Biology, Genetics & Bone Healing MCQs

In the standard Ilizarov technique of distraction osteogenesis, new bone formation across the distraction gap primarily occurs through which of the following biological processes?

Which of the following bone morphogenetic proteins (BMPs) is an osteoinductive agent that signals primarily through the SMAD intracellular pathway and is FDA-approved for use in acute, open tibial shaft fractures?

Osteoclasts resorb bone by creating an acidic microenvironment at the ruffled border. Which specific enzyme is primarily responsible for the generation of protons (H+) necessary to maintain this acidic environment?

During the remodeling phase of secondary fracture healing, woven bone is gradually replaced by lamellar bone oriented along lines of stress. This biological response to mechanical loading is governed by which of the following principles?

A postmenopausal woman is prescribed a bisphosphonate for osteoporosis. This medication primarily targets osteoclasts. Which of the following describes the microscopic feature by which actively resorbing osteoclasts attach to the bone surface?

Microscopic analysis of cortical bone demonstrates the presence of Volkmann's canals. What is the primary function of these structures?

Osteoblasts regulate bone remodeling by modulating osteoclast activity through the secretion of specific cytokines. Which local factor, produced by osteoblasts, functions as a decoy receptor for RANKL to inhibit osteoclastogenesis?

A 3-year-old child is referred for evaluation of bowed legs. History reveals no dietary deficiencies; however, family history is significant for several members with bowed legs. Examination reveals genu varum, and the child is in the 5th percentile for height and weight. Laboratory studies show normal renal function, a normal calcium level, a decreased phosphate level, and an elevated alkaline phosphatase level. A plain radiograph of the lower extremities is shown in Figure 22. What is the most likely diagnosis?

A patient is scheduled for surgical excision of heterotopic ossification (HO) following previous acetabular trauma. To prevent recurrence, postoperative prophylaxis is planned. Which of the following is the most standard prophylactic regimen?

A 68-year-old woman who has been taking alendronate for 8 years presents with a transverse, non-comminuted fracture of the femoral shaft with a medial spike. What is the primary underlying mechanism of this fracture?

A 45-year-old woman with a history of systemic lupus erythematosus presents with severe groin pain. MRI confirms Ficat Stage II osteonecrosis of the femoral head without subchondral collapse. She undergoes a core decompression. What is the primary physiologic mechanism by which this procedure relieves pain?

A 55-year-old woman presents with severe thigh pain and a low-energy, transverse diaphyseal femur fracture with focal lateral cortical thickening. She has been taking alendronate for 8 years. Which of the following statements regarding her management is most accurate?

A 68-year-old woman on long-term alendronate therapy presents with a low-energy, transverse subtrochanteric femur fracture. Radiographs show lateral cortical thickening and a medial spike. What is the most crucial next step in the workup prior to surgical intervention?

A 72-year-old female on alendronate for 8 years presents with a transverse, minimally displaced subtrochanteric femur fracture after a ground-level fall. Radiographs of the contralateral asymptomatic femur show lateral cortical thickening and a 'beaked' appearance. What is the most appropriate management?

A 65-year-old woman presents with vague thigh pain. Radiographs demonstrate an impending subtrochanteric atypical femur fracture characterized by lateral cortical thickening. She has been on alendronate for 10 years. What is the most appropriate initial medical management alongside prophylactic intramedullary nailing?

A 68-year-old female presents with thigh pain and a low-energy subtrochanteric femur fracture. A representative radiograph is shown, demonstrating lateral cortical thickening and a transverse fracture pattern with a medial spike.

Which of the following medications is most strongly associated with this injury pattern?

A 65-year-old female with an 8-year history of alendronate use presents with a 3-month history of progressive thigh pain. Radiographs reveal lateral cortical thickening and an incomplete transverse radiolucent line in the subtrochanteric region of the femur.

What is the most appropriate next step in management?

A 78-year-old female presents with acute, severe mid-back pain after a minor fall. Radiographs show an acute L1 compression fracture with 30% loss of anterior height. Neurologic exam is intact. After 6 weeks of conservative management including bracing and analgesics, she continues to have debilitating pain. What is the most appropriate next step in management?

A 75-year-old woman with severe osteoporosis presents with a 2-week history of severe mechanical thoracic back pain. Radiographs show a T7 compression fracture with 30% loss of height. She is neurologically intact. She has failed bracing and opioid analgesia. What is the most appropriate next step in management?

A 72-year-old woman with osteoporosis presents with an acute T12 compression fracture. She has severe pain refractory to 6 weeks of maximal medical management and bracing.

What is the most appropriate next step in management?