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Knee Sports MCQs

Practice Set 97 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 1921

Topic: Knee Sports

A 19-year-old male presents with recurrent patellar instability. His MRI shows a TTPG distance of 25mm, severe trochlear dysplasia (Dejour Type D), and patella alta (Insall-Salvati ratio 1.5). He has failed extensive physical therapy. What is the MOST comprehensive surgical plan for this patient?

. MPFL reconstruction and lateral retinacular release.
. Isolated trochleoplasty.
. Tibial tubercle medialization and distalization osteotomy.
. Combined trochleoplasty, MPFL reconstruction, and tibial tubercle medialization/distalization osteotomy.
. VMO advancement and medial plication.

Correct Answer & Explanation

. Combined trochleoplasty, MPFL reconstruction, and tibial tubercle medialization/distalization osteotomy.

Explanation

This patient presents with severe patellar instability driven by multiple, significant bony risk factors: very high TT-TG, severe trochlear dysplasia, and patella alta. To achieve a stable outcome, all major contributors to instability should be addressed. Trochleoplasty will correct the severe trochlear dysplasia. MPFL reconstruction will restore the medial soft tissue restraint. Tibial tubercle osteotomy for medialization (to correct the TT-TG) and distalization (to correct patella alta) will address the extensor mechanism malalignment. A combined approach is necessary for such complex cases.

Question 1922

Topic: Knee Sports

What is the role of patellofemoral bracing in the conservative management of patellar instability?

. To prevent all future dislocations.
. To limit knee flexion and extension to promote healing.
. To provide proprioceptive feedback and some mechanical support, especially during activity.
. To solely replace the function of the MPFL.
. To significantly reduce the TT-TG distance.

Correct Answer & Explanation

. To provide proprioceptive feedback and some mechanical support, especially during activity.

Explanation

Patellofemoral braces, especially those with a J-shaped buttress or similar design, are used in conservative management to provide mechanical support, help guide the patella medially, and offer proprioceptive feedback. They are not foolproof in preventing all dislocations but can reduce the risk during activity and provide confidence. They limit motion to a controlled degree for protection, but their main role is dynamic support. They do not replace the MPFL or alter bony alignment like TT-TG.

Question 1923

Topic: Knee Sports

Which finding on a true lateral knee radiograph is indicative of patella alta?

. A crossover sign.
. Insall-Salvati ratio > 1.2.
. Increased sulcus angle.
. Decreased patellar tilt angle.
. Reduced medial patellar facet height.

Correct Answer & Explanation

. Insall-Salvati ratio > 1.2.

Explanation

Patella alta is diagnosed radiographically by an elevated patellar position relative to the femoral trochlea. Using the Insall-Salvati ratio (patellar tendon length / patellar articular length), a ratio greater than 1.2 is generally indicative of patella alta. A crossover sign and increased sulcus angle are related to trochlear dysplasia. Decreased patellar tilt means the patella is flatter, not higher. Reduced medial patellar facet height is not a standard measure for patellar height.

Question 1924

Topic: Knee Sports

During MPFL reconstruction, the surgeon places the femoral tunnel at Schottle's point. What is the anatomical landmark that is consistently used to identify Schottle's point?

. Midpoint of the lateral femoral epicondyle.
. Anterior border of the adductor tubercle.
. Proximal-most aspect of the medial epicondyle.
. Intersection of a line tangential to the posterior femoral cortex and a line anterior to Blumensaat's line.
. The most prominent point of the medial femoral condyle.

Correct Answer & Explanation

. Intersection of a line tangential to the posterior femoral cortex and a line anterior to Blumensaat's line.

Explanation

Schottle's point, a commonly used landmark for the isometric femoral attachment of the MPFL, is identified by specific radiographic or anatomical relationships: it is distal and posterior to the adductor tubercle, anterior to the posterior femoral cortex, and proximal to the level of the posterior femoral condylar cartilage. Specifically, on a lateral radiograph, it's typically described as the intersection of a line extending proximally from the posterior femoral cortex and a line drawn perpendicular to Blumensaat's line, passing through the posterior aspect of the trochlear groove. The option describes a specific radiographic method. The most consistent anatomical reference is its position relative to the adductor tubercle, but the description given in option 3 more accurately reflects a precise radiographic identification often used.

Question 1925

Topic: Knee Sports

Which of the following describes the 'crossover sign' on an axial MRI of the patellofemoral joint?

. The medial facet of the patella is significantly smaller than the lateral facet.
. The deepest point of the trochlear groove is lateral to the most anterior point of the medial condyle.
. The lateral trochlear facet is flat or convex.
. The patella is positioned entirely lateral to the trochlear groove.
. The lateral aspect of the patella articulates with the intercondylar notch.

Correct Answer & Explanation

. The deepest point of the trochlear groove is lateral to the most anterior point of the medial condyle.

Explanation

The 'crossover sign' is a key feature of trochlear dysplasia, particularly Dejour Types C and D. It is present when the line representing the lateral facet of the trochlea appears to cross over the line representing the medial facet, meaning the deepest part of the trochlear groove is lateral to the most anterior aspect of the medial condyle. This indicates a flattened or even convex trochlear shape, leading to inadequate patellar containment.

Question 1926

Topic: Knee Sports

What is the primary anatomical structure that guides patellar tracking into the trochlear groove as the knee flexes?

. The quadriceps tendon.
. The medial patellofemoral ligament (MPFL).
. The lateral patellar retinaculum.
. The vastus medialis obliquus (VMO) muscle.
. The bony morphology of the trochlear groove.

Correct Answer & Explanation

. The bony morphology of the trochlear groove.

Explanation

While the VMO and MPFL play crucial roles in dynamic and static medial patellar stability, respectively, the primary anatomical structure thatguidesthe patellaintothe trochlear groove and contains it during flexion is the bony morphology of the trochlear groove itself. A well-formed, deep trochlear groove provides the primary constraint, especially beyond 20-30 degrees of flexion where the MPFL becomes relatively less important. Dysplasia of this groove is a major cause of instability.

Question 1927

Topic: Knee Sports

In evaluating a patient for patellar instability, what information obtained from an axial CT scan is most critical for surgical planning?

. Insall-Salvati ratio.
. Q-angle.
. TT-TG distance.
. Size of osteochondral fragments.
. Presence of effusion.

Correct Answer & Explanation

. TT-TG distance.

Explanation

An axial CT scan is the gold standard for accurately measuring the Tibial Tubercle-Trochlear Groove (TT-TG) distance. This measurement quantifies the lateralization of the extensor mechanism relative to the trochlear groove and is a crucial parameter for determining the need for and extent of tibial tubercle medialization osteotomy. The Insall-Salvati ratio is for patellar height (lateral X-ray). Q-angle is clinical or plain X-ray. Osteochondral fragments and effusion are better assessed by MRI or plain X-rays respectively. Thus, TT-TG is the most critical information derived from an axial CT.

Question 1928

Topic: Knee Sports

A 22-year-old female presents with recurrent patellar dislocations. MRI shows an intact MPFL but a markedly increased TT-TG distance (24mm) and patellar tilt. There is no significant trochlear dysplasia or patella alta. Which procedure is most appropriate?

. Isolated MPFL reconstruction.
. Isolated lateral retinacular release.
. Tibial tubercle medialization osteotomy (e.g., Elmslie-Trillat or modified Fulkerson).
. Trochleoplasty.
. VMO advancement.

Correct Answer & Explanation

. Tibial tubercle medialization osteotomy (e.g., Elmslie-Trillat or modified Fulkerson).

Explanation

Given an intact MPFL and the primary issue being a markedly increased TT-TG distance and patellar tilt, a tibial tubercle medialization osteotomy is the most appropriate procedure. This addresses the lateralization of the extensor mechanism and realigns the patella. Isolated MPFL reconstruction is not indicated if the MPFL is intact. Isolated LRR is rarely indicated for instability. Trochleoplasty is for trochlear dysplasia, which is not significant here. VMO advancement is less potent for significant bony malalignment.

Question 1929

Topic: Knee Sports

Which of the following is considered a primary static stabilizer of the patella against lateral displacement?

. Vastus medialis obliquus (VMO).
. Rectus femoris.
. Medial patellofemoral ligament (MPFL).
. Lateral retinaculum.
. Patellar tendon.

Correct Answer & Explanation

. Medial patellofemoral ligament (MPFL).

Explanation

The MPFL is widely recognized as the primary static (passive) stabilizer of the patella, resisting lateral translation, especially in the initial 0-30 degrees of knee flexion. The VMO is a dynamic stabilizer. The rectus femoris and patellar tendon are components of the extensor mechanism, primarily involved in knee extension. The lateral retinaculum provides lateral soft tissue constraint.

Question 1930

Topic: Knee Sports

Following an acute patellar dislocation, what is the most common site of injury to the medial patellofemoral ligament (MPFL)?

. Mid-substance tear.
. Patellar avulsion.
. Femoral avulsion.
. Tear at the retinacular attachment.
. Complete MPFL avulsion from both patellar and femoral insertions.

Correct Answer & Explanation

. Femoral avulsion.

Explanation

While MPFL injuries can occur at any point, femoral avulsions are the most common site of MPFL rupture in acute patellar dislocations. This typically occurs through an avulsion of a small bone fragment from the medial femoral condyle (often called a 'sleeve avulsion' or 'avulsion fracture'). Patellar avulsions are less common than femoral avulsions but can also occur. Mid-substance tears are less frequent.

Question 1931

Topic: Knee Sports

A patient presents with a 'double contour' sign on an axial patellofemoral CT scan. This finding is indicative of:

. Patella baja.
. Generalized ligamentous laxity.
. Trochlear dysplasia with a flat or convex trochlea.
. Increased Q-angle.
. Isolated lateral retinacular tightness.

Correct Answer & Explanation

. Trochlear dysplasia with a flat or convex trochlea.

Explanation

The 'double contour' sign on an axial patellofemoral CT scan is a radiological indicator of trochlear dysplasia. It refers to the appearance where the posterior aspect of the lateral trochlear facet is more anterior than the anterior border of the medial trochlear facet, suggesting a flat or even convex trochlear groove rather than a concave one. This is a characteristic feature of more severe forms of trochlear dysplasia (e.g., Dejour Types C and D).

Question 1932

Topic: Knee Sports

Which imaging modality is considered the most comprehensive for evaluating the full spectrum of risk factors for patellar instability, including trochlear morphology, patellar height, TT-TG distance, and MPFL integrity?

. Plain radiographs (AP, lateral, axial).
. Dynamic ultrasound.
. Computed Tomography (CT) scan.
. Magnetic Resonance Imaging (MRI).
. SPECT-CT.

Correct Answer & Explanation

. Magnetic Resonance Imaging (MRI).

Explanation

Magnetic Resonance Imaging (MRI) is the most comprehensive imaging modality for evaluating patellar instability. It can assess soft tissues (MPFL integrity, chondral damage, effusion, bone bruising) as well as provide information on bony morphology (trochlear dysplasia, patellar height, TT-TG distance with sequences that mimic CT measurements). While plain radiographs are initial, and CT is excellent for bony measurements like TT-TG, MRI offers the best overall picture including all relevant soft tissue and bony components simultaneously.

Question 1933

Topic: Knee Sports

The Dejour classification for trochlear dysplasia identifies four types (A, B, C, D). Which type is characterized by a 'crossover sign' but without a supratrochlear spur?

. Type A.
. Type B.
. Type C.
. Type D.
. Type E.

Correct Answer & Explanation

. Type C.

Explanation

According to Dejour's classification: Type A is a shallow trochlea. Type B has a supratrochlear spur (bump). Type C has a 'crossover sign' (the medial facet lies lateral to the lateral facet) but no supratrochlear spur. Type D is the most severe, combining both a crossover sign and a supratrochlear spur, often with a 'cliff-like' appearance. Therefore, Type C is the correct answer.

Question 1934

Topic: Knee Sports

A 14-year-old female presents with persistent patellofemoral pain after a first-time patellar dislocation treated non-operatively. MRI shows mild trochlear dysplasia, a normal TT-TG distance, no patella alta, and a healed MPFL. What is the most likely cause of her ongoing pain?

. Recurrent MPFL insufficiency.
. Unrecognized patellar maltracking without instability.
. Osteochondritis dissecans of the lateral femoral condyle.
. Infection of the patellofemoral joint.
. A primary valgus deformity of the knee.

Correct Answer & Explanation

. Unrecognized patellar maltracking without instability.

Explanation

Given that the MPFL has healed and there are no significant bony malalignments or instability, persistent pain in this scenario often points to unresolved patellar maltracking or residual patellofemoral overload. The mild trochlear dysplasia, even if not causing overt instability, can contribute to poor tracking and increased contact pressures. Osteochondritis dissecans would typically be visible on MRI. Infection would have different symptoms. Primary valgus deformity would be a bony malalignment risk factor, which is stated as not significant. Recurrent MPFL insufficiency is ruled out by a healed MPFL. Therefore, subtle maltracking or altered patellofemoral mechanics due to the mild dysplasia is the most likely culprit for persistent pain, even without overt instability.

Question 1935

Topic: Knee Sports

What is the surgical principle behind medializing a tibial tubercle osteotomy in the management of patellar instability?

. To decrease patella alta.
. To increase the leverage of the quadriceps mechanism.
. To decrease the TT-TG distance, thereby moving the patellar tendon insertion medially.
. To release tension on the lateral patellar retinaculum.
. To deepen the trochlear groove.

Correct Answer & Explanation

. To decrease the TT-TG distance, thereby moving the patellar tendon insertion medially.

Explanation

Tibial tubercle medialization osteotomy (e.g., Elmslie-Trillat or modified Fulkerson) aims to reduce the TT-TG distance. By moving the tibial tubercle medially, the line of pull of the quadriceps mechanism (via the patellar tendon) is shifted medially, bringing the patella into better alignment with the trochlear groove and reducing the lateralizing force. Distalization addresses patella alta. The procedure does not directly deepen the trochlear groove or release the lateral retinaculum.

Question 1936

Topic: Knee Sports

When assessing the TT-TG distance on an axial CT scan, which anatomical plane is used for measurement?

. Coronal plane.
. Sagittal plane.
. Transverse (axial) plane.
. Oblique plane at 45 degrees.
. Three-dimensional reconstruction, but not a specific plane.

Correct Answer & Explanation

. Transverse (axial) plane.

Explanation

The Tibial Tubercle-Trochlear Groove (TT-TG) distance is measured in the transverse (axial) plane on a CT scan or MRI. This involves superimposing an axial cut through the deepest part of the trochlear groove onto an axial cut through the center of the tibial tubercle and measuring the horizontal distance between these two points. This measures the lateralization of the tibial tubercle relative to the trochlear groove.

Question 1937

Topic: Knee Sports

A patient with recurrent patellar instability, patella alta, and a normal TT-TG distance would most appropriately be treated with which surgical procedure?

. Isolated lateral retinacular release.
. Isolated MPFL reconstruction.
. Tibial tubercle distalization osteotomy.
. Trochleoplasty.
. Tibial tubercle medialization osteotomy.

Correct Answer & Explanation

. Tibial tubercle distalization osteotomy.

Explanation

For a patient with patella alta and recurrent instability, but a normal TT-TG distance (meaning no significant lateralization of the extensor mechanism) and no mention of trochlear dysplasia, a tibial tubercle distalization osteotomy (e.g., using a Maquet or Elmslie-Trillat type osteotomy with a distal shift) is the most appropriate procedure to lower the patella and improve its engagement in the trochlear groove. Isolated lateral release is rarely sufficient. MPFL reconstruction would address the soft tissue but not the underlying patella alta. Trochleoplasty is for dysplasia. Tibial tubercle medialization is for increased TT-TG, which is normal here.

Question 1938

Topic: Knee Sports

A surgeon is considering performing a trochleoplasty for a patient with severe trochlear dysplasia and recurrent patellar instability. What is a critical intraoperative maneuver to confirm the adequacy of the trochleoplasty?

. Measuring the TT-TG distance with a ruler.
. Performing a lateral retinacular release after the trochleoplasty.
. Assessing patellar tracking and stability dynamically through a full range of motion.
. Confirming graft tension of the MPFL reconstruction.
. Performing an arthroscopic debridement of the patellofemoral joint.

Correct Answer & Explanation

. Assessing patellar tracking and stability dynamically through a full range of motion.

Explanation

After performing a trochleoplasty, it is crucial to dynamically assess patellar tracking and stability through a full range of motion (often by flexing and extending the knee while manually attempting to sublux the patella). This allows the surgeon to confirm that the newly created trochlear groove adequately contains the patella and that there is no residual apprehension or instability. The other options are either not related to the adequacy of the trochleoplasty itself, or are separate procedures/measurements.

Question 1939

Topic: Knee Sports

The medial meniscus is firmly attached to which ligament?

. Anterior Cruciate Ligament (ACL).
. Posterior Cruciate Ligament (PCL).
. Lateral Collateral Ligament (LCL).
. Medial Collateral Ligament (MCL).
. Popliteofibular ligament.

Correct Answer & Explanation

. Medial Collateral Ligament (MCL).

Explanation

The medial meniscus is firmly attached to the deep fibers of the medial collateral ligament (MCL). This attachment, along with its broader capsular attachments, makes the medial meniscus less mobile than the lateral meniscus and contributes to the higher incidence of medial meniscal tears in conjunction with MCL injuries.

Question 1940

Topic: Knee Sports

Damage to the posterior horn of the lateral meniscus is frequently associated with injury to which ligament?

. Medial collateral ligament.
. Anterior cruciate ligament.
. Posterior cruciate ligament.
. Patellar ligament.
. Oblique popliteal ligament.

Correct Answer & Explanation

. Anterior cruciate ligament.

Explanation

Tears of the lateral meniscus, particularly the posterior horn, are frequently seen in conjunction with anterior cruciate ligament (ACL) ruptures. This association is thought to be due to the rotational forces and complex kinematics during the injury event, where the lateral meniscus is compressed and sheared by the rapidly translating lateral femoral condyle.

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