Biomechanics & Biomaterials MCQs

In evaluating a patient with a painful primary THA, you suspect a diagnosis of aseptic loosening due to massive osteolysis. What material property of modern titanium (Ti-6Al-4V) alloy stems helps reduce stress shielding compared to Cobalt-Chromium (CoCr) stems?

Trabecular metal (highly porous Tantalum) is frequently used in acetabular revision components. What is its main mechanical advantage over traditional sintered titanium bead porous coatings?

In the manufacturing of highly cross-linked polyethylene (HXLPE) for total joint arthroplasty, gamma irradiation is used to induce cross-linking to improve wear resistance. However, this process creates free radicals. Which of the following subsequent steps is utilized to eliminate these free radicals and reduce long-term oxidation, despite causing a slight decrease in the material's fatigue strength?

On a standard stress-strain curve representing the biomechanical properties of an orthopedic implant material, what specific mechanical behavior does the 'yield point' denote?

Titanium alloys (e.g., Ti-6Al-4V) are extensively utilized in modern orthopaedic implants due to excellent biocompatibility and osseointegration properties. Compared to Cobalt-Chromium (CoCr) alloys, Titanium alloys possess which of the following distinct biomechanical profiles?

A 65-year-old patient presents with acute, severe pain and swelling in the right knee. Joint fluid aspiration reveals weakly positively birefringent, rhomboid-shaped crystals under compensated polarized light microscopy. Which of the following is the most likely composition of these crystals?

In biomechanical evaluation of tendons, the phenomenon where a tendon subjected to a constant displacement demonstrates a gradual decrease in measured tension over time is best described by which of the following terms?

The introduction of highly cross-linked polyethylene in total hip arthroplasty has dramatically reduced wear rates. However, the process of cross-linking using irradiation negatively impacts the mechanical properties of the polyethylene. Which step is most commonly added to the manufacturing process to eliminate free radicals and prevent in vivo oxidation?

A surgeon plans to use a stainless steel screw with a titanium plate for fracture fixation. Which of the following best describes the primary mechanism of early implant failure associated with this specific metallurgical combination?

According to Wolff's Law, bone remodels in response to mechanical stress. Which of the following mechanical properties accurately describes bone's ability to exhibit different stiffness and strength depending on the speed (rate) at which a load is applied?

During an ulnar collateral ligament (UCL) reconstruction using the docking technique, where is the optimal location for the humeral tunnel to ensure proper isometry of the graft?

To minimize stress shielding after total hip arthroplasty, a femoral stem material with a Young's modulus closest to that of cortical bone is desired. Which of the following orthopedic materials possesses the lowest Young's modulus?

A ligament graft is tensioned and secured during an anterior cruciate ligament (ACL) reconstruction. Over time, the tension in the graft decreases despite the graft remaining at a constant length. This biomechanical phenomenon is known as:

Polymethylmethacrylate (PMMA) bone cement is often loaded with antibiotics for the treatment or prophylaxis of infection. To be effective and not compromise the cement's mechanical properties, the ideal antibiotic should possess which of the following characteristics?

Galvanic corrosion is a concern when mixing different metals in orthopedic implants. If a stainless steel screw is placed through a titanium alloy plate, which metal acts as the anode and is subject to accelerated corrosion?

During an anterior cruciate ligament reconstruction, the graft is tensioned to a specific length and fixed. Over the next several hours, the tension required to maintain this constant length gradually decreases. This viscoelastic property is best described by which of the following terms?

Titanium alloys (e.g., Ti-6Al-4V) are widely used in orthopedics due to their excellent biocompatibility and modulus of elasticity that is closer to cortical bone than stainless steel. Which of the following is a primary biomechanical disadvantage of using titanium alloys for internal fixation plates?