This practice set contains high-yield board review questions covering key concepts in 4. Pediatrics. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.
Question 4461
Topic: 4. Pediatrics
Which of the following conditions is characterized by osteochondrosis of the navicular bone?
Correct Answer & Explanation
. Kohler's disease
Explanation
Kohler's disease is osteochondrosis of the navicular bone, presenting with foot pain in children. Sever's disease is calcaneal apophysitis. Osgood-Schlatter disease is traction apophysitis of the tibial tubercle. Freiberg's disease is osteochondrosis of the metatarsal head (most commonly the second). Legg-Calvé-Perthes disease is avascular necrosis of the femoral head.
Question 4462
Topic: Pediatric Hip
A 4-year-old child presents with a Galeazzi sign (apparent shortening of one thigh with hips and knees flexed) and unequal skin folds in the groin. What is the most appropriate initial diagnostic imaging study?
Correct Answer & Explanation
. Plain radiographs of the pelvis
Explanation
The clinical signs (Galeazzi sign, unequal skin folds) are suggestive of Developmental Dysplasia of the Hip (DDH). In children under 4-6 months, ultrasound is the preferred imaging modality because the femoral head is largely cartilaginous and not ossified, making X-rays unreliable. However, for a 4-year-old, ossification is sufficient, and plain radiographs of the pelvis (AP and frog-leg lateral views) are the primary initial diagnostic imaging study to assess hip morphology, acetabular index, and femoral head position. MRI and CT are typically reserved for surgical planning or more complex cases. Bone scintigraphy is not indicated for DDH.
Question 4463
Topic: 4. Pediatrics
Which of the following statements regarding the management of clubfoot (Talipes Equinovarus) is TRUE?
Correct Answer & Explanation
. The Ponseti method involves serial casting with gentle manipulations and often percutaneous Achilles tenotomy.
Explanation
The Ponseti method is the gold standard initial treatment for congenital clubfoot. It involves a series of gentle manipulations and plaster casts, changed weekly, followed by a percutaneous Achilles tenotomy in most cases, and then a foot abduction brace to maintain correction. Surgical correction is reserved for failed conservative treatment. Bracing is crucial for preventing recurrence and is typically continued for several years, usually until around age 4-5. The deformity involves all aspects of the foot, including hindfoot equinus and varus, and forefoot adduction and supination.
Question 4464
Topic: 4. Pediatrics
Which type of Salter-Harris fracture involves a fracture through the physis and the epiphysis?
Correct Answer & Explanation
. Type IV
Explanation
Salter-Harris classification for physeal fractures: Type I: S = Slipped (through the physis only). Type II: A = Above (through physis and metaphysis). Type III: L = Lower (through physis and epiphysis). Type IV: T = Through (through metaphysis, physis, and epiphysis). Type V: R = Rammed (crush injury to physis). Therefore, Type III involves a fracture through the physis and the epiphysis.
Question 4465
Topic: 4. Pediatrics
Which of the following arteries is most at risk during surgical fixation of a displaced supracondylar humerus fracture in a child?
Correct Answer & Explanation
. Brachial artery
Explanation
The brachial artery is intimately associated with the distal humerus and is the most commonly injured neurovascular structure in displaced supracondylar humerus fractures. Injury to the brachial artery can lead to Volkmann's ischemic contracture. Other nerves (median, radial, ulnar) can also be injured, but the brachial artery is a primary concern for vascular compromise.
Question 4466
Topic: 4. Pediatrics
A 14-year-old obese male presents with a painful limp and external rotation of the affected limb. Radiographs of the hip show widening and irregularity of the physis, and posterior and inferior displacement of the femoral epiphysis relative to the metaphysis. What is the most appropriate management?
Correct Answer & Explanation
. In situ screw fixation
Explanation
The patient's age, obesity, painful limp, external rotation, and specific radiographic findings are pathognomonic for a Slipped Capital Femoral Epiphysis (SCFE). The most appropriate management, regardless of stability (though described as painful, suggesting instability), is immediate in situ screw fixation to prevent further slippage and promote physeal closure. Weight-bearing and observation are contraindicated. Closed reduction can cause further damage to the blood supply of the femoral head and is generally avoided. Open reduction and osteotomy are reserved for severe, chronic, or failed in situ fixation cases.
Question 4467
Topic: Pediatric Lower Extremity
Which of the following conditions is characterized by anterior knee pain, often exacerbated by prolonged sitting or climbing stairs, due to abnormal tracking of the patella?
Anterior knee pain, especially worsened by activities that load the patellofemoral joint (e.g., prolonged sitting, climbing stairs, squatting), is characteristic of patellofemoral pain syndrome (PFPS), also historically known as chondromalacia patellae when referring to cartilage softening. This condition often stems from patellar maltracking or muscle imbalances. Patellar tendinopathy causes pain inferior to the patella. Osgood-Schlatter is tibial tubercle apophysitis in adolescents. Fat pad impingement and plica syndrome are less common causes of similar symptoms.
Question 4468
Topic: 4. Pediatrics
Achondroplasia is the most common form of short-limb dwarfism. The underlying pathophysiology involves a gain-of-function mutation in the FGFR3 gene, which primarily inhibits chondrocyte function in which zone of the physis?
Correct Answer & Explanation
. Proliferative zone
Explanation
Achondroplasia is caused by a mutation in the Fibroblast Growth Factor Receptor 3 (FGFR3) gene. This gain-of-function mutation abnormally inhibits chondrocyte proliferation, specifically affecting the proliferative zone of the physis, leading to decreased endochondral ossification and shortened long bones.
Question 4469
Topic: 4. Pediatrics
A 10-year-old boy falls and sustains a distal radius fracture. Radiographs show a fracture line that passes transversely through the physis and exits through the metaphysis. According to the Salter-Harris classification, fractures that traverse the physis predominantly occur through which histologic zone?
Correct Answer & Explanation
. Hypertrophic zone
Explanation
Salter-Harris fractures most commonly occur through the hypertrophic zone of the physis, specifically at the junction of the calcified and uncalcified regions. This zone is mechanically the weakest part of the growth plate because the cells are enlarged and the extracellular matrix is relatively sparse.
Question 4470
Topic: 4. Pediatrics
Fibrous dysplasia is a benign developmental anomaly of bone characterized by replacement of normal medullary bone with fibro-osseous tissue. Which gene mutation is the underlying cause of this condition?
Correct Answer & Explanation
. GNAS1
Explanation
Fibrous dysplasia is caused by an activating post-zygotic somatic mutation in the GNAS1 gene, which encodes the alpha subunit of a stimulatory G-protein (Gs-alpha). This leads to increased intracellular cAMP, causing abnormal differentiation of osteoblasts. EXT1 is associated with multiple hereditary exostoses; FGFR3 with achondroplasia; COMP with multiple epiphyseal dysplasia; and COL1A1 with osteogenesis imperfecta.
Question 4471
Topic: 4. Pediatrics
Which of the following liver function tests (LFTs) is specifically assessed in the Child-Pugh score, used to classify the severity of liver dysfunction, which could impact sepsis prognosis in orthopedic patients?
Correct Answer & Explanation
. Serum albumin
Explanation
The Child-Pugh score (also known as Child-Turcotte-Pugh score) uses five clinical and laboratory criteria to assess the prognosis of chronic liver disease (cirrhosis). These are: total bilirubin, serum albumin, prothrombin time (or INR), ascites, and hepatic encephalopathy. Serum albumin is one of the key synthetic functions of the liver assessed by the score. ALT, AST, GGT, and ALP are markers of hepatocellular injury or cholestasis, but are not directly part of the Child-Pugh score itself.
Question 4472
Topic: Pediatric Hip
A 10-year-old male presents with a painful limp and limited internal rotation of the hip. Radiographs show a widening of the physis and posterior and inferior displacement of the femoral head relative to the femoral neck. Which of the following conditions is most likely, and what is the standard management?
Correct Answer & Explanation
. Slipped Capital Femoral Epiphysis (SCFE); requiring surgical pinning in situ.
Explanation
The clinical presentation (painful limp, limited internal rotation) and radiographic findings (widening of physis, posterior/inferior displacement of femoral head) are classic for Slipped Capital Femoral Epiphysis (SCFE). SCFE is a condition of adolescence where the growth plate weakens and the epiphysis slips off the metaphysis. It is an orthopedic emergency to prevent further slip and avascular necrosis, requiring immediate surgical pinning in situ. The other conditions have different presentations and management strategies.
Question 4473
Topic: Pediatric Hip
A 5-year-old child presents with a limp, hip pain, and restricted hip abduction and internal rotation. Radiographs show increased density (sclerosis) and fragmentation of the femoral head epiphysis. What is the most likely diagnosis?
Correct Answer & Explanation
. Legg-Calve-Perthes disease.
Explanation
The clinical picture (limp, hip pain, restricted motion in a young child) combined with radiographic findings of increased density and fragmentation of the femoral head epiphysis is classic for Legg-Calve-Perthes disease. This condition is idiopathic avascular necrosis of the femoral head. Transient synovitis is self-limiting inflammation without radiographic changes. Septic arthritis would present acutely with fever and severe pain. SCFE occurs in older children/adolescents with epiphyseal slip. DDH is a developmental abnormality of the hip joint.
Question 4474
Topic: Pediatric Lower Extremity
A 30-year-old male presents with chronic anterior knee pain, exacerbated by squatting and climbing stairs. He has a positive 'patellar grind test' and reproduces pain with compression of the patella into the trochlear groove. Radiographs are unremarkable. What is the most likely diagnosis?
The symptoms (anterior knee pain exacerbated by squatting/stairs) and physical exam findings (patellar grind test, pain with patellar compression) are highly suggestive of Patellofemoral Pain Syndrome (PFPS), sometimes referred to as chondromalacia patellae although chondromalacia is a specific cartilage finding rather than a clinical syndrome. PFPS is caused by abnormal tracking or overload of the patellofemoral joint. Meniscal tears typically cause joint line pain, catching, or locking. Patellar tendinopathy causes localized pain at the inferior pole of the patella. ACL injury causes instability. Osgood-Schlatter disease is common in adolescents and causes pain and swelling at the tibial tubercle.
Question 4475
Topic: 4. Pediatrics
A 4-year-old child presents with a painless limp. On examination, there is a positive Galeazzi sign and asymmetric thigh folds. Ortolani and Barlow tests are negative. Radiographs show a shallow acetabulum and superior and lateral displacement of the femoral head. Which of the following is the most appropriate management for this condition?
Correct Answer & Explanation
. Open reduction with capsulorrhaphy and osteotomy.
Explanation
The signs (painless limp, positive Galeazzi, asymmetric thigh folds) and radiographic findings (shallow acetabulum, superior/lateral displacement) are consistent with untreated or late-presenting Developmental Dysplasia of the Hip (DDH). Given the child's age (4 years old), the hip is likely significantly dislocated and irreducible by conservative means. Therefore, open reduction with capsulorrhaphy and potentially acetabular or femoral osteotomy is typically required to achieve and maintain reduction, as the soft tissues are contracted and osseous deformities are present. Pavlik harness is for infants, and closed reduction with spica cast is for younger children (typically <18 months) or those who failed harness treatment but do not have fixed deformities.
Question 4476
Topic: 4. Pediatrics
A 12-year-old male sustains a Salter-Harris Type II fracture of the distal tibia. Which of the following statements regarding this fracture type and its potential complications is most accurate?
Correct Answer & Explanation
. It involves the physis and the metaphysis, and has a good prognosis for growth.
Explanation
A Salter-Harris Type II fracture involves the physis (growth plate) and extends into the metaphysis, sparing the epiphysis and articular cartilage. It is the most common type of physeal fracture and generally has a good prognosis for growth, provided adequate reduction and fixation are achieved, and the periosteal hinge remains intact. Type I is through the physis. Type III involves the physis and epiphysis (intra-articular). Type IV involves the physis, metaphysis, and epiphysis (intra-articular), carrying a higher risk of growth arrest and avascular necrosis. Type V is a crush injury of the physis with a very high risk of growth arrest. The description in option A is Type IV, C is Type III or IV, D is not a specific type, and E implies a Type I or II with an intact periosteal hinge but the reduction implies open reduction which is not always needed for type II.
Question 4477
Topic: Pediatric Hip
A 1-year-old infant is diagnosed with a dislocated hip on routine screening examination. Ortolani and Barlow tests are positive. Radiographs confirm developmental dysplasia of the hip (DDH). Which of the following is the most appropriate initial management?
Correct Answer & Explanation
. Pavlik harness.
Explanation
For infants diagnosed with Developmental Dysplasia of the Hip (DDH), particularly those with a dislocated but reducible hip as indicated by positive Ortolani and Barlow tests, the Pavlik harness is the most appropriate initial management. It is a soft abduction brace that encourages hip flexion and abduction, allowing the hip to reduce spontaneously and stabilize. Open reduction is for older children or failed harness treatment. Observation is only for mild dysplasia. Osteotomy is a reconstructive procedure for older children. Physical therapy alone is insufficient.
Question 4478
Topic: Pediatric Lower Extremity
A 14-year-old male presents with chronic anterior knee pain, a prominent and tender bump at the tibial tubercle, exacerbated by sports activities. What is the most likely diagnosis?
Correct Answer & Explanation
. Osgood-Schlatter disease.
Explanation
The patient's presentation (chronic anterior knee pain, prominent and tender tibial tubercle, exacerbated by sports in an adolescent male) is classic for Osgood-Schlatter disease. This condition is an apophysitis of the tibial tubercle due to repetitive traction of the patellar tendon on the developing growth plate. Sinding-Larsen-Johansson syndrome is similar but affects the inferior pole of the patella. Patellofemoral pain syndrome causes pain around or behind the patella, without a prominent tubercle. Patellar tendinopathy affects older adolescents or adults. Plica syndrome is less common and causes pain with knee flexion/extension.
Question 4479
Topic: Pediatric Upper Extremity & Spine
A 7-year-old boy presents with a supracondylar humerus fracture (Gartland Type III). Initial radiographs show significant displacement and rotation. Which neurovascular structure is most commonly at risk in this type of fracture?
Correct Answer & Explanation
. Median nerve and brachial artery.
Explanation
Gartland Type III supracondylar humerus fractures are severely displaced and rotated, putting the median nerve and brachial artery at significant risk of injury due to their close proximity to the distal humerus. The radial nerve is also at risk but less commonly than the median nerve/brachial artery. Ulnar nerve injury is less common in extension-type supracondylar fractures but can occur with flexion-type fractures or during surgical manipulation. Axillary and musculocutaneous nerves are not typically injured in this fracture pattern.
Question 4480
Topic: Pediatric Hip
A 4-year-old child presents with a limp and right hip pain that started insidiously. X-rays show fragmentation and collapse of the right femoral head epiphysis. What is the most likely diagnosis?
Correct Answer & Explanation
. Legg-Calvé-Perthes disease.
Explanation
The clinical presentation (limp, hip pain, insidious onset in a young child) combined with radiographic findings of fragmentation and collapse of the femoral head epiphysis is classic for Legg-Calvé-Perthes disease, which is avascular necrosis of the femoral head in children. Septic arthritis has an acute onset with systemic signs. DDH is a developmental abnormality. SCFE typically affects older, obese adolescents. Transient synovitis is a self-limiting inflammatory condition with normal X-rays.
Test Yourself
Switch to an interactive, timed exam simulation to truly master this topic.