1. General Principles & Basic Science MCQs

A patient sustains a closed humerus fracture and presents with a radial nerve palsy. Electromyography at 4 weeks shows fibrillation potentials but no motor unit action potentials. If this represents a Sunderland third-degree nerve injury, which of the following structures remains intact?

A surgeon plans to use a stainless steel screw through a titanium plate. What is the primary mechanism of implant failure associated with mixing these two metals?

Romosozumab is an anabolic agent used for the treatment of severe osteoporosis. Which of the following best describes its mechanism of action at the cellular level?

Aggrecan is the most abundant proteoglycan in articular cartilage. Its ability to draw water into the extracellular matrix and resist compressive loads is primarily due to which of the following glycosaminoglycan side chains?

During material testing of a new orthopedic alloy, the specimen is loaded in tension. The point on the stress-strain curve where the material transitions from elastic to plastic deformation is known as the:

When applying tensile force to a normal ligament, the initial non-linear, low-stiffness portion of the load-elongation curve is primarily due to:

During the pathogenesis of a prosthetic joint infection, Staphylococcus epidermidis secures itself to the implant surface by producing a protective extracellular polymeric substance. Which of the following is the primary component of this biofilm matrix?

A patient with chronic kidney disease presents with severe renal osteodystrophy. Which of the following laboratory profiles is most characteristic of secondary hyperparathyroidism in this clinical setting?

Recombinant human BMP-2 (rhBMP-2) is frequently utilized in spine surgery to enhance bone fusion. Through which intracellular signaling cascade do bone morphogenetic proteins primarily exert their osteoinductive effects?

Which of the following biomechanical conditions is an absolute prerequisite for primary (direct) bone healing to occur without the formation of an intermediate cartilaginous callus?

When evaluating muscle fiber types in an elite long-distance runner, one would expect a higher proportion of Type I fibers compared to a sprinter. Which of the following is a key physiological characteristic of Type I muscle fibers?

Demineralized bone matrix (DBM) is commonly used as a graft substitute in orthopedic surgery. Which of the following biologic properties does DBM possess that synthetic calcium phosphate ceramics lack?

Tranexamic acid (TXA) has become the standard of care to reduce intraoperative blood loss in total joint arthroplasty. What is the specific mechanism of action of TXA?

A 55-year-old female with osteoporosis is started on a new treatment regimen. Normal bone homeostasis relies on the balance between osteoblastic and osteoclastic activity. Osteoprotegerin (OPG) functions to inhibit bone resorption by directly binding to which of the following molecules?

A revision total hip arthroplasty is performed for a failed implant. Intraoperatively, significant black debris and tissue necrosis are noted around the modular head-neck junction. Which of the following types of corrosion is most likely responsible for this phenomenon at a modular junction of dissimilar metals?

A synthetic polymer is being evaluated for use as an intervertebral disc replacement. When a constant sustained load is applied to the material over a prolonged period, it continues to deform progressively over time. What biomechanical property does this behavior describe?

In articular cartilage, compressive resilience and the ability to withstand physiological loads are primarily provided by the interaction between interstitial fluid and which of the following extracellular matrix components?