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3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 160 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 3181

Topic: 3. Adult Reconstruction (Hip & Knee)



In a patient undergoing primary THA with a ceramic-on-ceramic bearing, what is a specific known complication related to this bearing choice compared to others?

. Trunnionosis
. Osteolysis from severe volumetric wear
. Squeaking
. Galvanic corrosion
. Accelerated backside wear

Correct Answer & Explanation

. Trunnionosis

Explanation

Ceramic-on-ceramic articulations have excellent wear properties and minimal osteolysis risk, but they are uniquely associated with "squeaking" (an audible noise during movement) in approximately 1% to 10% of patients.

Question 3182

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old woman is evaluated for a painful THA 3 years postoperatively. Her serum CRP is 25 mg/L and ESR is 45 mm/hr. Hip aspiration yields 4,500 WBCs/uL with 85% neutrophils. What is the most appropriate next step?

. Prescribe oral antibiotics for 6 weeks
. Proceed with a 1-stage revision
. Proceed with a 2-stage revision
. Perform an arthroscopic washout
. Repeat the aspiration in 3 months

Correct Answer & Explanation

. Prescribe oral antibiotics for 6 weeks

Explanation

This patient has a chronic periprosthetic joint infection, diagnosed by elevated inflammatory markers and an aspirate >3,000 WBCs/uL with >80% PMNs. The gold standard treatment in the United States for chronic PJI is a 2-stage revision arthroplasty.

Question 3183

Topic: Total Hip Arthroplasty (THA)



To minimize the risk of dislocation, the acetabular component in a THA should ideally be placed within the "safe zone" described by Lewinnek. What are these target angles?

. 30 degrees abduction, 10 degrees retroversion
. 40 degrees abduction, 15 degrees anteversion
. 50 degrees abduction, 20 degrees anteversion
. 45 degrees abduction, 0 degrees version
. 35 degrees abduction, 30 degrees anteversion

Correct Answer & Explanation

. 30 degrees abduction, 10 degrees retroversion

Explanation

Lewinnek's safe zone for acetabular cup placement is historically defined as 40 +/- 10 degrees of abduction (inclination) and 15 +/- 10 degrees of anteversion to minimize dislocation risk.

Question 3184

Topic: Total Hip Arthroplasty (THA)

A patient with a history of severe heterotopic ossification (HO) following a contralateral THA is undergoing an ipsilateral THA. Which of the following is the most proven prophylactic treatment against HO?

. High-dose oral vitamin C
. Postoperative bracing for 6 weeks
. Single-dose radiation therapy within 24 hours postoperatively
. Preoperative continuous passive motion
. Postoperative calcium channel blockers

Correct Answer & Explanation

. High-dose oral vitamin C

Explanation

A single dose of radiation (typically 700 cGy) given within 24 hours preoperatively or postoperatively is a highly effective and proven method for heterotopic ossification prophylaxis. A course of NSAIDs like indomethacin is an alternative proven method.

Question 3185

Topic: 3. Adult Reconstruction (Hip & Knee)

A 28-year-old woman with systemic lupus erythematosus presents with groin pain. Radiographs show a subchondral lucent line (crescent sign) in the femoral head but no gross collapse. What Ficat and Arlet stage does this represent?

. Stage I
. Stage II
. Stage III
. Stage IV
. Stage V

Correct Answer & Explanation

. Stage I

Explanation

The crescent sign represents a subchondral fracture and is the hallmark of Ficat Stage III avascular necrosis. It indicates impending mechanical collapse of the femoral head and makes joint-preserving procedures like core decompression less effective.

Question 3186

Topic: 3. Adult Reconstruction (Hip & Knee)

Hip resurfacing arthroplasty is most appropriately indicated for which of the following patient profiles?

. A 70-year-old osteoporotic female with osteoarthritis
. A 45-year-old male with severe osteoarthritis and normal proximal femoral bone geometry
. A 60-year-old male with chronic kidney disease and hip dysplasia
. A 50-year-old female with inflammatory arthritis and a large femoral head cyst
. A 35-year-old male with Ficat stage IV avascular necrosis affecting 80% of the head

Correct Answer & Explanation

. A 70-year-old osteoporotic female with osteoarthritis

Explanation

Hip resurfacing is best suited for young, active males with osteoarthritis and strong bone stock. Contraindications include poor bone quality, large cystic changes, extensive avascular necrosis, and significant leg length discrepancies.

Question 3187

Topic: 3. Adult Reconstruction (Hip & Knee)



Stress shielding of the proximal femur following cementless THA is most commonly seen with which type of femoral stem design?

. Fully porous-coated cylindrical stems
. Proximally coated tapered stems
. Modular neck preserving stems
. Highly polished tapered cemented stems
. Short metaphyseal fitting stems

Correct Answer & Explanation

. Fully porous-coated cylindrical stems

Explanation

Fully porous-coated, extensively coated stems achieve rigid distal diaphyseal fixation, leading to stress unloading (stress shielding) of the proximal metaphyseal bone. This results in subsequent proximal bone resorption over time.

Question 3188

Topic: 3. Adult Reconstruction (Hip & Knee)

Figure 1 shows the radiograph of a 72-year-old man with severe groin pain 5 years after an uncemented total hip arthroplasty. Inflammatory markers are normal.

What is the most likely cause of his pain if symptoms are exacerbated by active hip flexion against resistance?

. Femoral component aseptic loosening
. Iliopsoas impingement
. Polyethylene wear with osteolysis
. Heterotopic ossification
. Abductor tendon avulsion

Correct Answer & Explanation

. Femoral component aseptic loosening

Explanation

Iliopsoas impingement typically presents with anterior groin pain that is exacerbated by active hip flexion or a straight leg raise. It is often caused by a prominent anterior edge of the acetabular component rubbing against the iliopsoas tendon.

Question 3189

Topic: 3. Adult Reconstruction (Hip & Knee)

In active, healthy elderly patients who sustain a displaced femoral neck fracture, what is the primary clinical advantage of total hip arthroplasty (THA) compared to hemiarthroplasty?

. Lower rate of postoperative dislocation
. Decreased operative time and intraoperative blood loss
. Lower risk of reoperation for acetabular erosion and improved functional scores
. Lower risk of deep periprosthetic joint infection
. Improved short-term mortality rates

Correct Answer & Explanation

. Lower rate of postoperative dislocation

Explanation

THA provides better functional outcomes and eliminates the risk of progressive acetabular wear and erosion seen with hemiarthroplasty in active patients. However, THA does carry a higher risk of postoperative dislocation compared to hemiarthroplasty.

Question 3190

Topic: 3. Adult Reconstruction (Hip & Knee)

When evaluating a patient for a primary total hip arthroplasty, increasing the femoral head offset without altering leg length will have which of the following biomechanical effects?

. Decreased abductor muscle tension
. Increased overall joint reaction force
. Increased abductor lever arm
. Decreased risk of impingement with internal rotation
. Increased polyethylene wear rates

Correct Answer & Explanation

. Decreased abductor muscle tension

Explanation

Increasing femoral offset increases the abductor lever arm, which decreases the abductor force required to maintain pelvic stability. This consequently decreases the overall joint reaction force.

Question 3191

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old woman sustains a posterior dislocation of her primary total hip arthroplasty 4 weeks postoperatively. Closed reduction is successful in the emergency department. What is the most appropriate initial management?

. Immediate revision of the acetabular component
. Immediate revision of the femoral component
. Application of an abduction brace for 6 weeks
. Open reduction and capsulorrhaphy
. Bed rest with skeletal traction for 2 weeks

Correct Answer & Explanation

. Immediate revision of the acetabular component

Explanation

For a first-time early posterior dislocation of a THA successfully treated with closed reduction, initial management consists of immobilization in an abduction brace. This allows the posterior soft tissues and capsule to heal.

Question 3192

Topic: 3. Adult Reconstruction (Hip & Knee)

A 78-year-old community-ambulating woman with mild dementia sustains a displaced femoral neck fracture. According to recent literature, which of the following surgical options is associated with the best functional outcome and lowest reoperation rate?

. Closed reduction and percutaneous pinning
. Open reduction and internal fixation with a sliding hip screw
. Unipolar hemiarthroplasty
. Bipolar hemiarthroplasty
. Total hip arthroplasty

Correct Answer & Explanation

. Closed reduction and percutaneous pinning

Explanation

In independent, community-ambulating older adults, total hip arthroplasty for displaced femoral neck fractures provides better functional outcomes and lower reoperation rates compared to internal fixation or hemiarthroplasty.

Question 3193

Topic: 3. Adult Reconstruction (Hip & Knee)

In total hip arthroplasty, which of the following bearing surface combinations is most characteristically associated with the phenomenon of "stripe wear"?

. Cobalt-chrome on highly cross-linked polyethylene
. Ceramic on ceramic
. Oxinium on highly cross-linked polyethylene
. Cobalt-chrome on cobalt-chrome
. Ceramic on standard polyethylene

Correct Answer & Explanation

. Cobalt-chrome on highly cross-linked polyethylene

Explanation

Stripe wear is a characteristic wear pattern seen almost exclusively in ceramic-on-ceramic articulations. It often occurs during microseparation when the edge of the cup contacts the femoral head.

Question 3194

Topic: 3. Adult Reconstruction (Hip & Knee)

Six months after a primary total hip arthroplasty, a patient presents with new-onset hip pain. Inflammatory markers are elevated. Aspiration yields 35,000 WBCs/mcL with 90% neutrophils. What is the most appropriate definitive management?

. Intravenous antibiotics for 6 weeks
. Irrigation and debridement with modular component exchange
. Single-stage revision arthroplasty
. Two-stage exchange arthroplasty
. Suppressive oral antibiotics

Correct Answer & Explanation

. Intravenous antibiotics for 6 weeks

Explanation

For chronic periprosthetic joint infections presenting more than 4 weeks postoperatively, two-stage exchange arthroplasty is the gold standard of treatment. Debridement and modular exchange are typically reserved for acute infections.

Question 3195

Topic: 3. Adult Reconstruction (Hip & Knee)



A 65-year-old man is undergoing preoperative templating for a total hip arthroplasty. To accurately restore leg length and offset, which anatomical landmark is most commonly used to reference the inferior margin of the acetabular component on an AP pelvis radiograph?

. The tip of the greater trochanter
. The lesser trochanter
. The teardrop
. The ischial tuberosity
. The anterior superior iliac spine

Correct Answer & Explanation

. The tip of the greater trochanter

Explanation

The radiographic teardrop is a reliable and constant bony landmark on the AP pelvis. It is routinely used to establish the anatomic center of rotation and guide vertical positioning of the acetabular cup.

Question 3196

Topic: 3. Adult Reconstruction (Hip & Knee)

In a cementless, fully porous-coated femoral component, initial mechanical stability (primary fixation) is most heavily dependent on which of the following factors?

. Hydroxyapatite coating
. Porous coating pore size between 50-400 micrometers
. Exact match of the stem collar to the medial calcar
. Scratch fit (press-fit) at the host bone-implant interface
. Postoperative weight-bearing status

Correct Answer & Explanation

. Hydroxyapatite coating

Explanation

Primary stability in cementless stems relies on a tight initial "scratch fit" or press-fit between the implant and the host bone. This limits micromotion, which is essential to allow for subsequent secondary biological ingrowth.

Question 3197

Topic: Total Hip Arthroplasty (THA)

Following a primary total hip arthroplasty performed via a posterior approach, the patient demonstrates a foot drop and decreased sensation over the dorsum of the foot. Which specific neural structure is most likely injured?

. Femoral nerve
. Obturator nerve
. Tibial division of the sciatic nerve
. Peroneal division of the sciatic nerve
. Superior gluteal nerve

Correct Answer & Explanation

. Femoral nerve

Explanation

The sciatic nerve is the most commonly injured nerve in THA, particularly with a posterior approach. Its peroneal division is anatomically lateral and has less connective tissue support, making it highly susceptible to stretch injury.

Question 3198

Topic: 3. Adult Reconstruction (Hip & Knee)

According to AAOS guidelines, what is the recommended duration of pharmacological venous thromboembolism (VTE) prophylaxis following an elective total hip arthroplasty?

. 7 to 10 days
. 10 to 14 days
. 28 to 35 days
. 60 days
. Prophylaxis is not routinely recommended

Correct Answer & Explanation

. 7 to 10 days

Explanation

Standard guidelines (including AAOS and ACCP) recommend extending pharmacological VTE prophylaxis to up to 35 days postoperatively for patients undergoing major orthopedic surgeries like total hip arthroplasty.

Question 3199

Topic: 3. Adult Reconstruction (Hip & Knee)



A patient presents with mechanical groin pain 10 years after a cementless THA. Radiographs show a continuous, progressive radiolucent line greater than 2 mm extending through all three DeLee and Charnley zones. This finding is most pathognomonic for which of the following?

. Aseptic loosening of the acetabular component
. Osteolysis secondary to polyethylene wear without loosening
. Low-grade periprosthetic joint infection
. Normal stress shielding
. Impingement of the iliopsoas tendon

Correct Answer & Explanation

. Aseptic loosening of the acetabular component

Explanation

A continuous radiolucent line greater than 2 mm that is progressive and present in all three DeLee and Charnley zones is the radiographic hallmark of aseptic loosening of the acetabular component.

Question 3200

Topic: 3. Adult Reconstruction (Hip & Knee)

Which of the following is a uniquely recognized complication of ceramic-on-ceramic total hip arthroplasty compared to other modern bearing surfaces?

. Elevated serum metal ions
. Extensive osteolysis from volumetric wear
. Mechanically assisted crevice corrosion
. Audible squeaking during ambulation
. Increased risk of adverse local tissue reaction

Correct Answer & Explanation

. Elevated serum metal ions

Explanation

Ceramic-on-ceramic bearings offer the lowest volumetric wear rates of all modern bearing combinations. However, they are associated with unique complications, most notably component fracture and audible squeaking.

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