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 1941
Topic: Knee Sports
Which statement about meniscal regeneration or repair is most accurate regarding the role of mesenchymal stem cells (MSCs)?
Correct Answer & Explanation
. MSCs have been shown to differentiate into fibrochondrocytes and enhance healing in vascularized regions.
Explanation
Mesenchymal stem cells (MSCs) hold promise for meniscal repair and regeneration. They can differentiate into fibrochondrocytes, the primary cell type of the meniscus, and produce extracellular matrix components. While not abundant in the avascular zones, exogenous MSCs (e.g., from bone marrow aspirate concentrate) or MSCs recruited to the vascularized periphery have shown potential to enhance healing in repairable tears, particularly in conjunction with other biological augmentation strategies.
Question 1942
Topic: Knee Sports
Which factor is generally considered detrimental to meniscal tear healing potential?
Correct Answer & Explanation
. Chronic, degenerative tear morphology.
Explanation
Chronic, degenerative tears, especially those in the avascular zones, have significantly reduced healing potential. They are often characterized by compromised tissue quality, multiple tear planes, and a diminished biological response compared to acute, traumatic tears in vascularized areas. While other factors listed are generally favorable for healing, a chronic degenerative tear presents a poor biological environment for repair.
Question 1943
Topic: Knee Sports
A 'ramp lesion' refers to a specific tear pattern of which meniscal region?
Correct Answer & Explanation
. Posterior horn of the medial meniscus, posteromedial capsule junction.
Explanation
A ramp lesion is a longitudinal tear of the posterior horn of the medial meniscus that occurs at the meniscocapsular junction, often extending into the posteromedial capsule. These lesions are frequently associated with ACL ruptures and can be difficult to diagnose arthroscopically from the standard anterior portals, often requiring a posteromedial portal for visualization and repair.
Question 1944
Topic: Knee Sports
Which of the following ligaments is considered the primary static stabilizer against anterior translation of the tibia relative to the femur?
Correct Answer & Explanation
. Anterior Cruciate Ligament (ACL)
Explanation
The Anterior Cruciate Ligament (ACL) is the primary static stabilizer that prevents anterior translation of the tibia on the femur, particularly in knee extension and near extension. It also resists internal rotation and hyperextension. The PCL prevents posterior translation, and the MCL and LCL primarily resist valgus and varus forces, respectively.
Question 1945
Topic: Knee Sports
A 30-year-old male sustains a bucket-handle tear of the medial meniscus. Arthroscopic examination confirms a displaced, reducible tear in the red-red zone (periphery) of the meniscus, measuring 3 cm in length, without significant chondral damage. What is the most appropriate management strategy?
Correct Answer & Explanation
. Meniscal repair
Explanation
A displaced bucket-handle tear in the red-red zone (vascularized periphery) of the meniscus, especially in a young, active patient, is an ideal candidate for meniscal repair. Repair preserves meniscal tissue, which is crucial for joint load distribution and preventing osteoarthritis. Partial meniscectomy is indicated for irreparable tears or tears in the avascular zone. Total meniscectomy leads to accelerated degenerative changes. Microfracture is for chondral defects. Observation is inappropriate for a displaced, symptomatic tear.
Question 1946
Topic: Knee Sports
A 55-year-old male undergoes arthroscopic ACL reconstruction using an autologous hamstring graft. Two months post-operatively, he complains of anterior knee pain and crepitus with knee flexion. Examination reveals localized tenderness over the patellar tendon insertion and pain with resisted knee extension. Radiographs are normal. What is the most likely diagnosis?
Correct Answer & Explanation
. Cyclops lesion
Explanation
The symptoms of anterior knee pain, crepitus, and catching with flexion after ACL reconstruction, especially at 2 months post-op, are classic for a Cyclops lesion. This is a nodule of fibrous tissue that forms anterior to the ACL graft in the intercondylar notch, causing impingement and blocking full extension. Patellar tendinopathy is less common with hamstring grafts, and graft failure would usually present with instability. Arthrofibrosis would present with more global stiffness and loss of range of motion. An MCL sprain would cause medial knee pain and instability.
Question 1947
Topic: Knee Sports
A 22-year-old football player sustains an injury to his knee during a tackle, resulting in a large hemarthrosis. Examination reveals a positive Lachman test and pivot shift test. MRI confirms a complete tear of the anterior cruciate ligament (ACL) and a medial meniscal tear. What is the optimal timing for ACL reconstruction in this patient?
Correct Answer & Explanation
. Delayed until knee inflammation subsides and full range of motion is achieved, typically 3-6 weeks post-injury
Explanation
For an acute ACL tear, especially with an associated meniscal tear, the optimal timing for reconstruction is typically delayed until the acute inflammation has subsided, and the patient has regained a near-full range of motion, usually 3-6 weeks post-injury. Early surgery (within 1-2 weeks) is associated with a significantly higher risk of arthrofibrosis (stiff knee syndrome). Waiting for full range of motion allows the knee to 'cool down,' improving surgical outcomes and rehabilitation potential. Delaying for 3 months or waiting for recurrent instability might be options for less active patients, but not typically for a football player aiming for return to sport.
Question 1948
Topic: Knee Sports
In a scenario involving multiple ligament knee injury (MLKI), what concept is most important to convey to an examiner regarding the treatment philosophy for optimal outcome?
Correct Answer & Explanation
. Early, accurate diagnosis and reduction/stabilization of the knee joint, often requiring a staged approach for ligament reconstruction based on injury pattern, patient factors, and rehabilitation potential, with a focus on restoring stability.
Explanation
MLKIs are severe and complex. A high-scoring answer will emphasize accurate diagnosis, early reduction and stabilization (often with external fixation), and a carefully planned, often staged, surgical approach for reconstruction of the injured ligaments. The goal is to restore stability and alignment while considering the overall limb viability (neurovascular checks are paramount). Ignoring associated injuries or applying a 'one-size-fits-all' approach is suboptimal.
Question 1949
Topic: Knee Sports
You are presenting a case of recurrent patellar dislocation. Which element of the workup is most crucial for identifying the underlying cause and guiding management for optimal marks?
Correct Answer & Explanation
. Detailed assessment of predisposing anatomical factors (e.g., trochlear dysplasia, patella alta, tibial tuberosity-trochlear groove distance [TT-TG], ligamentous laxity), patient activity level, and previous treatment failures, using specialized imaging (MRI/CT).
Explanation
Recurrent patellar dislocation often has complex underlying anatomical predispositions. A high-scoring answer will emphasize a detailed workup that identifies these factors, such as trochlear dysplasia, patella alta, increased TT-TG distance, and ligamentous laxity (e.g., MPFL insufficiency), using specialized imaging like MRI or CT. Understanding these factors is key to tailoring management (conservative vs. MPFL reconstruction, osteotomy) and preventing recurrence, demonstrating a deep understanding of patellofemoral biomechanics.
Question 1950
Topic: Knee Sports
You are presenting a case of recurrent patellar dislocation in an adolescent. The examiner asks, 'What specific anatomical or biomechanical factors predispose a patient to recurrent patellar instability, and how do you assess them?'
Correct Answer & Explanation
. Trochlear dysplasia, patella alta, increased tibial tuberosity-trochlear groove (TT-TG) distance, and generalized ligamentous laxity. These are assessed clinically (e.g., J-sign, apprehension test) and with imaging (radiographs for patella alta, MRI/CT for trochlear morphology and TT-TG distance).
Explanation
Recurrent patellar instability is typically multifactorial. Key predisposing factors include osseous abnormalities such as trochlear dysplasia (a shallow or flat trochlear groove), patella alta (high-riding patella), and an increased tibial tuberosity-trochlear groove (TT-TG) distance, which indicates lateralization of the patellar tendon insertion. Ligamentous laxity, especially medial patellofemoral ligament (MPFL) insufficiency, is also critical. These are assessed through clinical examination (e.g., patellar apprehension test, J-sign) and advanced imaging (MRI for trochlear morphology and MPFL integrity, CT for accurate TT-TG measurement). Quadriceps weakness (A) and retinacular tightness (D) are usually secondary or less dominant factors. Genu varum (B) is less common, and meniscal tears (E) are not a primary predisposing factor for patellar instability.
Question 1951
Topic: Knee Sports
You are asked about the management of an acute posterolateral corner (PLC) knee injury. The examiner states, 'You've discussed acute management. Now, if this injury is not adequately treated, what is the most significant long-term consequence for the knee?'
Correct Answer & Explanation
. Progressive medial compartment osteoarthritis due to altered biomechanics and chronic varus thrust.
Explanation
Inadequate treatment of a posterolateral corner (PLC) knee injury leads to persistent posterolateral rotatory instability and chronic varus (bowleg) thrust during gait. This alters the knee's biomechanics, significantly increasing stress on the medial compartment. The most significant long-term consequence is the progressive development of medial compartment osteoarthritis. Patellofemoral pain (A), popliteal cyst (C), DVT (D), and chronic anterior knee pain (E) are less direct or less significant long-term consequences directly attributable to untreated PLC instability leading to altered varus alignment and thrust.
Question 1952
Topic: Knee Sports
A 25-year-old female presents with persistent deep ankle pain following an inversion sprain 6 months ago. MRI reveals a 12 mm x 10 mm anterolateral osteochondral lesion of the talar dome with intact overlying cartilage. What is the most appropriate initial surgical management after failed conservative therapy?
Correct Answer & Explanation
. Arthroscopic bone marrow stimulation (microfracture)
Explanation
For primary osteochondral lesions of the talus smaller than 1.5 cm squared, arthroscopic bone marrow stimulation is the recommended first-line surgical treatment. OATS or ACI are typically reserved for larger lesions or failures of primary microfracture.
Question 1953
Topic: Knee Sports
During reconstruction of the Anterior Cruciate Ligament (ACL), the surgeon places the femoral tunnel too anteriorly (i.e., too high and shallow in the intercondylar notch). What is the primary clinical consequence of this specific technical error?
Correct Answer & Explanation
. The graft will be tight in flexion and loose in extension.
Explanation
Proper femoral tunnel placement is critical for the isometric function of an ACL graft. If the femoral tunnel is placed too anteriorly (high in the notch) relative to the anatomic footprint, the distance between the femoral and tibial attachments increases as the knee bends. This results in a graft that becomes excessively tight in flexion (often leading to a loss of full knee flexion) and loose in extension.
Question 1954
Topic: Knee Sports
A 14-year-old boy presents with vague, activity-related knee pain. MRI reveals a 1.5 cm osteochondritis dissecans (OCD) lesion on the lateral aspect of the medial femoral condyle. The physes are open, and the lesion shows no fluid signal behind the fragment. What is the most appropriate initial treatment?
Correct Answer & Explanation
. Non-operative management with activity restriction
Explanation
Juvenile osteochondritis dissecans (jOCD) occurring in patients with open physes and stable lesions (no fluid behind the fragment on MRI) has a high rate of spontaneous healing. A trial of non-operative management, including activity modification and brief immobilization, is the initial standard of care.
Question 1955
Topic: Knee Sports
During anterior cruciate ligament (ACL) reconstruction, graft selection is critical. What is the approximate ultimate tensile load of the native intact human ACL?
Correct Answer & Explanation
. 2160 N
Explanation
The native intact human ACL has an ultimate tensile load of approximately 2160 N. By comparison, a quadrupled hamstring graft is initially stronger at time zero, exceeding 4000 N.
Question 1956
Topic: Knee Sports
Understanding the biomechanics of the anterior cruciate ligament (ACL) is essential for anatomic reconstruction. The anteromedial (AM) bundle of the native ACL reaches its maximum tension in which position?
Correct Answer & Explanation
. Full extension
Explanation
The ACL is composed of two primary bundles. The anteromedial (AM) bundle is tightest in flexion (typically tested at 90 degrees with the anterior drawer), while the posterolateral (PL) bundle is tightest in extension.
Question 1957
Topic: Knee Sports
The anterior cruciate ligament (ACL) provides critical rotational and translational stability to the knee and is composed of two primary bundles. During knee flexion, how is the tension distributed between these two bundles?
Correct Answer & Explanation
. The anteromedial bundle tightens and the posterolateral bundle becomes lax
Explanation
The ACL consists of the Anteromedial (AM) and Posterolateral (PL) bundles. Biomechanically, the AM bundle tightens in flexion (controlling primarily anterior translation), while the PL bundle tightens in extension (providing significant rotational stability). Therefore, during flexion, the AM bundle is tight and the PL bundle is lax.
Question 1958
Topic: Knee Sports
A 24-year-old football player undergoes clinical evaluation following a knee injury. The dial test demonstrates 20 degrees of increased external rotation on the injured side at 30 degrees of flexion, but symmetric external rotation at 90 degrees of flexion compared to the uninjured knee. Which structural injury does this pattern indicate?
Correct Answer & Explanation
. Isolated posterolateral corner injury
Explanation
The dial test is used to evaluate the posterolateral corner (PLC) and posterior cruciate ligament (PCL). Increased external rotation (>10 degrees compared to the normal side) at 30 degrees of flexion but symmetric rotation at 90 degrees indicates an isolated PLC injury. If the external rotation is increased at both 30 and 90 degrees, it suggests a combined PCL and PLC injury.
Question 1959
Topic: Knee Sports
During an anterior cruciate ligament (ACL) reconstruction, the surgeon positions the femoral tunnel too anteriorly (shallow) within the intercondylar notch. What is the expected biomechanical consequence of this malpositioned tunnel during knee range of motion?
Correct Answer & Explanation
. The graft will be tight in flexion and loose in extension
Explanation
In ACL reconstruction, placing the femoral tunnel too anteriorly (i.e., too shallow or high in the notch when viewed arthroscopically) increases the distance between the tibial and femoral attachment sites as the knee flexes. This results in a graft that is loose in extension and tightens excessively in flexion, potentially leading to a loss of knee flexion or graft stretching/failure. Placing the femoral tunnel too posterior (deep) results in the opposite: tight in extension and loose in flexion.
Question 1960
Topic: Knee Sports
During the physical examination of a patient's knee, the pivot-shift test is utilized to assess rotatory instability. Which specific bundle of the anterior cruciate ligament (ACL) is primarily responsible for resisting internal rotation and is assessed during this maneuver?
Correct Answer & Explanation
. Posterolateral (PL) bundle
Explanation
The ACL is composed of two primary bundles: the anteromedial (AM) and posterolateral (PL) bundles. The AM bundle is tight in flexion and primarily controls anterior-posterior translation. The PL bundle is tight in extension and primarily controls rotatory stability (resists internal rotation). The pivot-shift test examines rotatory instability near full extension, thus specifically testing the integrity of the PL bundle.
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