3. Adult Reconstruction (Hip & Knee) MCQs

A 65-year-old female presents with progressive groin pain three years after undergoing a metal-on-metal total hip arthroplasty (THA). Aspiration of the hip yields clear fluid with negative cultures. An MRI with metal artifact reduction sequence (MARS) shows a large cystic periarticular mass. Which of the following serum markers are most likely to be significantly elevated in this patient?

During a primary total knee arthroplasty for a patient with a severe fixed valgus deformity, the surgeon finds that the lateral side is significantly tight in both flexion and extension. Which of the following structures is typically the first to be released in a step-wise soft tissue balancing of a valgus knee?

A 68-year-old female undergoes a primary total hip arthroplasty. To minimize the risk of dislocation, the surgeon pays close attention to component positioning. According to the Lewinnek safe zone, what is the ideal acetabular cup orientation?

During a posterior approach to the hip (Kocher-Langenbeck), the surgeon isolates the short external rotators. To protect the blood supply to the femoral head, particularly the medial femoral circumflex artery (MFCA), where should the obturator externus tendon be transected if its release is necessary?

During a total knee arthroplasty (TKA), the surgeon notices that the knee is tight in flexion but stable and balanced in extension. Which of the following adjustments is most appropriate to balance the flexion gap?

A 65-year-old man is undergoing a primary total hip arthroplasty (THA). The surgeon selects a high-offset femoral stem that increases femoral offset without altering leg length. Compared to a standard offset stem, what is the primary biomechanical consequence of this modification?

During a primary total knee arthroplasty (TKA), trial components are inserted. The surgeon observes that the knee is perfectly balanced and stable in full extension, but it is excessively tight in 90 degrees of flexion. Which of the following is the most appropriate surgical step to balance the knee?

A 55-year-old woman with a metal-on-metal THA presents with progressive groin pain 4 years postoperatively. Advanced imaging reveals a large solid and cystic pelvic mass. A subsequent biopsy of the pseudotumor demonstrates a dense perivascular lymphocytic infiltrate. This pathology is a result of which immunological mechanism?

Based on classical criteria, which of the following is considered an absolute contraindication for a medial unicompartmental knee arthroplasty (UKA) in a patient with medial compartment osteoarthritis?

A 68-year-old woman presents with persistent lateral anterior knee pain and clinical evidence of lateral patellar subluxation 1 year after a primary TKA. During revision surgery, malrotation of the components is suspected. Which of the following technical errors is the most common cause of lateral patellar maltracking in TKA?

According to the 2018 International Consensus Meeting (ICM) criteria for Periprosthetic Joint Infection (PJI), a synovial fluid analysis from a painful 2-year-old THA reveals a white blood cell (WBC) count of 4,500 cells/µL and 85% polymorphonuclear neutrophils (PMNs). How are these specific laboratory results interpreted in the diagnostic scoring algorithm?

During kinematic analysis of a posterior cruciate-retaining (CR) total knee arthroplasty, the patient is noted to have paradoxical anterior sliding of the femur on the tibia during deep flexion. What is the primary cause of this kinematic abnormality?

A 45-year-old man underwent an uncomplicated THA utilizing a ceramic-on-ceramic bearing surface. At his 2-year follow-up, he complains of a loud, audible 'squeaking' sound from his hip when transitioning from sitting to standing. Which of the following factors is most strongly associated with the development of this complication?

During a standard posterior approach (Moore/Southern) to the hip, which critical blood vessel is typically encountered near the superior border of the quadratus femoris and must be identified and coagulated to prevent significant postoperative hematoma?

During a primary TKA using a measured resection technique, trial components are placed. The knee exhibits a 15-degree flexion contracture (tight in extension) but demonstrates excessive varus-valgus play at 90 degrees of flexion (loose in flexion). Which of the following adjustments will best resolve this specific mismatch?

A patient presents with persistent anterior knee pain and a subjective feeling of instability 6 months following a primary TKA. Standing radiographs demonstrate a significantly elevated joint line and secondary patella baja. Which of the following complications is most specifically associated with an elevated joint line in TKA?

A 58-year-old woman undergoes a primary total hip arthroplasty (THA). To optimize hip biomechanics, the surgeon places the acetabular component medially and inferiorly to restore the anatomical center of rotation (COR). What is the effect of this component positioning on the overall joint reaction force (JRF) and the required abductor muscle force?

During a primary total knee arthroplasty (TKA) using a gap-balancing technique, the surgeon notes that with the trial components in place, the knee is symmetrically loose in full extension but perfectly balanced at 90 degrees of flexion. Which of the following is the most appropriate corrective action?

A 68-year-old man presents with a Vancouver B2 periprosthetic femur fracture 8 years after a primary THA. Radiographs reveal a grossly loose femoral stem, but the proximal femoral bone stock remains adequate. What is the most appropriate surgical management?