This practice set contains high-yield board review questions covering key concepts in Total Knee Arthroplasty (TKA). Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.
Question 1
Topic: Total Knee Arthroplasty (TKA)
A medial meniscus posterior root tear is most strongly associated with which of the following secondary knee pathologies on MRI?
Correct Answer & Explanation
. Meniscal extrusion greater than 3 mm
Explanation
Medial meniscus posterior root tears result in the loss of hoop stresses, which is functionally equivalent to a total meniscectomy. This biomechanical failure commonly leads to meniscal extrusion of >3 mm and rapid progression of unicompartmental osteoarthritis.
Question 2
Topic: Total Knee Arthroplasty (TKA)
Which of the following anatomic and biomechanical factors is most strongly associated with an increased risk of primary anterior cruciate ligament (ACL) injury and subsequent graft failure after reconstruction?
Correct Answer & Explanation
. Increased posterior tibial slope
Explanation
An increased posterior tibial slope (typically greater than 12 degrees) is a significant biomechanical risk factor for native ACL injury and reconstruction failure. It increases anterior tibial translation and places higher stress on the ACL graft under axial loading.
Question 3
Topic: Total Knee Arthroplasty (TKA)
A 16-year-old female soccer player sustains a non-contact pivoting injury to her knee. MRI confirms an isolated rupture of the anterior cruciate ligament (ACL). Which of the following anatomic factors is most strongly associated with an increased risk for this specific injury pattern?
Correct Answer & Explanation
. Increased posterior tibial slope
Explanation
An increased posterior tibial slope is a recognized anatomic risk factor for non-contact ACL tears due to increased anterior tibial translation under axial load. A narrow intercondylar notch and increased Q angle also predispose patients to ACL injuries.
Question 4
Topic: Total Knee Arthroplasty (TKA)
During a total knee arthroplasty (TKA), the surgeon checks the gap balancing. The knee is stable and symmetric in full extension, but tight in both medial and lateral compartments at 90 degrees of flexion. Which of the following adjustments is the most appropriate next step to correct this mismatch?
Correct Answer & Explanation
. Decrease the anterior-posterior (AP) size of the femoral component
Explanation
A gap that is balanced in extension but tight in flexion indicates an overly tight flexion gap. The best way to increase the flexion gap without altering the extension gap is to downsize the femoral component (decreasing AP diameter) or translate it anteriorly.
Question 5
Topic: Total Knee Arthroplasty (TKA)
A 1-year-old presents with a short right lower limb and foot deformities. The image below is obtained during the initial evaluation to assess the overall limb. The clinical team suspects fibular deficiency.
Based on the comprehensive assessment principles outlined in the case, what is the MOST critical next step in accurately evaluating this child's limb length discrepancy and overall mechanical alignment?
Correct Answer: BThe correct answer is standing full-length AP/Lateral radiographs (LLDograms). The case emphasizes the importance of radiographic imaging, stating: 'Standing Full-Length AP/Lateral Radiographs (LLDograms): Essential for accurate LLD measurement and assessment of overall mechanical alignment of the lower extremity. These are critical for quantifying angular deformities and planning osteotomies.' While MRI is useful for soft tissue and growth plate assessment, and genetic testing may be considered for associated syndromes, LLDograms are the most critical and standard initial imaging modality for precisely quantifying LLD and overall mechanical alignment, which are fundamental for diagnosis and treatment planning in fibular deficiency. Bone biopsy and surgical exploration are invasive procedures not indicated as initial diagnostic steps for LLD and alignment.
Question 6
Topic: Total Knee Arthroplasty (TKA)
Which of the following anatomic factors is most strongly associated with an increased risk of non-contact ACL ruptures in female athletes?
Correct Answer & Explanation
. Increased posterior tibial slope
Explanation
An increased posterior tibial slope increases anterior tibial translation under axial loading, significantly raising the risk of ACL rupture. Other risk factors in females include a narrow intercondylar notch and increased Q angle.
Question 7
Topic: Total Knee Arthroplasty (TKA)
A 4-year-old female with Langenskiöld Stage III infantile Blount disease requires a proximal tibial osteotomy. To fully address the typical three-dimensional deformity associated with this condition, the osteotomy must correct varus, as well as which of the following?
Correct Answer & Explanation
. Internal tibial torsion and procurvatum
Explanation
The classic multiplanar deformity in infantile Blount disease consists of varus, internal tibial torsion, and procurvatum (anterior bowing). A successful osteotomy must correct all these planes to restore normal mechanical alignment.
Question 8
Topic: Total Knee Arthroplasty (TKA)
During a total knee arthroplasty (TKA) using a measured resection technique, trial components are placed. The knee is symmetric and balanced in extension, but tight in flexion. Which of the following is the most appropriate intraoperative step to balance the knee?
Correct Answer & Explanation
. Downsize the femoral component and use anterior referencing
Explanation
A knee that is tight in flexion but balanced in extension requires an increase in the flexion gap without affecting the extension gap. This is achieved by downsizing the femoral component (resecting more posterior condyle) or recessing the posterior cruciate ligament.
Question 9
Topic: Total Knee Arthroplasty (TKA)
A 60-year-old patient with isolated medial compartment knee osteoarthritis is being evaluated for a unicompartmental knee arthroplasty (UKA). Which of the following is considered a classic contraindication for a medial UKA?
Correct Answer & Explanation
. Fixed varus deformity that does not passively correct
Explanation
A fixed, non-correctable varus deformity is a contraindication to a medial UKA, as releasing ligaments to correct the deformity in UKA will lead to instability. An intact ACL and correctable deformity are prerequisites for the procedure.
Question 10
Topic: Total Knee Arthroplasty (TKA)
A 62-year-old active male presents with chronic, localized right medial knee pain, unresponsive to 6 months of conservative management including NSAIDs, physical therapy, and corticosteroid injections. Clinical examination reveals tenderness over the medial joint line, a full range of motion from 0 to 130 degrees, and a stable knee to varus and valgus stress at 0 and 30 degrees of flexion. However, a Lachman test is positive with a firm endpoint, and a pivot shift test is equivocal. Weight-bearing radiographs show Kellgren-Lawrence Grade III osteoarthritis isolated to the medial compartment, with a healthy lateral and patellofemoral compartment. Long-leg alignment views demonstrate a 5-degree varus deformity that is passively correctable to neutral. Given these findings, which of the following is the most appropriate next step or consideration?
Correct Answer & Explanation
. Obtain an MRI of the knee to definitively assess the integrity of the anterior cruciate ligament (ACL).
Explanation
Cruciate ligament integrity is non-negotiable for most UKR systems. The patient presents with a positive Lachman test, which is a primary indicator of ACL insufficiency. An MRI is useful in ambiguous cases to confirm cartilage status or evaluate cruciate ligament status if the clinical exam is inconclusive. Therefore, definitively assessing the ACL integrity with an MRI is the most appropriate next step before proceeding with a UKR.
Question 11
Topic: Total Knee Arthroplasty (TKA)
A 55-year-old female is undergoing pre-operative planning for a medial unicompartmental knee replacement (UKR). Her clinical assessment confirms isolated medial compartment osteoarthritis, intact cruciate ligaments, and a passively correctable varus deformity. During the radiographic series, which of the following views is MOST critical for assessing overall limb alignment and confirming the health of the contralateral compartment?
Correct Answer & Explanation
. Long-leg standing AP (full-length mechanical axis) view.
Explanation
Correct Answer: DThe case states, 'Long-leg standing AP (full-length mechanical axis) view: Critical for assessing overall limb alignment, identifying the true mechanical axis, and quantifying varus/valgus deformity. It also helps confirm that the contralateral compartment is healthy.' This view provides a comprehensive assessment of the entire lower limb, allowing the surgeon to understand the mechanical axis and ensure that the uninvolved compartments are truly healthy and not contributing to the overall deformity or symptoms.Option A (Weight-bearing AP view with 30-45 degrees of flexion):While important for visualizing joint space narrowing and posterior condylar wear in the tibiofemoral compartments, it does not provide information on overall limb alignment or the health of the entire contralateral compartment in the context of the mechanical axis.Option B (Lateral view of the knee):This view is essential for assessing osteophytes, posterior condylar wear, and fixed flexion deformity, but it does not provide information on coronal plane alignment or the contralateral compartment.Option C (Patellofemoral (Merchant/Skyline) view):This view is crucial for evaluating the patellofemoral joint space, patellar tilt, and tracking, which is a key contraindication for UKR if symptomatic. However, it does not assess overall limb alignment or the tibiofemoral compartments.Option E (Varus/Valgus stress views):These views are beneficial for assessing the correctability of deformity and quantifying ligamentous laxity, especially in equivocal cases. While important for confirming ligamentous stability, they do not provide the comprehensive limb alignment assessment that the long-leg standing AP view offers.
Question 12
Topic: Total Knee Arthroplasty (TKA)
A 70-year-old male with a BMI of 32 kg/m² is undergoing a medial unicompartmental knee replacement (UKR). During the surgical procedure, after the tibial and femoral resections, trial components are inserted. The surgeon notes that the extension gap is excessively tight, making it difficult to fully extend the knee without significant force, and the MCL appears to be under excessive tension. The flexion gap, however, feels appropriate. Which of the following is the most appropriate initial step to address this issue?
Correct Answer & Explanation
. Re-evaluate and remove any remaining osteophytes from the medial femoral condyle and tibial plateau.
Explanation
If the extension gap is too tight, the first step is to re-evaluate for any remaining osteophytes, particularly from the posterior aspect of the femoral condyle or the tibial plateau, which can impinge and cause tightness in extension. Removing these can often resolve the issue without further bone resection or soft tissue release.
Question 13
Topic: Total Knee Arthroplasty (TKA)
A 58-year-old male is undergoing a medial unicompartmental knee replacement (UKR). During the femoral preparation, the surgeon is selecting the appropriate size for the femoral component. Which of the following is the MOST important consideration when sizing the femoral component?
Correct Answer & Explanation
. Matching the contour of the medial femoral condyle without oversizing or undersizing.
Explanation
Correct Answer: CThe case states under 'Femoral Preparation' -> 'Sizing and Resection Guide Placement': 'Select the appropriate size to match the contour of the condyle without oversizing (leading to impingement) or undersizing (leading to poor coverage).' This emphasizes the importance of precise sizing to ensure optimal fit, coverage, and prevent complications.Option A (Matching the component size to the patient's overall height):Patient height is not a direct determinant for femoral component sizing in UKR. Sizing is based on the specific anatomy of the femoral condyle.Option B (Selecting the largest possible component):Oversizing can lead to impingement with surrounding soft tissues or bone, causing pain, stiffness, or altered kinematics. It does not necessarily maximize contact area in a beneficial way if it's an ill-fitting component.Option D (Ensuring the component extends as far anteriorly as possible):While anterior-posterior positioning is important, extending 'as far anteriorly as possible' could lead to patellar impingement or overstuffing of the patellofemoral joint, especially if it alters the native joint line. The goal is to match the resected bone to the thickness of the femoral component and ensure proper anterior/posterior reference.Option E (Prioritizing the posterior cut to ensure maximum flexion):While maintaining flexion is important, prioritizing it to the detriment of anterior coverage or overall fit can lead to instability, patellar tracking issues, or poor implant longevity. A balanced approach is required.
Question 14
Topic: Total Knee Arthroplasty (TKA)
A 65-year-old male with isolated medial compartment osteoarthritis is being considered for a unicompartmental knee replacement (UKR). He is concerned about the long-term outcomes compared to a total knee arthroplasty (TKA). Based on current literature and guidelines, which of the following statements regarding UKR outcomes relative to TKA is MOST accurate?
Correct Answer & Explanation
. UKR typically results in a faster recovery, earlier return to activities, and often better range of motion post-operatively than TKA.
Explanation
Correct Answer: CThe case states under 'UKR vs TKA Outcomes': 'UKR typically results in a faster recovery, earlier return to activities, and often better range of motion post-operatively than TKA.' This is a well-established advantage of UKR due to less bone resection and preservation of native structures.Option A (UKR consistently demonstrates significantly higher long-term (15-20 year) survival rates than TKA):The text states, 'Modern UKR designs demonstrate 10-year survival rates comparable to TKA (typically 90-95%).' While long-term rates are encouraging, it does not state 'significantly higher' than TKA. Revision rates for UKR tend to be slightly higher, primarily due to progression of OA in uninvolved compartments.Option B (Patients undergoing UKR generally report lower satisfaction rates and less 'natural-feeling' knees compared to TKA):This is incorrect. The text states, 'Multiple studies and meta-analyses suggest that patients undergoing UKR often report higher satisfaction rates and a more 'natural-feeling' knee compared to TKA.'Option D (UKR has a higher rate of major complications (e.g., DVT, PE, infection) compared to TKA):This is incorrect. The text states, 'While UKR typically has lower rates of major complications (e.g., DVT, PE, infection) compared to TKA due to less surgical trauma...'Option E (Revision of a UKR to TKA is generally more complex and yields inferior results compared to revision of a failed TKA):This is incorrect. The text states, 'However, revision of a UKR to TKA is generally less complex and yields good results compared to revision of a failed TKA.' This is often cited as an advantage of UKR.
Question 15
Topic: Total Knee Arthroplasty (TKA)
A 52-year-old female with isolated lateral compartment osteoarthritis is scheduled for a lateral unicompartmental knee replacement (UKR). During the surgical approach, the surgeon must be particularly vigilant about protecting which of the following neurovascular structures, given its superficial location laterally?
Correct Answer & Explanation
. Common peroneal nerve.
Explanation
Correct Answer: CThe case states under 'Lateral UKA Technique': 'Requires careful attention to protecting the peroneal nerve, which is more superficial laterally.' The common peroneal nerve courses around the fibular head and neck, making it vulnerable during lateral approaches to the knee.Option A (Saphenous nerve):The saphenous nerve and its infrapatellar branch are at risk during medial approaches (e.g., medial parapatellar, sub-vastus) for medial UKR, not lateral UKR.Option B (Femoral artery):The femoral artery is located in the anterior thigh and is not typically at direct risk during a lateral knee approach.Option D (Posterior tibial nerve):The posterior tibial nerve is located in the posterior compartment of the leg and is not typically at direct risk during a lateral knee approach.Option E (Popliteal artery):The popliteal artery is located in the popliteal fossa (posterior knee) and is generally not at direct risk during a lateral knee approach, although deep dissection in the posterior aspect of the joint could theoretically endanger it. The peroneal nerve is the primary concern for lateral approaches.
Question 16
Topic: Total Knee Arthroplasty (TKA)
A 72-year-old female presents with chronic, diffuse bilateral knee pain. Her medical history includes rheumatoid arthritis, well-controlled with medication. Radiographs show Kellgren-Lawrence Grade III osteoarthritis in both medial and lateral compartments of both knees, with significant patellofemoral joint narrowing. She has a fixed flexion contracture of 20 degrees in both knees. She expresses a desire for a less invasive surgical option. Which of the following is the most compelling contraindication for a unicompartmental knee replacement (UKR) in this patient?
Correct Answer & Explanation
. Her history of rheumatoid arthritis.
Explanation
Inflammatory arthropathies like rheumatoid arthritis are a strong contraindication for UKR because the disease process is systemic and affects all joint compartments, making isolated unicompartmental disease unlikely and increasing the risk of progression in the uninvolved compartments.
Question 17
Topic: Total Knee Arthroplasty (TKA)
A 72-year-old female, similar to the patient in the case, undergoes TKR for a valgus knee. Intraoperatively, after femoral and tibial cuts, the surgeon observes persistent lateral subluxation of the patella despite appropriate component rotation and a mild distal femoral valgus cut. What is the most appropriate next step to address this issue?
Correct Answer & Explanation
. Option C: Perform a lateral retinacular release.
Explanation
Correct Answer: CThe case states: 'Patients with severe valgus deformity usually require lateral retinacular release to achieve proper patella tracking.' The scenario describes persistent lateral subluxation, indicating the need to release the tight lateral structures that are pulling the patella laterally.Option A is incorrectbecause while a distal femoral cut of 7 degrees can help in mild valgus, increasing it further is not the primary solution for persistent patellar subluxation after initial cuts and may lead to other issues like over-resection or instability. The case mentions 7 degrees formildvalgus toavoidrelease, implying that for persistent issues, a release is needed.Option B (Medial retinacular release) is incorrectas this would worsen lateral patellar subluxation by releasing the medial restraints.Option D (Downsizing the femoral component) is incorrectas this would primarily affect flexion gap and overall knee size, not directly address patellar tracking issues caused by tight lateral retinaculum.Option E (Use a thicker polyethylene insert) is incorrectas this primarily addresses flexion-extension gap balancing and joint line elevation, not patellar tracking.
Question 18
Topic: Total Knee Arthroplasty (TKA)
A 65-year-old patient with a mild valgus deformity (8 degrees) is undergoing TKR. The surgeon is focused on optimizing patellar tracking and avoiding unnecessary lateral retinacular release. According to the case, what specific distal femoral cut angle can be utilized to improve patellar tracking in this scenario?
Correct Answer & Explanation
. Option C: A distal femoral cut of 7 degrees of valgus.
Explanation
Correct Answer: CThe case specifically mentions: 'In mild valgus deformity (7–10) a distal femoral cut of 7 can improve patella tracking and avoid the need for lateral retinacular release.' This directly provides the recommended angle for mild valgus deformities to aid patellar tracking.Option A (3 degrees) is incorrectas this is a common valgus angle for a varus knee or a neutral knee, but not specifically highlighted for improving patellar tracking in mild valgus.Option B (5 degrees) is incorrectas the case specifies 7 degrees for this particular purpose.Option D (9 degrees) is incorrectas while it falls within the 7-10 degree range of mild valgus, the specific recommendation for the cut is 7 degrees to improve tracking and avoid release.Option E (0 degrees) is incorrectas a neutral cut would not address the valgus deformity or specifically aid patellar tracking in a valgus knee.
Question 19
Topic: Total Knee Arthroplasty (TKA)
A 55-year-old male presents with severe, bilateral knee pain, worse with activity and stair climbing. Radiographs reveal tricompartmental osteoarthritis with significant joint space narrowing, subchondral sclerosis, and osteophytes. He has failed extensive conservative management including NSAIDs, physical therapy, and intra-articular injections. His BMI is 32. He is otherwise healthy. What is the most appropriate next step in management?
Correct Answer & Explanation
. Proceed with bilateral total knee arthroplasties (TKA).
Explanation
Correct Answer: CGiven the severe tricompartmental osteoarthritis, failure of conservative management, and the patient's age and activity level, bilateral total knee arthroplasty (TKA) is the most appropriate next step. UKA is only suitable for isolated unicompartmental disease. HTO is typically for younger, more active patients with unicompartmental varus malalignment and good bone stock, not tricompartmental disease. Arthroscopic debridement and lavage have shown limited long-term benefits for advanced osteoarthritis. While weight loss is beneficial, it's unlikely to fully resolve symptoms in severe, end-stage osteoarthritis and should be pursued as an adjunct to TKA, not as a replacement for surgical intervention when conservative measures have failed.
Question 20
Topic: Total Knee Arthroplasty (TKA)
Which of the following anatomic variants is a well-documented intrinsic anatomic risk factor for a non-contact anterior cruciate ligament (ACL) tear?
Correct Answer & Explanation
. Decreased intercondylar notch width
Explanation
A narrow intercondylar notch (decreased notch width index) limits the space for the ACL and is a significant intrinsic risk factor for non-contact ACL injuries. Increased (not decreased) posterior tibial slope is another recognized risk factor.
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