3. Adult Reconstruction (Hip & Knee) MCQs

When performing a direct lateral (Hardinge) approach to the hip, proximal splitting of the gluteus medius must be strictly limited to less than 3 to 5 cm from the tip of the greater trochanter. This safe zone prevents denervation of the muscle by protecting which nerve?

A 7-year-old boy with spastic quadriplegic cerebral palsy is evaluated during a routine surveillance visit. His AP pelvis radiograph demonstrates a Reimers migration percentage (MP) of 45% in the right hip. He has 30 degrees of hip abduction. What is the recommended management?

During a posterior-stabilized total knee arthroplasty, trial reduction is performed. The knee is noted to be symmetric and balanced in flexion, but tight in extension. What is the most appropriate next step to balance the knee?

A 65-year-old woman undergoes total knee arthroplasty. Intraoperatively, the surgeon notes that the patella tracks laterally and has a tendency to subluxate during flexion. Which of the following component adjustments would most effectively improve patellar tracking?

During a posterior-stabilized total knee arthroplasty using an anterior referencing system, the surgeon evaluates the gaps and notes that the joint is tight in flexion but symmetric and balanced in extension. Which of the following is the most appropriate next step?

A patient undergoes a primary THA via a direct anterior approach. Postoperatively, they report a burning sensation and numbness over the anterolateral aspect of the operative thigh. Which nerve is most likely affected, and where is it most vulnerable during this surgical exposure?

A 72-year-old man presents with knee pain 2 years following a TKA. Synovial fluid analysis reveals a WBC count of 4,500 cells/µL with 85% PMNs. Which of the following additional findings would definitively confirm a periprosthetic joint infection (PJI) according to the major criteria of the 2018 International Consensus Meeting?

A 55-year-old man presents with medial-sided knee pain. Radiographs reveal medial compartment osteoarthritis. He is being considered for a medial unicompartmental knee arthroplasty (UKA). Which of the following is considered an absolute contraindication to UKA?

A 68-year-old woman undergoes a primary total hip arthroplasty via a posterior approach. Six weeks postoperatively, she experiences recurrent posterior dislocations. Radiographic evaluation shows the cup position.

The acetabular component is measured in 25 degrees of abduction and 5 degrees of retroversion. What is the most appropriate management?

A 62-year-old woman complains of anterior knee pain and a clunking sensation 1 year after a posterior-stabilized total knee arthroplasty. Examination reveals patellar maltracking with a lateral tilt. Radiographs and a CT scan demonstrate internal rotation of both the tibial and femoral components. Which of the following is the most likely consequence of this combined malrotation?

Intraoperative assessment during a primary posterior-stabilized total knee arthroplasty (TKA) reveals a flexion gap that is excessively tight, while the extension gap is perfectly balanced. Which of the following modifications is the most appropriate step to achieve a balanced knee?

Which of the following is considered an absolute contraindication to a medial unicompartmental knee arthroplasty (UKA)?

A 70-year-old man presents with a painful, swollen right knee 4 years after a primary TKA. Joint aspiration yields synovial fluid with a white blood cell count of 45,000 cells/mcL and 92% polymorphonuclear neutrophils. Which of the following is the most appropriate next step in management?

A 55-year-old man presents with worsening groin pain 7 years after receiving a metal-on-polyethylene total hip arthroplasty with a large-diameter cobalt-chromium femoral head. Radiographs show well-fixed components without osteolysis. A MARS MRI demonstrates a thick-walled cystic mass communicating with the joint. Joint aspiration yields sterile fluid with markedly elevated cobalt levels. What is the most likely diagnosis?

A 68-year-old woman complains of recurrent knee swelling and a sense of instability when descending stairs 2 years after a primary posterior-stabilized total knee arthroplasty (TKA). Physical examination reveals a stable knee in full extension to varus and valgus stress, but marked anteroposterior translation at 90 degrees of flexion. Which of the following intraoperative technical errors is the most likely cause of this presentation?

When evaluating histologic tissue samples from a patient undergoing revision total hip arthroplasty for an adverse local tissue reaction (ALTR) associated with a metal-on-metal articulation, which of the following findings is most characteristic of ALVAL (aseptic lymphocyte-dominated vasculitis-associated lesion)?

A 78-year-old woman sustains a fall 5 years after a primary cementless THA.

Radiographs demonstrate a fracture around the femoral stem. Intraoperative assessment confirms that the femoral stem is grossly loose, but there is adequate cortical bone distal to the fracture in the diaphysis. What is the most appropriate management for this Vancouver B2 periprosthetic fracture?

A 72-year-old female with a history of recurrent THA dislocations was revised to a dual mobility articulation 3 years ago. She now presents with a new-onset, painless "clunk" with hip motion. Radiographs demonstrate an asymmetric, eccentric position of the metallic femoral head within the acetabular shell. What is the most likely diagnosis?

According to the 2018 International Consensus Meeting (ICM) criteria for diagnosing periprosthetic joint infection (PJI), which of the following synovial fluid biomarkers is considered a highly specific major criterion for confirming the diagnosis?

A 64-year-old woman is 1 year status post a posterior-stabilized TKA. She reports a painful catching sensation and an audible "clunk" at approximately 30 to 45 degrees of extension from a flexed position.

What is the most appropriate definitive management for this condition if conservative measures fail?