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Total Knee Arthroplasty (TKA) MCQs

Practice Set 16 of 23

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 301

Topic: Total Knee Arthroplasty (TKA)

During trialing of a primary TKA, the surgeon notes that the knee is perfectly balanced and achieves full extension, but it is unacceptably tight in 90 degrees of flexion, preventing full range of motion. Which of the following is the most appropriate next step in management?

. Resect more distal femur
. Increase the posterior tibial slope
. Use a thicker polyethylene insert
. Upsize the femoral component
. Release the medial collateral ligament

Correct Answer & Explanation

. Increase the posterior tibial slope

Explanation

A knee that is tight in flexion but balanced in extension requires a modification that only increases the flexion gap. Increasing the posterior tibial slope or downsizing the femoral component (with anterior referencing) will selectively open the flexion gap.

Question 302

Topic: Total Knee Arthroplasty (TKA)

During a mechanically aligned primary TKA, the surgeon uses an intramedullary guide for the distal femoral cut. To achieve a neutral mechanical axis, the valgus cut angle set on the distal femoral cutting block is typically based on the angle between which two axes?

. The femoral mechanical axis and the tibial mechanical axis
. The femoral anatomical axis and the clinical epicondylar axis
. The femoral anatomical axis and the femoral mechanical axis
. The tibial anatomical axis and the tibial mechanical axis
. The trans-epicondylar axis and the posterior condylar axis

Correct Answer & Explanation

. The femoral anatomical axis and the femoral mechanical axis

Explanation

In mechanical alignment, the goal is a femoral cut perpendicular to the mechanical axis. Because the intramedullary guide follows the femoral anatomical axis, the valgus cut angle (usually 5-7 degrees) compensates for the natural divergence between the anatomical and mechanical axes of the femur.

Question 303

Topic: Total Knee Arthroplasty (TKA)

During a TKA, a surgeon inadvertently uses a patellar button that is significantly thicker than the native resected patella, leading to an 'overstuffed' anterior compartment. What is the most likely clinical consequence of this error?

. Increased maximum knee flexion
. Decreased strain on the extensor mechanism
. Recurrent patellar subluxation due to medial retinacular laxity
. Reduced post-operative range of motion and anterior knee pain
. Increased risk of patellar clunk syndrome

Correct Answer & Explanation

. Reduced post-operative range of motion and anterior knee pain

Explanation

Overstuffing the patellofemoral joint increases tension on the extensor mechanism. This leads to increased retropatellar contact forces, resulting in anterior knee pain, and a mechanical block that reduces terminal knee flexion.

Question 304

Topic: Total Knee Arthroplasty (TKA)

A surgeon is performing a primary TKA on a patient with a severe fixed valgus deformity (Krackow Type II). After bone cuts, the lateral compartment remains excessively tight in extension but is adequately balanced in flexion. Which structure should be selectively released to correct this specific imbalance?

. Popliteus tendon
. Iliotibial band (ITB)
. Lateral collateral ligament (LCL)
. Posterior cruciate ligament (PCL)
. Medial collateral ligament (MCL)

Correct Answer & Explanation

. Iliotibial band (ITB)

Explanation

The iliotibial band (ITB) acts as a primary lateral tether in extension but relaxes in flexion. Therefore, a tight extension gap with a balanced flexion gap on the lateral side dictates selective release of the ITB or lateral capsule.

Question 305

Topic: Total Knee Arthroplasty (TKA)
A 77-year-old man who had right total knee replacement surgery 2½ years ago has had knee pain since surgery. The pain is diffuse, constant, and made worse with activity. He notes warmth and swelling in his knee. Examination shows a well-healed incision, no erythema, moderate warmth, synovitis, and an effusion. The knee is stable, and has an arc of flexion between 3 and 120 degrees. Radiographs show well-fixed and well-aligned implants. What is the most appropriate initial treatment?
. Knee aspiration for culture
. CT scan of the knee to assess implant rotation
. Indium, technetium-sulfur colloid scan of the knee
. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) labs

Correct Answer & Explanation

. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) labs

Explanation

This patient’s history and physical findings are concerning for deep infection. Inflammatory markers (ESR and CRP) should first be obtained, and, if levels are elevated, proceed to knee aspiration for synovial cell count and culture. A bone scan is not indicated in an initial investigation for deep infection, rarely is helpful, and is not cost effective. A CT scan to assess implant rotation is an appropriate investigation for knee pain when the clinical scenario is not suspicious for a deep infection and when infection has been excluded.

Question 306

Topic: Total Knee Arthroplasty (TKA)
A 70-year-old woman who underwent total knee replacement 18 months ago has had 3 weeks of moderate drainage from a previously healed wound. What is the most appropriate treatment?
. Wound vacuum-assisted closure dressing
. IV antibiotics for 6 weeks followed by long-term oral antibiotics
. Irrigation and debridement and polyethylene exchange
. Two-stage debridement and reconstruction

Correct Answer & Explanation

. Two-stage debridement and reconstruction

Explanation

This situation represents a definitively and chronically infected knee replacement. Antibiotic therapy alone may suppress the infection but will not eradicate it. Debridement and polyethylene exchange would be appropriate treatment for an early postoperative infection. The treatment of choice is to perform a 2-stage debridement and reconstruction. Although not among the listed choices, an aspiration or culture can be done presurgically and may help clinicians identify the best antibiotics to treat the condition. Antibiotic selection would not affect the need for the 2-stage reconstruction, however.

Question 307

Topic: Total Knee Arthroplasty (TKA)
What is the difference in outcome when comparing high tibial osteotomy (HTO) to total knee arthroplasty (TKA)?
. TKA has a longer recovery period than HTO.
. HTO provides more complete pain relief than TKA.
. HTO is more reliable in older patients than TKA.
. HTO outcomes among thin, active, young patients who undergo this procedure approach outcomes associated with TKA.

Correct Answer & Explanation

. HTO outcomes among thin, active, young patients who undergo this procedure approach outcomes associated with TKA.

Explanation

The ideal candidate for HTO is a thin, active person with a stable knee, unicompartmental knee symptoms, and age younger than 60. TKA offers a shorter recovery period and more complete pain relief than HTO. TKA is believed to be more reliable than HTO for patients older than age 60.

Question 308

Topic: Total Knee Arthroplasty (TKA)
A 70-year-old man complains of symptomatic medial knee pain that has become progressively worse during the past year. An MRI scan reveals a complex posterior horn medial meniscus tear with associated medial and patellofemoral cartilage defects. Radiographs reveal medial joint space narrowing and osteophytes in the other compartments. What treatment is most likely to provide long-term, durable symptom relief?
. High tibial osteotomy
. Total knee replacement
. Unicondylar knee replacement
. Arthroscopic partial meniscectomy

Correct Answer & Explanation

. Total knee replacement

Explanation

Total knee replacement is a well-established surgery for diffuse, symptomatic osteoarthritis of the knee joint, and its efficacy has been shown in many studies. According to the 2008 AAOS Clinical Practice Guideline, Treatment of Osteoarthritis of the Knee, arthroscopy in the setting of existing osteoarthritis is efficacious for relieving the signs and symptoms of a torn meniscus, but not osteoarthritis. Likewise, in young and active patients, clinical outcomes show improvement after realignment osteotomy for single-compartment osteoarthritis. Unicondylar knee replacement is not indicated for tricompartmental disease of the knee.

Question 309

Topic: Total Knee Arthroplasty (TKA)

A 70-year-old female presents with an inability to actively extend her knee 6 months following a primary total knee arthroplasty. Clinical examination and imaging confirm a chronic disruption of the extensor mechanism at the mid-substance of the patellar tendon. The components are well-fixed without evidence of infection. What is the most reliable reconstructive option for this chronic failure?

. Primary end-to-end repair using heavy non-absorbable sutures
. Reconstruction using synthetic mesh (e.g., Marlex) or extensor mechanism allograft
. Total patellectomy
. Immobilization in a hinged knee brace locked in extension for 12 weeks
. Medial gastrocnemius rotational flap with split-thickness skin graft

Correct Answer & Explanation

. Primary end-to-end repair using heavy non-absorbable sutures

Explanation

Extensor mechanism disruption after TKA is a catastrophic complication. Primary repair of chronic disruptions yields unacceptably high failure rates due to poor tissue quality and tension. The standard of care for chronic patellar tendon ruptures in the setting of TKA is reconstruction using an extensor mechanism allograft (tibial tubercle, patellar tendon, patella, quad tendon) or synthetic mesh (e.g., Marlex mesh), which acts as a scaffold for fibrous tissue ingrowth.

Question 310

Topic: Total Knee Arthroplasty (TKA)

In kinematic alignment (KA) for total knee arthroplasty, the primary surgical goal differs significantly from mechanical alignment (MA). Which of the following best describes the core principle of kinematic alignment?

. Creating a neutral mechanical axis perpendicular to the floor
. Resecting the distal femur at 5 degrees of valgus to the anatomical axis
. Co-aligning the components with the three kinematic axes of the normal knee to restore the pre-arthritic joint lines
. Releasing the medial collateral ligament to balance a varus deformity
. Ensuring the tibial component is strictly perpendicular to the tibial mechanical axis

Correct Answer & Explanation

. Creating a neutral mechanical axis perpendicular to the floor

Explanation

Kinematic alignment aims to restore the patient's pre-arthritic anatomy and native joint lines by aligning the implants with the natural kinematic axes of the knee. This minimizes the need for soft tissue releases, unlike traditional mechanical alignment.

Question 311

Topic: Total Knee Arthroplasty (TKA)

A 55-year-old male presents with isolated medial compartment osteoarthritis of the right knee. He is being evaluated for a medial unicompartmental knee arthroplasty (UKA). Which of the following physical examination or radiographic findings is an absolute contraindication to a medial UKA?

. Chondrocalcinosis in the lateral compartment
. A flexion contracture of 10 degrees
. Absent anterior cruciate ligament (ACL) with subjective instability
. Body Mass Index (BMI) of 34 kg/m2
. Patellofemoral osteoarthritis isolated to the medial facet

Correct Answer & Explanation

. Chondrocalcinosis in the lateral compartment

Explanation

An intact ACL is generally considered a prerequisite for a standard medial UKA. An absent ACL with subjective instability or anterior subluxation of the tibia on a lateral radiograph is a contraindication because it leads to eccentric wear of the UKA components and early failure. A BMI < 35, mild patellofemoral arthritis (especially medial facet or asymptomatic), and a flexion contracture up to 15 degrees are generally acceptable. Chondrocalcinosis is no longer considered an absolute contraindication if the lateral cartilage is otherwise intact.

Question 312

Topic: Total Knee Arthroplasty (TKA)

A surgeon is performing a primary TKA and decides to use the surgical epicondylar axis (SEA) to set the rotation of the femoral component. Which of the following best defines the SEA?

. A line connecting the most prominent point of the medial epicondyle to the most prominent point of the lateral epicondyle
. A line connecting the medial sulcus (sulcus of the medial epicondyle) to the lateral epicondylar prominence
. A line perpendicular to Whiteside's line
. A line parallel to the posterior condylar axis
. A line connecting the adductor tubercle to the lateral epicondyle

Correct Answer & Explanation

. A line connecting the most prominent point of the medial epicondyle to the most prominent point of the lateral epicondyle

Explanation

The Surgical Epicondylar Axis (SEA) is defined as the line connecting the sulcus of the medial epicondyle to the most prominent point of the lateral epicondyle. This axis more closely approximates the flexion-extension axis of the knee. The Clinical Epicondylar Axis (CEA) connects the most prominent points of both epicondyles and is typically internally rotated about 3 degrees relative to the SEA. Whiteside's line (the anteroposterior axis) is typically perpendicular to the SEA.

Question 313

Topic: Total Knee Arthroplasty (TKA)

A 70-year-old female presents 6 months post-total knee arthroplasty with an inability to actively extend her knee. Examination reveals a palpable defect at the superior pole of the patella. What is the most appropriate surgical reconstruction option for a chronic quadriceps tendon rupture following TKA with inadequate remaining tissue?

. Direct end-to-end repair using non-absorbable sutures
. V-Y quadricepsplasty
. Reconstruction with synthetic mesh (e.g., Marlex) or extensor mechanism allograft
. Patellectomy and advancement of the rectus femoris
. Hamstring autograft augmentation

Correct Answer & Explanation

. Direct end-to-end repair using non-absorbable sutures

Explanation

Chronic extensor mechanism disruption post-TKA is a devastating complication. Direct repair usually fails due to poor tissue quality and the mechanics of the joint. When tissue is inadequate, the current gold standard treatments involve either reconstruction using a synthetic mesh (like Marlex mesh, which allows for robust fibrous tissue ingrowth) or a full extensor mechanism allograft (tibial tubercle, patellar tendon, patella, and quad tendon). The mesh technique has shown increasingly favorable long-term results and avoids the disease transmission/resorption risks of allograft.

Question 314

Topic: Total Knee Arthroplasty (TKA)

During primary total knee arthroplasty using a measured resection technique, the surgeon aims to restore the joint line. Which of the following anatomic landmarks is most reliable for approximating the native joint line level if the articular surface is severely distorted?

. 3 cm distal to the medial epicondyle
. 10 mm distal to the fibular head
. 2.5 to 3 cm distal to the adductor tubercle
. 15 mm proximal to the tibial tubercle
. Level with the inferior pole of the patella in extension

Correct Answer & Explanation

. 3 cm distal to the medial epicondyle

Explanation

In revision TKA or primary TKA with severe bone loss/distortion, restoring the joint line is critical for proper kinematics and patellar tracking. Reliable osseous landmarks for estimating the joint line include: ~2.5 to 3 cm distal to the adductor tubercle, ~2.5 cm distal to the medial epicondyle, and ~1.5 cm proximal to the fibular head. Option 0 (3 cm from medial epicondyle) is slightly inaccurate (usually 2.5 cm). The adductor tubercle is a very consistent landmark, and the joint line sits approximately 2.5 to 3 cm distal to it.

Question 315

Topic: Total Knee Arthroplasty (TKA)

A 68-year-old female presents with an inability to perform a straight leg raise 3 months following a primary TKA. Examination reveals a palpable gap at the superior pole of the patella. What is the most appropriate surgical management for this complication?

. Primary end-to-end repair with nonabsorbable sutures
. Patellectomy and advancement of the quadriceps tendon
. Reconstruction using a synthetic mesh or extensor mechanism allograft
. Revision TKA with a hinged prosthesis
. Cylinder cast immobilization in extension for 6 weeks

Correct Answer & Explanation

. Primary end-to-end repair with nonabsorbable sutures

Explanation

Quadriceps tendon ruptures (or any major extensor mechanism disruption) following TKA have very high failure rates with simple primary end-to-end repair due to poor tissue quality and tension. Reconstruction using an extensor mechanism allograft or synthetic mesh (e.g., Marlex mesh) is the recommended treatment to provide a durable biologic or synthetic scaffold.

Question 316

Topic: Total Knee Arthroplasty (TKA)



A patient presents with a feeling of the knee "giving way" when descending stairs 1 year post-TKA. On examination, the knee is stable in full extension but has significant anteroposterior laxity at 90 degrees of flexion. Which of the following technical errors during the index surgery is the most likely cause?

. Oversized femoral component
. Excessive distal femoral resection
. Undersized femoral component with excessive posterior condylar resection
. Excessive proximal tibial resection
. Isolated medial collateral ligament rupture

Correct Answer & Explanation

. Oversized femoral component

Explanation

Flexion instability is characterized by laxity in flexion while maintaining stability in extension. It is typically caused by an excessive resection of the posterior femoral condyles or the use of an undersized femoral component, leading to a loose flexion gap. Compensating by using a thicker polyethylene insert would result in a tight extension gap.

Question 317

Topic: Total Knee Arthroplasty (TKA)

During a primary TKA for a varus osteoarthritic knee, after making the standard measured bone cuts, the knee has a symmetric tight medial gap in both flexion and extension. The lateral gap is well-balanced. Which of the following is the most appropriate next step in soft tissue balancing?

. Release the iliotibial band (ITB)
. Downsize the femoral component
. Release the deep medial collateral ligament (MCL) and posteromedial capsule
. Recut the proximal tibia with more valgus alignment
. Increase the polyethylene insert thickness

Correct Answer & Explanation

. Release the iliotibial band (ITB)

Explanation

A tight medial gap in both flexion and extension indicates a symmetrically tight medial compartment. The most appropriate step is to release the medial structures, typically starting with the deep MCL and posteromedial capsule. Modifying bone cuts is not indicated if the mechanical axis cuts were correct, and increasing poly thickness would overstuff the entire joint.

Question 318

Topic: Total Knee Arthroplasty (TKA)

A 70-year-old female undergoes a right TKA for a severe fixed valgus deformity. Postoperatively in the recovery room, she is noted to have a foot drop and decreased sensation over the dorsum of the right foot. What is the most appropriate initial management?

. Immediate surgical exploration and neurolysis of the common peroneal nerve
. Removal of the compressive knee dressing, flexion of the knee to 20-30 degrees, and application of an AFO
. Revision TKA to loosen the lateral collateral ligament
. Electromyography (EMG) and nerve conduction studies
. Administration of high-dose intravenous corticosteroids

Correct Answer & Explanation

. Immediate surgical exploration and neurolysis of the common peroneal nerve

Explanation

Peroneal nerve palsy is a known complication of TKA in patients with severe valgus and flexion contractures, primarily due to traction on the nerve upon deformity correction. Initial management includes relieving any extrinsic pressure (loosening dressings) and relaxing the nerve by flexing the knee to 20-30 degrees. An AFO prevents equinus contracture. Surgical exploration is generally reserved for failure to recover after several months.

Question 319

Topic: Total Knee Arthroplasty (TKA)

Which of the following statements best describes the surgical principle of true kinematic alignment in total knee arthroplasty?

. Making femoral and tibial bone cuts strictly perpendicular to the mechanical axis of the lower extremity
. Restoring the pre-arthritic constitutional alignment of the knee by matching the patient's individual anatomy
. Creating a neutral mechanical axis (0 degrees of hip-knee-ankle angle) in all patients to equalize load distribution
. Using a computer-navigated system to assure exactly 3 degrees of varus in the tibial cut for all patients
. Extensively releasing the collateral ligaments to create equal rectangular gaps before making any bone cuts

Correct Answer & Explanation

. Making femoral and tibial bone cuts strictly perpendicular to the mechanical axis of the lower extremity

Explanation

Kinematic alignment (KA) aims to restore the patient's native, pre-arthritic constitutional joint lines and alignment (co-alignment of the kinematic axes of the knee). This involves making bone cuts that match the individual anatomy, often leaving the tibia in slight varus and the femur in slight valgus. This is in contrast to mechanical alignment, which aims for a neutral (0-degree) mechanical axis.

Question 320

Topic: Total Knee Arthroplasty (TKA)

During a complex revision TKA, the surgeon notes profound laxity and attenuation of the medial collateral ligament (MCL) such that the knee cannot be balanced coronally in either flexion or extension. The extensor mechanism and posterior capsule remain completely intact. Which level of prosthetic constraint is most appropriate in this scenario?

. Cruciate-retaining (CR)
. Posterior-stabilized (PS)
. Constrained non-hinged (CCK / VVC)
. Rotating-hinge
. Unicompartmental

Correct Answer & Explanation

. Cruciate-retaining (CR)

Explanation

A completely deficient or non-functional MCL that prevents coronal balancing is an indication for a rotating-hinge prosthesis. A constrained non-hinged (CCK/VVC) implant requires an intact or minimally competent MCL and LCL to act as a soft-tissue tether; it cannot overcome profound global collateral deficiency.

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