1. General Principles & Basic Science MCQs

Bone Morphogenetic Proteins (BMPs) induce osteoblastic differentiation from mesenchymal stem cells. Which intracellular signaling molecules are directly phosphorylated by BMP receptors to translocate to the nucleus?

A surgeon secures a cerclage wire around a femoral shaft. Over several months, the wire remains intact but becomes loose due to continuous deformation of the bone under constant strain. What viscoelastic property is this?

Articular cartilage exhibits rate-dependent stiffness, acting much stiffer under rapid impact loading than under slow loading. This biomechanical property is primarily due to:

During distraction osteogenesis (Ilizarov technique), bone forms directly under tensional stress without a cartilaginous intermediate. This process is best characterized as:

Denosumab is utilized in the treatment of osteoporosis and giant cell tumor of bone. Its mechanism of action most closely mimics which naturally occurring endogenous molecule?

According to Perren's strain theory, what is the maximum interfragmentary strain that allows for primary bone healing to occur?

A 45-year-old male undergoes a revision total hip arthroplasty with a fully porous-coated diaphyseal fitting stem. Postoperatively, he experiences severe thigh pain attributed to stress shielding. Which of the following material properties of the stem is most responsible for this phenomenon?

The pullout strength of a cortical screw is most heavily dependent on which of the following geometric parameters?

A surgeon incorrectly mixes a stainless steel screw with a titanium plate during internal fixation of a femur fracture. Which type of corrosion is most likely to occur, and which metal will degrade?

During a biomechanical study of the ACL, a constant tensile load is applied to the ligament over an extended period. The investigator notes that the ligament continues to slowly elongate despite the load remaining unchanged. What biomechanical property does this represent?

Demineralized bone matrix (DBM) is commonly used as a bone graft substitute in spinal fusions. Which of the following best describes its biological properties?

The compressive stiffness of articular cartilage is primarily provided by which of its structural components?

Bone morphogenetic protein-2 (BMP-2) utilizes a specific intracellular signaling pathway to induce osteoblast differentiation. Which of the following molecules acts as the primary intracellular mediator for this pathway?

A massive structural cortical allograft is used for reconstruction after an osteosarcoma resection. Which of the following best describes the healing process of this allograft compared to a cancellous autograft?

On a standard stress-strain curve for a ductile biomaterial like stainless steel, what does the total area under the curve up to the point of failure represent?

A patient with severe osteoporosis is treated with romosozumab. This medication primarily increases bone formation by targeting sclerostin. Which cellular pathway is directly upregulated as a result of this inhibition?

An orthopaedic implant manufacturer is designing a new cementless hip stem. They wish to use a metal with the lowest modulus of elasticity that still provides adequate fatigue strength to minimize stress shielding. Which of the following metals should they select?