ligament

Explanation

The Anterior Cruciate Ligament (ACL) is the primary static stabilizer preventing anterior translation of the tibia on the femur. The Posterior Cruciate Ligament (PCL) prevents posterior translation. The Medial Collateral Ligament (MCL) resists valgus stress, and the Lateral Collateral Ligament (LCL) resists varus stress. The meniscofemoral ligament (Humphry and Wrisberg ligaments) are secondary stabilizers and attachments to the menisci.

Question 1653

Topic: Knee Sports

A 28-year-old professional athlete sustains an acute knee injury while pivoting during a basketball game, hearing a "pop." He experiences immediate pain and swelling. On examination, a positive Lachman test and pivot shift test are present. Radiographs are normal. What is the MOST likely diagnosis?

. Meniscal tear
. Patellar dislocation
. Medial collateral ligament (MCL) sprain
. Anterior cruciate ligament (ACL) rupture
. Posterior cruciate ligament (PCL) rupture

Correct Answer & Explanation

. Anterior cruciate ligament (ACL) rupture

Explanation

The classic triad of an acute knee injury involving a 'pop,' immediate swelling (hemarthrosis), and positive Lachman and pivot shift tests is highly indicative of an Anterior Cruciate Ligament (ACL) rupture. Meniscal tears cause mechanical symptoms but less immediate swelling unless associated with ACL. Patellar dislocation is usually obvious with patellar displacement. MCL sprains typically present with valgus instability. PCL ruptures manifest with a positive posterior drawer test and sag sign.

Question 1654

Topic: Knee Sports

A 25-year-old female presents with recurrent anterior knee pain, particularly with stair climbing and prolonged sitting. Physical examination reveals tenderness along the medial patellar facet and a positive patellar apprehension test. What is the MOST likely diagnosis?

. Meniscal tear
. ACL tear
. Patellar tendonitis
. Patellofemoral pain syndrome
. Osteochondritis dissecans

Correct Answer & Explanation

. Patellofemoral pain syndrome

Explanation

Recurrent anterior knee pain, exacerbated by stair climbing, prolonged sitting ('theater sign'), and tenderness along the patellar facets, particularly with a positive patellar apprehension test (indicating patellar instability), is classic for patellofemoral pain syndrome, or patellar instability if the apprehension is severe. Meniscal and ACL tears present differently with mechanical or instability symptoms. Patellar tendonitis is pain at the inferior patellar pole. Osteochondritis dissecans is less common and localized bone/cartilage lesion.

Question 1655

Topic: Knee Sports

Which biomechanical principle is most critical for the successful healing of an articular cartilage defect treated with microfracture?

. Maintenance of a stable bone-cartilage interface through rigid fixation.
. Creation of a low-friction surface that resists shear forces.
. Formation of a fibrocartilaginous repair tissue with improved wear properties.
. Controlled, cyclic loading to stimulate chondrocyte differentiation and matrix production.
. Elimination of all weight-bearing for at least 6 months post-operatively.

Correct Answer & Explanation

. Controlled, cyclic loading to stimulate chondrocyte differentiation and matrix production.

Explanation

Microfracture aims to stimulate the growth of fibrocartilaginous repair tissue from mesenchymal stem cells (MSCs) released from subchondral bone. Controlled, cyclic loading (e.g., non-weight bearing range of motion or continuous passive motion) is crucial post-microfracture. This mechanical stimulation helps guide the differentiation of MSCs towards a chondrogenic lineage and promotes the production of a more organized and resilient repair matrix. While a stable interface is important, it's not the primary biomechanical principle guiding microfracture healing itself. The repair tissue formed (fibrocartilage) is generally inferior to native hyaline cartilage in wear properties, but the goal is to improve upon the defect. Eliminating all weight-bearing for 6 months is overly restrictive and detrimental to cartilage formation. Low friction is a characteristic of healthy cartilage, but the principle for healing involves stimulating cell differentiation.

Question 1656

Topic: Knee Sports

Which of the following describes the most common long-term complication after anterior cruciate ligament (ACL) reconstruction, despite a successful surgery?

. Graft re-rupture.
. Chronic patellofemoral pain.
. Development of osteoarthritis.
. Infection.
. Arthrofibrosis.

Correct Answer & Explanation

. Development of osteoarthritis.

Explanation

Despite successful ACL reconstruction, the most common long-term complication is the development of osteoarthritis of the knee. Even with anatomical reconstruction and restoration of stability, the initial injury itself, associated meniscal or cartilage damage, and altered joint kinematics contribute to an accelerated degenerative process, leading to osteoarthritis in a significant percentage of patients over time. While graft re-rupture, patellofemoral pain, infection, and arthrofibrosis are all possible complications, osteoarthritis remains the most prevalent long-term issue impacting joint health and function.

Question 1657

Topic: Knee Sports

Which of the following ligaments is the primary static stabilizer preventing anterior translation of the tibia on the femur?

. Posterior Cruciate Ligament (PCL)
. Medial Collateral Ligament (MCL)
. Anterior Cruciate Ligament (ACL)
. Lateral Collateral Ligament (LCL)
. Patellar Tendon

Correct Answer & Explanation

. Anterior Cruciate Ligament (ACL)

Explanation

The Anterior Cruciate Ligament (ACL) is the primary static stabilizer preventing excessive anterior translation of the tibia relative to the femur and also limits internal rotation. The PCL prevents posterior translation. The MCL and LCL provide valgus and varus stability, respectively. The patellar tendon connects the patella to the tibia and is involved in knee extension.

Question 1658

Topic: Knee Sports

A 25-year-old basketball player lands awkwardly and feels a 'pop' in his knee. He experiences immediate pain and swelling. On examination, a positive Lachman test is noted. Which ligament is most likely injured?

. Medial collateral ligament (MCL)
. Lateral collateral ligament (LCL)
. Posterior cruciate ligament (PCL)
. Anterior cruciate ligament (ACL)
. Patellar ligament

Correct Answer & Explanation

. Anterior cruciate ligament (ACL)

Explanation

A 'pop' sensation, immediate pain and swelling (hemarthrosis), and a positive Lachman test (anterior translation of the tibia on the femur with the knee in 20-30 degrees of flexion) are classic signs of an Anterior Cruciate Ligament (ACL) tear. MCL injuries typically result from valgus stress and show tenderness over the medial joint line. PCL injuries result from a direct blow to the tibia or hyperflexion. LCL injuries result from varus stress. Patellar ligament injury would affect the extensor mechanism.

Question 1659

Topic: Knee Sports

What is the most common location for osteochondritis dissecans (OCD) in the knee?

. Lateral femoral condyle
. Medial femoral condyle
. Patella
. Tibial plateau
. Fibular head

Correct Answer & Explanation

. Medial femoral condyle

Explanation

The most common location for osteochondritis dissecans (OCD) in the knee is the lateral aspect of the medial femoral condyle. This location accounts for approximately 85% of all knee OCD lesions. Other less common sites include the lateral femoral condyle and the patella.

Question 1660

Topic: Knee Sports

A 22-year-old collegiate athlete sustains an injury to his knee during a soccer match. He reports hearing a 'pop,' followed by immediate swelling and inability to continue playing. Lachman test is positive. What is the most likely diagnosis?

. Medial collateral ligament (MCL) tear.
. Lateral collateral ligament (LCL) tear.
. Anterior cruciate ligament (ACL) tear.
. Posterior cruciate ligament (PCL) tear.
. Meniscus tear.

Correct Answer & Explanation

. Anterior cruciate ligament (ACL) tear.

Explanation

The classic presentation of an ACL tear includes a 'pop' at the time of injury, immediate knee swelling (hemarthrosis), inability to continue activity, and a positive Lachman test (anterior translation of the tibia relative to the femur with the knee at 30 degrees flexion). While meniscal tears can also cause popping and swelling, the Lachman test is specific for ACL laxity. MCL and LCL tears present with valgus/varus instability respectively. PCL tears cause posterior instability.

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