Practice Set 71 of 212
This practice set contains high-yield board review questions covering key concepts in Biology, Genetics & Bone Healing. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.
Absolute stability of a fracture (e.g., rigid compression plating) leads to which type of bone healing?
. Primary (Haversian) bone healing
Bone Morphogenetic Proteins (BMPs) transmit signals to the nucleus of osteoprogenitor cells primarily through which of the following intracellular mediators?
. beta-catenin
Which of the following histologic findings is characteristic of osteomalacia?
. Decreased osteoid volume
Osteoprotegerin (OPG) functions to inhibit osteoclastogenesis by directly binding to which of the following molecular targets?
. Receptor activator of nuclear factor kappa-B (RANK)
Nitrogen-containing bisphosphonates, such as alendronate, inhibit osteoclastic bone resorption primarily by targeting which of the following enzymes in the mevalonate pathway?
. HMG-CoA reductase
According to Perren's strain theory, what is the maximum local tissue strain environment that allows for the formation of lamellar bone?
. Less than 2%
Which process accurately describes the incorporation of a massive cortical structural allograft, characterized by simultaneous osteoclastic resorption and osteoblastic bone formation that gradually replaces the dead graft?
. Osteoinduction
A patient with chronic severe vitamin C deficiency presents with joint effusions, gingival bleeding, and poor wound healing. The underlying pathophysiologic mechanism directly impairs which step of collagen synthesis?
. Cleavage of procollagen C-terminal propeptides
According to Perren's strain theory, what is the maximum strain tolerated by lamellar bone before it fails?
. 2 percent
Bone morphogenetic proteins (BMPs) primarily exert their osteoinductive effects by binding to cell surface receptors and directly activating which of the following intracellular signaling pathways?
. Smad proteins
The compressive stiffness and elasticity of articular cartilage are primarily provided by which of its molecular components?
. Type I collagen
Distraction osteogenesis, when performed under stable mechanical conditions, primarily results in new bone formation through which of the following biological processes?
. Endochondral ossification
In the process of secondary fracture healing, the soft callus phase is characterized predominantly by the formation of:
. Lamellar bone
A 35-year-old man undergoes open reduction and internal fixation of a transverse radial shaft fracture. A dynamic compression plate is applied to achieve absolute stability. Which of the following best describes the primary mechanism of bone healing expected in this scenario?
. Endochondral ossification
During distraction osteogenesis using the Ilizarov technique, if mechanical stability is maintained and the distraction rate is optimal (1 mm/day), new bone formation in the distraction gap predominantly occurs via which process?
. Endochondral ossification
Bone morphogenetic proteins (BMP-2 and BMP-7) are frequently used in complex fusions and nonunion surgery. They promote bone healing primarily through which of the following mechanisms?
. Chemotaxis of circulating macrophages
Primary (strain-free) bone healing across a fracture requires highly specific mechanical conditions. Which of the following is absolutely required for primary bone healing to occur?
. Intramedullary nailing to permit micromotion
Absolute stability with interfragmentary compression of a fracture leads to primary bone healing. Which of the following is the primary cellular mechanism responsible for this type of healing?
. Endochondral ossification
Which cytokine is considered most critical for the initiation of the inflammatory phase of fracture healing?
. Interleukin-1 (IL-1)
The Hueter-Volkmann principle describes which of the following phenomena in bone mechanics?
. Bone remodels internally in response to mechanical stress