1. General Principles & Basic Science MCQs

A patient with osteopetrosis is scheduled for an elective orthopedic procedure. The pathogenesis of this disease is primarily linked to a defect in which of the following cellular mechanisms?

During a maximum voluntary muscle contraction, the theoretical maximum force generated by skeletal muscle is directly proportional to which of the following?

Secondary fracture healing occurs with the formation of a callus. Which of the following mechanical conditions is required for secondary fracture healing to occur rather than primary healing?

Following a crush injury to the forearm, a patient suffers a nerve injury where the axon and myelin sheath are disrupted, but the endoneurium, perineurium, and epineurium remain completely intact. According to the Sunderland classification, what grade of injury is this?

A patient presents with acute monoarticular knee swelling. A joint aspirate reveals 65,000 white blood cells/hpf, predominantly polymorphonuclear leukocytes, and negatively birefringent needle-shaped crystals. Which of the following crystals is present?

The pullout strength of a solid cortical bone screw is most significantly increased by maximizing which of the following geometric parameters?

Bisphosphonates are frequently used in the management of osteoporosis and metastatic bone disease. What is the primary cellular mechanism of action for nitrogen-containing bisphosphonates such as alendronate?

In the pathogenesis of periprosthetic joint infection, bacteria commonly form a biofilm on the implant surface. Which phase of biofilm development involves the irreversible attachment of bacteria and synthesis of an extracellular polymeric substance (EPS) matrix?

In adult articular cartilage, what is the primary physiological mechanism by which deep chondrocytes receive oxygen and essential nutrients?

Viscoelastic materials such as ligaments and tendons exhibit which of the following properties when subjected to a constant physiological load over an extended period of time?

In normal mature articular cartilage, which structural zone has the highest concentration of water, the lowest concentration of proteoglycans, and collagen fibers oriented parallel to the joint surface?

Which of the following bone morphogenetic proteins (BMPs) is an FDA-approved osteoinductive agent for use as an adjunct in acute, open tibial shaft fractures treated with intramedullary nailing?

A 45-year-old patient with chronic kidney disease presents with diffuse bone pain and proximal muscle weakness. Laboratory studies show low serum calcium, high parathyroid hormone (PTH), and elevated alkaline phosphatase. Histologic evaluation of this patient's bone would most likely show:

A 35-year-old woman presents with knee pain. Radiographs reveal an eccentric, lytic lesion in the distal femur extending to the subchondral bone. Biopsy shows multinucleated giant cells and mononuclear stromal cells. The neoplastic cells in this tumor strongly express:

In a randomized controlled trial comparing two surgical techniques, the authors find no statistically significant difference in clinical outcomes. However, they conclude that a difference truly exists but their study failed to detect it. This scenario represents:

Parathyroid hormone (PTH) plays a crucial role in calcium homeostasis. Which of the following describes its direct physiologic action on the kidneys?

Which of the following biomaterial combinations poses the highest risk for galvanic corrosion when used together in orthopedic internal fixation?

During the pathogenesis of periprosthetic joint infection, Staphylococcus aureus produces a robust biofilm. What is the primary structural component of the extracellular polymeric substance in this biofilm?

During skeletal muscle contraction, calcium ions released from the sarcoplasmic reticulum initiate cross-bridge cycling by binding directly to which of the following proteins?