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 21
Topic: Total Knee Arthroplasty (TKA)
A 65-year-old woman develops catching and popping in her knee 1 year after a Total Knee Arthroplasty (TKA). She undergoes arthroscopy which reveals a fibrosynovial nodule. This complication is most uniquely associated with which TKA design?
Correct Answer & Explanation
. Posterior-stabilized (PS)
Explanation
Patellar clunk syndrome is classically associated with posterior-stabilized (PS) TKA designs. It is caused by a fibrosynovial nodule forming at the superior pole of the patella, which catches in the intercondylar box of the femoral component during knee extension.
Question 22
Topic: Total Knee Arthroplasty (TKA)
A 55-year-old female patient with medial compartment osteoarthritis and low physical demand is considering surgical options. She has a varus deformity of 7 degrees, no fixed flexion deformity, and good knee flexion. She expresses concern about the cosmetic appearance of angular deformity. Based on the case discussion, which surgical option would be most appropriate for her?
Correct Answer & Explanation
. Medial Unicondylar Knee Arthroplasty (UKA)
Explanation
Correct Answer: CThe case states that while indications for HTO and UKA are similar, women often prefer UKA because they do not tolerate the angular deformity created by HTO very well. Additionally, patients with low physical demand may benefit from UKA. This patient fits both criteria: she is female, has low physical demand, and is concerned about angular deformity. UKA offers a less invasive option with potentially better cosmetic outcomes and is suitable for her activity level.A. High Tibial Osteotomy (HTO), while a viable option for unicompartmental OA, might not be preferred by this patient due to the angular deformity it creates, which women may not tolerate well.B. Total Knee Arthroplasty (TKA)is generally considered for more severe, multi-compartmental arthritis or older, less active patients. It is an overtreatment for isolated medial compartment OA in a 55-year-old with low physical demand.D. Arthroscopic lavage and debridementare typically palliative and offer limited long-term benefit for established osteoarthritis with structural deformity.E. Distal Femoral Osteotomyis indicated for lateral compartment osteoarthritis with valgus deformity, which is not the patient's presentation.
Question 23
Topic: Total Knee Arthroplasty (TKA)
A 50-year-old patient undergoes an opening wedge High Tibial Osteotomy (HTO) for medial compartment osteoarthritis. Which of the following is a known disadvantage or potential complication specifically associated with the opening wedge technique, as described in the case?
The image shows a post-operative radiograph of an opening wedge HTO.
Correct Answer & Explanation
. Late collapse with loss of correction
Explanation
Correct Answer: DThe case states that the opening wedge osteotomy 'has the disadvantage of having to use bone graft and late collapse with loss of correction'. This directly identifies 'late collapse with loss of correction' as a specific disadvantage of the opening wedge technique.A. Loss of bone stock making TKA technically difficultis a disadvantage specifically attributed to closing wedge osteotomy.B. Increased patellar heightis associated with closing wedge osteotomy, while opening wedge osteotomy is noted to lower patellar height.C. Risk of peroneal nerve injuryis a specific risk associated with closing wedge osteotomy, particularly with proximal fibular osteotomy or disruption of the tibiofibular joint.E. Disruption of the tibiofibular jointis mentioned as a potential consequence of closing wedge osteotomy.
Question 24
Topic: Total Knee Arthroplasty (TKA)
The case discusses the comparative outcomes of HTO versus UKA, referencing a review by Dettoni et al. (2010). What was the primary conclusion of this review regarding the superiority of one treatment over the other for medial unicompartmental arthrosis of the knee?
Correct Answer & Explanation
. Both treatments produce durable and predictable outcomes with correct indications, with no evidence of superior results of one over the other.
Explanation
Correct Answer: CThe case explicitly states, referencing Dettoni et al., that 'They concluded that with the correct indications, both treatments produce durable and predictable outcomes in the treatment of medial unicompartmental arthrosis of the knee. There is no evidence of superior results of one treatment over the other.'A. UKA consistently shows significantly better survivorship and functional outcomes.The review reported 'slightly better results for UKA in terms of survivorship and functional outcome,' but immediately qualified this by stating 'the differences are not remarkable' and 'no evidence of superior results of one treatment over the other.'B. HTO consistently shows significantly better survivorship and functional outcomes.This is incorrect, as the review suggested slightly better results for UKA, though not remarkably so.D. HTO is superior for high-demand patients, while UKA is superior for low-demand patients.While this is the clinical recommendation made by the candidate in the case based on practical considerations (accelerated wear of UKA in high-demand jobs), the Dettoni et al. review's conclusion was specifically about the lack of evidence forsuperiorityin outcomes between the two treatments when indications are correct, not a direct endorsement of one over the other based on activity level in terms ofoverall outcome superiority.E. The review found no reliable data to compare the two treatments effectively.This is incorrect. The review did compare studies but noted that 'the study methods are not homogeneous' and that most papers reported on closing wedge HTOs, which limited strong conclusions, but it still drew a conclusion about the comparable efficacy.
Question 25
Topic: Total Knee Arthroplasty (TKA)
A 47-year-old patient, similar to the bricklayer in the case, undergoes a High Tibial Osteotomy (HTO). Several years later, his osteoarthritis has progressed, and he now requires a Total Knee Arthroplasty (TKA). The surgeon notes that the previous HTO has complicated the TKA conversion. Which of the following is a specific implication of a prior opening wedge HTO on patellar height during subsequent TKA?
The image shows a post-operative radiograph of an HTO, which may have implications for patellar height.
Correct Answer & Explanation
. It typically leads to patella baja, which can complicate patellar tracking and component placement.
Explanation
Correct Answer: BThe case states, 'More recent studies show that closing wedge osteotomy increases patellar height, whereas opening wedge osteotomy lowers patellar height and this can have implications following TKA.' Patella baja (lowered patellar height) can significantly complicate TKA by making patellar tracking more difficult, increasing the risk of patellar impingement, and potentially affecting the choice and placement of prosthetic components.A. It typically leads to patella alta, making patellar tracking easier.This is incorrect. Opening wedge HTO lowers patellar height, leading to patella baja. Closing wedge HTO increases patellar height.C. It has no significant effect on patellar height, simplifying TKA conversion.This is incorrect, as the case explicitly states it 'can have implications following TKA.'D. It causes lateral patellar subluxation, requiring a lateral release.While patellar tracking issues can occur, the primary effect on patellar height is lowering it, not necessarily causing lateral subluxation as a direct consequence of the osteotomy type itself.E. It increases the risk of patellar fracture during TKA.While TKA after HTO can have increased risks, the direct implication on patellar height is patella baja, not necessarily an increased fracture risk as the primary concern related to patellar height.
Question 26
Topic: Total Knee Arthroplasty (TKA)
The candidate in the case mentions difficulties with conversion of HTO to TKA. Beyond patellar height changes, what is another significant challenge or disadvantage of a prior closing wedge HTO when converting to a Total Knee Arthroplasty (TKA)?
Correct Answer & Explanation
. Loss of bone stock making TKA technically difficult
Explanation
Correct Answer: BThe case states that closing wedge osteotomy 'has the risk of peroneal nerve injury, there is also loss of bone stock making it technically difficult to perform TKA.' This loss of bone stock, particularly from the proximal tibia, can significantly complicate the preparation of the tibial plateau for TKA components, potentially requiring bone grafting or specialized implants.A. Increased risk of infection due to retained hardwareis a general risk with any retained hardware, but 'loss of bone stock' is a more specific and direct difficulty related to theconversionitself, as highlighted in the text.C. Improved bone quality for implant fixationis incorrect; the loss of bone stock generally implies a more challenging bone bed for TKA.D. Reduced need for soft tissue balancingis incorrect; prior HTO can alter soft tissue tension and ligamentous balance, often making TKA soft tissue balancing more complex, not less.E. Easier restoration of the mechanical axisis incorrect; the altered anatomy and bone loss from HTO can make accurate restoration of the mechanical axis more challenging during TKA.
Question 27
Topic: Total Knee Arthroplasty (TKA)
Which of the following patients is the most ideal candidate for a medial opening wedge high tibial osteotomy (HTO)?
Correct Answer & Explanation
. A 50-year-old active male with isolated medial compartment OA, intact ligaments, and a 5-degree varus malalignment
Explanation
The ideal candidate for an HTO is a young, active patient with isolated unicompartmental osteoarthritis, correctable malalignment, and intact ligaments. Contraindications include inflammatory arthritis, flexion contractures >15 degrees, patellofemoral arthritis, and lateral compartment disease.
Question 28
Topic: Total Knee Arthroplasty (TKA)
The patient, described as "reasonably young," has extensive bone loss around the failed total knee replacement. The surgeon is planning the revision procedure.
Correct Answer & Explanation
. Restoration of bone stock using structural or morselized bone graft, potentially with metaphyseal sleeves.
Explanation
Correct Answer: CThe case explicitly states, "In this patient who is reasonably young restoration of bone stock is preferable, because of likelihood of further revision surgery." For younger patients with extensive bone loss, preserving and restoring bone stock is paramount to facilitate potential future revisions. This is best achieved through the use of bone grafting (structural or morselized) and/or modular metaphyseal sleeves, which allow for biological ingrowth and reconstruction of the metaphyseal bone. While cement, modular augments, or even hinged prostheses can address defects, they do not primarily restore bone stock. Avoiding complex bone grafting for the sake of surgical time would compromise the long-term outcome and future revision potential in a young patient.
Question 29
Topic: Total Knee Arthroplasty (TKA)
The patient is described as "reasonably young" with extensive bone loss, and the examiner emphasizes the importance of long-term planning.
Correct Answer & Explanation
. Preserving and restoring bone stock to facilitate potential future revisions.
Explanation
Correct Answer: CThe case explicitly states, "In this patient who is reasonably young restoration of bone stock is preferable, because of likelihood of further revision surgery." For younger patients, the expectation of a longer lifespan means a higher probability of requiring additional revision surgeries in the future. Therefore, the primary long-term goal in the current revision is to preserve and, if possible, restore the existing bone stock. This approach ensures that there is adequate bone available for subsequent procedures, making future revisions technically feasible and potentially more successful. While range of motion, cost, and hospital stay are important, they are secondary to the fundamental goal of bone stock management in a young patient with extensive defects. An RHK is not indicated in all cases of extensive bone loss; the choice depends on the specific type of instability and bone defect.
Question 30
Topic: Total Knee Arthroplasty (TKA)
According to the Anderson Orthopaedic Research Institute (AORI) classification, what characterizes a Type III bone defect in revision TKA?
Correct Answer & Explanation
. Deficient metaphyseal segment requiring structural graft or custom implants
Explanation
AORI Type III defects involve severe bone loss comprising a major portion of the condyles or plateau, compromising the entire metaphyseal segment. They typically require structural allograft, metaphyseal cones/sleeves, or a hinge prosthesis for stable fixation.
Question 31
Topic: Total Knee Arthroplasty (TKA)
During a revision TKA, the surgeon notes that the flexion gap is extremely tight, but the extension gap is perfectly balanced. Which of the following is the most appropriate corrective step?
Correct Answer & Explanation
. Downsize the femoral component
Explanation
A tight flexion gap with a balanced extension gap is managed by reducing the anteroposterior (AP) dimension of the femur. Downsizing the femoral component achieves this without altering the distal cut or the extension gap.
Question 32
Topic: Total Knee Arthroplasty (TKA)
In revision TKA, long diaphyseal engaging stems are frequently used to achieve stable implant fixation. According to the zonal fixation concept, in which zone do these stems primarily function?
Correct Answer & Explanation
. Zone 4
Explanation
The zonal fixation classification for revision TKA divides the bone into the joint surface/epiphysis (Zone 1), the metaphysis (Zone 2), and the diaphysis (Zone 3). Engaging stems primarily achieve robust fixation in Zone 3.
Question 33
Topic: Total Knee Arthroplasty (TKA)
A patient presents with a chronic patellar tendon rupture 3 years after a primary TKA, demonstrating an active extension lag of 40 degrees. What is currently considered the most reliable surgical reconstruction method?
Correct Answer & Explanation
. Synthetic mesh (Marlex) reconstruction
Explanation
Synthetic mesh (e.g., Marlex) reconstruction has become the preferred and most reliable method for treating chronic extensor mechanism disruption post-TKA. It demonstrates superior early tensioning and lower failure rates compared to traditional whole extensor mechanism allografts.
Question 34
Topic: Total Knee Arthroplasty (TKA)
A patient requires a revision TKA with significant uncontained metaphyseal bone defects but an intact diaphysis. The surgeon opts for highly porous tantalum cones. What is the primary biomechanical and biologic advantage of these cones in this setting?
Correct Answer & Explanation
. They provide immediate load-bearing support and potential for long-term biologic fixation
Explanation
Porous tantalum cones fill large, uncontained metaphyseal defects (Zone 2) and provide immediate structural support. Their highly porous, trabecular metal surface allows for robust biologic osseointegration, ensuring long-term stable fixation.
Question 35
Topic: Total Knee Arthroplasty (TKA)
A 71-year-old patient presents with a painful, loose primary total knee arthroplasty. Intraoperatively, the surgeon notes AORI Type III bone loss on both the femur and tibia, with complete incompetence of the medial collateral ligament. Which of the following implant constraints is most appropriate?
Correct Answer & Explanation
. Rotating hinge
Explanation
A rotating hinge prosthesis is indicated for profound collateral ligament incompetence (especially the MCL) combined with severe bone loss. A CCK device relies on an intact, though potentially attenuated, MCL to prevent post fracture and dislocation.
Question 36
Topic: Total Knee Arthroplasty (TKA)
A surgeon is balancing the gaps during a revision TKA. With trial components in place, the extension gap is perfectly balanced, but the flexion gap is unacceptably loose. Which of the following is the most appropriate step to achieve a balanced knee?
Correct Answer & Explanation
. Upsize the femoral component in the anteroposterior (AP) dimension
Explanation
A loose flexion gap with a balanced extension gap requires isolated tightening of the flexion space. Upsizing the AP dimension of the femoral component or using posterior femoral augments achieves this without altering the extension gap.
Question 37
Topic: Total Knee Arthroplasty (TKA)
A 68-year-old male sustains a traumatic avulsion of the patellar tendon from the tibial tubercle 3 years after a primary TKA. Primary repair is attempted but fails. For definitive reconstruction using an allograft extensor mechanism, what postoperative protocol is mandatory for success?
Correct Answer & Explanation
. Immobilization in full extension for a minimum of 6 to 8 weeks
Explanation
Allograft extensor mechanism reconstruction for chronic TKA disruption requires strict immobilization in full extension for 6 to 8 weeks to allow for allograft-host tissue healing. Early motion invariably leads to stretching and failure of the graft.
Question 38
Topic: Total Knee Arthroplasty (TKA)
In the setting of revision TKA for highly porous metal cones versus metaphyseal sleeves, which of the following best describes a biomechanical characteristic of metaphyseal sleeves?
Correct Answer & Explanation
. They are typically primarily bonded or mechanically coupled directly to the revision stem
Explanation
Metaphyseal sleeves are distinct from cones in that they typically taper-lock directly onto the revision stem, functioning as a single unit to share loads between the metaphysis and diaphysis. Cones are generally implanted independently and cemented to the implant.
Question 39
Topic: Total Knee Arthroplasty (TKA)
A patient undergoes a revision TKA complicated by a complete, intraoperative disruption of the patellar tendon from the tibial tubercle. Primary repair is tenuous. Which of the following reconstruction options provides the best long-term outcome?
Correct Answer & Explanation
. Achilles tendon allograft with calcaneal bone block
Explanation
Extensor mechanism disruption in TKA is a catastrophic complication. Extensor mechanism allograft (often an Achilles tendon with calcaneal bone block) is the gold standard for reconstruction when primary repair is impossible or tenuous in the revision setting.
Question 40
Topic: Total Knee Arthroplasty (TKA)
During a difficult revision TKA, the surgeon cannot evert the patella or gain adequate flexion without risking patellar tendon avulsion. Which of the following extensile exposures provides the most direct lateral translation of the extensor mechanism while maintaining blood supply?
Correct Answer & Explanation
. Tibial tubercle osteotomy
Explanation
A tibial tubercle osteotomy allows for excellent exposure and lateral translation of the extensor mechanism, especially when stem removal is anticipated. It provides reliable bone-to-bone healing, unlike V-Y quadricepsplasty which often results in an extensor lag.
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