1. General Principles & Basic Science MCQs

In evaluating the biomechanical behavior of ligaments, a constant static load is applied to a ligamentous specimen over a prolonged period. It is observed that the specimen undergoes a progressive increase in deformation over time. This viscoelastic property is termed:

A 70-year-old woman with severe osteoporosis is treated with romosozumab, a monoclonal antibody that targets sclerostin. By inhibiting sclerostin, this medication primarily enhances bone formation through which of the following cellular mechanisms?

During a cemented total knee arthroplasty, polymethylmethacrylate (PMMA) is utilized for component fixation. Which of the following statements regarding the biomechanical properties and function of PMMA is true?

During mechanical testing of a novel titanium alloy plate, the material is loaded in tension until catastrophic failure occurs. The total area under the stress-strain curve prior to failure represents the material's:

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:

Continuous hypersecretion of parathyroid hormone (PTH) leads to net bone resorption. However, once-daily subcutaneous administration of teriparatide results in net bone formation. This anabolic effect of intermittent PTH is primarily mediated 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?

Which of the following cells is the primary source of osteoprotegerin (OPG), and what is its molecular mechanism of action in bone remodeling?

According to Perren's strain theory of fracture healing, primary (contact) bone healing with the direct formation of lamellar bone can only occur when the strain environment at the fracture gap is maintained below what threshold?

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:

Osteocytes act as the primary mechanosensors within bone. Under conditions of decreased mechanical strain (unloading), osteocytes upregulate the secretion of which molecule to inhibit osteoblast differentiation?

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?

A patient with chronic kidney disease presents with renal osteodystrophy. Laboratory analysis reveals elevated parathyroid hormone (PTH). What is the direct mechanism by which persistently elevated PTH drives bone resorption?

Which of the following bone morphogenetic proteins (BMPs) utilizes an absorbable collagen sponge carrier and is FDA-approved for the treatment of acute, open tibial shaft fractures?

Normal articular cartilage is divided into distinct zones. Which zone is characterized by the highest water content and collagen fibers that are oriented parallel to the joint surface to resist shear forces?

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?