Menu

Knee Sports MCQs

Practice Set 24 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 461

Topic: Knee Sports

A 60-year-old patient with severe, long-standing knee flexion contracture (FFD) of 45 degrees presents for evaluation. A lateral radiograph shows the tibia appearing significantly translated posteriorly relative to the femur.

. This represents true posterior knee subluxation requiring immediate joint distraction.
. This is likely apparent subluxation due to the FFD; the primary focus should be on correcting the flexion contracture.
. This indicates a severe PCL rupture requiring reconstruction prior to FFD correction.
. This is a normal finding in severe FFD and requires no specific intervention.
. This necessitates a tibial tubercle distalization procedure to reduce the subluxation.

Correct Answer & Explanation

. This is likely apparent subluxation due to the FFD; the primary focus should be on correcting the flexion contracture.

Explanation

Correct Answer: BThe case content explicitly addresses this diagnostic pitfall: 'One of the most dangerous traps in sagittal plane analysis is misinterpretingapparent subluxationin the setting of a severe Fixed Flexion Deformity (FFD).' It states that 'When a knee is locked in a flexion contracture, the tibia naturally appears to be translated posteriorly relative to the femur on a standard lateral radiograph.' The radiographic clue for apparent subluxation is that 'The posterior translation mathematically resolves as the flexion deformity is corrected.' The correct treatment is to 'Focus entirely on correcting the flexion contracture (e.g., performing a distal femoral extension osteotomy or soft tissue release).'Option A is incorrect as it misinterprets apparent subluxation as true subluxation and suggests an inappropriate treatment (distraction). Option C is incorrect; while PCL rupture causes true subluxation, the context of severe FFD points to apparent subluxation. Option D is incorrect because while it's a common finding, it's not 'normal' in the sense of being benign; it's a consequence of the FFD that needs to be understood for correct treatment. Option E (tibial tubercle distalization) is used for patella alta, not for reducing posterior subluxation in this context.

Question 462

Topic: Knee Sports

A 28-year-old patient presents with a painful knee recurvatum deformity following a previous trauma. Radiographs reveal a Mechanical Posterior Proximal Tibial Angle (mPPTA) of 96° (normal 77°-84°). Which ligamentous structure is subjected to the highest strain due to this specific bony deformity?

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

Correct Answer & Explanation

. Posterior cruciate ligament (PCL)

Explanation

An mPPTA >84° indicates an anterior tilt of the proximal tibial articular surface (anterior slope). This anterior slope forces the tibia posteriorly relative to the femur during weight-bearing, abnormally increasing strain on the PCL.

Question 463

Topic: Knee Sports

A patient undergoes a proximal tibial osteotomy that inadvertently overcorrects the sagittal alignment, creating an mPPTA of 70°. This excessive posterior tibial slope will place maximum detrimental strain on which of the following post-operative conditions?

. A concurrent ACL reconstruction
. A concurrent PCL reconstruction
. The medial collateral ligament
. The popliteus tendon
. The patellar tendon

Correct Answer & Explanation

. A concurrent ACL reconstruction

Explanation

An mPPTA of 70° corresponds to a very high posterior tibial slope. Excessive posterior slope forces the tibia anteriorly relative to the femur during weight-bearing, significantly increasing the strain on the Anterior Cruciate Ligament (ACL) or its graft.

Question 464

Topic: Knee Sports

Altering the sagittal alignment of the proximal tibia significantly impacts knee ligament biomechanics. If a surgeon performs an osteotomy that decreases the posterior tibial slope (increases mPPTA), which ligament is placed under increased strain?

. Anterior Cruciate Ligament (ACL)
. Posterior Cruciate Ligament (PCL)
. Medial Collateral Ligament (MCL)
. Lateral Collateral Ligament (LCL)
. Anterolateral Ligament (ALL)

Correct Answer & Explanation

. Posterior Cruciate Ligament (PCL)

Explanation

Decreasing the posterior tibial slope shifts the resting position of the tibia posteriorly relative to the femur, increasing tension on the PCL. Wait, decreasing posterior slope reduces anterior tibial translation, increasing tension on the PCL.

Question 465

Topic: Knee Sports

A 50-year-old female undergoes an anterior opening-wedge High Tibial Osteotomy (HTO) to correct a complex deformity, effectively decreasing her mPPTA. What biomechanical effect does this specific sagittal change have on the anterior cruciate ligament (ACL)?

. Decreases ACL strain by promoting posterior tibial translation
. Increases ACL strain by promoting anterior tibial translation
. No effect on ACL strain as long as coronal alignment is neutral
. Isolates the ACL from rotatory forces during gait
. Transfers sheer forces entirely to the posterolateral corner

Correct Answer & Explanation

. Increases ACL strain by promoting anterior tibial translation

Explanation

Decreasing the mPPTA means increasing the posterior tibial slope. An increased posterior slope drives the tibia anteriorly relative to the femur during axial loading, thereby increasing strain on the ACL.

Question 466

Topic: Knee Sports

A surgeon corrects a clinically severe genu recurvatum caused entirely by a proximal tibial deformity (mPPTA = 68°). To 'straighten the leg' without operating on the tibia, the surgeon performs a distal femoral flexion osteotomy. What is the primary long-term consequence of this compensatory correction?

. Nonunion of the femoral osteotomy
. Inability to achieve full extension
. Severe sagittal joint line obliquity leading to shear stresses and premature osteoarthritis
. Development of a secondary coronal plane deformity
. Permanent laxity of the anterior cruciate ligament

Correct Answer & Explanation

. Severe sagittal joint line obliquity leading to shear stresses and premature osteoarthritis

Explanation

Correcting a tibial deformity by operating on the femur creates parallel mechanical axes but an oblique joint line in the sagittal plane. This unphysiologic orientation induces shear forces and accelerates joint degeneration.

Question 467

Topic: Knee Sports

A 45-year-old male presents with symptomatic knee hyperextension. Preoperative analysis shows a normal distal femur (mPDFA = 83 degrees) but an abnormal proximal tibia with an mPPTA of 95 degrees. What compensatory change in knee ligament mechanics is most likely occurring due to this tibial morphology?

. Decreased tension on the posterior cruciate ligament (PCL)
. Increased tension on the anterior cruciate ligament (ACL)
. Increased tension on the posterior cruciate ligament (PCL)
. Medial collateral ligament (MCL) attenuation
. Lateral collateral ligament (LCL) contracture

Correct Answer & Explanation

. Increased tension on the posterior cruciate ligament (PCL)

Explanation

An increased mPPTA implies a decreased or reversed posterior tibial slope (apex posterior deformity/recurvatum). This abnormal anterior tilt of the tibial plateau increases posterior tibial translation forces, thereby increasing tension on the PCL.

Question 468

Topic: Knee Sports

A patient sustained a proximal tibial fracture resulting in malunion. The current mPPTA is 88 degrees (normal 81 degrees). The patient complains of giving way. Which ligament is most likely rendered functionally incompetent by this osseous malalignment?

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

Correct Answer & Explanation

. Posterior cruciate ligament (PCL)

Explanation

An mPPTA of 88 degrees means the proximal tibia is in recurvatum (decreased/reversed posterior slope). A flattened or reversed tibial slope shifts the resting position of the tibia posteriorly and forces the femur anteriorly, dramatically reducing the functional tension and efficiency of the ACL.

Question 469

Topic: Knee Sports

A 30-year-old competitive runner presents with chronic anterior knee pain and a feeling of instability, particularly during deceleration. MRI reveals a chronic Anterior Cruciate Ligament (ACL) deficiency. Preoperative planning for an ACL reconstruction and potential concomitant osteotomy includes a detailed assessment of sagittal plane alignment. Based on the provided case, which of the following angles is most critical to evaluate for its impact on ACL strain and knee kinematics?

. A. Mechanical Lateral Distal Femoral Angle (mLDFA)
. B. Posterior Distal Femoral Angle (PDFA)
. C. Medial Proximal Tibial Angle (MPTA)
. D. Posterior Proximal Tibial Angle (PPTA)
. E. Lateral Distal Tibial Angle (LDTA)

Correct Answer & Explanation

. D. Posterior Proximal Tibial Angle (PPTA)

Explanation

Correct Answer: DThe correct answer is D, the Posterior Proximal Tibial Angle (PPTA). The case explicitly states that the posterior tibial slope, which is directly related to the PPTA (normal 77-84°, equating to ~9° posterior slope), is 'absolutely critical for knee kinematics and ligamentous stability.' An increased posterior slope (meaning a decreased PPTA) shifts the resting position of the tibia anteriorly, thereby increasing strain on the Anterior Cruciate Ligament (ACL). Conversely, a decreased slope (increased PPTA) places excessive strain on the Posterior Cruciate Ligament (PCL). Therefore, evaluating the PPTA is paramount in a patient with ACL deficiency, as an abnormal slope could contribute to instability or impact the success of reconstruction.Option A (mLDFA)is the mechanical Lateral Distal Femoral Angle. This angle assesses frontal plane distal femoral alignment (normal 85-90°) and is not directly related to sagittal plane ACL strain.Option B (PDFA)is the Posterior Distal Femoral Angle. This angle assesses sagittal plane distal femoral alignment (normal 79-87°). While important for overall knee extension/flexion, it does not directly dictate the tibial slope's impact on ACL strain.Option C (MPTA)is the Medial Proximal Tibial Angle. This angle assesses frontal plane proximal tibial alignment (normal 85-90°) and is primarily relevant for varus/valgus deformities, not sagittal plane ligamentous stability.Option E (LDTA)is the Lateral Distal Tibial Angle. This angle assesses frontal plane distal tibial alignment (normal 86-92°) and is relevant for ankle deformities, not knee ligamentous stability.

Question 470

Topic: Knee Sports

A 40-year-old male with chronic posterolateral corner (PLC) and PCL deficiency presents with varus malalignment. He is planned for an opening wedge high tibial osteotomy (HTO). How should the sagittal plane be managed during the osteotomy?

. Increase the posterior tibial slope
. Maintain the native posterior tibial slope exactly
. Decrease the posterior tibial slope
. Neutralize the slope to 0 degrees
. Induce a mild anterior tibial slope

Correct Answer & Explanation

. Increase the posterior tibial slope

Explanation

In a PCL-deficient knee, increasing the posterior tibial slope shifts the tibia anteriorly relative to the femur under axial load. This reduces the posterior sag and protects the PCL/PLC reconstruction.

Question 471

Topic: Knee Sports

A 50-year-old male presents with severe genu valgum. The standing long-leg radiograph shows a lateral mechanical axis deviation. The mLDFA is 82 degrees, mMPTA is 87 degrees, and JLCA is 7 degrees (medial opening). What is the primary contributor to the high JLCA in this clinical scenario?

. Structural valgus deformity of the distal femur.
. Medial collateral ligament laxity.
. Lateral meniscus tear.
. Proximal tibiofibular joint arthritis.
. Lateral collateral ligament contracture.

Correct Answer & Explanation

. Medial collateral ligament laxity.

Explanation

A high joint line convergence angle (JLCA) indicates intra-articular deformity or ligamentous laxity. In a valgus knee with a medially opening JLCA, this reflects stretching or laxity of the medial collateral ligament (MCL).

Question 472

Topic: Knee Sports

A 58-year-old female presents with severe medial compartment osteoarthritis of the right knee. Full-length standing radiographs confirm a significant varus malalignment. The image provided demonstrates the effect of increasing varus angulation on knee joint contact pressures. Based on this biomechanical understanding, what is the primary mechanism by which this malalignment leads to arthrosis?

. Increased shear forces across the anterior cruciate ligament, leading to instability.
. Progressive stretching of the medial collateral ligament, causing dynamic valgus thrust.
. Concentration of supraphysiologic loads onto a smaller contact area of articular cartilage, leading to degradation.
. Reduced range of motion due to osteophyte formation, causing joint stiffness.
. Increased patellofemoral contact pressures on the lateral facet.

Correct Answer & Explanation

. Concentration of supraphysiologic loads onto a smaller contact area of articular cartilage, leading to degradation.

Explanation

Correct Answer: CThe image clearly illustrates that as varus angulation increases (right side of the image), the contact pressure becomes highly concentrated on a progressively smaller area of the medial compartment. This phenomenon, described as the concentration of supraphysiologic loads onto small, unprepared areas of articular cartilage, is the primary mechanism by which malalignment initiates and accelerates cartilage degradation, subchondral sclerosis, and ultimately, end-stage degenerative arthropathy. The cartilage is overwhelmed by the excessive stress, leading to its breakdown.Option A is incorrectbecause while severe malalignment can affect ligamentous stability, the primary mechanism of arthrosis in this context is direct cartilage overload, not primarily ACL shear forces.Option B is incorrectbecause varus malalignment causes stretching of thelateralcollateral ligament (LCL), leading to alateralthrust, not medial collateral ligament stretching or valgus thrust. Valgus deformity stretches the MCL.Option D is incorrectbecause osteophyte formation and stiffness are consequences of the arthritic process, not the primary mechanism by which malalignment initiates the cartilage damage.Option E is incorrectbecause varus malalignment typically increases patellofemoral contact pressures on themedialfacet, not the lateral. Valgus malalignment is associated with lateral facet arthritis.

Question 473

Topic: Knee Sports

A 28-year-old active duty soldier presents with chronic right knee pain and a feeling of instability, particularly during cutting maneuvers. Clinical examination reveals a varus thrust during gait. Full-length standing radiographs show a 7-degree varus alignment of the knee. Which of the following is the most likely underlying soft tissue pathology contributing to the dynamic instability?

. Medial collateral ligament (MCL) attenuation.
. Posterior cruciate ligament (PCL) insufficiency.
. Lateral collateral ligament (LCL) attenuation.
. Medial meniscus tear.
. Anterior cruciate ligament (ACL) rupture.

Correct Answer & Explanation

. Lateral collateral ligament (LCL) attenuation.

Explanation

Correct Answer: CThe text states, 'Chronic varus alignment places a continuous, pathologic stretch on the Lateral Collateral Ligament (LCL). The LCL acts as a primary static restraint to the varus moment arm experienced with each step during single-leg stance. When the LCL gradually stretches and attenuates due to this chronic overload, the primary resistance to the varus moment arm is lost. Clinically, this manifests as alateral thrust.' Therefore, a varus thrust in a varus-aligned knee is most indicative of LCL attenuation.Option A is incorrectbecause MCL attenuation is associated with valgus deformity and a medial thrust.Option B is incorrectbecause PCL insufficiency primarily causes posterior instability and sag, not typically a varus thrust.Option D is incorrectbecause while a medial meniscus tear can contribute to medial compartment overload and pain in a varus knee, it is not the primary cause of a dynamic varus (lateral) thrust, which is a ligamentous phenomenon.Option E is incorrectbecause ACL rupture primarily causes anterior instability, not a varus thrust.

Question 474

Topic: Knee Sports

A 50-year-old female is undergoing a medial opening wedge high tibial osteotomy (HTO) for medial compartment osteoarthritis.

If the anterior gap is opened significantly more than the posterior gap during the procedure, what unintended biomechanical consequence is most likely to occur?

. Anterior cruciate ligament (ACL) laxity due to decreased posterior tibial slope.
. Increased posterior tibial slope leading to increased stress on the ACL.
. A varus thrust during the stance phase of gait.
. Patella alta leading to extensor mechanism dysfunction.
. Posterior cruciate ligament (PCL) rupture due to altered kinematics.

Correct Answer & Explanation

. Increased posterior tibial slope leading to increased stress on the ACL.

Explanation

Because the proximal tibia is triangular, opening the anterior cortex the same amount as (or more than) the posterior cortex in an HTO will inadvertently increase the posterior tibial slope. An increased posterior slope exacerbates anterior tibial translation, increasing stress on the ACL.

Question 475

Topic: Knee Sports

A surgeon is performing an opening wedge high tibial osteotomy (HTO) for medial compartment osteoarthritis. During the procedure, the gap is inadvertently opened more anteriorly than posteriorly. What is the expected biomechanical consequence on the knee kinematics?

. Decreased posterior tibial slope and knee hyperextension
. Decreased posterior tibial slope and increased anterior cruciate ligament (ACL) tension
. Increased posterior tibial slope and increased ACL tension
. Increased posterior tibial slope and increased posterior cruciate ligament (PCL) tension
. No change in slope but increased patellofemoral contact pressure

Correct Answer & Explanation

. Increased posterior tibial slope and increased ACL tension

Explanation

Opening the HTO gap more anteriorly than posteriorly increases the posterior tibial slope. This translates the tibia anteriorly relative to the femur, which increases tension on the ACL and may be beneficial for patients with PCL deficiency but detrimental to those with ACL insufficiency.

Question 476

Topic: Knee Sports

A 50-year-old female presents with an osseous distal femoral procurvatum deformity measuring 35 degrees. However, clinical examination demonstrates a fixed flexion deformity of only 15 degrees. Based on Paley's principles, what accounts for this 20-degree discrepancy?

. Posterior capsule contracture
. Anterior cruciate ligament laxity
. Compensatory soft tissue recurvatum at the knee joint
. Patella alta
. Quadriceps contracture

Correct Answer & Explanation

. Compensatory soft tissue recurvatum at the knee joint

Explanation

A discrepancy between a large osseous procurvatum and a smaller clinical fixed flexion deformity indicates that the knee joint has developed a compensatory soft tissue hyperextension (recurvatum). This soft tissue laxity partially absorbs the bony deformity to improve upright posture.

Question 477

Topic: Knee Sports

A patient undergoes a high tibial osteotomy. Postoperatively, the posterior proximal tibial angle (PPTA) is measured at 89 degrees on the lateral radiograph. What is the most likely clinical consequence of this alignment?

. Increased stress on the posterior cruciate ligament (PCL)
. Increased stress on the anterior cruciate ligament (ACL)
. Patella infera
. Decreased patellofemoral contact pressure
. Genu recurvatum

Correct Answer & Explanation

. Increased stress on the posterior cruciate ligament (PCL)

Explanation

A normal PPTA is approximately 81 degrees, reflecting a 9-degree posterior tibial slope. A PPTA of 89 degrees indicates a significantly decreased (flattened) posterior slope, which increases posterior tibial translation and stress on the PCL.

Question 478

Topic: Knee Sports

A 35-year-old male with medial compartment osteoarthritis and varus malalignment undergoes a medial opening wedge high tibial osteotomy (HTO). Postoperatively, he complains of new-onset anterior knee pain and a feeling of instability. Radiographs reveal an unintended change in the sagittal plane alignment. Which of the following is the most common sagittal plane complication of an opening wedge HTO, and what is its direct effect on knee biomechanics?

. Decreased posterior tibial slope, increasing strain on the PCL
. Decreased posterior tibial slope, increasing strain on the ACL
. Increased posterior tibial slope, increasing strain on the ACL
. Increased posterior tibial slope, increasing strain on the PCL
. Anterior tibial slope creation, increasing patellofemoral pressure

Correct Answer & Explanation

. Increased posterior tibial slope, increasing strain on the ACL

Explanation

Medial opening wedge HTO commonly increases the posterior tibial slope if the anterior gap is inadvertently made larger than the posterior gap. An increased posterior slope effectively shifts the tibia anteriorly relative to the femur, placing increased strain on the anterior cruciate ligament (ACL).

Question 479

Topic: Knee Sports

A 55-year-old male presents with progressive right knee pain and a noticeable 'giving way' sensation during ambulation. On physical examination, he exhibits a visible and sudden shift of his knee into varus during the stance phase of gait on the affected limb. Varus stress testing at 30° of flexion reveals significant lateral joint line opening compared to the contralateral side. Which of the following is the most accurate interpretation of these clinical findings?

. The patient likely has isolated medial compartment osteoarthritis with compensatory lateral thrust.
. The primary pathology is a fixed bony varus deformity of the distal femur, causing the gait abnormality.
. These findings are pathognomonic for dynamic coronal plane instability due to Lateral Collateral Ligament (LCL) insufficiency.
. The 'giving way' sensation suggests anterior cruciate ligament (ACL) deficiency, which is causing secondary varus thrust.
. The sudden shift into varus indicates a severe medial collateral ligament (MCL) tear with associated posteromedial instability.

Correct Answer & Explanation

. These findings are pathognomonic for dynamic coronal plane instability due to Lateral Collateral Ligament (LCL) insufficiency.

Explanation

Correct Answer: CThe clinical presentation of a 'visible and sudden shift of his knee into varus during the stance phase of gait' is the classic description of alateral thrust. This sign, combined with significant lateral joint line opening on varus stress testing at 30° of flexion, is pathognomonic for dynamic coronal plane instability primarily due to Lateral Collateral Ligament (LCL) insufficiency. The LCL is the primary static restraint against varus stress, and its incompetence allows the lateral compartment to abnormally gap open under load.Option A is incorrectbecause while medial compartment osteoarthritis can be present, the dynamic lateral thrust and LCL laxity indicate a more complex instability that is not simply compensatory. The LCL insufficiency is a primary driver of the instability.Option B is incorrectbecause while a fixed bony varus deformity can contribute, the description emphasizes adynamicshift and 'giving way' sensation, which points to ligamentous instability rather than solely a fixed bony malalignment. The case highlights that bony malalignment is easily measured on static radiographs, but dynamic instability is often hidden.Option D is incorrectbecause an ACL deficiency primarily causes anteroposterior instability, not typically a sudden varus thrust during gait. While multi-ligamentous injuries can occur, the specific description points to coronal plane instability.Option E is incorrectbecause a severe MCL tear would lead to valgus instability and opening of the medial joint line, not a varus thrust or lateral joint line opening. The findings are opposite to what would be expected with MCL pathology.

Question 480

Topic: Knee Sports

A 50-year-old patient with a severe varus knee deformity and significant LCL laxity is scheduled for surgical correction. The surgeon opts for the Paley method of gradual LCL retensioning via fibular transport using a circular external fixator. What is the most significant advantage of this method over acute fibular head advancement?

. It completely eliminates the need for any bony osteotomy, simplifying the procedure.
. It allows for simultaneous correction of multiplanar tibial or femoral bony deformities with enhanced safety for the peroneal nerve.
. It is a faster method, allowing for immediate full weight-bearing post-operatively.
. It relies solely on soft tissue plication, avoiding any bone cuts.
. It is primarily indicated for isolated LCL tears without associated bony malalignment.

Correct Answer & Explanation

. It allows for simultaneous correction of multiplanar tibial or femoral bony deformities with enhanced safety for the peroneal nerve.

Explanation

Correct Answer: BThe case highlights the 'profound, game-changing advantages' of the gradual fibular transport method. Specifically, it states: 'Greatly Enhanced Safety: The fibular osteotomy is made in the diaphysis, well distal to the nerve, and the transport is done gradually (typically 1 mm per day). This requires minimal dissection around the nerve itself, dramatically reducing the risk of iatrogenic nerve palsy.' And 'Simultaneous Bony Correction: The true beauty of this method is that the exact same external fixator used for the fibular transport can be utilized to simultaneously and perfectly correct any associated multiplanar tibial or femoral bony deformities.'Option A is incorrectbecause the method involves a fibular osteotomy and can simultaneously correct tibial or femoral bony deformities, meaning bony osteotomies are part of the process.Option C is incorrectbecause gradual correction involves a period of distraction and external fixation, which is not a faster method for immediate full weight-bearing. It's a controlled, slower process.Option D is incorrectbecause it involves a fibular osteotomy and transport, which is a bone-based procedure to retension ligaments, not solely soft tissue plication.Option E is incorrectbecause the method is presented as a solution for 'complex knee malalignment complicated by ligamentous incompetence,' implying its use for deformities with associated bony malalignment, not just isolated LCL tears.

Test Yourself

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

On this Page