3. Adult Reconstruction (Hip & Knee) MCQs

During a primary total hip arthroplasty, the acetabular component is inadvertently placed in 45 degrees of abduction and 40 degrees of anteversion. This specific malpositioning places the patient at highest risk for which of the following complications?

A surgeon is evaluating a patient for the surgical management of a confirmed chronic periprosthetic joint infection of the hip. Under current consensus guidelines, which of the following is considered an absolute contraindication to performing a single-stage revision?

In a primary total hip arthroplasty, the surgeon decides to upsize the femoral head from 28 mm to 36 mm. Assuming the neck geometry remains the same, this modification increases stability primarily by improving which two factors?

A 72-year-old woman sustains a fall and complains of left hip pain. Radiographs reveal a periprosthetic femur fracture located around the tip of her cemented femoral stem. The stem demonstrates circumferential radiolucent lines indicating loosening, but her proximal bone stock remains robust and adequate. According to the Vancouver classification, what is the appropriate categorization and optimal management?

A 68-year-old man presents with recurrent posterior dislocations of his primary total hip arthroplasty. Postoperative CT imaging demonstrates that the acetabular component is positioned at 10 degrees of anteversion and 35 degrees of inclination. The femoral stem has 15 degrees of anteversion. Which of the following is the most likely primary mechanical cause for his instability?

A 40-year-old man taking high-dose corticosteroids for systemic lupus erythematosus presents with severe right groin pain. Radiographs reveal a subchondral crescent sign in the anterosuperior aspect of the femoral head, without gross flattening of the articular surface. What is the most reliable definitive treatment to relieve his pain and restore function?

A 28-year-old highly active woman is undergoing total hip arthroplasty for severe secondary osteoarthritis due to hip dysplasia. To minimize volumetric wear and avoid complications associated with metal ion release, what is the most appropriate articulating surface combination?

A 65-year-old man presents with a painful total hip arthroplasty 3 years postoperatively. His ESR is 45 mm/hr and CRP is 25 mg/L. Aspiration of the hip yields synovial fluid with a WBC count of 4,500 cells/uL and 85% polymorphonuclear neutrophils. What is the most appropriate next step in management?

A 55-year-old man complains of mild groin pain 12 years after a primary total hip arthroplasty. Radiographs show a well-fixed cementless femoral stem and a well-fixed porous-coated acetabular shell. However, there is significant eccentric polyethylene wear and a large superior uncontained acetabular osteolytic defect. What is the most appropriate management?

A 60-year-old woman with a metal-on-metal total hip arthroplasty presents 4 years postoperatively with groin pain and a palpable anterior thigh mass. MRI demonstrates a large cystic collection. Aspiration reveals sterile, cloudy fluid. What is the most likely histologic finding in the periarticular tissues?

A 68-year-old man is scheduled for a revision total hip arthroplasty. He has a history of severe, functionally limiting heterotopic ossification (Brooker class III) following his primary surgery. What is the most effective and appropriate prophylactic regimen to prevent recurrence?

A 40-year-old active man reports a loud, audible "squeaking" sound originating from his hip when he bends to tie his shoes, 3 years after a primary total hip arthroplasty. He has no pain. Which of the following bearing surface combinations is most commonly associated with this specific phenomenon?

Lewinnek established a radiographic "safe zone" for acetabular component positioning to reduce the risk of postoperative dislocation in total hip arthroplasty. What are the classically described recommended target angles for cup inclination and anteversion?

A 62-year-old woman complains of localized, sharp anterior groin pain that is exacerbated by initiating an active straight leg raise. Her symptoms began 6 months following an uncemented total hip arthroplasty. Radiographs reveal a slightly oversized acetabular component with anterior rim overhang. What is the most likely diagnosis?

A 68-year-old woman presents with her third posterior dislocation of a total hip arthroplasty (THA) performed 6 months ago. Radiographs demonstrate an acetabular component inclination of 40 degrees and anteversion of 5 degrees. The femoral stem has 15 degrees of anteversion. What is the most likely cause of her recurrent instability?

A 55-year-old man presents with insidious onset of groin pain 8 years after a metal-on-metal total hip arthroplasty. Radiographs show well-fixed components with no osteolysis. Laboratory tests show normal ESR and CRP. What is the most appropriate next step in evaluation?

A 60-year-old man with a ceramic-on-ceramic total hip arthroplasty complains of a loud, reproducible squeaking noise coming from his hip when he walks or bends. What is the most commonly associated cause of this phenomenon?

A 65-year-old man with a metal-on-polyethylene total hip arthroplasty (large cobalt-chromium head on a titanium alloy stem) presents with new-onset hip pain 5 years postoperatively. Blood work reveals a markedly elevated serum cobalt level with a normal serum chromium level. What is the most likely diagnosis?

During the placement of a cementless acetabular component in a THA, supplemental screw fixation is planned. To minimize the risk of devastating vascular injury, screws should be placed exclusively in which quadrant?

A patient presents for a 6-week follow-up after a left THA complaining that the operative leg feels significantly longer. Standing radiographs confirm that the center of rotation is restored and absolute leg lengths are equal, but the femoral offset is increased by 8 mm on the operative side. What is the cause of the patient's perceived leg length discrepancy?