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Knee Sports MCQs

Practice Set 89 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 1761

Topic: Knee Sports

The anterior cruciate ligament (ACL) is composed of two primary bundles that function synergistically during the knee arc of motion. During knee flexion, which bundle is the primary restraint to anterior tibial translation?

. Posterolateral bundle
. Anteromedial bundle
. Anterolateral bundle
. Posteromedial bundle
. Ligament of Humphrey

Correct Answer & Explanation

. Posterolateral bundle

Explanation

The ACL consists of the Anteromedial (AM) and Posterolateral (PL) bundles. The AM bundle is tight in flexion and serves as the primary restraint to anterior tibial translation at higher degrees of knee flexion. The PL bundle is tight in extension and is the primary restraint to rotatory instability (pivot shift) as the knee approaches full extension.

Question 1762

Topic: Knee Sports

When performing an anterior cruciate ligament (ACL) reconstruction using a bone-patellar tendon-bone (BTB) autograft, placement of the femoral tunnel too far anteriorly will result in which kinematic abnormality?

. 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 restrict internal rotation at all angles
. The graft will cause obligatory posterior subluxation of the tibia
. The graft will be universally loose throughout the range of motion

Correct Answer & Explanation

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

Explanation

Placing the femoral tunnel too anteriorly (ventral) is a common technical error in ACL reconstruction. It increases the distance between the tibial and femoral attachment sites during flexion, resulting in a graft that is tight in flexion and loose in extension, ultimately limiting knee flexion.

Question 1763

Topic: Knee Sports

Which of the following nerve injuries is most classically associated with a high-energy posterolateral dislocation of the knee?

. Tibial nerve
. Common peroneal nerve
. Saphenous nerve
. Deep femoral nerve
. Obturator nerve

Correct Answer & Explanation

. Tibial nerve

Explanation

Posterolateral corner injuries or knee dislocations place the common peroneal nerve at immense risk for traction injury due to its tethered anatomical course around the fibular neck. Patients typically present with a foot drop and lateral leg numbness.

Question 1764

Topic: Knee Sports

In native knee kinematics, femoral rollback during deep flexion is essential to improve the moment arm of the extensor mechanism and prevent posterior impingement. This rollback is primarily driven by the tension in which of the following structures?

. Anterior cruciate ligament
. Posterior cruciate ligament
. Medial collateral ligament
. Lateral collateral ligament
. Popliteus tendon

Correct Answer & Explanation

. Anterior cruciate ligament

Explanation

As the knee flexes, the tension in the posterior cruciate ligament (PCL) forces the femur to roll and translate posteriorly on the tibial plateau. This femoral rollback allows for increased flexion before the posterior femur impinges on the posterior tibia.

Question 1765

Topic: Knee Sports

A posterior-stabilized (PS) total knee arthroplasty utilizes a cam-and-post mechanism. What is the primary biomechanical function of this design during deep knee flexion?

. To substitute for the anterior cruciate ligament (ACL) and prevent anterior tibial translation
. To substitute for the posterior cruciate ligament (PCL) and enforce posterior femoral rollback
. To provide varus-valgus constraint in the setting of collateral ligament deficiency
. To prevent hyperextension of the knee
. To increase the patellofemoral joint reaction force

Correct Answer & Explanation

. To substitute for the anterior cruciate ligament (ACL) and prevent anterior tibial translation

Explanation

In a posterior-stabilized (PS) TKA, the PCL is sacrificed. The tibial post and femoral cam engage during flexion to substitute for the PCL's function. This engagement forces the femur to roll posteriorly on the tibia (posterior femoral rollback), preventing anterior sliding of the femur, improving impingement-free flexion, and maximizing the quadriceps moment arm.

Question 1766

Topic: Knee Sports

A 16-year-old gymnast presents with chronic elbow pain and mechanical catching. Imaging confirms a large osteochondritis dissecans (OCD) lesion of the capitellum. Which of the following is considered an indication for osteochondral autograft transfer (OATS) rather than arthroscopic microfracture?

. Patient age less than 12 years
. Lesion size measuring 8 mm in diameter
. Involvement of the uncontained lateral capitellar margin
. Completely intact articular cartilage over the subchondral cyst
. A contained central capitellar lesion

Correct Answer & Explanation

. Patient age less than 12 years

Explanation

Arthroscopic debridement and microfracture yield poor functional outcomes for large OCD lesions or those involving the uncontained lateral margin of the capitellum. OATS is specifically indicated for lesions greater than 1 cm or those with lateral margin involvement.

Question 1767

Topic: Knee Sports

A newborn is evaluated for a congenital lower extremity deformity. Examination reveals a shortened right leg, anteromedial bowing of the tibia, absence of the lateral two rays of the foot, and a dimple over the anterior aspect of the tibia. What intra-articular knee anomaly is most frequently associated with this diagnosis?

. Absent or hypoplastic posterior cruciate ligament (PCL)
. Absent or hypoplastic anterior cruciate ligament (ACL)
. Habitual patellar dislocation
. Meniscal agenesis
. Discoid lateral meniscus

Correct Answer & Explanation

. Absent or hypoplastic posterior cruciate ligament (PCL)

Explanation

The clinical description is classic for fibular hemimelia. It is the most common congenital long bone deficiency. It is characterized by anteromedial tibial bowing, equinovalgus foot, absent lateral rays, and a shortened limb. In the knee, there is a very high association with an absent or hypoplastic anterior cruciate ligament (ACL), leading to anteroposterior instability, though patients often adapt well functionally without reconstruction.

Question 1768

Topic: Knee Sports

A 9-year-old boy presents with an asymptomatic snapping sensation in his right knee, which his mother notes occurs predominantly when he extends his knee. He has no history of trauma, pain, or swelling. Which of the following anatomic variations is most likely responsible for this symptomatic presentation?

. Absence of the anterior meniscofemoral ligament of Humphrey
. Absence of the posterior meniscotibial attachments of the lateral meniscus
. Abnormal attachment of the medial meniscus to the anterior cruciate ligament
. Bifurcate morphology of the medial meniscus
. Hypertrophy of the transverse intermeniscal ligament

Correct Answer & Explanation

. Absence of the anterior meniscofemoral ligament of Humphrey

Explanation

The patient has the Wrisberg variant of a discoid lateral meniscus. This variant is characterized by the absence of the normal posterior meniscotibial capsular attachments; its only posterior attachment is the meniscofemoral ligament of Wrisberg. This instability allows the meniscus to subluxate anteriorly during knee extension, producing a palpable or audible 'snap' or 'clunk'.

Question 1769

Topic: Knee Sports

A 10-year-old boy presents with a painful, swollen knee after falling off his bicycle. Radiographs reveal a displaced, completely elevated fracture of the anterior tibial spine (Meyers and McKeever Type 3). Which of the following structures is most commonly entrapped, blocking anatomic closed reduction?

. Anterior cruciate ligament
. Transverse intermeniscal ligament
. Anterior horn of the medial meniscus
. Posterior cruciate ligament
. Patellar tendon

Correct Answer & Explanation

. Anterior cruciate ligament

Explanation

In Meyers and McKeever Type 3 tibial eminence (spine) fractures, the anterior horn of the medial meniscus is the most common structure that becomes entrapped under the avulsed fragment, blocking anatomic reduction. The intermeniscal ligament can also be involved. This entrapment necessitates arthroscopic or open reduction.

Question 1770

Topic: Knee Sports

In anterior cruciate ligament (ACL) reconstruction, placing the femoral tunnel too anteriorly (shallow) will result in which of the following kinematic abnormalities?

. Tight in extension and loose in flexion
. Tight in flexion and loose in extension
. Tight in both flexion and extension
. Loose in both flexion and extension
. Impingement in the intercondylar notch in extension

Correct Answer & Explanation

. Tight in extension and loose in flexion

Explanation

An anteriorly placed femoral tunnel (too shallow or anterior to the anatomic footprint) results in the graft being tight in flexion and loose in extension, often limiting full flexion. A posteriorly placed femoral tunnel results in a graft that is tight in extension and loose in flexion. Notch impingement in extension is typically caused by an excessively anterior tibial tunnel.

Question 1771

Topic: Knee Sports

A 24-year-old professional soccer player undergoes anterior cruciate ligament (ACL) reconstruction using an autologous bone-patellar tendon-bone graft. The graft must undergo a process of "ligamentization" to restore function. At what postoperative time frame is the structural graft mechanically at its weakest due to the revascularization and necrosis phase?

. 1 to 2 weeks
. 6 to 8 weeks
. 12 to 16 weeks
. 6 to 8 months
. 12 to 18 months

Correct Answer & Explanation

. 1 to 2 weeks

Explanation

The "ligamentization" of a free tendon graft involves stages of necrosis, revascularization, cellular proliferation, and remodeling. The graft is generally at its weakest biomechanical point around 6 to 8 weeks postoperatively, which must be considered when designing rehabilitation protocols to prevent premature failure.

Question 1772

Topic: Knee Sports

A 22-year-old soccer player sustains a twisting injury to his knee. Radiographs reveal an avulsion fracture of the lateral tibial plateau (Segond fracture). This radiographic finding is virtually pathognomonic for an injury to which of the following structures?

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

Correct Answer & Explanation

. Posterior cruciate ligament (PCL)

Explanation

A Segond fracture is an avulsion fracture of the anterolateral proximal tibia. It represents an avulsion of the anterolateral ligament (ALL) or lateral capsular attachment and is highly specific for an anterior cruciate ligament (ACL) tear.

Question 1773

Topic: Knee Sports

During anterior cruciate ligament (ACL) reconstruction, improper placement of the femoral tunnel can lead to graft failure or loss of motion. Placing the femoral tunnel too anteriorly (shallow) within the intercondylar notch results in which of the following graft tension patterns?

. Tight in extension and loose in flexion
. Loose in extension and tight in flexion
. Tight in both extension and flexion
. Loose in both extension and flexion
. Isometric throughout the entire range of motion

Correct Answer & Explanation

. Tight in extension and loose in flexion

Explanation

Femoral tunnel malposition is the most common cause of technical failure in ACL reconstruction. A femoral tunnel placed too anteriorly (shallow) will result in a graft that is loose in extension and pathologically tight in flexion, limiting terminal knee flexion.

Question 1774

Topic: Knee Sports

Injury to the popliteal artery during total knee arthroplasty (TKA) is most likely to occur when placing a

sharp retractor

. directly posterior to the posterior cruciate ligament (PCL).
. posteromedial to the PCL.
. posterolateral to the PCL.
. in the posteromedial corner of the knee.

Correct Answer & Explanation

. directly posterior to the posterior cruciate ligament (PCL).

Explanation

Vascular complications during TKA are rare but do occur. Traditionally, it was taught that the popliteal artery was situated posterior to the PCL; however, more recent anatomic dissections have demonstrated that this artery is usually located posterolateral to the PCL.

Question 1775

Topic: Knee Sports

Figures below show the radiographs, and the MRIs obtained from a 32-year-old man with worsening left

knee pain. A 3-foot hip-to-ankle radiograph shows a 13-degree varus knee deformity. The patient sustained a major left knee injury 5 years ago and a confirmed complete anterior cruciate ligament (ACL) tear. He managed this injury nonsurgically with a functional brace but experienced worsening pain. He was seen by an orthopaedic surgeon 18 months ago, and a medial meniscus tear was diagnosed; the tear was treated with an arthroscopic partial medial meniscectomy. Since then, his knee has been giving way more often, and he no longer feels safe working on a pitched roof. The patient received 6 months of formal physical therapy and was fitted for a new functional ACL brace, but he still has pain and instability. He believes he has exhausted his nonsurgical options and would like to undergo surgery. What is the most appropriate treatment at this time?


. ACL reconstruction and subsequent proximal tibial osteotomy
. ACL reconstruction alone
. Distal femoral osteotomy with simultaneous ACL reconstruction
. Proximal tibial osteotomy with subsequent ACL reconstruction

Correct Answer & Explanation

. ACL reconstruction and subsequent proximal tibial osteotomy

Explanation

Proximal tibial osteotomy is the most appropriate intervention to correct varus malalignment and to reduce stress on the ACL. In some cases, proximal tibial osteotomy alone may address both pain and instability, but if instability persists, particularly in the setting in which instability can be dangerous, subsequent ACL reconstruction can further stabilize the knee with less stress on the graft after the correction of malalignment. Varus alignment places increased stress on the native or reconstructed ACL. ACL reconstruction should be performed only at the same time as or following proximal tibial osteotomy to correct alignment in the setting of varus malalignment. It is not appropriate to perform ACL reconstruction prior to proximal tibial osteotomy in this setting. Distal femoral osteotomy is not indicated to correct varus malalignment. Varus alignment places increased stress on the native or reconstructed ACL, and ACLreconstruction alone is not indicated for this patient.

Question 1776

Topic: Knee Sports

The anterior cruciate ligament (ACL) is composed of the anteromedial (AM) and posterolateral (PL) functional bundles. Which of the following statements accurately describes the biomechanical relationship of these bundles during normal knee kinematics?

. The anteromedial bundle is tight in extension and controls anterior translation
. The posterolateral bundle is tight in flexion and controls internal rotation
. The anteromedial bundle is tight in flexion and is the primary restraint to anterior tibial translation at 90 degrees
. The posterolateral bundle is tight in flexion and is the primary restraint to anterior tibial translation at 90 degrees
. Both bundles remain equally isometric throughout the entire 0-140 degree arc of motion

Correct Answer & Explanation

. The anteromedial bundle is tight in extension and controls anterior translation

Explanation

The native ACL has two distinct bundles named for their tibial insertions. Biomechanically, the anteromedial (AM) bundle is tight in flexion and is the primary restraint to anterior tibial translation when the knee is flexed (tested via Anterior Drawer test at 90 degrees). The posterolateral (PL) bundle is tight in extension and is the primary restraint to rotatory loads and anterior translation near extension (tested via Lachman test at 20-30 degrees and the Pivot Shift test). Reconstructing both functional roles is the theoretical basis behind double-bundle ACL reconstruction techniques.

Question 1777

Topic: Knee Sports

In the process of anterior cruciate ligament (ACL) reconstruction, the graft must undergo a biological process known as ligamentization. During which phase of this process does the graft exhibit its lowest mechanical strength?

. Initial necrosis phase
. Revascularization phase
. Cellular proliferation phase
. Collagen remodeling phase
. Maturation phase

Correct Answer & Explanation

. Initial necrosis phase

Explanation

The revascularization phase occurs 6 to 12 weeks postoperatively. During this time, the graft undergoes remodeling by host fibroblasts and vascular ingrowth, resulting in a transient but significant decrease in its mechanical strength.

Question 1778

Topic: Knee Sports

A 20-year-old female presents with recurrent lateral patellar instability. MRI reveals an intact MPFL but a Tibial Tubercle-Trochlear Groove (TT-TG) distance of 24 mm. Which of the following is the most appropriate surgical management?

. MPFL reconstruction alone
. Tibial tubercle medialization and MPFL reconstruction
. Lateral retinacular release alone
. Trochleoplasty
. Tibial tubercle anteriorization

Correct Answer & Explanation

. MPFL reconstruction alone

Explanation

The TT-TG distance is a crucial measurement in patellar instability. A distance > 20 mm is considered abnormal and generally an indication for tibial tubercle medialization (e.g., Fulkerson osteotomy). MPFL reconstruction alone in the setting of a TT-TG > 20 mm is associated with a significantly higher failure rate due to uncorrected excessive lateral pull.

Question 1779

Topic: Knee Sports
A 25-year-old male sustains a knee dislocation. Exam reveals a grade III Lachman, grade III posterior drawer, and increased opening to varus stress at 0 and 30 degrees. Valgus stress is stable. According to the Schenck classification, what type of knee dislocation is this?
. KD-I
. KD-II
. KD-III M
. KD-III L
. KD-IV

Correct Answer & Explanation

. KD-III L

Explanation

The Schenck classification describes knee dislocations based on the ligaments torn. KD-I: one cruciate. KD-II: both cruciates. KD-III: both cruciates and one collateral (M for MCL, L for LCL). KD-IV: all four ligaments. This patient has ACL, PCL, and LCL tears (varus instability) with an intact MCL (stable valgus), classifying it as KD-III L.

Question 1780

Topic: Knee Sports

A 50-year-old male feels a "pop" in the back of his knee while squatting. MRI shows a medial meniscus posterior root tear. Which of the following radiographic findings is most strongly associated with chronic untreated medial meniscus posterior root tears?

. Spontaneous osteonecrosis of the knee (SONK)
. Osteochondritis dissecans of the lateral femoral condyle
. Rapidly progressive lateral compartment osteoarthritis
. Patellofemoral arthritis
. Segond fracture

Correct Answer & Explanation

. Spontaneous osteonecrosis of the knee (SONK)

Explanation

Medial meniscus root tears result in a loss of hoop stresses, effectively acting like a total meniscectomy. This drastically increases peak contact pressures in the medial compartment, predisposing the patient to subchondral insufficiency fractures, spontaneous osteonecrosis of the knee (SONK), and rapidly progressive osteoarthritis.

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