Total Hip Arthroplasty (THA) MCQs

A 42-year-old active male underwent a ceramic-on-ceramic total hip arthroplasty 3 years ago. He presents with an audible 'squeaking' noise from the hip during deep flexion, though he denies any pain. Radiographs show no loosening. What is the most common factor associated with this phenomenon?

A patient experiences recurrent posterior dislocations of their THA. The acetabular component is evaluated on CT scan and found to be placed in 5 degrees of anteversion and 30 degrees of abduction. Which parameter falls outside the traditional Lewinnek safe zone and is contributing most to the instability?

Following a primary THA using a posterior approach, a patient exhibits a foot drop and inability to extend the great toe. Which specific portion of the sciatic nerve is most vulnerable to injury during this procedure?

A 52-year-old female complains of a high-pitched squeaking noise coming from her total hip arthroplasty during ambulation. The implant is a ceramic-on-ceramic bearing. Which of the following is the most significant risk factor for this phenomenon?

Trunnionosis, or mechanically assisted crevice corrosion, has emerged as a significant mode of failure in modern total hip arthroplasties. Which of the following implant characteristics most increases the risk of this complication?

A 55-year-old male complains of numbness and burning over the anterolateral aspect of his thigh following a primary total hip arthroplasty. Which surgical approach was most likely utilized?

During a total hip arthroplasty via a posterior approach, the surgeon meticulously repairs the short external rotators and the posterior capsule to the greater trochanter. What is the primary established clinical benefit of this step?

A 68-year-old man presents with his third posterior dislocation of a primary THA performed 4 months ago. Radiographs demonstrate the acetabular component is in 35 degrees of abduction and 5 degrees of retroversion. The femoral stem is stable and in neutral version. What is the most appropriate definitive management?

During a posterior approach THA, trial reduction reveals that the leg is lengthened by 1.5 cm and the offset is decreased by 1 cm compared to the preoperative template. Shuck testing shows significant soft tissue laxity. Which modular adjustment will best restore proper offset and soft tissue tension while minimizing further leg lengthening?

During a posterior approach to the hip, which muscle is most critical to protect and repair to minimize the risk of postoperative dislocation?

To minimize the risk of dislocation, the acetabular component in a THA should ideally be placed within the "safe zone" described by Lewinnek. What are these target angles?

A patient with a history of severe heterotopic ossification (HO) following a contralateral THA is undergoing an ipsilateral THA. Which of the following is the most proven prophylactic treatment against HO?

Following a primary total hip arthroplasty performed via a posterior approach, the patient demonstrates a foot drop and decreased sensation over the dorsum of the foot. Which specific neural structure is most likely injured?

During a posterior approach to the hip, the short external rotators are tenotomized. Which of the following muscles inserts on the medial aspect of the greater trochanter, immediately superior to the superior gemellus?

In repairing a posterior column acetabular fracture via a Kocher-Langenbeck approach, the surgeon must identify and protect the primary blood supply to the adult femoral head. Which of the following arteries provides this primary supply?

To preserve the primary blood supply to the adult femoral head during a posterior approach to the hip, which anatomical structure protects the main arterial contribution before it enters the joint capsule?

The primary blood supply to the adult femoral head is the medial circumflex femoral artery (MCFA). The deep branch of the MCFA consistently courses between which two muscles prior to ascending to the trochanteric fossa?

The medial femoral circumflex artery (MFCA) provides the primary blood supply to the adult femoral head. Which of the following muscles must be protected during a posterior approach to the hip to avoid injury to the deep branch of the MFCA?

To protect the posterior interosseous nerve (PIN) during an anterior (Henry) approach to the proximal radius, the forearm should be positioned in what way and why?

The blood supply to the adult femoral head is predominantly provided by the lateral epiphyseal artery. This artery is a direct terminal branch of which of the following vessels?