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3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 298 of 326

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 5941

Topic: 3. Adult Reconstruction (Hip & Knee)

In a viva discussing total ankle arthroplasty (TAA), what specific contraindication is most critical to articulate, reflecting a deep understanding of its limitations compared to total knee or hip arthroplasty?

. Patient age over 65.
. Obesity.
. Active infection, severe avascular necrosis of the talus, neuropathic arthropathy (Charcot joint), and significant ankle deformity with uncorrectable ligamentous instability.
. Mild ankle pain.
. Previous ankle sprain.

Correct Answer & Explanation

. Active infection, severe avascular necrosis of the talus, neuropathic arthropathy (Charcot joint), and significant ankle deformity with uncorrectable ligamentous instability.

Explanation

TAA has more stringent contraindications than knee or hip arthroplasty due to the unique biomechanics of the ankle. Active infection, severe talar AVN, neuropathic arthropathy (Charcot joint) which compromises bone quality and sensation, and significant, uncorrectable ligamentous instability are absolute or strong relative contraindications. Articulating these demonstrates a nuanced understanding of TAA's specific challenges and patient selection criteria, which is vital for high marks.

Question 5942

Topic: 3. Adult Reconstruction (Hip & Knee)

When presenting a case of failed total joint arthroplasty (e.g., failed TKA), what specific approach to diagnosis is most indicative of expert-level reasoning?

. Assuming infection is the cause and immediately starting antibiotics.
. Ordering a single X-ray and deciding based on that.
. Systematic evaluation for all potential etiologies, including infection, aseptic loosening, instability, malalignment, periprosthetic fracture, and component wear, using a combination of clinical assessment, blood tests (ESR, CRP), specific imaging (X-rays, CT, bone scan, aspiration for culture).
. Focusing only on the implant manufacturer.
. Blaming the patient for non-compliance.

Correct Answer & Explanation

. Systematic evaluation for all potential etiologies, including infection, aseptic loosening, instability, malalignment, periprosthetic fracture, and component wear, using a combination of clinical assessment, blood tests (ESR, CRP), specific imaging (X-rays, CT, bone scan, aspiration for culture).

Explanation

Failure of a total joint arthroplasty is complex and rarely attributable to a single, obvious cause. Expert-level reasoning involves a systematic differential diagnosis covering infection, aseptic loosening, instability, malalignment, fracture, and wear. This requires a multimodal diagnostic approach integrating clinical findings, inflammatory markers (ESR/CRP), and various imaging modalities (including joint aspiration for culture) to pinpoint the precise etiology. This methodical approach scores highly.

Question 5943

Topic: 3. Adult Reconstruction (Hip & Knee)

You are asked about prosthetic infection following total knee arthroplasty. To score highly, your answer should encompass:

. Only mentioning the need for antibiotics.
. Discussing only acute infections.
. Classifying infections by timing (acute, subacute, chronic), detailing diagnostic workup (blood tests, aspiration, imaging), and outlining specific treatment algorithms (DAIR vs. 2-stage revision) based on timing, organism, and host factors.
. Assuming all prosthetic infections require immediate amputation.
. Focusing only on the implant type.

Correct Answer & Explanation

. Classifying infections by timing (acute, subacute, chronic), detailing diagnostic workup (blood tests, aspiration, imaging), and outlining specific treatment algorithms (DAIR vs. 2-stage revision) based on timing, organism, and host factors.

Explanation

Prosthetic joint infection (PJI) is a critical topic. A high-scoring answer will categorize PJI by timing (acute, subacute, chronic), describe a comprehensive diagnostic approach (ESR, CRP, joint aspiration with microscopy, culture, cell count, alpha-defensin), and detail treatment algorithms that vary based on the infection's timing, organism virulence, and host factors (e.g., Debridement, Antibiotics, Implant Retention [DAIR] for acute vs. 2-stage revision for chronic). This nuanced approach demonstrates expert knowledge.

Question 5944

Topic: 3. Adult Reconstruction (Hip & Knee)

When discussing the indications for total hip arthroplasty (THA), what key principle should be the overarching theme of your answer for optimal marks?

. Patient age is the primary indicator.
. The specific diagnosis is the sole indicator.
. Failure of extensive non-operative management, severe pain refractory to conservative measures, and functional disability significantly impacting quality of life, alongside patient comorbidities and expectations.
. Radiographic evidence of any arthritis.
. The availability of a surgeon.

Correct Answer & Explanation

. Failure of extensive non-operative management, severe pain refractory to conservative measures, and functional disability significantly impacting quality of life, alongside patient comorbidities and expectations.

Explanation

The primary indications for THA revolve around failed conservative management. A high-scoring answer emphasizes intractable pain, significant functional disability, and diminished quality of life despite maximal non-operative measures, all within the context of appropriate patient comorbidities and realistic expectations. Radiographic arthritis alone is insufficient; it's the clinical correlation that truly drives the decision, reflecting patient-centered care.

Question 5945

Topic: 3. Adult Reconstruction (Hip & Knee)

To score maximally on a question about osteoarthritis management, beyond pharmacological and surgical options, what crucial non-pharmacological element should be comprehensively detailed?

. Only recommending total joint replacement.
. Ignoring exercise.
. Patient education, weight management, structured exercise programs (strengthening, aerobic, flexibility), use of assistive devices, and referral to allied health professionals (physiotherapy, occupational therapy).
. Only discussing NSAIDs.
. Promoting unproven alternative therapies.

Correct Answer & Explanation

. Patient education, weight management, structured exercise programs (strengthening, aerobic, flexibility), use of assistive devices, and referral to allied health professionals (physiotherapy, occupational therapy).

Explanation

Comprehensive management of osteoarthritis, particularly for optimal marks, requires a strong emphasis on non-pharmacological strategies. This includes detailed patient education, weight loss (if indicated), structured exercise programs (targeting strength, flexibility, and aerobic fitness), and the judicious use of assistive devices. Referrals to physiotherapy and occupational therapy demonstrate a multidisciplinary, holistic approach that is highly valued.

Question 5946

Topic: 3. Adult Reconstruction (Hip & Knee)

You are asked about the indications for osteotomy around the knee (e.g., high tibial osteotomy). To score highly, you should emphasize:

. That it is a definitive treatment for all forms of knee arthritis.
. It is only for young, high-demand athletes.
. Varus/valgus malalignment with unicompartmental osteoarthritis, typically in younger, active patients with intact ligaments, aiming to shift weight-bearing loads to the healthier compartment and delay arthroplasty.
. It is for severe, multi-compartmental arthritis.
. Ignoring patient activity level.

Correct Answer & Explanation

. Varus/valgus malalignment with unicompartmental osteoarthritis, typically in younger, active patients with intact ligaments, aiming to shift weight-bearing loads to the healthier compartment and delay arthroplasty.

Explanation

High tibial osteotomy (HTO) is a salvage procedure with specific indications. A high-scoring answer will articulate that it is for unicompartmental osteoarthritis (medial or lateral) associated with significant varus or valgus malalignment, primarily in younger, active patients. The goal is to offload the diseased compartment, improve alignment, alleviate pain, and potentially delay the need for total knee arthroplasty. It's not for multi-compartmental disease or universally applicable.

Question 5947

Topic: 3. Adult Reconstruction (Hip & Knee)

When discussing the indications for total elbow arthroplasty, what specific patient factor is most critical to consider and articulate to an examiner?

. Patient's height.
. Occupation requiring heavy lifting or impact loading, which is a relative contraindication due to high complication rates (e.g., loosening, infection).
. Patient's hair color.
. Previous carpal tunnel surgery.
. Only the presence of pain.

Correct Answer & Explanation

. Occupation requiring heavy lifting or impact loading, which is a relative contraindication due to high complication rates (e.g., loosening, infection).

Explanation

Total elbow arthroplasty (TEA) has higher complication rates, particularly aseptic loosening and infection, compared to hip or knee replacements. A critical patient factor to articulate for high marks is the patient's activity level and occupational demands. Heavy manual labor, lifting, or impact loading are strong relative contraindications for TEA due to the increased risk of implant failure. This shows an understanding of the unique biomechanics and limitations of TEA.

Question 5948

Topic: 3. Adult Reconstruction (Hip & Knee)
An examiner asks you about the indications for total hip arthroplasty in a 35-year-old patient. After you list the common indications, the examiner presses, 'What are the two most common reasons for early revision (<5 years) in this specific demographic?' Which pair of reasons is most accurate?
. Aseptic loosening and polyethylene wear.
. Periprosthetic joint infection and instability/dislocation.
. Osteolysis and heterotopic ossification.
. Femoral component fracture and nerve injury.
. Vascular injury and deep vein thrombosis.

Correct Answer & Explanation

. Periprosthetic joint infection and instability/dislocation.

Explanation

For young, active patients undergoing total hip arthroplasty, the most common reasons for early revision (within 5 years) are periprosthetic joint infection (PJI) and instability/dislocation. While aseptic loosening and polyethylene wear are significant long-term failure modes, they typically manifest later. Osteolysis is a long-term consequence of wear. Femoral component fracture, nerve injury, vascular injury, and DVT are less common causes for early revision compared to PJI and dislocation.

Question 5949

Topic: 3. Adult Reconstruction (Hip & Knee)

In a viva discussing total hip arthroplasty, the examiner asks, 'What is the primary advantage of a direct anterior approach (DAA) compared to posterior or lateral approaches, and what is its main technical challenge?'

. Advantage: Lower risk of deep vein thrombosis; Challenge: Longer operative time.
. Advantage: Potentially lower dislocation rate due to preservation of posterior soft tissues; Challenge: Steeper learning curve, increased risk of lateral femoral cutaneous nerve injury, and potentially more difficult femoral exposure in obese patients.
. Advantage: Superior visualization of the acetabulum; Challenge: Higher risk of sciatic nerve injury.
. Advantage: Fewer restrictions post-operatively; Challenge: Increased blood loss.
. Advantage: Easier access for revision surgery; Challenge: Higher risk of heterotopic ossification.

Correct Answer & Explanation

. Advantage: Potentially lower dislocation rate due to preservation of posterior soft tissues; Challenge: Steeper learning curve, increased risk of lateral femoral cutaneous nerve injury, and potentially more difficult femoral exposure in obese patients.

Explanation

The primary advantage of the direct anterior approach (DAA) for total hip arthroplasty is its potential for a lower dislocation rate post-operatively due to preservation of the posterior soft tissue structures (capsule, external rotators). It is often associated with less post-operative pain and faster initial rehabilitation and fewer post-operative restrictions. However, its main technical challenges include a steeper learning curve, increased risk of lateral femoral cutaneous nerve (LFCN) injury (resulting in meralgia paresthetica), and potentially more difficult femoral exposure, especially in obese or muscular patients, or those with significant deformity. Higher risk of sciatic nerve injury (C) is generally associated with posterior approaches. Dislocation is a concern for posterior/lateral approaches not DAA. The other options are either less accurate or not the primary advantage/challenge.

Question 5950

Topic: 3. Adult Reconstruction (Hip & Knee)

During a viva, an examiner presents a patient with a proximal humerus fracture. You outline your management options. The examiner then asks, 'What are the two most common and distinct complications associated with the use of a hemiarthroplasty for complex proximal humerus fractures?'

. Periprosthetic joint infection and deep vein thrombosis.
. Aseptic loosening of the glenoid component and polyethylene wear.
. Malposition of the tuberosities (leading to poor rotator cuff function) and glenoid erosion.
. Heterotopic ossification and nerve injury.
. Stiffness and implant fracture.

Correct Answer & Explanation

. Malposition of the tuberosities (leading to poor rotator cuff function) and glenoid erosion.

Explanation

For hemiarthroplasty in complex proximal humerus fractures, the primary goal is often pain relief, but functional outcomes can be limited. The two most common and distinct complications are malposition or nonunion of the tuberosities, which compromises rotator cuff function and leads to poor active elevation, and progressive glenoid erosion due to articulation of the prosthetic humeral head with the native glenoid cartilage, leading to pain and often requiring revision to rTSA. PJI and DVT (A) are general surgical complications. Aseptic loosening of the glenoid and poly wear (B) are specific tototalshoulder arthroplasty. Heterotopic ossification (D) and nerve injury (D) can occur but are less common or less unique to hemiarthroplasty for fracture than the tuberosity and glenoid issues. Stiffness (E) is a common outcome, but tuberosity malposition is the underlying reason, and implant fracture is less common than glenoid erosion or tuberosity issues.

Question 5951

Topic: Total Hip Arthroplasty (THA)

In a viva discussing total hip arthroplasty, the examiner presents a scenario where a patient develops a leg length discrepancy post-operatively. What is the MOST crucial initial step in managing this complaint?

. Immediately perform revision surgery to equalize leg lengths.
. Prescribe custom orthotics or shoe lifts for the patient.
. Thoroughly assess the patient's symptoms, functional impact, and measure the discrepancy clinically and radiographically to differentiate true from perceived leg length discrepancy, and determine its magnitude and impact.
. Refer the patient to a physical therapist for gait training.
. Reassure the patient that some leg length discrepancy is normal after hip replacement.

Correct Answer & Explanation

. Thoroughly assess the patient's symptoms, functional impact, and measure the discrepancy clinically and radiographically to differentiate true from perceived leg length discrepancy, and determine its magnitude and impact.

Explanation

The MOST crucial initial step in managing post-operative leg length discrepancy (LLD) is a thorough assessment. This involves eliciting the patient's symptoms (pain, gait disturbance, low back pain), determining the functional impact, and objectively measuring the LLD both clinically and radiographically. It's important to distinguish between true LLD and perceived LLD (often due to pelvic obliquity or soft tissue imbalances). Only after a comprehensive assessment can an appropriate management plan (e.g., shoe lift, therapy, or rarely, revision) be formulated. Immediate revision (A) or prescribing orthotics (B) without assessment is premature. Reassurance (E) is dismissive without a proper evaluation.

Question 5952

Topic: 3. Adult Reconstruction (Hip & Knee)

You are presenting a case of a patient with hip pain and functional limitations, and you are considering total hip arthroplasty. The examiner asks, 'What are the two most common complications leading to early reoperation or revision within the first few years after total hip arthroplasty?'

. Periprosthetic joint infection and instability/dislocation.
. Aseptic loosening and osteolysis.
. Deep vein thrombosis and pulmonary embolism.
. Heterotopic ossification and nerve injury.
. Implant fracture and leg length discrepancy.

Correct Answer & Explanation

. Periprosthetic joint infection and instability/dislocation.

Explanation

While all listed options can be complications, the two most common reasons for early reoperation or revision within the first few years following total hip arthroplasty are periprosthetic joint infection (PJI) and instability/dislocation. These complications are typically acute or subacute. Aseptic loosening and osteolysis (B) are generally long-term failure mechanisms. DVT/PE (C) are serious but usually medical complications, not typically leading toreoperationunless the PE is fatal. Heterotopic ossification and nerve injury (D) are less common causes for early reoperation. Implant fracture (E) is rare, and LLD (E) often managed non-surgically unless severe and symptomatic.

Question 5953

Topic: 3. Adult Reconstruction (Hip & Knee)

For an orthopedic viva that includes a 'short case' station (e.g., examining a stiff knee), what is the most important preparatory activity the day before?

. Memorizing the entire anatomy of the knee joint in isolation.
. Practicing a systematic, time-efficient, and focused physical examination sequence for various joints.
. Reading comprehensive review articles on obscure knee conditions.
. Focusing on the pharmacology of anti-inflammatory drugs.
. Watching surgical videos of total knee arthroplasty.

Correct Answer & Explanation

. Practicing a systematic, time-efficient, and focused physical examination sequence for various joints.

Explanation

Short cases demand a systematic and efficient physical examination. Practicing this flow ensures all critical components are covered within the time limit and allows for smooth, confident execution. It's about practical application of examination skills.

Question 5954

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old male with end-stage post-traumatic ankle osteoarthritis is being evaluated for a total ankle arthroplasty. Which of the following is considered an absolute contraindication to this procedure?

. Age greater than 60 years
. Bilateral ankle osteoarthritis
. Charcot neuroarthropathy of the ankle
. Prior ankle fracture hardware in place
. Mild varus deformity of 5 degrees

Correct Answer & Explanation

. Charcot neuroarthropathy of the ankle

Explanation

Absolute contraindications for total ankle arthroplasty include Charcot neuroarthropathy, active infection, severe avascular necrosis of the talar body, and profound neuropathy. Age >60 and bilateral disease are general indications rather than contraindications.

Question 5955

Topic: Total Knee Arthroplasty (TKA)

During a primary total knee arthroplasty (TKA), the surgeon checks the gap balancing with spacer blocks. The extension gap is symmetric and rectangular, allowing appropriate tension. However, the flexion gap is tight and symmetric. Which of the following is the most appropriate next step to balance the knee?

. Release the posterior cruciate ligament (if retaining) or downsize the femoral component.
. Resect more distal femur.
. Increase the posterior slope of the tibial cut.
. Release the medial collateral ligament.
. Upsize the femoral component.

Correct Answer & Explanation

. Release the posterior cruciate ligament (if retaining) or downsize the femoral component.

Explanation

A tight flexion gap with a balanced extension gap implies that the anteroposterior dimension of the femoral component is too large, or the posterior soft tissues are too tight. The appropriate surgical options include releasing the PCL (if it is a cruciate-retaining knee), down-sizing the femoral component (which removes more posterior condylar bone and opens the flexion gap), or translating the femoral component anteriorly. Resecting more distal femur would affect the extension gap. Increasing the posterior tibial slope affects both gaps but preferentially opens the flexion gap; however, changing the femoral component size or PCL release are the primary direct corrections.

Question 5956

Topic: Total Hip Arthroplasty (THA)

A 35-year-old highly active man underwent a primary total hip arthroplasty with a ceramic-on-ceramic bearing. Two years later, he complains of a loud squeaking sound emanating from his hip when he walks or bends, though it is painless. Which of the following technical factors is most strongly associated with the development of this specific complication?

. Placement of the acetabular component in excessive anteversion and steep inclination leading to edge loading.
. Use of a larger diameter ceramic femoral head (>36 mm).
. Placement of the femoral stem in excessive anteversion.
. Impingement of the iliopsoas tendon over the anterior aspect of the acetabulum.
. Routine use of highly cross-linked polyethylene as a liner.

Correct Answer & Explanation

. Placement of the acetabular component in excessive anteversion and steep inclination leading to edge loading.

Explanation

Squeaking is a known complication of ceramic-on-ceramic bearings. The most common technical cause is malposition of the acetabular component, specifically extreme inclination or excessive anteversion. This malposition causes 'edge loading', where the femoral head articulates directly on the rim of the ceramic liner. This focal stress disrupts the fluid film lubrication, resulting in localized wear, stripe wear, and the characteristic squeaking sound.

Question 5957

Topic: 3. Adult Reconstruction (Hip & Knee)

During a total knee arthroplasty, the surgeon inadvertently positions the femoral component in internal rotation relative to the epicondylar axis. Which of the following complications is most likely to result from this malrotation?

. Medial patellar subluxation and increased lateral flexion gap.
. Lateral patellar subluxation and increased medial flexion gap.
. Symmetric patellar tracking but excessive tightness in extension.
. Patella baja and loss of terminal knee extension.
. Early polyethylene failure primarily on the medial plateau.

Correct Answer & Explanation

. Lateral patellar subluxation and increased medial flexion gap.

Explanation

Internal rotation of the femoral component in TKA medializes the trochlear groove, which effectively increases the dynamic Q-angle. This predisposes the knee to lateral patellar subluxation or dislocation. Additionally, internal rotation of the femoral component creates an asymmetric flexion gap, specifically making the medial flexion gap larger (looser) and the lateral flexion gap tighter.

Question 5958

Topic: 3. Adult Reconstruction (Hip & Knee)

The diagnosis of periprosthetic joint infection (PJI) involves multiple diagnostic modalities. The synovial fluid alpha-defensin test is increasingly used for its high sensitivity and specificity. What is the fundamental biological origin of alpha-defensin in this setting?

. It is an endotoxin released by Gram-negative bacteria.
. It is an antimicrobial peptide released by host neutrophils in response to pathogens.
. It is a structural component of the bacterial biofilm matrix.
. It is a host acute-phase reactant synthesized primarily by the liver.
. It is a degradative enzyme released by osteoclasts during periprosthetic osteolysis.

Correct Answer & Explanation

. It is an antimicrobial peptide released by host neutrophils in response to pathogens.

Explanation

Alpha-defensin is a biomarker used in the diagnosis of PJI. It is a naturally occurring antimicrobial peptide that is released by activated host neutrophils in response to a bacterial challenge. Because it is highly specific to the presence of an active infection in the joint, its levels in synovial fluid are an excellent marker for PJI, outperforming general inflammatory markers in terms of specificity.

Question 5959

Topic: 3. Adult Reconstruction (Hip & Knee)
A patient requires revision of a failed total hip arthroplasty due to massive aseptic loosening. Preoperative radiographs demonstrate superior migration of the acetabular component greater than 3 cm, complete destruction of the teardrop, and medial migration past Kohler's line with disruption of the ischium. According to the Paprosky classification, what grade is this defect, and what is the most appropriate reconstructive strategy?
. Type IIA; Jumbo cup and particulate allograft
. Type IIC; Hemispherical cup with multiple screws
. Type IIIA; Jumbo cup and structurally supportive allograft
. Type IIIB; Cup-cage construct or custom triflange component
. Type IV; Resection arthroplasty (Girdlestone)

Correct Answer & Explanation

. Type IIIB; Cup-cage construct or custom triflange component

Explanation

The description perfectly matches a Paprosky Type IIIB acetabular defect. Type IIIB defects are characterized by severe bone loss, superior migration >3 cm, destruction of the teardrop, and disruption of Kohler's line (indicating medial migration and pelvic dissociation or severe ischial bone loss). Standard hemispherical cups cannot achieve stability. The recommended reconstructive strategies involve bridging the defect with a cup-cage construct, custom triflange acetabular component, or massive structural allografts with cages.

Question 5960

Topic: 3. Adult Reconstruction (Hip & Knee)

A 55-year-old patient presents with symptomatic isolated medial compartment knee osteoarthritis. You are considering a unicompartmental knee arthroplasty (UKA). Which of the following is generally considered an absolute contraindication to performing a UKA?

. Patient age less than 60 years
. Patient weight over 90 kg
. Inflammatory arthropathy (e.g., Rheumatoid Arthritis)
. Presence of a patellofemoral osteophyte without anterior knee pain
. A preoperative flexion contracture of 5 degrees

Correct Answer & Explanation

. Inflammatory arthropathy (e.g., Rheumatoid Arthritis)

Explanation

Inflammatory arthropathy (such as Rheumatoid Arthritis) is generally considered an absolute contraindication to unicompartmental knee arthroplasty. Because RA is a systemic disease affecting the entire synovium, progression of arthritis in the unresurfaced compartments is virtually inevitable and rapid. Age and weight constraints have largely been loosened, asymptomatic patellofemoral changes are acceptable, and a mild flexion contracture (<15 degrees) is acceptable.

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