3. Adult Reconstruction (Hip & Knee) MCQs

Six months after a primary THA, a 55-year-old woman reports sharp, catching groin pain that occurs specifically when lifting her leg to get into a car or climbing stairs. Passive hip rotation is painless, but resisted straight leg raise reproduces her pain. Radiographs reveal an acetabular component placed in 45 degrees of inclination and 10 degrees of retroversion, with the anterior edge of the cup overhanging the bone.

What is the most likely diagnosis?

A 55-year-old male presents with new-onset groin pain 6 years after undergoing a total hip arthroplasty with a metal-on-polyethylene bearing and a modular titanium stem with a cobalt-chromium head. Infection workup including aspiration is negative. MRI shows a solid/cystic mass in the periprosthetic soft tissues. What is the most likely pathophysiologic mechanism for this patient's condition?

A 62-year-old female presents with chronic pain 2 years after a primary total hip arthroplasty. Serologic inflammatory markers (ESR and CRP) are equivocal. Aspiration is performed to rule out periprosthetic joint infection (PJI). Which of the following synovial fluid biomarkers provides the highest sensitivity and specificity for diagnosing PJI?

According to Lewinnek's classically described safe zone for total hip arthroplasty, what acetabular component orientation is recommended to minimize the risk of postoperative dislocation?

A 78-year-old male sustains a fall 8 years following an uncemented total hip arthroplasty. Radiographs reveal a periprosthetic femur fracture around the middle of the femoral stem. The stem has subsided 2 cm compared to previous films, but the proximal femur demonstrates thick, excellent cortical bone stock. According to the Vancouver classification, what is the fracture type and the recommended surgical management?

When evaluating patients for metal-on-metal hip resurfacing arthroplasty, which of the following characteristics represents the most ideal candidate and is associated with the lowest long-term failure rates?

A 68-year-old man presents with recurrent posterior dislocations of his total hip arthroplasty (THA). He underwent a primary THA through a posterior approach 6 months ago. Radiographs demonstrate a well-fixed, uncemented acetabular cup with 40 degrees of inclination and 0 degrees of anteversion. The femoral stem is well-fixed with 15 degrees of anteversion.

To optimally stabilize this hip during revision surgery, the surgeon should aim to:

A 52-year-old highly active man underwent a total hip arthroplasty (THA) using a ceramic-on-ceramic bearing surface 3 years ago. He now complains of an audible squeaking noise from the hip while walking. He denies any pain, fevers, or limitation in his functional activities. Radiographs demonstrate well-fixed components with 45 degrees of cup inclination and 15 degrees of anteversion. Inflammatory markers are within normal limits. What is the most appropriate next step in management?

A 60-year-old woman presents with progressive groin pain and a palpable anterior thigh mass 7 years after a metal-on-metal total hip arthroplasty. Her serum cobalt level is significantly elevated at 18 ppb. A Metal Artifact Reduction Sequence (MARS) MRI reveals a large cystic mass communicating with the hip joint.

If a biopsy of this periprosthetic tissue is performed, what is the expected predominant histological finding?

A 72-year-old man complains of chronic right hip pain 2 years after a primary total hip arthroplasty. He has not had any acute exacerbation but states the pain has been constant for the last 6 months. Laboratory studies reveal an ESR of 60 mm/hr and a CRP of 45 mg/L. Joint aspiration yields synovial fluid with 4,500 WBCs/µL (85% neutrophils), and an alpha-defensin test is positive. Radiographs show lucency around the femoral stem. Based on the Musculoskeletal Infection Society (MSIS) criteria, what is the most appropriate definitive surgical management?

A 55-year-old woman complains of new-onset, sharp groin pain radiating to the anterior thigh 8 months after an uncomplicated primary total hip arthroplasty. The pain is worst when initiating movement, particularly when lifting her leg to get into a car or climbing stairs. Physical examination reveals severe pain with resisted active straight leg raise. A diagnostic anesthetic injection into the psoas bursa provides complete relief. Which of the following is the most common radiographic finding associated with this condition?

A 78-year-old woman presents to the emergency department after a mechanical fall. She underwent a cementless total hip arthroplasty 10 years ago. Radiographs reveal a spiral fracture around the tip of the femoral stem, extending slightly distal to the tip. Comparison to previous films confirms the stem remains rigidly fixed with no signs of subsidence, loosening, or osteolysis.

According to the Vancouver classification, what is the standard treatment for this injury?

A 65-year-old man presents with his third posterior dislocation of a total hip arthroplasty performed 6 months ago via a posterior approach. Radiographs reveal the acetabular component has 5 degrees of anteversion and 40 degrees of abduction. The femoral stem is well-fixed with 15 degrees of anteversion. What is the most appropriate surgical management?

A 58-year-old woman with a metal-on-metal total hip arthroplasty presents with progressive groin pain. Laboratory tests show significantly elevated serum cobalt and chromium levels. A metal artifact reduction sequence (MARS) MRI shows a thick-walled cystic mass communicating with the hip joint space causing displacement of the surrounding soft tissues. What is the most appropriate management?

A 72-year-old man with a well-functioning right total hip arthroplasty placed 8 years ago presents with 3 days of acute, severe right hip pain and an inability to bear weight. He reports having a tooth extracted for a severe dental abscess 2 weeks ago. Hip aspiration yields synovial fluid with 65,000 WBC/uL and 95% polymorphonuclear cells. Radiographs show stable components with no radiolucencies. What is the most appropriate surgical management?

A 78-year-old woman sustains a ground-level fall and presents with severe right thigh pain.

Radiographs show a periprosthetic fracture around her femoral stem. There is clear evidence of stem subsidence and a wide radiolucent line at the cement-bone interface, indicating aseptic loosening prior to the fall. The fracture extends to just distal to the tip of the stem, but there is adequate cortical bone stock distally. According to the Vancouver classification, what is the most appropriate treatment?

A 64-year-old man presents with a 6-month history of progressive right hip pain 5 years after receiving a cementless total hip arthroplasty with a 36-mm cobalt-chromium head on a titanium stem. Radiographs show well-fixed components with no evidence of osteolysis. Laboratory evaluation reveals a markedly elevated serum cobalt level with a normal serum chromium level. Hip aspiration is negative for infection. What is the most likely cause of this patient's symptoms?

A 52-year-old highly active man underwent a total hip arthroplasty with a ceramic-on-ceramic bearing surface 3 years ago. He is highly satisfied with his hip function but complains of a loud, audible "squeaking" noise when bending, walking, or rising from a chair. Which of the following component positions or surgical factors is most strongly associated with this phenomenon?

A 38-year-old male is involved in a high-speed motor vehicle collision.

Radiographs demonstrate a completely displaced, intracapsular femoral neck fracture (Garden IV). He has no significant past medical history and is highly active. What is the most appropriate initial surgical management?