3. Adult Reconstruction (Hip & Knee) MCQs

A 65-year-old man presents with progressive thigh pain 10 years after a cementless total hip arthroplasty. Radiographs demonstrate eccentric positioning of the femoral head within the acetabular shell and focal endosteal radiolucencies in Gruen zones 1 and 7. What is the primary biologic mechanism responsible for these radiographic findings?

Following a primary total hip arthroplasty performed via a posterolateral approach, the patient develops a foot drop and decreased sensation over the dorsum of the foot. Which of the following intrinsic anatomic factors makes the affected nerve particularly susceptible to this surgical injury?

The primary wear mechanism responsible for generating the majority of submicron particulate debris in a well-functioning, traditional metal-on-polyethylene total hip arthroplasty is:

The predominant mechanism of wear in conventional ultra-high-molecular-weight polyethylene (UHMWPE) that historically contributed to osteolysis in total hip arthroplasty is:

In total joint arthroplasty, wear particles generated by the physical scratching of the polyethylene bearing surface by a harder metal or ceramic surface is best described as:

The endurance limit of an orthopedic implant material is defined as the:

When selecting a biomaterial for a total hip arthroplasty femoral stem to minimize stress shielding, the surgeon should consider the elastic modulus. Which of the following orthopedic biomaterials has an elastic modulus most closely approximating that of human cortical bone?

Aseptic loosening in total joint arthroplasty is primarily driven by a biological host response to particulate wear debris. Which cell type is the primary initial responder that engulfs these particles and releases pro-inflammatory cytokines like TNF-alpha and IL-1?

Particle-induced osteolysis after total joint arthroplasty is primarily driven by the phagocytosis of wear debris by which of the following cells?

Highly cross-linked ultra-high molecular weight polyethylene (UHMWPE) reduces adhesive and abrasive wear in total hip arthroplasty primarily through which of the following mechanisms?

Aseptic loosening and osteolysis around a total hip arthroplasty are most commonly initiated by macrophage phagocytosis of which type of wear particles?

According to Archard's law of adhesive wear in total joint arthroplasty, the volume of wear debris generated is inversely proportional to which of the following variables?

When placing screws into the acetabulum during total hip arthroplasty, the "safe zone" that provides optimal bone stock while minimizing the risk of neurovascular injury is located in which quadrant?

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?

A patient sustains a displaced scaphoid waist fracture. The high risk of proximal pole avascular necrosis is due to the retrograde blood supply originating from branches of which artery?

During a total hip arthroplasty using a posterior approach, the surgeon carefully identifies the sciatic nerve. In roughly 10-15% of the population, a common anatomic variation exists concerning the relationship of the sciatic nerve to the piriformis muscle. Which of the following describes this most frequent variant?

During acetabular component fixation in a total hip arthroplasty, the surgeon defines the safe zones based on Wasielewski's quadrant system, using a line from the ASIS through the center of the acetabulum and a perpendicular line at the center. Placing a screw in the anterosuperior quadrant places which structure at highest risk?

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?

A 60-year-old woman exhibits a prominent Trendelenburg gait post-total hip arthroplasty via a direct lateral (Hardinge) approach. Injury to which nerve is the most likely cause, and what are its contributing nerve roots?