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 1901
Topic: Knee Sports
During a posterolateral corner (PLC) reconstruction, identifying the exact femoral footprint of the popliteus tendon is crucial. Where is the popliteus footprint located relative to the lateral collateral ligament (LCL) femoral attachment?
Correct Answer & Explanation
. Anterior and distal
Explanation
On the lateral femoral epicondyle, the footprint for the popliteus tendon is located anterior and distal (inferior) to the origin of the lateral collateral ligament (LCL). The LCL attachment is situated posterior and proximal to the popliteus.
Question 1902
Topic: Knee Sports
During a reconstruction of the posterolateral corner of the knee, identifying the exact femoral footprints is critical. Which of the following accurately describes the relationship of the popliteus tendon insertion relative to the fibular collateral ligament (FCL) femoral attachment?
Correct Answer & Explanation
. Popliteus is proximal and posterior
Explanation
On the lateral femoral epicondyle, the popliteus inserts at the anterior end of the popliteal sulcus. The FCL origin is proximal and posterior to the popliteus insertion. Restoring this anatomic relationship is crucial for proper biomechanical function of the reconstructed posterolateral corner.
Question 1903
Topic: Knee Sports
A 16-year-old female experiences recurrent lateral patellar dislocations after a traumatic first dislocation. She now presents with another acute dislocation. Which of the following structures is most commonly deficient or injured in recurrent patellar instability?
Correct Answer & Explanation
. Medial patellofemoral ligament (MPFL)
Explanation
The medial patellofemoral ligament (MPFL) is the primary soft tissue stabilizer preventing lateral patellar displacement. It is almost always torn during a first-time traumatic patellar dislocation. Its deficiency is a key contributor to recurrent patellar instability. While other factors like trochlear dysplasia, patella alta, and increased Q-angle contribute, MPFL injury is paramount. The ACL, PCL, and LCL are key knee joint stabilizers but are not directly involved in patellar tracking. The patellar tendon connects the patella to the tibia.
Question 1904
Topic: Knee Sports
A 30-year-old male sustains a multi-ligamentous knee injury (dislocation equivalent) involving the ACL, PCL, and MCL. He has palpable but diminished distal pulses. What is the most appropriate imaging study to assess for vascular injury?
Correct Answer & Explanation
. Computed tomography angiography (CTA) of the lower extremity.
Explanation
Multi-ligamentous knee injuries, particularly those involving dislocation, have a high association with popliteal artery injury, even with palpable pulses. Given the diminished pulses (a 'soft sign' of vascular injury), a high-resolution imaging study is warranted to thoroughly evaluate the popliteal artery and its branches. Computed tomography angiography (CTA) has become the preferred imaging modality in this setting due to its rapid acquisition, high sensitivity, and ability to simultaneously assess for associated bony injuries or soft tissue hematomas. Duplex ultrasound can be useful but is highly operator-dependent. MRI is excellent for ligamentous and soft tissue detail but is not ideal for acute vascular assessment. Plain radiographs show only bony changes, and a venogram assesses veins, not arteries.
Question 1905
Topic: Knee Sports
A 25-year-old male presents with severe knee pain and swelling after a forced valgus injury. Physical examination reveals tenderness over the medial femoral condyle, but radiographs are normal. What is the most likely acute soft tissue injury?
Correct Answer & Explanation
. Medial collateral ligament (MCL) tear.
Explanation
A forced valgus injury (force applied to the lateral side of the knee, pushing the knee inwards) primarily stresses the medial collateral ligament (MCL). This typically results in an MCL tear, which causes pain and tenderness over the medial aspect of the knee. While ACL and meniscal tears can also occur with valgus injuries, an isolated MCL tear is very common and would present with localized medial tenderness and instability to valgus stress. LCL tears result from varus stress. PCL tears are often from dashboard injuries or hyperflexion. Patellar tendon rupture presents with inability to extend the knee and a high-riding patella.
Question 1906
Topic: Knee Sports
A 48-year-old construction worker presents with chronic knee pain and instability after a previous knee dislocation treated non-operatively. Examination reveals a positive Lachman test and pivot shift. What is the most appropriate management at this stage?
A positive Lachman test and pivot shift are clinical signs highly suggestive of anterior cruciate ligament (ACL) deficiency. Given the history of knee dislocation, significant ligamentous injury, including ACL rupture, is highly likely. For a relatively young, active patient with symptomatic instability, ACL reconstruction is the definitive treatment to restore stability and prevent further meniscal and articular cartilage damage. Quadriceps strengthening can help but won't address the mechanical instability. Arthroscopic debridement or partial meniscectomy address specific intra-articular pathologies but not primary instability. Total knee arthroplasty is reserved for end-stage arthritis.
Question 1907
Topic: Knee Sports
Which of the following describes a 'terrible triad' injury of the knee?
Correct Answer & Explanation
. ACL, MCL, and medial meniscus tear.
Explanation
The 'terrible triad' of the knee classically refers to a combined injury involving the Anterior Cruciate Ligament (ACL), Medial Collateral Ligament (MCL), and medial meniscus. This injury typically results from a valgus stress with external rotation to a flexed knee. While other combinations of injuries can occur, this specific combination is historically known as the 'terrible triad' due to its prevalence and complexity.
Question 1908
Topic: Knee Sports
What is the most common mechanism of injury for a posterior cruciate ligament (PCL) rupture?
Correct Answer & Explanation
. Direct blow to the anterior tibia with the knee flexed.
Explanation
The most common mechanism for a PCL rupture is a direct blow to the anterior tibia when the knee is flexed, often referred to as a 'dashboard injury' in motor vehicle accidents, or a fall onto a flexed knee. This forces the tibia posteriorly relative to the femur, stressing the PCL. Hyperextension can also injure the PCL but is less common. Twisting injuries, valgus, and varus stresses typically injure the ACL, MCL, or LCL, respectively.
Question 1909
Topic: Knee Sports
Which of the following is a potential complication of placing the tibial component with insufficient posterior slope?
Correct Answer & Explanation
. Difficulty achieving full knee flexion
Explanation
Insufficient tibial posterior slope (i.e., the tibial cut being too flat or even anteriorly sloped) can create a relatively 'tight' flexion gap, making it difficult to achieve full knee flexion. It can also cause anterior impingement. Hyperextension instability is associated withexcessiveposterior slope. Increased wear of the anterior polyethylene is less direct. Increased PCL tension can occur, but difficulty with flexion is a more primary functional consequence. Lateral patellar subluxation is usually related to rotational alignment.
Question 1910
Topic: Knee Sports
To correct an extension gap that is tight laterally but appropriately balanced medially, what specific soft tissue release might be considered?
Correct Answer & Explanation
. Popliteus tendon release or posterolateral corner release
Explanation
If the extension gap is tight laterally while the medial side is balanced, it indicates tightness of the lateral structures. A popliteus tendon release, or a more comprehensive posterolateral corner release (depending on the degree of tightness and specific structures involved), would be indicated to balance the lateral compartment in extension. MCL releases are for medial tightness. PCL release addresses a tight flexion gap when the PCL is causative. Pes anserinus release primarily affects flexion contracture in some cases.
Question 1911
Topic: Knee Sports
What is the preferred reference for rotational alignment of the tibial component?
Correct Answer & Explanation
. The line connecting the center of the tibial tubercle to the center of the posterior cruciate ligament insertion
Explanation
The preferred reference for rotational alignment of the tibial component is typically a line connecting the center of the tibial tubercle to the center of the posterior cruciate ligament (PCL) insertion (or the middle of the medial third of the tibial tuberosity to the center of the ankle joint). This ensures proper orientation relative to the extensor mechanism and the native knee anatomy. The intermalleolar axis is a valid external reference, but the internal anatomical landmarks are key for component placement.
Question 1912
Topic: Knee Sports
A 14-year-old female presents with her first traumatic lateral patellar dislocation. She has significant knee swelling and pain. Lateral X-ray shows patella alta, and MRI confirms a partial tear of the MPFL at its femoral insertion, extensive bone bruising of the lateral femoral condyle and medial patella, and a small osteochondral fragment off the medial patellar facet. What is the most appropriate initial management strategy?
Correct Answer & Explanation
. Immediate MPFL reconstruction and osteochondral fragment fixation.
Explanation
The presence of a significant osteochondral fragment following a first-time dislocation is an absolute indication for surgical intervention, typically involving fixation or removal of the fragment. Given her age and the acute nature, fixation is preferred if the fragment is salvageable. While conservative management is often appropriate for first-time dislocations without significant concomitant injuries, the osteochondral fragment necessitates surgical intervention. MPFL reconstruction may be considered concurrently or at a later stage depending on residual instability, but the immediate priority is addressing the intra-articular injury. Tibial tubercle osteotomy is too aggressive for a first-time dislocation unless there are severe underlying malalignment issues, and initial conservative management or fragment fixation would precede. Closed reduction is already done, and immobilization in full extension is outdated and detrimental to recovery.
Question 1913
Topic: Knee Sports
What is the primary anatomical feature that contributes to the 'J-sign' observed in patients with patellar instability?
Correct Answer & Explanation
. Excessive lateral translation of the patella in terminal knee extension.
Explanation
The J-sign describes the sudden, exaggerated lateral deviation of the patella as the knee approaches full extension during active extension from a flexed position. This phenomenon is a dynamic manifestation of patellar instability and is primarily caused by an underlying trochlear dysplasia (a shallow or flat trochlear groove) that fails to adequately engage and constrain the patella until the very end of extension, leading to a 'jump' laterally. While other factors like lateral retinacular tightness or VMO weakness can contribute to patellar tracking issues, the J-sign itself is most directly linked to the patella failing to engage the trochlear groove early in extension, often due to trochlear dysplasia.
Question 1914
Topic: Knee Sports
When performing a trochleoplasty, what is the primary goal of the procedure?
Correct Answer & Explanation
. To deepen the trochlear groove, creating a more congruent articulation with the patella.
Explanation
Trochleoplasty is a bony procedure specifically designed to address severe trochlear dysplasia. The primary goal is to reshape the distal femur by deepening the trochlear groove and often creating a medial facet, thus improving the bony containment and engagement of the patella, thereby reducing the risk of lateral dislocation. It does not directly affect quadriceps length, patellar tendon insertion point, lateral retinaculum tension (though it indirectly reduces lateral force), or patellar height.
Question 1915
Topic: Knee Sports
A 30-year-old competitive athlete with chronic patellofemoral pain and a history of recurrent patellar subluxation presents. MRI shows mild trochlear dysplasia, increased TT-TG (18mm), and a normal MPFL. She has failed a comprehensive rehabilitation program. Which procedure would be most appropriate?
Correct Answer & Explanation
. Tibial tubercle osteotomy for medialization.
Explanation
This patient has chronic subluxation with an increased TT-TG and failed conservative management, but anormal MPFL. While an MPFL reconstruction would usually be the first-line surgical treatment for patellar instability, the question states the MPFL is normal, implying the instability is due to a primary bony malalignment. With an increased TT-TG of 18mm and mild trochlear dysplasia, a tibial tubercle osteotomy for medialization (e.g., Elmslie-Trillat or modified Fulkerson) would address the primary mechanical driver of her subluxation. Trochleoplasty is generally reserved for more severe dysplasia. Lateral retinacular release is rarely indicated as an isolated procedure. VMO advancement is less effective for bony malalignment. Isolated MPFL reconstruction would be redundant if the MPFL is intact and functional.
Question 1916
Topic: Knee Sports
Which of the following describes the most accurate anatomical reference for the femoral attachment of the MPFL?
Correct Answer & Explanation
. Distal and posterior to the adductor tubercle, between it and the medial epicondyle.
Explanation
The femoral attachment of the MPFL is consistently found in a sulcus located distal and posterior to the adductor tubercle and anterior to the posterior cortex of the femur, between the adductor tubercle and the medial epicondyle. This 'Schottle's Point' or 'Blumensaat's Line' position is critical for isometric reconstruction. Incorrect placement can lead to graft over-tensioning or laxity.
Question 1917
Topic: Knee Sports
Which of the following describes a Type D trochlear dysplasia according to Dejour's classification?
Correct Answer & Explanation
. 'Cliff-like' trochlea with a supratrochlear spur and patellar subluxation.
Explanation
Dejour's classification of trochlear dysplasia is based on axial imaging. Type A is a shallow trochlea, Type B has a supratrochlear spur, Type C has a crossover sign (the medial facet lies lateral to the lateral facet) but no spur, and Type D (the most severe) has both a crossover sign and a supratrochlear spur, often with a 'cliff-like' appearance and clear signs of patellar subluxation. The 'cliff-like' description specifically refers to the combination of these features.
Question 1918
Topic: Knee Sports
Which of the following statements regarding the role of lateral retinacular release in patellar instability surgery is most accurate?
Correct Answer & Explanation
. It is rarely indicated as an isolated procedure and may lead to iatrogenic instability.
Explanation
Lateral retinacular release (LRR) as an isolated procedure is rarely indicated for recurrent patellar instability, especially in the presence of MPFL insufficiency or bony malalignment. Historically, it was overused, leading to medial instability or patellofemoral pain. Its primary indication now is typically for severe lateral patellar tilt without instability or as an adjunct in cases of persistent lateral tracking after comprehensive realignment procedures, where lateral tightness is proven. It does not address trochlear dysplasia, patella alta, or directly MPFL deficiency, and performing it alone for recurrent instability can lead to iatrogenic medial instability. It is generally not performed routinely with MPFL reconstruction unless specific lateral tightness exists.
Question 1919
Topic: Knee Sports
What is the typical age range at which trochlear dysplasia begins to clinically manifest as patellar instability?
Correct Answer & Explanation
. Late childhood to adolescence (10-16 years old).
Explanation
Patellar instability due to trochlear dysplasia most commonly manifests clinically during late childhood to adolescence (10-16 years old). This is often when activity levels increase, and the growth plates are still open, but the patellofemoral joint is undergoing significant remodeling. While the dysplasia is congenital, symptoms typically emerge during growth spurts and increased biomechanical stress on the knee.
Question 1920
Topic: Knee Sports
What is the primary mechanism by which the vastus medialis obliquus (VMO) muscle contributes to patellar stability?
Correct Answer & Explanation
. It pulls the patella medially and superiorly, especially in terminal extension.
Explanation
The VMO is the most distal and medial portion of the quadriceps femoris. Its unique fiber orientation (approximately 50-55 degrees to the femoral shaft) allows it to exert a significant medial and superior pull on the patella, particularly in the last 20-30 degrees of knee extension. This dynamic medializing force is crucial for centering the patella within the trochlear groove and preventing lateral subluxation or dislocation. It is a dynamic stabilizer, whereas the MPFL is a static stabilizer.
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