Practice Set 25 of 789
This practice set contains high-yield board review questions covering key concepts in 1. General Principles & Basic Science. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.
. Lateral pillar C
A 4-year-old boy presents with delayed motor milestones and uses his hands to walk up his thighs to stand. Laboratory testing reveals significantly elevated creatine kinase. A muscle biopsy would most likely show an absence of which protein?
. Dystrophin
. Increased osteoclast activity and deficient osteoblast function
In a sonogram, the normal alpha angle of the neonatal hip measures:
. >50°
Diagnosis of Duchenne muscular dystrophy in a female patient could be explained if the patient had which of the following:
. Turner syndrome
Which of the following agents is contraindicated in children with open physes:
. Teriparatide
A 14-year-old girl is diagnosed with a traumatic posterior hip dislocation. Closed reduction is performed in the emergency department within 2 hours. Post-reduction CT scan reveals a 2 mm intra-articular fragment. The joint is congruent. What is the next best step in management?
. Observation with protected weight bearing
. > 90%
. GNAS1 gene leading to increased cAMP
What is the recommended definitive management for an adult patient diagnosed with a confirmed adamantinoma of the tibia?
. Wide en bloc resection and reconstruction
A 65-year-old man of European descent presents with deep, aching pain in his right pelvis and thigh, accompanied by increasing head size. Laboratory studies show normal serum calcium, normal phosphorus, and markedly elevated alkaline phosphatase.
Which gene mutation is most strongly associated with the familial form of this disease?
. SQSTM1
A 55-year-old female with symptomatic Paget's disease of the femur is started on a nitrogen-containing bisphosphonate (e.g., zoledronate). What is the primary molecular mechanism of action of this medication in treating her condition?
. Inhibition of farnesyl pyrophosphate synthase in the mevalonate pathway
In Paget's disease of bone, which of the following phases is characterized by a pathognomonic "mosaic" pattern of lamellar bone with prominent cement lines upon histological examination?
. The late osteosclerotic (inactive) phase
A 30-year-old patient with polyostotic fibrous dysplasia complains of intractable bone pain in the pelvis and lower extremities. Which of the following is the most appropriate initial medical therapy?
. Intravenous pamidronate
A 35-year-old female presents with an unresectable giant cell tumor of the sacrum. Which of the following targeted biologic therapies is most appropriate?
. Denosumab
A 3-year-old boy presents with anterior bowing of his tibia. Radiographs show a well-circumscribed, intracortical osteolytic lesion involving the anterior tibial diaphysis. Biopsy reveals benign fibrous tissue with woven bone trabeculae lined by prominent osteoblasts. What is the most appropriate initial management?
. Observation alone
A 16-year-old boy undergoes a biopsy of a solitary radiolucent lesion in the proximal femur with a 'ground-glass' matrix. The histological evaluation demonstrates trabeculae of woven bone in a fibrous stroma.
Which of the following classically distinguishes this lesion from normal woven bone formation?
. Absence of osteoblastic rimming
A 6-year-old boy presents with back pain and a mild kyphotic deformity. Radiographs demonstrate complete collapse of the T8 vertebral body (vertebra plana) with preservation of the adjacent disc spaces. A biopsy is performed. Which of the following markers will be strongly expressed in the lesional cells?
. S-100 and CD1a
A 9-year-old boy presents with an isolated expansile, 'ground-glass' lytic lesion in the proximal femur causing a progressive deformity. If histological analysis is performed, what is the classic hallmark finding?
. Woven bone trabeculae lacking osteoblastic rimming within a fibrous stroma
A 12-year-old girl is diagnosed with polyostotic fibrous dysplasia. She presents with severe, recalcitrant bone pain in her lower extremities limiting her daily activities. Radiographs show no impending fractures. What is the most appropriate initial medical management?
. Intravenous bisphosphonates