Biomechanics & Biomaterials MCQs

Radiographic evaluation of a patient 2 years after an uncemented total hip arthroplasty shows proximal femoral bone resorption. This phenomenon, known as stress shielding, can be minimized by selecting a stem material with an elastic modulus closer to that of cortical bone. Which of the following solid metals best fits this description?

Articular cartilage exhibits complex biphasic viscoelastic behavior. Under rapid, heavy compressive loading, the initial resistance to deformation is primarily provided by:

An intramedullary nail is used to stabilize a transverse midshaft femur fracture. If the surgeon chooses to ream the canal and insert a solid nail with a diameter of 12 mm instead of 10 mm, the torsional rigidity of the nail increases by approximately what factor?

A diaphyseal tibia fracture is treated with rigid plate fixation. According to the principles of stress shielding, which material property of the plate most heavily dictates the degree of osteopenia that will occur underneath the plate?

Articular cartilage exhibits distinct viscoelastic properties during weight-bearing. Which of the following biomechanical phenomena describes the progressive deformation of cartilage over time when subjected to a constant static load?

When a normal flexor tendon is subjected to tensile loading, the initial "toe region" of its load-elongation curve corresponds to which microstructural event?

Cortical bone exhibits vastly different mechanical properties (e.g., strength and stiffness) depending on the direction of the applied load. This fundamental material property is best described as:

To reduce wear in total joint arthroplasty, ultra-high-molecular-weight polyethylene (UHMWPE) is often highly cross-linked using gamma or electron beam irradiation. What subsequent manufacturing step is essential to prevent long-term oxidative degradation of the implant?

When utilizing a solid cylindrical intramedullary nail for diaphyseal fracture fixation, the torsional rigidity of the implant is proportional to its radius raised to which power?

Polymethylmethacrylate (PMMA) bone cement provides immediate fixation of total joint arthroplasty components. By which of the following mechanisms does PMMA secure the implant to the surrounding host bone?

During the physiological loading of a normal ligament, the initial non-linear "toe region" of the stress-strain curve represents which of the following microstructural events?

Mixing stainless steel and titanium implants in the same surgical field can lead to accelerated degradation of the implants. Which of the following best describes the primary mechanism of this process?

Because bone is a viscoelastic material, its mechanical properties depend heavily on the rate of loading. When cortical bone is subjected to a high strain rate (fast loading), how do its properties change compared to low strain rate loading?

Which of the following wear mechanisms is defined as the removal of material resulting from two articulating surfaces rubbing against each other, leading to local microscopic welding and subsequent tearing off of particles?

Which of the following common orthopaedic biomaterials possesses the highest modulus of elasticity (stiffness)?

Which of the following mechanical properties is determined by the slope of the linear elastic region of a stress-strain curve?

When designing a solid intramedullary nail, doubling the radius of the nail will increase its torsional rigidity by a factor of:

A tendon graft used for ACL reconstruction is tensioned to a specific length and fixed in place. Over time, the tension in the graft progressively decreases while the length remains constant. This viscoelastic property is known as:

A surgeon uses a stainless steel screw with a titanium plate for fracture fixation. Which of the following is the most likely consequence of using these mixed metals in vivo?

Cortical bone is stronger in compression along its longitudinal axis than it is when subjected to transverse loading. This material property, where mechanical behavior depends on the direction of loading, is known as: