1. General Principles & Basic Science MCQs

During the swing phase and normal walking, the primary mechanism of lubrication in the human hip joint, where the articular surfaces are separated by a continuous dynamic fluid film, is best described as:

Nitrogen-containing bisphosphonates (e.g., alendronate) inhibit osteoclast function primarily by interfering with which of the following intracellular pathways?

Which of the following mechanical properties is determined by the slope of the linear elastic region of a stress-strain curve?

Denosumab is a monoclonal antibody used in the treatment of osteoporosis and giant cell tumors of bone. It functions by binding to which of the following targets to inhibit osteoclastogenesis?

When designing a solid intramedullary nail, doubling the radius of the nail will increase its torsional rigidity by a factor of:

Romosozumab increases bone mineral density primarily through the inhibition of sclerostin. Sclerostin normally inhibits bone formation by directly blocking which of the following intracellular signaling pathways?

A tendon graft used for ACL reconstruction is tensioned to a specific length and fixed in place. Over time, the tension in the graft progressively decreases while the length remains constant. This viscoelastic property is known as:

A surgeon uses a stainless steel screw with a titanium plate for fracture fixation. Which of the following is the most likely consequence of using these mixed metals in vivo?

Teriparatide is an anabolic agent used for severe osteoporosis. Its mechanism of action requires which of the following administration profiles to stimulate bone formation rather than resorption?

The pullout strength of a cortical bone screw is directly proportional to which of the following geometric parameters?

Osteoclasts degrade the organic matrix of bone primarily through the secretion of which of the following enzymes into the resorption pit?

According to Perren's strain theory, what dictates the type of tissue that forms during fracture healing if the interfragmentary strain is maintained between 2% and 10%?

The final conversion of 25-hydroxyvitamin D to its most active hormonal form, 1,25-dihydroxyvitamin D, occurs primarily in the kidney. This conversion is directly stimulated by which of the following?

Which of the following modifications will most significantly increase the bending stiffness of a unilateral external fixator construct?

A 65-year-old patient presents with diffuse bone pain and a history of gastric bypass surgery. Laboratory workup reveals low serum calcium, low phosphorus, high alkaline phosphatase, and elevated PTH. What is the most likely underlying basic science pathology?

Cortical bone is stronger in compression along its longitudinal axis than it is when subjected to transverse loading. This material property, where mechanical behavior depends on the direction of loading, is known as:

Which of the following best describes the biological process of "creeping substitution" during the incorporation of a massive cortical structural allograft?

Chronic use of nonsteroidal anti-inflammatory drugs (NSAIDs) may impair early fracture healing primarily by inhibiting the synthesis of which of the following mediators?

During the single-leg stance phase of gait, using a cane in the contralateral hand reduces the hip joint reaction force primarily by:

A 12-year-old child presents with recurrent fractures and diffuse osteosclerosis. A mutation in the gene encoding Carbonic Anhydrase II is identified. This mutation prevents osteoclasts from performing which essential step in bone resorption?