1. General Principles & Basic Science MCQs

Platelet-rich plasma (PRP) is used clinically to augment healing in various tendinopathies. The alpha granules of platelets contain numerous growth factors. Which growth factor in PRP is most responsible for stimulating angiogenesis?

Bone morphogenetic proteins (BMPs) initiate intracellular signaling pathways critical for osteoblast differentiation. Upon binding to their transmembrane serine/threonine kinase receptors, which intracellular proteins are directly phosphorylated to translocate to the nucleus?

According to Perren's strain theory of fracture healing, what type of tissue will form in a fracture gap if the local interfragmentary strain is maintained between 2% and 10%?

Which recombinant bone morphogenetic protein is FDA-approved for use as an alternative to autograft in acute, open tibial shaft fractures treated with an intramedullary nail?

A marathon runner's gastrocnemius-soleus complex relies heavily on endurance muscle fibers. Which characteristic best describes Type I (slow-twitch) skeletal muscle fibers?

Staphylococcus aureus forms a robust biofilm on orthopaedic implants. Which extracellular matrix component is synthesized by the bacteria to initiate irreversible adhesion to the implant surface?

During bone resorption, osteoclasts create an acidic microenvironment in the sealed zone (Howship's lacuna) to dissolve hydroxyapatite. Which enzyme is primarily responsible for generating the intracellular protons required for this acidification?

Following closure of the physes, adult articular cartilage is strictly avascular and relies entirely on diffusion for cellular nutrition. Where does the majority of nutrient supply for the superficial and transitional zones originate?

While continuous high-dose Parathyroid Hormone (PTH) causes net bone resorption, intermittent low-dose PTH administration drives net bone formation. The anabolic effect of intermittent PTH is primarily mediated by upregulating which pathway?

During the repair of a lacerated flexor digitorum profundus (FDP) tendon in Zone II, the surgeon notes damage to the flexor tendon sheath. To prevent biomechanical failure and 'bowstringing' of the flexor tendon, which two annular pulleys are the most critical to preserve or reconstruct?

A patient undergoes early active mobilization following a zone II flexor tendon repair. Which of the following rehabilitation protocols relies on the concept of active extension and passive flexion using rubber band traction?

A 60-year-old patient with rheumatoid arthritis presents with an inability to actively extend the small and ring fingers at the MCP joints. Passive extension is intact. What is the most common cause of this deformity?

A 60-year-old female presents with a small, clear, fluid-filled nodule on the dorsal aspect of her right index finger DIP joint. Radiographs show underlying osteoarthritis with a prominent osteophyte. What is the most appropriate definitive surgical management to minimize recurrence?

A 40-year-old aquarium maintenance worker presents with an indolent, slowly progressive swelling and restricted motion of his right index finger, accompanied by a painless nodule on the dorsum of his hand that seems to be spreading proximally up his arm.

A biopsy reveals non-caseating granulomas and acid-fast bacilli. Which of the following antimicrobial regimens is most appropriate?

A 62-year-old woman undergoes a ligament reconstruction and tendon interposition (LRTI) using the flexor carpi radialis (FCR) tendon for advanced thumb carpometacarpal (CMC) arthritis. Postoperatively, she complains of new-onset numbness and tingling over the dorsal-radial aspect of the hand. Injury to which of the following nerves most likely occurred during the surgical approach?

A 30-year-old industrial painter presents to the ER 2 hours after accidentally injecting his left index finger with an oil-based paint gun at 3,000 psi. The entry wound is 2 mm, but the finger is slightly swollen and exquisitely tender. What is the most appropriate management?

You are reviewing an axial cross-section of the shoulder during a pre-operative imaging review for a posterior approach.

What structure forms the superior boundary of the quadrangular space, and what is its primary innervation?