This practice set contains high-yield board review questions covering key concepts in 3. Adult Reconstruction (Hip & Knee). Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.
Question 641
Topic: 3. Adult Reconstruction (Hip & Knee)
During a primary total knee arthroplasty, trial components are placed. The surgeon notes that the knee is perfectly balanced and stable in full extension but is excessively tight in 90 degrees of flexion. Which of the following is the most appropriate step to achieve a balanced knee?
Correct Answer & Explanation
. Decrease the femoral component size
Explanation
A knee that is balanced in extension but tight in flexion requires an isolated increase in the flexion gap. Downsizing the femoral component (with posterior referencing) or increasing the posterior slope of the tibial cut will increase the flexion gap without altering the extension gap.
Question 642
Topic: 3. Adult Reconstruction (Hip & Knee)
When counseling a 40-year-old active patient undergoing a total hip arthroplasty, the surgeon discusses bearing surfaces. Which of the following bearing surface combinations offers the lowest volumetric wear rate but carries a risk of catastrophic component fracture and squeaking?
Correct Answer & Explanation
. Ceramic on ceramic
Explanation
Ceramic-on-ceramic bearings have the lowest reported volumetric wear rates of any modern bearing combination, virtually eliminating particle-induced osteolysis. However, they carry unique risks including audible squeaking and catastrophic, brittle fracture of the ceramic components.
Question 643
Topic: 3. Adult Reconstruction (Hip & Knee)
In a total hip arthroplasty, increasing the femoral head diameter from 32 mm to 36 mm using standard highly cross-linked polyethylene has which of the following effects on wear and stability?
Correct Answer & Explanation
. Increases volumetric wear and increases impingement-free range of motion
Explanation
Increasing the femoral head size increases the impingement-free range of motion and the jump distance, thus enhancing stability. However, the larger contact area inherently increases volumetric wear, although linear wear may remain unchanged.
Question 644
Topic: 3. Adult Reconstruction (Hip & Knee)
In total hip arthroplasty, the use of highly cross-linked polyethylene (HXLPE) has significantly reduced the incidence of osteolysis. Which of the following mechanical trade-offs is inherently associated with using high-dose gamma irradiation to increase cross-linking?
Correct Answer & Explanation
. Decreased resistance to fatigue crack propagation
Explanation
While high-dose radiation greatly increases cross-linking and dramatically reduces adhesive/abrasive wear, it negatively alters internal mechanical properties. This results in decreased ductility, lower yield strength, and reduced resistance to fatigue crack propagation.
Question 645
Topic: 3. Adult Reconstruction (Hip & Knee)
In total hip arthroplasty, which of the following represents the primary advantage of utilizing a ceramic-on-ceramic bearing surface compared to highly cross-linked polyethylene?
Correct Answer & Explanation
. Lower volumetric wear rates
Explanation
Ceramic-on-ceramic bearings offer the lowest volumetric wear rates of all current THA bearing surfaces, making them desirable in young, highly active patients. However, they are notoriously less forgiving to component malposition and carry unique risks of squeaking and catastrophic component fracture.
Question 646
Topic: 3. Adult Reconstruction (Hip & Knee)
During an ABOS Part 1 oral examination, a candidate, Dr. Smith, begins his first topic on hip arthroplasty. The examiner asks a foundational question regarding the indications for total hip replacement in a 65-year-old patient with osteoarthritis. Dr. Smith hesitates, then states, "I'm not entirely sure of the precise indications at this moment." Based on the provided viva tactics, what is the most likely immediate consequence of Dr. Smith's response?
Correct Answer & Explanation
. B. Dr. Smith's initial score, formulated within the first two minutes, will likely be negatively impacted and difficult to significantly improve.
Explanation
Correct Answer: BThe case states, "It very rapidly becomes apparent to the examiners how well a candidate has prepared for the structured oral examination. Usually within the first two minutes or so a score is formulated and tends to stay constant. It is unusual for a candidate to significantly change their performance throughout the remainder of the oral viva." It also explicitly warns, "If you donโt know an answer to a question say so and the examiners can move on to a different question. Easier said than done if the question is at the beginning of a topic and is straightforward. Not knowing the answer is going to go down like a lead balloon with the examiners." A foundational question on indications for THA is straightforward and at the beginning of a topic. Therefore, a poor answer here will significantly and negatively impact the initial score, which is difficult to change.A. The examiner will immediately move to a more difficult, obscure question to test Dr. Smith's depth of knowledge.This is incorrect. The case states, "Unless a candidate is doing exceptionally well they will not be asked difficult or obscure questions. A candidate who is performing poorly is never put through this ordeal." Dr. Smith's initial stumble suggests he is not doing exceptionally well.C. The examiner will offer a hint or rephrase the question, as questions are never asked to trick candidates.While questions are not meant to trick, the text emphasizes the severe negative impact of not knowing a straightforward answer at the beginning of a topic. While an examiner might rephrase, the primary consequence highlighted is the negative impact on the score.D. Dr. Smith will be advised to delay sitting the exam to the next scheduled set of exams due to this initial stumble.This is an extreme measure suggested for a scenario where a candidate anticipates such a stall, not an immediate consequence during the exam itself. The text says, "If this scenario could occur it is perhaps wiser to delay sitting the exam to the next scheduled set of exams." This is a pre-exam consideration, not an in-exam outcome.E. The examiner will disregard the answer, understanding that stress can affect initial recall, and proceed with easier questions.While examiners are aware of stress, the text explicitly states that not knowing a straightforward answer at the beginning of a topic "is going to go down like a lead balloon with the examiners," indicating it will not be disregarded without consequence.
Question 647
Topic: 3. Adult Reconstruction (Hip & Knee)
In an exam scenario, you are discussing informed consent for total hip arthroplasty. Beyond the common risks (infection, DVT, dislocation), what specific element would an examiner expect you to highlight to demonstrate a thorough understanding of the consent process for this procedure?
Correct Answer & Explanation
. Discussion of alternative treatments, including non-operative options, and the expected outcomes if surgery is not performed.
Explanation
Correct Answer: CA truly informed consent process, as expected in advanced orthopedic exams, requires a comprehensive discussion beyond just the risks of the chosen procedure. It critically includes outlining viable alternative treatments (both operative and non-operative), their respective risks, benefits, and the natural history/expected outcomes if no intervention is undertaken. This demonstrates a deep understanding of shared decision-making and patient autonomy, essential for optimal marking.
Question 648
Topic: 3. Adult Reconstruction (Hip & Knee)
In a discussion about total knee arthroplasty (TKA), an examiner asks about potential complications. To score highly, beyond listing common complications, what advanced understanding should you convey?
Correct Answer & Explanation
. Discussion of specific risk factors for each major complication, strategies for prevention, and initial management steps.
Explanation
Correct Answer: CBeyond merely listing complications, a high-scoring candidate will demonstrate a deeper understanding by discussing the specific patient and surgical risk factors associated with each major complication (e.g., diabetes for infection, DVT prophylaxis for VTE), proactive preventative strategies, and the initial steps for recognition and management should they occur. This comprehensive approach showcases clinical judgment and preparedness, highly valued by examiners.
Question 649
Topic: 3. Adult Reconstruction (Hip & Knee)
A 72-year-old female presents with a periprosthetic femur fracture around a total hip arthroplasty stem placed 10 years ago. Radiographs show a fracture at the tip of the stem. The stem is visibly subsided and loose, but there is adequate proximal bone stock. According to the Vancouver classification, what is the most appropriate surgical management?
Correct Answer & Explanation
. Revision to an uncemented, extensively porous-coated diaphyseal-fitting long stem.
Explanation
This is a Vancouver B2 fracture (fracture around a loose stem with adequate bone stock). The standard of care is revision to a longer uncemented stem that bypasses the fracture by at least two cortical diameters to achieve distal fixation.
Question 650
Topic: 3. Adult Reconstruction (Hip & Knee)
A 68-year-old patient with an uncemented total hip arthroplasty presents with progressive thigh pain. Radiographs demonstrate focal areas of endosteal bone loss (osteolysis) around the femoral stem. Which cell type is the primary mediator of this osteolytic process in response to polyethylene wear debris?
Correct Answer & Explanation
. Macrophages.
Explanation
Particulate wear debris, most commonly polyethylene, is phagocytosed by macrophages. These activated macrophages then release pro-inflammatory cytokines (such as TNF-alpha and IL-1) that stimulate osteoclast-mediated bone resorption, leading to osteolysis.
Question 651
Topic: 3. Adult Reconstruction (Hip & Knee)
A 68-year-old active female undergoes a total hip arthroplasty. To minimize the risk of bearing surface wear, a ceramic-on-ceramic articulation is chosen. What is the most unique and distinctive complication associated with this specific bearing surface?
Correct Answer & Explanation
. Audible squeaking
Explanation
Ceramic-on-ceramic bearings exhibit exceptionally low wear rates but are uniquely associated with audible squeaking and a small risk of catastrophic ceramic fracture. Pseudotumors are more typical of metal-on-metal articulations.
Question 652
Topic: Total Hip Arthroplasty (THA)
In an oral viva setting, an examiner presents a radiograph of a healthy 75-year-old female with a displaced femoral neck fracture and asks the candidate to justify their choice of total hip arthroplasty (THA) over hemiarthroplasty. Which of the following responses demonstrates the best grasp of current orthopedic literature?
Correct Answer & Explanation
. THA provides better long-term functional outcomes and lower reoperation rates for active older patients.
Explanation
For active, independent older patients with displaced femoral neck fractures, THA provides superior functional outcomes and lower reoperation rates compared to hemiarthroplasty. Hemiarthroplasty is typically reserved for lower-demand or medically frail patients.
Question 653
Topic: 3. Adult Reconstruction (Hip & Knee)
During an oral examination, Dr. Lee is shown a radiograph of an aggressive bone lesion he has never seen before. He does not know the exact diagnosis. According to optimal viva tactics, what is his best immediate course of action?
Correct Answer & Explanation
. Describe the radiographic findings systematically using first principles, such as location, margins, and periosteal reaction.
Explanation
When faced with an unknown entity, falling back on a systematic approach demonstrates safe, logical clinical reasoning. Examiners evaluate the candidate's process and safety, not just their ability to instantly recognize rare diagnoses.
Question 654
Topic: 3. Adult Reconstruction (Hip & Knee)
During a viva, Dr. Patel describes her plan for a complex revision knee arthroplasty. The examiner asks a series of probing questions that make Dr. Patel realize her proposed sequence for removing the well-fixed femoral component is technically flawed. What is the best strategy for her to adopt?
Correct Answer & Explanation
. Politely acknowledge the flaw, explain why it was incorrect, and provide a revised, safer plan.
Explanation
Examiners value humility, adaptability, and patient safety over rigid adherence to a flawed plan. Recognizing a mistake and safely adjusting the surgical plan demonstrates mature clinical judgment.
Question 655
Topic: Total Hip Arthroplasty (THA)
A candidate is asked to describe the surgical approach for a total hip arthroplasty in a dysplastic hip. The examiner repeatedly interrupts the candidate's description of the posterior approach to ask about the internervous plane. How should the candidate handle this?
Correct Answer & Explanation
. Clarify that the posterior approach is a muscle-splitting approach and does not utilize a true internervous plane.
Explanation
The posterior approach to the hip splits the gluteus maximus (inferior gluteal nerve) and is not a true internervous plane. Correctly answering foundational anatomical questions without getting flustered by interruptions is a key viva skill.
Question 656
Topic: 3. Adult Reconstruction (Hip & Knee)
A 24-year-old male presents with persistent wrist pain 8 months after a fall. Imaging reveals a scaphoid nonunion with avascular necrosis of the proximal pole. What is the most appropriate surgical management?
Correct Answer & Explanation
. Vascularized bone graft (e.g., 1,2-ICSRA) and internal fixation
Explanation
Avascular necrosis of the proximal pole of the scaphoid compromises healing potential. A vascularized bone graft is required to restore blood supply and promote union.
Question 657
Topic: 3. Adult Reconstruction (Hip & Knee)
A 68-year-old male presents with acute onset of severe right knee pain, swelling, and fever, 3 weeks after a primary total knee arthroplasty. Joint aspiration shows 65,000 WBCs with 95% neutrophils. What is the most appropriate management?
Correct Answer & Explanation
. Debridement, antibiotics, and implant retention (DAIR) with modular polyethylene exchange
Explanation
Acute periprosthetic joint infection occurring within 4 weeks of the index surgery is best managed with a DAIR procedure. This must include the exchange of modular components to reduce biofilm load.
Question 658
Topic: Total Hip Arthroplasty (THA)
In your oral examination, you are discussing a case from your collection where a patient experienced a major complication (e.g., foot drop after THA). The examiner presses you on what went wrong. What is the most successful tactic for defending your case?
Correct Answer & Explanation
. Take personal responsibility, describe the intraoperative challenge that led to it, and explain how you altered your practice to prevent it.
Explanation
Examiners are evaluating you for safe, mature surgical practice. Taking responsibility, demonstrating reflective learning, and showing subsequent practice improvement is the hallmark of a passing candidate.
Question 659
Topic: 3. Adult Reconstruction (Hip & Knee)
A 42-year-old bricklayer presents with chronic medial knee pain that has failed extensive non-surgical management. He is otherwise fit and well. Physical examination reveals tenderness over the medial joint line, a varus deformity that is correctable, and a full range of motion with stable ligaments. The patient is keen to return to his high-demand job. An AP weightbearing radiograph is shown below.
Based on this presentation and the provided image, which of the following is the most appropriate initial surgical recommendation for this patient?
Correct Answer & Explanation
. High Tibial Osteotomy (HTO)
Explanation
Correct Answer: CThe patient is a 42-year-old bricklayer with medial compartment osteoarthritis, a correctable varus deformity, and a high-demand physical job. High Tibial Osteotomy (HTO) is the most appropriate initial surgical recommendation in this scenario. HTO is indicated for younger, active patients (physiological age < 60 years) with unicompartmental osteoarthritis and a varus deformity, especially those with high physical demands. It aims to shift the mechanical axis laterally, offloading the medial compartment and preserving the native knee joint, which is advantageous for patients engaged in heavy labor.A. Total Knee Arthroplasty (TKA)is generally reserved for older patients with more diffuse or severe osteoarthritis, or those with lower activity demands, as it involves replacing the entire joint. A 42-year-old active bricklayer would likely wear out a TKA prematurely.B. Medial Unicondylar Knee Arthroplasty (UKA)is an option for unicompartmental OA, but the case explicitly states that UKA is generally not recommended for patients with highly physically demanding jobs due to the risk of accelerated wear. While women may prefer UKA due to better tolerance of angular deformity, and patients with low physical demand may benefit, it is less suitable for this patient's specific occupational demands.D. Arthroscopic debridement and microfractureare typically considered for smaller, contained chondral defects, not for moderate medial compartment osteoarthritis with a varus deformity, which implies more widespread cartilage loss and mechanical malalignment. These procedures are unlikely to provide long-term relief for this patient's condition.E. Patellofemoral Arthroplastyaddresses isolated patellofemoral osteoarthritis. The patient's symptoms and radiographic findings are consistent with medial compartment osteoarthritis, not primarily patellofemoral involvement.
Question 660
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.
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