Biology, Genetics & Bone Healing MCQs

Bone Morphogenetic Proteins (BMP-2 and BMP-7) are potent osteoinductive agents utilized in spine fusion and fracture nonunions. Following binding to cell surface receptors, which intracellular signaling proteins do BMPs primarily phosphorylate to induce osteoblastic gene transcription?

Bone morphogenetic protein-2 (BMP-2) has potent osteoinductive properties and is utilized in various orthopedic fusion procedures. The intracellular signaling cascade initiated by BMP-2 binding to its cell surface serine/threonine kinase receptors relies primarily on the phosphorylation and activation of which of the following molecules?

During fracture healing, bone morphogenetic proteins (BMPs) play a crucial role in osteoinduction by directing mesenchymal stem cells to differentiate into osteoblasts. Which of the following BMPs is FDA-approved for use in acute open tibial shaft fractures treated with an intramedullary nail?

According to Perren's strain theory of bone healing, what is the maximum interfragmentary strain environment that will permit primary (contact) bone healing to occur via osteoclast cutting cones?

Giant cell tumor of bone (GCTB) is a locally aggressive benign tumor. In cases where surgery is morbid and systemic therapy with Denosumab is utilized, what specific molecular interaction is being targeted by this medication?

A patient with a history of severe heterotopic ossification (Brooker Class IV) following a primary THA is undergoing revision surgery. Prophylactic radiation therapy is planned to prevent recurrence. To maximize clinical efficacy, when is the optimal timeframe to administer the radiation dose?

Which of the following stages of fracture healing is most reliant on the presence of transforming growth factor-beta (TGF-beta) and platelet-derived growth factor (PDGF) released from degranulating platelets?

Which Bone Morphogenetic Protein (BMP) is FDA approved as an alternative to autograft for anterior lumbar interbody fusion (ALIF)?

Bone morphogenetic proteins (BMPs) induce bone formation primarily through which of the following mechanisms?

A 65-year-old man presents with dull aching pain in his right thigh and an increasing hat size. Radiographs of his femur demonstrate cortical thickening, increased trabecular markings, and a 'blade of grass' lucency. A bone biopsy would most likely reveal which of the following cellular abnormalities?

A 30-year-old female is diagnosed with a giant cell tumor (GCT) of the distal femur. Because the tumor is marginally resectable, she is treated with denosumab to downstage the lesion. Denosumab exerts its therapeutic effect by binding directly to which of the following targets?

According to Perren’s strain theory of bone healing, the type of tissue that forms in a fracture gap is determined by the local mechanical strain environment. Which of the following biological tissues can tolerate the highest degree of strain before mechanical failure?

A 45-year-old female undergoes open reduction and internal fixation of a transverse midshaft radius fracture. The surgeon utilizes absolute stability by applying a dynamic compression plate (DCP). Under these highly stable biomechanical conditions, bone healing occurs primarily via which of the following biological processes?

Denosumab is an increasingly utilized pharmacological agent in orthopedics, particularly in the management of osteoporosis and as a neoadjuvant therapy for Giant Cell Tumor of Bone (GCTB). At a molecular level, Denosumab exerts its primary effect by acting as a monoclonal antibody that binds directly to which of the following targets?

During secondary bone healing following a closed diaphyseal fracture treated with a cast, a cartilaginous soft callus forms. Which of the following growth factors is most critical in promoting the differentiation of mesenchymal stem cells into chondrocytes during this phase?

A 35-year-old female presents with knee pain. Radiographs reveal an eccentric, lytic epiphyseal lesion extending into the metaphysis of the distal femur. Biopsy confirms a Giant Cell Tumor of bone. What is the mechanism of action of denosumab, a potential medical treatment?

A 45-year-old patient is scheduled to undergo a posterolateral spinal fusion using a structural cortical autograft. What is the primary mechanism by which a cortical autograft is initially incorporated into the host bone?

A 70-year-old female treated with alendronate for 8 years presents with thigh pain and a transverse subtrochanteric fracture with lateral cortical thickening. What is the molecular mechanism of action of the medication responsible for this atypical fracture?

A 6-year-old child presents with progressive bowing of the lower extremities. Laboratory studies reveal normal serum calcium, critically low serum phosphorus, and elevated alkaline phosphatase. Genetic testing confirms a mutation in the PHEX gene. Which of the following substances is excessively produced in this patient's condition?

According to Perren's strain theory of bone healing, the type of tissue that forms in a fracture gap is dictated by the amount of mechanical strain the tissue can tolerate without failing. What is the approximate maximum strain tolerance of granulation tissue?