1. General Principles & Basic Science MCQs

Intermittent administration of low-dose parathyroid hormone (PTH), such as teriparatide, is used to treat severe osteoporosis. The primary mechanism underlying its anabolic effect on bone is:

An infant presents with multiple fractures and generalized increased bone density on radiographs, lacking clear medullary canals. The severe infantile form of this disease is most commonly caused by a mutation affecting which of the following?

A 35-year-old woman is diagnosed with an aggressive giant cell tumor of the distal femur. She is prescribed denosumab to shrink the tumor prior to surgical curettage. Denosumab exerts its effect in this disease process by binding directly to which of the following targets?

A 45-year-old man undergoes distraction osteogenesis of the tibia using an Ilizarov frame following a complex nonunion. The formation of new bone in the distraction gap primarily occurs via which of the following biologic processes?

The resistance of articular cartilage to compressive loads is primarily provided by which of the following extracellular matrix components?

During the incorporation of a structural cortical bone allograft, the process by which osteoclasts resorb the graft and osteoblasts lay down new viable bone is termed:

A 68-year-old woman with severe osteoporosis is started on teriparatide. Which of the following describes the mechanism by which this medication increases bone mineral density?

When comparing the mechanical properties of orthopedic implant materials, which of the following correctly orders the Young's modulus of elasticity from highest (stiffest) to lowest (most flexible)?

Which of the following histologic findings is the hallmark of Paget disease of bone in its mixed phase?

In the peripheral nervous system, the myelin sheath that surrounds axons to facilitate rapid nerve conduction is produced by which of the following cell types?

During orthopedic implant infections, bacteria such as Staphylococcus epidermidis evade host immunity and antibiotics by forming a biofilm. The crucial structural component of this biofilm is the extracellular polymeric substance (EPS), which is primarily composed of:

A 65-year-old woman is starting treatment for severe osteoporosis. Her physician prescribes a medication that acts as a recombinant form of parathyroid hormone (PTH). What is the primary mechanism of action of this drug when administered intermittently?

A 20-year-old man develops a large, eccentric, lytic lesion in the distal femur epiphysis. Biopsy shows numerous multinucleated giant cells in a background of mononuclear stromal cells. The neoplastic cells in this tumor express high levels of which of the following?

In the context of peripheral nerve injury, a Seddon axonotmesis corresponds most closely to which Sunderland classification?

A 40-year-old woman is diagnosed with osteomalacia. Laboratory evaluation is likely to show which of the following profiles?

A 7-year-old child sustains a fracture. During the repair process, which cells are primarily responsible for clearing the necrotic tissue and hematoma in the initial inflammatory phase?

What is the primary function of sclerostin in bone metabolism?