Biomechanics & Biomaterials MCQs

A 66-year-old man presents with new-onset groin pain 6 years after a primary total hip arthroplasty using a metal-on-polyethylene bearing. Serum metal ion testing reveals a cobalt level of 12 ppb and a chromium level of 1.5 ppb. Which of the following implant characteristics most increases the risk of this condition?

The introduction of highly cross-linked polyethylene in total hip arthroplasty has significantly reduced volumetric wear rates. What mechanical trade-off results from the irradiation process used to cross-link the polyethylene?

In the production of highly cross-linked polyethylene for arthroplasty, what is the primary biomechanical consequence of remelting the plastic after irradiation?

Highly cross-linked polyethylene (HXLPE) is used in modern arthroplasty to reduce volumetric wear. During its manufacturing, irradiation is typically followed by a thermal treatment such as remelting or annealing. What is the primary purpose of the remelting process?

Highly cross-linked polyethylene is utilized in THA to reduce wear rates. What is the primary purpose of the post-irradiation melting or annealing process during its manufacture?

Highly cross-linked polyethylene (HXLPE) is widely used in total hip arthroplasty to reduce wear rates. Which of the following manufacturing steps is primarily responsible for eliminating free radicals to prevent in vivo oxidation?

On a typical stress-strain curve for a ductile orthopedic implant material, what term describes the point where the material begins to deform plastically rather than elastically?

When a stainless steel plate is fixed with titanium screws in a fracture construct, which of the following electrochemical processes is most likely to cause early implant failure?

Which of the following modifications to a cortical bone screw most significantly increases its pullout strength?

When a ligament is subjected to a constant, sustained sub-failure load, it experiences a progressive increase in length over time. What is this time-dependent biomechanical property called?

Cortical bone is stronger in longitudinal compression than it is in transverse loading or tension. What is the biomechanical term for a material that exhibits different mechanical properties depending on the direction of loading?

In the biomechanical evaluation of orthopedic implants, the total area under a material's stress-strain curve represents which of the following properties?

Review the provided biomechanical graphic.

On a standard stress-strain curve for cortical bone, what represents the point beyond which the material will no longer return to its original shape upon unloading?

A polymer undergoes continued progressive deformation over time when subjected to a constant load. This biomechanical phenomenon is best described as:

To reduce stress shielding around a femoral stem, an implant designer wishes to use a material whose modulus of elasticity most closely approximates that of cortical bone. Which of the following materials has a Young's modulus closest to cortical bone?

Highly cross-linked polyethylene (HXLPE) is used in total hip arthroplasty to reduce wear rates. What biomechanical trade-off is most commonly associated with increasing the cross-linking of polyethylene?

A typical stress-strain curve for cortical bone is being analyzed.

What term is used to describe the area under the entire stress-strain curve before the point of complete failure?

In a stress-strain curve of a cortical bone specimen under tension, the area under the entire curve represents which of the following mechanical properties?