1. General Principles & Basic Science MCQs

Which of the following best describes the biochemical changes in articular cartilage associated with normal aging compared to the changes seen in early osteoarthritis?

A physical therapist applies a constant load to a patient's contracted Achilles tendon, resulting in a gradual increase in tendon length over time. This phenomenon is a demonstration of which viscoelastic property?

A 70-year-old female with osteoporosis is scheduled for an elective spine fusion and is currently taking denosumab. This medication exerts its antiresorptive effect by targeting which of the following?

In periprosthetic joint infections, Staphylococcus epidermidis evades the host immune response and resists antimicrobial therapy primarily through the production of a biofilm. Which of the following is the main structural component of this biofilm matrix?

A 45-year-old mechanic presents with chronic lateral forearm pain and weakness in finger extension, with no sensory deficits. Electromyography confirms compression of the posterior interosseous nerve. The most common site of compression for this nerve is between the two heads of which muscle?

During the incorporation of a massive cortical bone allograft, the graft undergoes a process of creeping substitution. Which of the following represents the initial phase of this process after the inflammatory response?

A marathon runner sustains a gastrocnemius strain. The predominantly active muscle fibers in this athlete's gastrocnemius during a long-distance run rely on oxidative metabolism. Which of the following is a characteristic of these specific muscle fibers?

In the evaluation of pediatric septic arthritis of the hip, the original Kocher criteria utilized four predictors. Subsequent studies (e.g., Caird et al.) added a fifth predictor which was found to be the strongest independent predictor of septic arthritis. Which biomarker is this?

A 22-year-old healthy female presents with an acutely swollen, painful left wrist. She reports a history of migratory polyarthralgia over the past week and multiple scant vesiculopustular skin lesions. Synovial fluid aspiration shows a WBC count of 40,000 cells/uL. If this condition is suspected, what is the optimal culture medium required for diagnosis?

A 9-year-old boy from New England presents with a massive, minimally painful knee effusion and is able to bear weight without significant difficulty. Synovial aspiration reveals a WBC count of 35,000 cells/uL with 80% PMNs. You suspect Lyme arthritis. What is the most appropriate initial diagnostic test for confirming this specific etiology?

A 65-year-old male with a history of recurrent gout presents with acute severe pain, swelling, and redness in his native left knee. Aspiration yields cloudy fluid with 65,000 WBCs/uL. Polarized light microscopy confirms the presence of abundant needle-shaped, strongly negative birefringent crystals. Gram stain is negative. What is the most appropriate next step in management regarding the diagnosis of infection?

A 50-year-old immunocompromised patient from the San Joaquin Valley presents with chronic swelling of the knee. Native joint aspiration yields a WBC count of 25,000 cells/uL with a lymphocytic predominance. A fungal etiology is suspected. Which of the following culture media is the most appropriate for isolating the likely pathogen?

A 60-year-old male presents with an acutely swollen, erythematous native knee. Aspiration yields cloudy fluid with a WBC count of 65,000 cells/uL. Polarized microscopy reveals negatively birefringent needle-shaped crystals. What is the most critical next step?

A 24-year-old sexually active female presents with migratory polyarthralgia and an acutely swollen wrist. Aspiration reveals a WBC count of 45,000 cells/uL. Routine synovial cultures remain negative at 48 hours. What is the most sensitive test to confirm the suspected diagnosis?

Which of the following best describes the primary advantage of implant sonication over standard periprosthetic tissue cultures in the diagnosis of periprosthetic joint infection?

A 5-year-old boy presents with a temperature of 38.8 C, refusal to bear weight on the right leg, an ESR of 55 mm/hr, and a peripheral WBC of 14,000 cells/mcL. According to the Kocher criteria, what is the most appropriate next step in management?

Which of the following synovial fluid profiles is most characteristic of disseminated gonococcal infection of a native joint?

When processing explanted orthopedic hardware, sonication of the components is utilized to improve microbiological yield. By what mechanism does sonication primarily enhance bacterial detection?