Total Hip Arthroplasty (THA) MCQs

When performing a posterior approach to the hip (Kocher-Langenbeck), the medial femoral circumflex artery (MFCA) is at risk. The main ascending branch of the MFCA consistently runs deep to which muscle?

A 65-year-old patient undergoes a primary THA. Postoperatively, the acetabular component is found to have 10 degrees of anteversion and 30 degrees of inclination. The patient is at highest risk for dislocation in which of the following positions?

Following a right total hip arthroplasty, a patient complains of a prominent right-sided limp. Clinical exam shows the right leg is 2 cm longer than the left, and the shuck test demonstrates excessive soft tissue tension. How does increased femoral offset during THA affect hip biomechanics?

A 62-year-old male with a metal-on-polyethylene THA presents with painful swelling in the thigh 6 years postoperatively. Aspirate is negative for infection, but serum cobalt levels are significantly elevated. Which of the following is the most likely source of the metal debris?

Following a difficult THA for developmental dysplasia of the hip, the patient develops a foot drop and is unable to actively extend the toes or dorsiflex the ankle. Sensation is intact on the plantar aspect of the foot. Which division of the sciatic nerve is most commonly injured during THA?

A patient presents with recurrent anterior dislocations following a total hip arthroplasty performed via a posterior approach. Radiographs show the acetabular component has 55 degrees of inclination and 45 degrees of anteversion. What is the primary cause of dislocation in this patient?

A 45-year-old female undergoes total hip arthroplasty with a ceramic-on-ceramic bearing. Three years later, she complains of a reproducible squeaking noise during gait. Which of the following factors is most strongly associated with this phenomenon?

A patient reports persistent groin pain and catching when actively rising from a seated position following an uncemented THA. A diagnostic injection of lidocaine into the iliopsoas bursa provides complete relief. What radiographic finding is most likely present?

Based on the HEALTH trial and recent evidence, which of the following is true regarding THA compared to hemiarthroplasty for displaced femoral neck fractures in active older adults?

A patient complains of an apparent leg length discrepancy immediately following a primary THA. Examination reveals the operative leg appears longer, but true leg length measurement (ASIS to medial malleolus) is equal bilaterally. What is the most likely cause?

During a posterior approach to the hip, protecting the medial circumflex femoral artery (MFCA) is critical. The main branch of the MFCA typically courses posterior to the obturator externus tendon and anterior to which of the following muscles?

A surgeon is performing a direct lateral (Hardinge) approach to the hip. To avoid injury to the superior gluteal nerve, the proximal split in the gluteus medius should not extend beyond what distance from the tip of the greater trochanter?

During a posterior approach to the hip, extreme external rotation of the femur places which of the following vascular structures at highest risk, potentially compromising the main blood supply to the adult femoral head?

A 60-year-old man experiences recurrent posterior dislocations after a total hip arthroplasty. Radiographs demonstrate a well-fixed stem and cup, but with significantly decreased femoral offset compared to the contralateral normal hip. Which of the following best describes the biomechanical consequence of increasing the femoral offset during revision surgery?

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?

During a complex revision THA for a well-fixed extensively porous-coated stem, the surgeon decides to perform an extended trochanteric osteotomy (ETO). Which muscle attachments must be maintained on the osteotomized fragment to ensure viability and subsequent healing?

In total hip arthroplasty, successfully increasing the femoral offset without altering the leg length will have which of the following biomechanical effects?

According to the quadrant system described by Wasielewski for acetabular screw placement during THA, placing a screw into the anterior-superior quadrant places which of the following structures at greatest risk?

A 65-year-old man receives a ceramic-on-ceramic total hip arthroplasty. Two years later, he complains of a reproducible squeaking noise during gait. What is the most common biomechanical or radiographic finding associated with this phenomenon?

During a posterior approach to the hip, excessive retraction or release of the short external rotators close to the intertrochanteric crest endangers the primary blood supply to the femoral head. These critical retinacular vessels are terminal branches of which artery?