1. General Principles & Basic Science MCQs

Which of the following cytokines is the primary stimulator of osteoclastogenesis and acts by directly binding to receptors on the surface of osteoclast precursors?

In cortical bone healing following rigid plate fixation with absolute stability, primary bone healing occurs without cartilaginous callus formation. Which of the following is the key cellular mechanism driving this process?

Articular cartilage derives its compressive stiffness primarily from the interaction between water and which of the following macromolecular structures?

A 45-year-old woman with a history of Roux-en-Y gastric bypass presents with generalized bone pain and a Looser zone on pelvic radiographs. Which of the following laboratory profiles is most consistent with her underlying metabolic bone disease?

A viscoelastic material undergoes continuous deformation when subjected to a constant load over a prolonged period. Which of the following terms best describes this biomechanical property?

When incorporating antibiotics into polymethylmethacrylate (PMMA) bone cement, which of the following antibiotic properties is most critical to ensure effective local elution without compromising cement curing?

Nitrogen-containing bisphosphonates are frequently used in the management of osteoporosis. What is the primary intracellular mechanism of action of these medications?

A patient develops a chronic periprosthetic joint infection due to Staphylococcus epidermidis. Which of the following components of the bacterial biofilm is primarily responsible for conferring resistance to both host immune cells and systemic antibiotics?

A 55-year-old female presents with recurrent nephrolithiasis, bone pain, and fatigue. Radiographs demonstrate subperiosteal bone resorption in the phalanges. Which of the following laboratory findings is expected?

Skeletal muscle contractions are classified by how the muscle changes length under tension. Which type of contraction generates the highest amount of force and is most commonly associated with delayed onset muscle soreness (DOMS)?

A surgeon uses a stainless steel screw to fix a titanium plate in a fracture construct. Over time, localized corrosion occurs. What type of corrosion is caused by the electrochemical potential difference between these two dissimilar metals?

According to Seddon's classification of nerve injuries, which of the following accurately describes axonotmesis?

Demineralized bone matrix (DBM) is widely used in orthopedics as a bone graft substitute. Which of the following combinations of properties best describes DBM?

Which mode of joint lubrication is primarily responsible for reducing friction in a healthy human hip joint during the heel strike phase of walking, when high loads and low speeds are present?

A surgeon plans to use a stainless steel screw to secure a titanium plate during an open reduction and internal fixation. What type of corrosion is most likely to occur at the interface of these two metals?

A 72-year-old female with severe osteoporosis is started on teriparatide to reduce her fracture risk. By what primary mechanism does this medication increase bone mineral density?

A 65-year-old undergoes a total knee arthroplasty and later develops a chronic periprosthetic joint infection due to Staphylococcus epidermidis. Which phase of biofilm formation is characterized by the production of a polysaccharide intercellular adhesin (PIA) matrix?

Osteoclasts degrade bone matrix by creating an acidic microenvironment within Howship's lacunae. Which enzyme is primarily responsible for generating the intracellular hydrogen ions necessary to acidify this extracellular space?

Articular cartilage maintains a nearly frictionless surface. Which molecule is the primary mediator of boundary lubrication, functioning to protect the articular surfaces during high-load, low-velocity activities?