1. General Principles & Basic Science MCQs

Bone morphogenetic proteins (BMPs) induce osteoblastic differentiation of mesenchymal stem cells. Which of the following intracellular signaling pathways is primarily responsible for mediating this osteoinductive effect?

A 30-year-old carpenter undergoes a 4-strand core suture repair of a Zone II flexor digitorum profundus (FDP) laceration. Which of the following rehabilitation protocols is most appropriate to minimize adhesion formation while protecting the repair?

A 32-year-old female presents with an expansile, eccentric lytic lesion in the distal femur epimetaphysis. Biopsy confirms Giant Cell Tumor of bone (GCT). She is treated with denosumab preoperatively to consolidate the tumor margins. Denosumab targets which of the following mechanisms?

Which of the following mechanical environments most strongly drives secondary bone healing (endochondral ossification) rather than primary bone healing in fracture repair?

Which of the following is the primary mechanism of wear in a well-functioning, non-impinging metal-on-polyethylene total joint arthroplasty?

A 4-year-old boy presents refusing to bear weight on his right leg. He has a fever of 39 C, ESR of 55 mm/hr, WBC of 14,000/mm3, and resists all hip range of motion. According to Kocher's criteria, what is the predictive probability that this child has septic arthritis?

According to the Sunderland classification of nerve injuries, an injury involving disruption of the axon, myelin, and endoneurium, but with an intact perineurium and epineurium, corresponds to which degree?

Denosumab, a monoclonal antibody used in the treatment of osteoporosis and giant cell tumors of bone, exerts its primary effect by binding to and inhibiting which of the following targets?

A 28-year-old manual laborer sustains a volar laceration to his index finger at the proximal phalangeal crease, completely severing the FDS and FDP tendons (Zone II injury). After an uncomplicated core suture repair, which post-operative rehabilitation protocol is best supported to prevent severe tendon adhesions while safeguarding the repair?

Recombinant human Bone Morphogenetic Protein-2 (rhBMP-2) is utilized extensively in spine fusion and complex fracture nonunions to promote osteogenesis. Upon binding to its specific serine/threonine kinase cell surface receptor, which primary intracellular signaling pathway does rhBMP-2 activate?

What is the primary mechanism of bone healing when absolute stability is achieved with a lag screw and neutralization plate?

In articular cartilage, which zone contains the highest concentration of water and collagen fibers oriented parallel to the joint surface?

What is the mechanism of action of denosumab in the treatment of osteoporosis?

During tensile testing of a normal tendon, the initial 'toe region' of the stress-strain curve represents which of the following physiological events?

A 45-year-old malnourished patient presents with bleeding gums, petechiae, and joint pain. A deficiency in which of the following vitamins is responsible for this condition, and what is its role in collagen synthesis?

During the normal gait cycle, at what phase does the maximum force on the hip joint occur?

When a stainless steel screw is placed through a titanium plate in a physiological environment, which of the following phenomena is most likely to occur?

A patient presents with an acutely swollen and painful knee. Joint aspiration yields synovial fluid with a WBC count of 85,000 cells/µL, 90% polymorphonuclear leukocytes, and a glucose level significantly lower than serum glucose. What is the most likely diagnosis?