Menu

Total Knee Arthroplasty (TKA) MCQs

Practice Set 11 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 201

Topic: Total Knee Arthroplasty (TKA)

In a TKA, which of the following soft-tissue releases is most appropriate to correct a severe fixed valgus deformity?

. Deep medial collateral ligament (MCL) followed by the superficial MCL
. Iliotibial band, lateral collateral ligament (LCL), and popliteus tendon
. Semimembranosus and pes anserine tendons
. Posterior cruciate ligament (PCL) alone
. Medial retinaculum and vastus medialis obliquus

Correct Answer & Explanation

. Iliotibial band, lateral collateral ligament (LCL), and popliteus tendon

Explanation

A fixed valgus deformity in TKA requires stepwise release of contracted structures on the lateral side. The standard sequence typically involves the iliotibial (IT) band, the lateral collateral ligament (LCL), and the popliteus tendon, depending on whether the tightness is in flexion or extension.

Question 202

Topic: Total Knee Arthroplasty (TKA)

During a primary TKA, after making the initial bony cuts, the surgeon notices that the knee is tight in flexion but well-balanced in extension. Which of the following maneuvers is most appropriate to balance the knee?

. Resect more distal femur
. Upsize the femoral component
. Release the medial collateral ligament
. Increase the posterior slope of the tibial cut
. Recess the popliteus tendon

Correct Answer & Explanation

. Increase the posterior slope of the tibial cut

Explanation

A knee that is tight in flexion but balanced in extension requires an increase in the flexion gap without altering the extension gap. Increasing the posterior tibial slope, resecting more posterior femoral condyle, or releasing the PCL will achieve this.

Question 203

Topic: Total Knee Arthroplasty (TKA)

A 48-year-old female presents with complete disruption of her extensor mechanism 3 months following a primary TKA. Examination shows a palpable gap at the patellar tendon and an inability to actively extend the knee. What is the most reliable surgical treatment?

. Primary end-to-end repair with nonabsorbable suture
. Reconstruction with an extensor mechanism allograft or synthetic mesh
. Medial gastrocnemius rotational flap
. Patellar tendon tenodesis to the tibial tubercle
. Revision of the tibial component

Correct Answer & Explanation

. Reconstruction with an extensor mechanism allograft or synthetic mesh

Explanation

Primary repair of late extensor mechanism ruptures post-TKA has an extremely high failure rate. Reconstruction utilizing a whole extensor mechanism allograft or synthetic mesh (e.g., Marlex) offers the most reliable results.

Question 204

Topic: Total Knee Arthroplasty (TKA)

During a posterior-stabilized TKA, trial reduction reveals the knee is tight in flexion but well-balanced and symmetric in extension. What is the most appropriate next step to balance the knee?

. Increase the size of the femoral component
. Downsize the femoral component
. Resect more distal femur
. Release the posterior cruciate ligament
. Recut the proximal tibia

Correct Answer & Explanation

. Downsize the femoral component

Explanation

A knee that is tight in flexion and balanced in extension requires an increase in the flexion gap without affecting the extension gap. Downsizing the femoral component (with an anterior referencing system) translates the posterior condyles anteriorly, effectively opening the flexion gap.

Question 205

Topic: Total Knee Arthroplasty (TKA)

You are performing a TKA on a severe valgus knee. After making the standard bony cuts, the knee remains tight laterally in extension but balanced in flexion. Which structure is typically released first to balance the extension gap?

. Popliteus tendon
. Iliotibial band
. Lateral collateral ligament
. Biceps femoris
. Lateral head of gastrocnemius

Correct Answer & Explanation

. Iliotibial band

Explanation

For a valgus knee that is tight specifically in extension, the iliotibial band (ITB) is typically the first structure released, often via pie-crusting. The popliteus affects flexion more than extension, and the LCL affects both.

Question 206

Topic: Total Knee Arthroplasty (TKA)



When establishing correct femoral component rotation in a TKA, the anterior-posterior (AP) axis (Whiteside's line) is commonly used. To what reference line should Whiteside's line be strictly perpendicular?

. The transepicondylar axis
. The mechanical axis of the femur
. The posterior condylar axis
. The anatomic axis of the femur
. The joint line of the tibia

Correct Answer & Explanation

. The transepicondylar axis

Explanation

Whiteside's line (the AP axis) runs from the deepest part of the trochlear groove to the center of the intercondylar notch and is anatomically perpendicular to the surgical transepicondylar axis.

Question 207

Topic: Total Knee Arthroplasty (TKA)

Following the implantation of total knee arthroplasty components, trial reduction reveals lateral patellar subluxation. The components are correctly sized. Which of the following component malrotations is the most likely cause?

. Internal rotation of the femoral component
. External rotation of the femoral component
. Excessive valgus of the tibial component
. Excessive flexion of the femoral component
. External rotation of the tibial component

Correct Answer & Explanation

. Internal rotation of the femoral component

Explanation

Internal rotation of the femoral component medializes the trochlear groove and increases the Q angle, leading to lateral patellar tracking and subluxation. External rotation of the femoral component helps optimize patellar tracking.

Question 208

Topic: Total Knee Arthroplasty (TKA)

When converting a failed medial unicompartmental knee arthroplasty (UKA) to a total knee arthroplasty (TKA), what is the most common intraoperative challenge compared to a primary TKA?

. Need for lateral collateral ligament reconstruction
. Use of a highly constrained hinged prosthesis
. Management of a medial tibial bone defect often requiring augments
. Difficulty correcting a residual valgus deformity
. Severe patella baja requiring tubercle osteotomy

Correct Answer & Explanation

. Management of a medial tibial bone defect often requiring augments

Explanation

Revision of a UKA to a TKA frequently reveals substantial bone loss on the involved side (usually medial tibial plateau), necessitating the use of metal augments, bone grafting, or tibial stems to achieve stable fixation.

Question 209

Topic: Total Knee Arthroplasty (TKA)

A 68-year-old woman is 2 years status-post a posterior stabilized total knee arthroplasty. She complains of a painful catching sensation in her knee when extending from a flexed position. What is the most appropriate management?

. Revision of the patellar component
. Arthroscopic debridement
. Open synovectomy
. Femoral component revision
. Manipulation under anesthesia

Correct Answer & Explanation

. Arthroscopic debridement

Explanation

This patient is presenting with patellar clunk syndrome, which occurs in posterior stabilized TKAs due to a fibrous nodule catching in the intercondylar box. Arthroscopic debridement of the nodule is highly successful and the treatment of choice.

Question 210

Topic: Total Knee Arthroplasty (TKA)

A patient requires revision TKA for severe valgus deformity combined with medial collateral ligament (MCL) incompetency. Which level of implant constraint is most appropriate?

. Posterior stabilized
. Cruciate retaining
. Unconstrained varus-valgus plus
. Rotating hinge
. Condylar constrained knee (CCK)

Correct Answer & Explanation

. Rotating hinge

Explanation

In the setting of severe collateral ligament incompetency (such as a completely deficient MCL), a rotating hinge knee is indicated to provide the necessary coronal stability. A CCK device relies on intact, functional collateral ligaments.

Question 211

Topic: Total Knee Arthroplasty (TKA)

Following a primary TKA, the surgeon observes that the patella subluxates laterally during deep knee flexion. Which of the following component malpositions is the most likely technical cause?

. External rotation of the femoral component
. Internal rotation of the tibial component
. Lateral translation of the femoral component
. Lateral translation of the tibial tray
. Anterior placement of the femoral component

Correct Answer & Explanation

. External rotation of the femoral component

Explanation

Internal rotation of either the femoral or tibial components increases the Q-angle, which exacerbates lateral patellar maltracking. Correct external rotation of these components optimizes patellofemoral tracking.

Question 212

Topic: Total Knee Arthroplasty (TKA)

A 19-year-old female soccer player sustains a noncontact anterior cruciate ligament (ACL) tear. Which of the following anatomic factors is most strongly associated with an increased risk of this injury?

. Decreased posterior tibial slope
. Increased posterior tibial slope
. Decreased femoral anteversion
. Decreased Q angle
. Increased intercondylar notch width

Correct Answer & Explanation

. Decreased posterior tibial slope

Explanation

An increased posterior tibial slope increases anterior tibial translation under axial loads, elevating the risk of ACL rupture. Other anatomic risk factors include a narrow intercondylar notch and increased generalized joint laxity.

Question 213

Topic: Total Knee Arthroplasty (TKA)

A patient presents with anterior knee pain, particularly during stair climbing and descending. Patellar tracking issues are suspected. Which quadriceps muscle primarily contributes to the lateral pull on the patella, potentially exacerbating patellofemoral pain syndrome?

. Rectus femoris
. Vastus medialis obliquus (VMO)
. Vastus lateralis
. Vastus intermedius
. Sartorius

Correct Answer & Explanation

. Rectus femoris

Explanation

The vastus lateralis muscle exerts a strong lateral pull on the patella, which, if unopposed, can lead to lateral patellar subluxation or tilt and contribute to patellofemoral pain syndrome. The vastus medialis obliquus (VMO) is crucial for providing a medial stabilizing force to counteract this lateral pull. Rectus femoris and vastus intermedius primarily contribute to patellar elevation and extension without a significant directional pull. Sartorius is not part of the quadriceps. Maintaining VMO strength and flexibility is key in managing patellar tracking disorders.

Question 214

Topic: Total Knee Arthroplasty (TKA)

A patient with a patellar fracture undergoes surgical repair. To ensure proper patellar tracking and stability post-operatively, which of the following muscles acts as the primary dynamic medial stabilizer of the patella?

. Vastus lateralis
. Rectus femoris
. Vastus medialis obliquus (VMO)
. Vastus intermedius
. Sartorius

Correct Answer & Explanation

. Vastus lateralis

Explanation

The vastus medialis obliquus (VMO) is the most distal and oblique part of the vastus medialis muscle. Its fibers run at a more horizontal angle, providing a crucial dynamic medial pull on the patella. This medial vector opposes the strong lateral pull exerted by the vastus lateralis, thus acting as the primary dynamic medial stabilizer of the patella. Weakness or dysfunction of the VMO is a common contributor to lateral patellar maltracking and patellofemoral pain syndrome. The rectus femoris and vastus intermedius provide primary knee extension. The vastus lateralis is a lateral stabilizer but pulls laterally.

Question 215

Topic: Total Knee Arthroplasty (TKA)

A 65-year-old woman undergoes total knee arthroplasty. Intraoperatively, the surgeon notes that the patella tracks laterally and has a tendency to subluxate during flexion. Which of the following component adjustments would most effectively improve patellar tracking?

. Internal rotation of the femoral component
. External rotation of the femoral component
. Medial translation of the femoral component
. Lateral translation of the tibial tray
. Internal rotation of the tibial component

Correct Answer & Explanation

. External rotation of the femoral component

Explanation

External rotation of the femoral component lateralizes the anterior femoral sulcus, thereby decreasing the Q angle and improving central patellar tracking. Conversely, internal rotation of either the femoral or tibial components increases the Q angle and exacerbates lateral maltracking.

Question 216

Topic: Total Knee Arthroplasty (TKA)

A 64-year-old woman is 1 year status post a posterior-stabilized TKA. She reports a painful catching sensation and an audible "clunk" at approximately 30 to 45 degrees of extension from a flexed position.

What is the most appropriate definitive management for this condition if conservative measures fail?

. Revision of the femoral component to a cruciate-retaining design
. Arthroscopic or open debridement of the fibrous nodule
. Lateral retinacular release
. Tibial tubercle osteotomy to alter patellar tracking
. Exchange of the polyethylene insert to a thicker size

Correct Answer & Explanation

. Arthroscopic or open debridement of the fibrous nodule

Explanation

Patellar clunk syndrome occurs primarily in posterior-stabilized TKA designs when a fibrous nodule forms at the superior pole of the patella and catches in the intercondylar box of the femoral component during extension. Treatment is arthroscopic or open excision of the fibrous nodule.

Question 217

Topic: Total Knee Arthroplasty (TKA)

A 55-year-old male with severe tri-compartmental knee osteoarthritis is scheduled for TKA. He has a history of a healed midshaft femoral fracture with a residual 22-degree extra-articular coronal varus deformity. Attempting an intra-articular resection to correct this deformity would compromise the collateral ligament attachments. What is the most appropriate surgical management?

. Standard TKA using a highly constrained rotating-hinge prosthesis
. Standard TKA with extensive medial collateral ligament release
. Simultaneous or staged corrective femoral osteotomy and TKA
. TKA using a kinematic alignment technique without ligament release
. Medial unicompartmental knee arthroplasty to balance the defect

Correct Answer & Explanation

. Simultaneous or staged corrective femoral osteotomy and TKA

Explanation

Extra-articular deformities >20 degrees in the coronal plane typically cannot be compensated for with intra-articular resections alone without violating collateral ligament attachments. The appropriate management is a simultaneous or staged extra-articular corrective osteotomy and TKA.

Question 218

Topic: Total Knee Arthroplasty (TKA)

In the concept of true kinematic alignment for total knee arthroplasty, the primary goal is to co-align the axes of the prosthetic components with the three kinematic axes of the native knee. Which axis serves as the primary reference for positioning the femoral component?

. The clinical transepicondylar axis
. Whiteside's line (anteroposterior axis)
. The cylindrical (flexion-extension) axis of the femoral condyles
. The mechanical axis of the femur
. The anatomic axis of the femur

Correct Answer & Explanation

. The cylindrical (flexion-extension) axis of the femoral condyles

Explanation

Kinematic alignment aims to restore the pre-arthritic joint lines. The primary reference is the cylindrical axis of the femoral condyles, which dictates the primary flexion-extension axis of the knee, rather than standard mechanical alignment axes.

Question 219

Topic: Total Knee Arthroplasty (TKA)

A 68-year-old man requires a TKA for severe osteoarthritis. He has a history of a femoral shaft fracture resulting in a 15-degree coronal plane extra-articular varus deformity.

How should this deformity ideally be managed during the TKA to ensure a balanced knee?

. Routine intra-articular resection using the anatomic axis as a guide
. Intra-articular compensatory bone cuts if the collateral ligaments remain balanced
. Use of a constrained hinged knee prosthesis without correcting the femoral deformity
. Preoperative isolated femoral osteotomy followed by TKA 12 months later
. Over-resection of the proximal tibia to compensate for the femoral varus

Correct Answer & Explanation

. Intra-articular compensatory bone cuts if the collateral ligaments remain balanced

Explanation

Extra-articular deformities of the femur < 20 degrees in the coronal plane can typically be managed with compensatory intra-articular bone cuts, provided ligamentous balance is achievable. If the deformity is >20 degrees or compromises collateral balance, an extra-articular osteotomy may be required.

Question 220

Topic: Total Knee Arthroplasty (TKA)

A 68-year-old woman sustains a complete patellar tendon rupture 2 years after a primary TKA. Primary repair is attempted but fails. She undergoes extensor mechanism reconstruction with a synthetic mesh. What is the optimal postoperative rehabilitation protocol?

. Immediate active range of motion to prevent stiffness
. Immobilization in full extension for 6 to 8 weeks
. Weight-bearing as tolerated in a hinged brace locked at 30 degrees of flexion
. Continuous passive motion starting postoperative day 1
. Non-weight-bearing for 12 weeks with unrestricted range of motion

Correct Answer & Explanation

. Immobilization in full extension for 6 to 8 weeks

Explanation

Following extensor mechanism reconstruction (using synthetic mesh or allograft) in the setting of TKA, prolonged immobilization in full extension for 6-8 weeks is critical. This protects the reconstruction from excessive tension while host tissue ingrowth and healing occur.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page