Biology, Genetics & Bone Healing MCQs

According to Perren's interfragmentary strain theory, what is the maximum strain tolerated by granulation tissue before it ruptures and prevents the progression of secondary bone healing?

A 72-year-old female taking alendronate for 8 years presents with progressive thigh pain. Radiographs reveal focal lateral cortical thickening and a transverse radiolucent line in the subtrochanteric region. What is the most appropriate management?

A 62-year-old diabetic patient develops acute Charcot neuroarthropathy. Which of the following molecular pathways is primarily responsible for the aggressive osteolysis seen in the acute phase of this condition?

Which of the following histological features is considered the classic hallmark of fibrous dysplasia?

In the biological microenvironment of chronic, retracted rotator cuff tears, which specific enzymes are known to be significantly upregulated, leading to collagen degradation and impairment of tendon-to-bone healing post-repair?

A 6-year-old child is undergoing gradual tibial lengthening using an external fixator for fibular deficiency. The surgical team is establishing the post-operative distraction protocol to optimize regenerate bone formation and minimize complications.

According to the principles of distraction osteogenesis described in the case, what is the typical daily distraction rate and latency period for optimal regenerate bone formation?

During secondary bone healing, which growth factor is primarily responsible for stimulating the differentiation of mesenchymal stem cells into chondrocytes during the formation of the soft callus?

Which type of bone healing occurs under conditions of absolute stability, such as following rigid compression plating of a transverse forearm fracture?

A 30-year-old female presents with a destructive, eccentric, lytic lesion in the proximal tibial epiphysis extending to the subchondral bone. Biopsy reveals multinucleated giant cells interspersed with mononuclear stromal cells. If systemic therapy is considered, which molecular target is most appropriate to inhibit?

A 70-year-old female on alendronate for 12 years presents with persistent right thigh pain for 3 months. Radiographs reveal lateral cortical thickening and a transverse radiolucent line in the subtrochanteric femur without complete displacement. What is the most appropriate primary management step?

A 17-year-old female runner presents with increased leg pain and is diagnosed with a stress fracture. Her physician is concerned about the female athlete triad. Which of the following is NOT considered one of the three core components of the female athlete triad?

According to Perren's strain theory, absolute stability is required for primary bone healing. Primary bone healing occurs without visible callus formation when the interfragmentary strain is maintained below what threshold?

A 32-year-old female has a large, eccentric lytic lesion in the distal femur epiphysis confirmed by biopsy to be a Giant Cell Tumor (GCT). If medical therapy is considered to downstage the tumor prior to surgery, which mechanism of action is utilized?

A 30-year-old female undergoes intralesional curettage and cementation for a giant cell tumor of the distal femur. Two years later, she presents with recurrence. She is started on denosumab therapy prior to re-operation. What is the specific mechanism of action of this medication?

A 55-year-old male sustains an isolated ulnar shaft fracture and is treated non-operatively in a functional brace. At 14 weeks, radiographs demonstrate a hypertrophic nonunion. What is the most appropriate management?

According to Perren's strain theory, what is the maximum allowable interfragmentary tissue strain for primary bone healing to occur via cutting cones?

A 72-year-old female with osteoporosis presents with severe lower back and gluteal pain without a specific traumatic event. Plain radiographs of the pelvis and lumbar spine are unremarkable. What is the most sensitive imaging modality to confirm the suspected diagnosis?

The patient in the vignette has a history of osteoporosis and discontinued alendronate therapy. A critical component of her postoperative protocol, beyond surgical fixation, is the reinstitution of metabolic bone management. Which of the following best describes the recommended approach for optimizing her bone health?

A 60-year-old male presents with thigh pain and a radiographic 'dreaded black line' on the lateral cortex of the subtrochanteric femur, consistent with an incomplete atypical femur fracture after 8 years of bisphosphonate therapy. What is the standard surgical recommendation to prevent completion of this fracture?