1. General Principles & Basic Science MCQs

To maximize primary (direct) bone healing, a fracture construct must provide absolute stability. According to Perren's strain theory, direct Haversian remodeling without intermediate callus formation requires the fracture gap strain to be less than:

During distraction osteogenesis (e.g., Ilizarov bone transport), new bone forms within the distraction gap. This primarily occurs through which underlying biologic process?

To minimize stress shielding around a femoral stem, the implant's material should have a stiffness (modulus of elasticity) as comparable to cortical bone as possible. Which of the following biomaterials most closely approximates the Young's modulus of cortical bone?

According to the rule of mixtures, the stiffness of a composite material depends on its distinct components. In normal cortical bone, which component is primarily responsible for providing its tensile strength?

You are applying a uniplanar external fixator to a tibia fracture. To maximize the bending stiffness of the construct, altering which parameter of the half-pins will have the most profound mathematical effect?

Normal articular cartilage is divided into specific structural zones. The deep zone is characterized by which of the following properties when compared to the superficial zone?

Denosumab is a targeted pharmacological therapy utilized in the treatment of osteoporosis and giant cell tumor of bone. What is its precise mechanism of action at the cellular level?

When a constant force is applied to a ligament over an extended period of time, it undergoes a gradual increase in deformation. What is this biomechanical property called?

Which of the following enzymes is primarily responsible for creating the acidic environment in the resorption pit beneath an active osteoclast?

For a hollow cylindrical bone undergoing a bending load, the bending stiffness is directly proportional to which of the following geometric properties?

Bone morphogenetic proteins (BMPs) induce osteogenesis primarily by signaling through which of the following intracellular pathways?

In articular cartilage, which structural component is primarily responsible for resisting compressive loads?

The pullout strength of a cortical screw is most heavily influenced by which of the following design parameters?

Which transcription factor is considered the master regulator essential for the commitment of mesenchymal stem cells to the osteoblast lineage?

When a cylindrical long bone is subjected to pure torsional loading, the maximum shear stress occurs at which location?

According to Perren's strain theory, which type of tissue is capable of tolerating the highest amount of interfragmentary strain before rupturing?

Sclerostin is a protein secreted by osteocytes that inhibits bone formation. It accomplishes this by antagonizing which of the following signaling pathways?

Which of the following combinations of orthopedic implants is most likely to result in significant galvanic corrosion in vivo?

Cortical bone exhibits different mechanical properties depending on the direction in which the load is applied (e.g., stronger in longitudinal compression than in transverse loading). This characteristic is best termed: