1. General Principles & Basic Science MCQs

A 25-year-old man with Marfan syndrome requires surgery for a severe scoliosis. His condition is caused by a mutation in the fibrillin-1 gene. This mutation leads to dysregulation of which of the following signaling molecules?

Which of the following represents the primary difference in mechanical properties between cortical bone and cancellous bone?

The transcription factor Runx2 (Cbfa1) is essential for the differentiation of which cell type?

Which of the following bone graft substitutes possesses both osteoconductive and osteoinductive properties, but lacks osteogenic potential?

In the biomechanical design of orthopedic screws, which of the following modifications most significantly increases the pullout strength in cancellous bone?

Which zone of articular cartilage is characterized by chondrocytes aligned parallel to the joint surface, the highest water content, and the lowest proteoglycan concentration?

A 55-year-old patient with end-stage renal disease presents with diffuse bone pain. Laboratory evaluation reveals hypocalcemia, hyperphosphatemia, and significantly elevated parathyroid hormone (PTH) levels. The underlying pathogenesis of this patient's metabolic bone disease is primarily initiated by a deficiency of which enzyme?

During bone resorption, osteoclasts attach to the underlying bone matrix via a specific cell surface receptor that binds to osteopontin and bone sialoprotein. Which of the following is the primary receptor involved in this sealing zone formation?

When comparing titanium alloy (Ti-6Al-4V) to 316L stainless steel for fracture fixation plates, which of the following statements is true regarding titanium?

During an anterior cruciate ligament reconstruction, the graft is tensioned to 80 Newtons and secured at a fixed length. Over the next several minutes, the tension within the graft progressively decreases. Which viscoelastic property does this describe?

During distraction osteogenesis (e.g., Ilizarov technique), the newly formed bone in the distraction gap regenerates primarily via which biological process?

Which of the following characteristics accurately describes Type I (slow-twitch) skeletal muscle fibers?

Teriparatide is used in the treatment of severe osteoporosis. Its anabolic effect on bone is primarily achieved through which of the following mechanisms?

Which of the following is the most abundant non-collagenous protein in the bone extracellular matrix and serves as a marker for mature osteoblast activity?

A genetic mutation in the gene encoding carbonic anhydrase II results in the inability of osteoclasts to acidify the resorption pit. This defect is the primary pathogenesis of which condition?

If a surgeon chooses to upsize a solid intramedullary nail by doubling its radius, the torsional rigidity of the new nail increases by a factor of what?

The high compressive strength and stiffness of articular cartilage are primarily provided by the interaction between interstitial water and which macromolecule?

Fibroblast growth factor 23 (FGF-23) plays a critical role in mineral metabolism. Which of the following describes its primary physiological effect?

During the early phases of fracture healing, mesenchymal stem cells differentiate into chondrocytes to form a soft callus. Which transcription factor is essential for committing these cells to the chondrogenic lineage?

Which of the following forms of implant corrosion occurs specifically due to microscopic cyclic motion between two closely fitted metal surfaces, leading to disruption of the passive oxide layer?