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3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 200 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 3981

Topic: 3. Adult Reconstruction (Hip & Knee)

A 75-year-old female sustains a fall 5 years after undergoing a primary total hip arthroplasty. Radiographs reveal a fracture extending around the femoral stem, and the stem is found to be grossly loose, though the proximal femur bone stock is adequate.

According to the Vancouver classification, what is the most appropriate management?

. Open reduction and internal fixation with a lateral locking plate and cables
. Cable fixation alone around the fracture site
. Revision to a long cementless extensively porous-coated or fluted tapered stem
. Revision to a standard length cemented stem
. Impaction bone grafting with a short cemented stem

Correct Answer & Explanation

. Revision to a long cementless extensively porous-coated or fluted tapered stem

Explanation

This is a Vancouver B2 fracture, defined as a fracture around a loose stem with adequate bone stock. The standard of care is revision arthroplasty bypassing the fracture by at least two cortical diameters, typically using a long cementless stem.

Question 3982

Topic: 3. Adult Reconstruction (Hip & Knee)
A 45-year-old man presents with severe right hip pain. Magnetic resonance imaging demonstrates Ficat Stage III avascular necrosis (AVN) of the femoral head with the presence of a crescent sign and early subchondral collapse. What is the most appropriate definitive treatment?
. Core decompression with bone marrow aspirate concentrate
. Non-vascularized fibular strut grafting
. Free vascularized fibular graft
. Total hip arthroplasty
. Prolonged protected weight-bearing and bisphosphonates

Correct Answer & Explanation

. Total hip arthroplasty

Explanation

Ficat Stage III AVN is characterized by subchondral collapse (crescent sign). Joint-preserving procedures like core decompression are highly ineffective at this stage, making total hip arthroplasty the most reliable and appropriate treatment.

Question 3983

Topic: 3. Adult Reconstruction (Hip & Knee)

According to the traditional Lewinnek criteria, what is the safe zone for acetabular component positioning during a total hip arthroplasty to minimize the risk of dislocation?

. 15 ± 10 degrees of anteversion and 40 ± 10 degrees of abduction
. 25 ± 10 degrees of anteversion and 45 ± 10 degrees of abduction
. 10 ± 5 degrees of retroversion and 40 ± 10 degrees of abduction
. 20 ± 10 degrees of anteversion and 50 ± 10 degrees of abduction
. 15 ± 10 degrees of retroversion and 30 ± 10 degrees of abduction

Correct Answer & Explanation

. 15 ± 10 degrees of anteversion and 40 ± 10 degrees of abduction

Explanation

The Lewinnek safe zone describes optimal cup positioning as 15° ± 10° of anteversion and 40° ± 10° of abduction. Placing the cup within this zone has historically been associated with a lower rate of postoperative dislocation.

Question 3984

Topic: 3. Adult Reconstruction (Hip & Knee)

A 62-year-old woman with a metal-on-metal total hip arthroplasty presents with worsening groin pain 6 years postoperatively. Workup reveals elevated serum cobalt and chromium levels and a large solid pseudotumor compressing the femoral vein. Infection has been ruled out. What is the most appropriate management?

. Observation and serial MRI in 6 months
. Ultrasound-guided aspiration and corticosteroid injection
. Revision of the bearing surfaces to non-metal-on-metal and excision of the pseudotumor
. Isolated open synovectomy leaving the implants in situ
. Oral chelation therapy for heavy metal toxicity

Correct Answer & Explanation

. Revision of the bearing surfaces to non-metal-on-metal and excision of the pseudotumor

Explanation

Adverse local tissue reactions (ALTR) or pseudotumors in metal-on-metal hips with progressive symptoms or elevated metal ions require revision arthroplasty. The bearing surface must be changed to non-metal-on-metal alongside extensive soft-tissue debridement.

Question 3985

Topic: 3. Adult Reconstruction (Hip & Knee)

Which of the following is considered an absolute contraindication to performing a metal-on-metal hip resurfacing arthroplasty?

. Male gender
. Age under 50 years
. Osteoarthritis secondary to mild developmental dysplasia
. Chronic kidney disease
. Body mass index greater than 30

Correct Answer & Explanation

. Chronic kidney disease

Explanation

Chronic kidney disease is an absolute contraindication to metal-on-metal bearings. Impaired renal function prevents the clearance of metal ions (cobalt and chromium), leading to systemic toxicity and early failure.

Question 3986

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old woman presents with recurrent posterior dislocations of her total hip arthroplasty. Radiographs and CT scans show a well-fixed femoral stem with 15 degrees of retroversion and a well-fixed acetabular cup in 40 degrees of abduction and 20 degrees of anteversion.

What is the most definitive surgical intervention?

. Application of a constrained acetabular liner
. Placement of a posterior elevated rim liner
. Revision of the femoral stem to correct version
. Revision of the acetabular component to increase anteversion
. Greater trochanteric advancement

Correct Answer & Explanation

. Revision of the femoral stem to correct version

Explanation

The primary cause of instability in this patient is the retroverted femoral stem. Definitive management requires revising the malpositioned, well-fixed stem to restore appropriate anteversion and prevent recurrent posterior dislocation.

Question 3987

Topic: 3. Adult Reconstruction (Hip & Knee)

According to the 2018 International Consensus Meeting (ICM) criteria, which of the following is considered a major definitive criterion for diagnosing periprosthetic joint infection (PJI)?

. Elevated serum erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)
. Elevated synovial fluid white blood cell (WBC) count
. Positive leukocyte esterase test strip
. Two positive periprosthetic cultures with phenotypically identical organisms
. A single positive tissue culture for a highly virulent organism

Correct Answer & Explanation

. Two positive periprosthetic cultures with phenotypically identical organisms

Explanation

Under the 2018 ICM criteria, the presence of a sinus tract communicating with the joint or two positive periprosthetic cultures with phenotypically identical organisms are the only major definitive criteria for PJI.

Question 3988

Topic: 3. Adult Reconstruction (Hip & Knee)
A 72-year-old woman is undergoing a complex revision total hip arthroplasty. Intraoperatively, she is found to have a severe Paprosky type IIIB defect with pelvic discontinuity. Which of the following is the most appropriate method for acetabular reconstruction?
. Standard hemispherical jumbo non-cemented cup
. Standard cemented cup alone
. Cup-cage construct or custom triflange acetabular component
. Impaction bone grafting with a cemented polyethylene cup
. High hip center placement using a standard cup

Correct Answer & Explanation

. Cup-cage construct or custom triflange acetabular component

Explanation

Pelvic discontinuity requires mechanical bridging of the superior and inferior halves of the pelvis. Constructs such as a cup-cage, custom triflange component, or highly porous metal cups with internal plating provide the necessary stability.

Question 3989

Topic: 3. Adult Reconstruction (Hip & Knee)

A 60-year-old woman complains of intractable lateral hip pain and a profound Trendelenburg gait one year after undergoing a primary total hip arthroplasty via a direct lateral (Hardinge) approach. An MRI demonstrates a complete, retracted tear of the gluteus medius tendon without significant muscle atrophy. What is the most appropriate management?

. Conversion to a constrained acetabular liner
. Abductor tendon repair
. Botulinum toxin injection to the hip adductors
. Revision of the femoral stem to increase offset
. Physical therapy focusing on isolated abductor strengthening

Correct Answer & Explanation

. Abductor tendon repair

Explanation

The patient has a symptomatic, complete avulsion of the abductor mechanism following a direct lateral approach. Since muscle quality is preserved (no atrophy/fatty infiltration), surgical abductor tendon repair is indicated to restore function and relieve pain.

Question 3990

Topic: Total Hip Arthroplasty (THA)

A 55-year-old man presents with intractable groin pain when actively flexing the hip, specifically when rising from a seated position, 18 months after a THA. A diagnostic injection of local anesthetic into the iliopsoas bursa completely relieves his pain. Radiographs reveal 12 mm of anterior overhang of the acetabular component.

What is the most definitive surgical management?

. Open iliopsoas tenotomy at the lesser trochanter
. Revision of the acetabular component
. Revision of the femoral component
. Application of a constrained liner
. Arthroscopic labral debridement

Correct Answer & Explanation

. Revision of the acetabular component

Explanation

The patient has iliopsoas impingement secondary to significant anterior cup overhang. While iliopsoas tenotomy is an option for mild overhang, severe anterior prominence (>8-10 mm) definitively requires revision of the acetabular component to eliminate the structural impingement.

Question 3991

Topic: 3. Adult Reconstruction (Hip & Knee)

During preoperative templating for a total hip arthroplasty, the surgeon plans to increase the femoral offset without altering the vertical height of the center of rotation. What effect will this specific geometric change have on the hip's biomechanics?

. Decreases the abductor moment arm
. Increases the joint reactive force across the hip
. Increases the abductor moment arm and soft tissue tension
. Lengthens the operative leg significantly
. Increases the risk of bony impingement during abduction

Correct Answer & Explanation

. Increases the abductor moment arm and soft tissue tension

Explanation

Increasing femoral offset moves the femur further from the center of rotation laterally. This increases the abductor moment arm, which improves abductor efficiency, decreases the joint reactive force, and enhances overall joint stability through improved soft tissue tension.

Question 3992

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old male presents with groin pain 5 years after a primary total hip arthroplasty. Aspiration of the hip yields a synovial fluid white blood cell count of 4,500/uL with 85% neutrophils. Alpha-defensin is positive. What is the most appropriate next step in management?

. Debridement, antibiotics, and implant retention (DAIR)
. Single-stage revision arthroplasty
. Two-stage revision arthroplasty
. Suppressive oral antibiotics
. Observation and repeat aspiration in 3 months

Correct Answer & Explanation

. Two-stage revision arthroplasty

Explanation

This patient meets the criteria for a chronic periprosthetic joint infection. Two-stage revision arthroplasty is the gold standard for chronic PJI to ensure eradication of infection before placing a new prosthesis.

Question 3993

Topic: 3. Adult Reconstruction (Hip & Knee)



A 75-year-old female sustains a periprosthetic femur fracture around a well-fixed cementless stem with adequate surrounding bone stock. According to the Vancouver classification, what is the most appropriate surgical management?

. Nonoperative management with protected weight-bearing
. Open reduction and internal fixation with a plate and cables
. Revision to a fully porous-coated long stem
. Revision with impaction bone grafting
. Proximal femoral replacement

Correct Answer & Explanation

. Open reduction and internal fixation with a plate and cables

Explanation

A fracture around a well-fixed stem with adequate bone stock is classified as Vancouver B1. The standard of care for a Vancouver B1 fracture is open reduction and internal fixation.

Question 3994

Topic: Total Hip Arthroplasty (THA)

Mechanically assisted crevice corrosion (trunnionosis) at the head-neck junction in total hip arthroplasty is most strongly associated with which of the following component characteristics?

. Small femoral head diameter
. Large femoral head diameter
. Ceramic femoral head
. Short femoral neck offset
. Cemented femoral stem

Correct Answer & Explanation

. Large femoral head diameter

Explanation

Trunnionosis is driven by increased fretting and corrosion at the modular head-neck junction. Large diameter femoral heads increase the lever arm and torsional forces on the trunnion, significantly increasing this risk.

Question 3995

Topic: 3. Adult Reconstruction (Hip & Knee)

What is the primary biomechanical advantage of using a dual mobility construct in revision total hip arthroplasty for instability?

. Decreased volumetric polyethylene wear
. Reduced risk of mechanically assisted crevice corrosion
. Elimination of the risk of edge loading
. Enhanced effective head size and jump distance
. Increased biological fixation at the cup-bone interface

Correct Answer & Explanation

. Enhanced effective head size and jump distance

Explanation

Dual mobility components feature a large polyethylene liner that articulates within a metal shell, effectively acting as a large femoral head. This increases the jump distance required for dislocation, significantly enhancing stability.

Question 3996

Topic: 3. Adult Reconstruction (Hip & Knee)



A 62-year-old woman with a metal-on-metal total hip arthroplasty complains of a progressive groin mass. Serum cobalt and chromium levels are highly elevated. What is the primary histologic finding expected in the periprosthetic tissue?

. Acute neutrophilic infiltrate
. Birefringent polyethylene particles with giant cells
. Extensive perivascular lymphocytic infiltrate
. Granulomas with acid-fast bacilli
. Malignant spindle cells

Correct Answer & Explanation

. Extensive perivascular lymphocytic infiltrate

Explanation

Adverse local tissue reactions (ALTR/ALVAL) secondary to metal wear debris are characterized histologically by an extensive perivascular lymphocytic infiltrate. This represents a delayed-type hypersensitivity reaction to metal ions.

Question 3997

Topic: Total Hip Arthroplasty (THA)
Radiographs of a 70-year-old female reveal severe superior migration of the acetabular component with discontinuity of the pelvic ring (>60% host bone loss). Which of the following is the most reliable reconstruction option for this Paprosky Type IIIB defect?
. Jumbo uncemented hemispherical cup
. Standard cup with multiple screws and allograft
. Cup-cage construct or custom triflange
. Impaction bone grafting alone
. Bipolar hemiarthroplasty

Correct Answer & Explanation

. Cup-cage construct or custom triflange

Explanation

Paprosky IIIB defects with pelvic discontinuity require bypassing the defect to achieve stable fixation in the ilium and ischium. A cup-cage construct or a custom triflange component provides the necessary mechanical stability.

Question 3998

Topic: Total Hip Arthroplasty (THA)

A patient develops anterior groin pain reproducible with active straight-leg raise and rising from a seated position immediately following a primary THA. Cross-sectional imaging reveals significant anterior overhang of the acetabular component. If conservative management fails, what is the best initial surgical intervention?

. Adductor tenotomy
. Revision of the femoral stem
. Gluteus medius repair
. Iliopsoas fractional lengthening or tenotomy
. Sciatic nerve neurolysis

Correct Answer & Explanation

. Iliopsoas fractional lengthening or tenotomy

Explanation

Anterior overhang of the acetabular cup can cause iliopsoas impingement, presenting as pain with active hip flexion. If conservative measures fail, an iliopsoas tenotomy or fractional lengthening is the preferred initial surgical treatment before attempting cup revision.

Question 3999

Topic: 3. Adult Reconstruction (Hip & Knee)



A 35-year-old man presents with non-traumatic hip pain. Radiographs show sclerosis and cystic changes in the femoral head without subchondral fracture or collapse. What is the most appropriate initial surgical management?

. Total hip arthroplasty
. Resurfacing arthroplasty
. Core decompression
. Proximal femoral osteotomy
. Hip arthroscopy with labral repair

Correct Answer & Explanation

. Core decompression

Explanation

The patient has Ficat Stage II avascular necrosis (AVN) of the femoral head (sclerosis/cysts, but no crescent sign or collapse). Core decompression is indicated for pre-collapse stages of AVN to decrease intraosseous pressure and promote revascularization.

Question 4000

Topic: Total Hip Arthroplasty (THA)

A ceramic-on-ceramic total hip arthroplasty is associated with a distinct risk of 'squeaking'. Which of the following technical factors is most strongly associated with the development of this complication?

. Excessively large femoral head diameter
. Use of an un-cemented femoral stem
. High body mass index of the patient
. Acetabular component malposition causing edge loading
. Profound leg length discrepancy

Correct Answer & Explanation

. Acetabular component malposition causing edge loading

Explanation

Squeaking in ceramic-on-ceramic bearings is strongly correlated with edge loading. This abnormal wear pattern is typically caused by malpositioning of the acetabular component, such as excessive inclination or anteversion.

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