3. Adult Reconstruction (Hip & Knee) MCQs

A 62-year-old male with a metal-on-polyethylene total hip arthroplasty presents with new-onset groin pain and swelling 6 years postoperatively. Aspiration yields fluid with markedly elevated cobalt levels and normal chromium levels. An MRI demonstrates a cystic pseudotumor. What is the most likely etiology of this patient's presentation?

During trialing of a primary total knee arthroplasty, the surgeon notes that the extension gap is perfectly balanced, but the knee is significantly tight in flexion. Which of the following technical adjustments is the most appropriate next step?

A 75-year-old female sustains a periprosthetic femur fracture around a cemented total hip arthroplasty after a fall. Radiographs show a transverse fracture just distal to the tip of the stem. The stem is radiographically loose, but there is excellent diaphyseal bone stock. How is this fracture classified and best treated?

A 66-year-old male presents 1 year after a posterior-stabilized total knee arthroplasty complaining of a painful catching sensation when extending his knee from a seated position. On examination, a palpable 'pop' is felt at the anterior knee at roughly 35 degrees of flexion. What is the underlying cause?

A patient presents with a painful total knee arthroplasty 2 years postoperatively. Synovial fluid aspiration reveals a white blood cell count of 4,500 cells/uL with 88% neutrophils. The synovial alpha-defensin test is positive, and serum CRP is 18 mg/L. According to the 2018 MSIS/ICM criteria, what is the diagnosis?

A patient suffers a recurrent anterior dislocation of their total hip arthroplasty, which was placed via a posterior approach. CT scan reveals an acetabular cup with 45 degrees of inclination and 30 degrees of anteversion. The femoral stem is placed in 20 degrees of anteversion. What is the primary cause of instability?

Modern total hip arthroplasties utilize highly cross-linked polyethylene (HXLPE) to significantly reduce wear rates and subsequent osteolysis. Which manufacturing process is primarily responsible for inducing the cross-linking in the polyethylene?

During a primary total knee arthroplasty for a severe varus deformity, the surgeon notes symmetric medial tightness in both flexion and extension after making the initial bony cuts. Which soft tissue structure should be sequentially released first to balance the gaps?

A 58-year-old female presents with persistent groin pain 6 months after an uncemented total hip arthroplasty. The pain is worst when she actively lifts her leg to get into a car. Resisted straight leg raise reproduces her symptoms. Radiographs show the acetabular component is well-fixed but has a prominent anterior edge. What is the most likely diagnosis?

A 72-year-old female presents with a periprosthetic fracture around a cemented total hip arthroplasty implanted 10 years ago. Radiographs demonstrate a fracture around the tip of the stem with radiolucent lines indicating a loose stem, but with adequate remaining proximal bone stock (Vancouver Type B2). What is the most appropriate management?

An 82-year-old nursing home resident sustained a minimally displaced femoral neck fracture treated with in situ percutaneous pinning. Nine months later, she presents with severe, progressive groin pain. Radiographs demonstrate advanced avascular necrosis with structural collapse of the femoral head. What is the most appropriate salvage procedure?

An 82-year-old female presents with groin pain after a mechanical fall. X-rays show a periprosthetic fracture around a cemented femoral stem. The fracture extends just below the tip of the stem. The stem is radiographically loose with subsidence, but there is adequate proximal femoral bone stock. According to the Vancouver classification, what is the most appropriate management?

During a primary total knee arthroplasty, trial reduction reveals that the knee is well-balanced in full extension, but the flexion gap is unacceptably tight. The surgeon has used a measured resection, posterior referencing technique. Which of the following intraoperative adjustments is most appropriate to balance the gaps?

A 60-year-old male with a metal-on-polyethylene total hip arthroplasty (THA) placed 6 years ago presents with new-onset groin pain. Radiographs show a well-fixed stem and cup. Serum metal ion testing reveals elevated cobalt levels with normal chromium levels. MRI with MARS sequencing shows a cystic periarticular mass. What is the most likely etiology of his symptoms?

A 70-year-old male sustains a fall 5 years after undergoing a right total hip arthroplasty. Radiographs reveal a spiral fracture around the distal aspect of a fully porous-coated femoral stem. The fracture extends 5 cm distal to the tip of the stem. Radiographic and clinical evaluation confirms the stem is solidly fixed. According to the Vancouver classification, what is the most appropriate surgical management?

A healthy, independent, and highly active 68-year-old male sustains a displaced femoral neck fracture. The decision is made to perform a Total Hip Arthroplasty (THA) rather than a Bipolar Hemiarthroplasty. In this specific patient population, THA is associated with which of the following outcomes compared to hemiarthroplasty?

An 82-year-old male with a history of a cementless total hip arthroplasty presents with a periprosthetic femur fracture following a ground-level fall. Radiographs demonstrate a fracture around the stem with obvious component subsidence and severe proximal osteolysis and bone loss extending to the diaphysis. According to the Vancouver classification, what is the most appropriate surgical management?

A 65-year-old female experiences recurrent anterior dislocations of her total hip arthroplasty. CT imaging is performed to evaluate component positioning. Which of the following component profiles is the most likely etiology of her anterior instability?

A 45-year-old male is being evaluated for a hip resurfacing arthroplasty (HRA). Which of the following patient factors represents an absolute contraindication to this specific procedure?