Pediatric Orthopaedics Practice Questions

Q: What is the most common cause of genu valgum (knock knee)?

Idiopathic. **Explanation:** **Genu Valgum**, commonly known as "knock knees," is a condition where the knees angle inward and touch each other while the feet remain apart. 1. **Why Idiopathic is correct:** In the pediatric population, the most common cause of genu valgum is **idiopathic (physiological)**. It is a normal part of the lower limb's rotational and angular development. Children typically transition from physiological genu varum (bow legs) at birth to a neutral alignment at 18–24 months, followed by a peak of **physiological genu valgum between ages 3 and 4**. This usually resolves spontaneously by age 7. 2. **Why other options are incorrect:** * **Osteoarthritis:** While it can cause knee deformities, it more commonly results in genu varum (medial compartment wear) and is a disease of the elderly, not the primary cause in the general population. * **Rheumatoid Arthritis:** This can lead to genu valgum due to lateral compartment erosion and ligamentous laxity, but it is an inflammatory pathology and far less common than idiopathic causes. * **Trauma:** Injuries to the lateral proximal tibial growth plate (e.g., Cozen’s fracture) can cause asymmetric genu valgum, but these are specific, localized incidents rather than the most common cause. **High-Yield Clinical Pearls for NEET-PG:** * **The "3-4 Rule":** Peak physiological genu valgum occurs at **3–4 years** of age. * **Measurement:** It is clinically assessed by the **Intermalleolar Distance (IMD)**. An IMD >8 cm is generally considered pathological if it persists beyond age 8. * **Pathological Causes:** If not idiopathic, consider **Rickets** (most common metabolic cause), skeletal dysplasias, or post-traumatic physeal arrest. * **Surgery:** If correction is needed in a growing child, **Guided Growth (Hemi-epiphysiodesis)** using tension band plates (e.g., 8-plates) is the preferred intervention.

Q: Which of the following is NOT a cause of pseudoarthrosis?

Osteomyelitis. **Explanation:** The term **Pseudoarthrosis** (false joint) refers to a specific pathological condition where there is a failure of bone union, resulting in a fibrocartilaginous interface between bone ends. In pediatric orthopaedics, this is most commonly seen in the tibia. **Why Osteomyelitis is the correct answer:** Osteomyelitis typically leads to **Non-union** or **Infected Non-union**, but not "Pseudoarthrosis" in the clinical sense. In chronic osteomyelitis, the hallmark is the formation of a *Sequestrum* (dead bone) and *Involucrum* (new bone sheath). While the bone may fail to unite due to infection, the underlying pathophysiology involves necrosis and suppuration rather than the specific dysplastic fibrovascular tissue characteristic of Congenital Pseudoarthrosis of the Tibia (CPT). **Analysis of other options:** * **Neurofibromatosis (Type 1):** This is the most common association. Approximately 50% of patients with CPT have NF-1. It is caused by a defect in the periosteum which leads to hamartomatous fibrous tissue formation. * **Idiopathic:** Many cases of pseudoarthrosis occur spontaneously without an identifiable systemic syndrome, though they share the same clinical presentation of bowing and subsequent fracture. * **Multiple Compound Fractures:** Severe trauma with extensive soft tissue loss and bone loss can lead to an acquired pseudoarthrosis, where the bone ends become sclerotic and the medullary canal closes, preventing union. **NEET-PG High-Yield Pearls:** * **Most common site:** Distal third of the Tibia. * **NF-1 Association:** CPT is a "diagnostic criteria" for NF-1 if present with other signs like Café-au-lait spots. * **Radiological sign:** "Pre-pseudarthrosis" shows anterolateral bowing of the tibia. * **Treatment:** Very difficult; often requires the **Ilizarov technique** or **Vascularized Fibular Graft**. Avoid simple casting as it rarely leads to union.

Q: Which of the following is NOT a feature of cleidocranial dysostosis?

Short metacarpals. **Cleidocranial Dysostosis (CCD)** is an autosomal dominant skeletal dysplasia caused by a mutation in the **RUNX2 gene**, which is essential for osteoblast differentiation and intramembranous ossification. ### Why "Short Metacarpals" is the Correct Answer: In CCD, the hands typically show **long second metacarpals** and the presence of **pseudo-epiphyses** at the base of the metacarpals. Short metacarpals (specifically the 4th and 5th) are characteristic of conditions like *Pseudohypoparathyroidism* (Albright's Hereditary Osteodystrophy) or *Turner Syndrome*, but not CCD. ### Analysis of Other Options: * **Short Stature (A):** This is a common feature of CCD. Patients are generally shorter than their peers due to generalized skeletal dysplasia. * **Wide Foramen Magnum (B):** CCD involves delayed ossification of the skull. This leads to wide sutures, late closure of fontanelles (sometimes remaining open for life), and a characteristically **wide foramen magnum**. * **Absent Clavicle (D):** This is the hallmark of the condition. There is partial or complete aplasia of the clavicles (usually the lateral part). This allows the patient to abnormally approximate their shoulders in the midline. ### High-Yield Clinical Pearls for NEET-PG: * **Genetics:** RUNX2 gene (Chromosome 6p21). * **Skull:** Presence of **Wormian bones**, frontal bossing, and hypertelorism. * **Dental:** Highly characteristic **supernumerary teeth** (extra teeth) and delayed eruption of permanent teeth. * **Pelvis:** Delayed ossification of the pubic symphysis (appears wide/absent on X-ray). * **Clinical Sign:** Ability to touch shoulders together in front of the chest.

Q: What is the etiology of Pyaar's disease?

Unknown. **Explanation:** **Pyaar’s disease** (also known as **Legg-Calvé-Perthes Disease** or LCPD) is a childhood condition characterized by idiopathic avascular necrosis of the femoral head. **1. Why the correct answer is "Unknown":** The fundamental etiology of Pyaar’s disease remains **idiopathic** (unknown). While the underlying pathology involves a temporary interruption of the blood supply to the capital femoral epiphysis, the precise trigger for this vascular compromise is not established. Current theories suggest a multifactorial origin involving genetic predisposition, coagulation abnormalities (like Protein C or S deficiency), and environmental factors (e.g., secondhand smoke or low socioeconomic status). **2. Why other options are incorrect:** * **Pyogenic (A):** This refers to bacterial infections (e.g., Septic Arthritis). While septic arthritis can cause femoral head destruction, it presents with acute systemic symptoms (fever, high ESR/CRP), which are absent in Pyaar’s disease. * **Tubercular (B):** Tuberculosis of the hip (Caries hip) is a chronic granulomatous infection. It typically presents with a "cold abscess" and marked synovial thickening, unlike the self-limiting necrotic cycles of LCPD. * **Traumatic (C):** While trauma can cause avascular necrosis (AVN), Pyaar’s disease occurs spontaneously without a definitive history of significant injury. **Clinical Pearls for NEET-PG:** * **Demographics:** Most common in boys aged 4–8 years. * **Clinical Sign:** Early loss of **internal rotation and abduction**. * **Radiology:** Look for the **"Crescent sign"** (subchondral fracture) and increased bone density (sclerosis). * **Prognosis:** Determined by the **Catterall classification** or **Herring Lateral Pillar classification**. The younger the age at onset, the better the prognosis.

Q: What is the characteristic radiological sign in a case of Legg-Calvé-Perthes disease?

Lateral subluxation of the femur head. **Explanation:** **Legg-Calvé-Perthes Disease (LCPD)** is an idiopathic avascular necrosis of the capital femoral epiphysis in children (typically aged 4–8 years). The radiological progression follows the Waldenström classification, moving through stages of necrosis, fragmentation, reossification, and remodeling. **Why Option C is Correct:** **Lateral subluxation of the femoral head** is a critical radiological finding and is considered one of the **"Head at Risk" signs** (Catterall’s criteria). It occurs due to hypertrophy of the acetabular cartilage and synovitis, which pushes the femoral head laterally. This lateralization is a poor prognostic indicator as it leads to extrusion and subsequent deformity (Coxa Magna/Plana). **Analysis of Incorrect Options:** * **A & B (Calcification):** While the femoral head undergoes increased radiodensity (sclerosis) and fragmentation, "organized calcification" is not a specific radiological sign of LCPD. The hallmark is bone resorption and replacement, not primary soft tissue calcification. * **D (Restriction of abduction):** While this is a classic **clinical finding** in LCPD (along with loss of internal rotation), the question specifically asks for a **radiological sign**. **NEET-PG High-Yield Pearls:** * **Early Sign:** The earliest radiological sign is the **"Crescent Sign"** (subchondral fracture). * **Gage’s Sign:** A small V-shaped lucency on the lateral side of the epiphysis (another "Head at Risk" sign). * **Catterall Classification:** Used to determine the extent of epiphyseal involvement. * **Herring Classification:** Based on the height of the **lateral pillar** of the capital femoral epiphysis; it is the most commonly used prognostic classification today. * **Management Goal:** "Containment" of the femoral head within the acetabulum to prevent deformity.

Q: The primary defects in Congenital Talipes Equinovarus (CTEV) are the following EXCEPT:

Calcaneus. **Explanation:** Congenital Talipes Equinovarus (CTEV), also known as Clubfoot, is a complex congenital deformity characterized by a specific sequence of malalignments. The standard mnemonic to remember the primary components of CTEV is **CAVE**. 1. **C – Cavus:** Excessive longitudinal arch of the foot (due to tight intrinsic muscles). 2. **A – Adduction:** Forefoot adduction at the Tarsometatarsal joints. 3. **V – Varus:** Inversion and adduction of the hindfoot at the Subtalar joint. 4. **E – Equinus:** Plantarflexion at the Ankle joint (due to tight Achilles tendon). **Why Calcaneus is the Correct Answer:** "Calcaneus" refers to a deformity where the foot is dorsiflexed at the ankle (the opposite of Equinus). In CTEV, the heel is in **Equinus** (pointed downwards). Therefore, Calcaneus is not a component of CTEV; rather, it is the hallmark of a different condition called *Talipes Calcaneovalgus*. **Analysis of Incorrect Options:** * **Equinus:** A primary defect caused by the contracture of the Tendo-Achilles, leading to the inability to dorsiflex the foot. * **Adduction:** Occurs primarily at the midtarsal joints where the forefoot moves medially in relation to the hindfoot. * **Varus:** A key hindfoot deformity where the heel tilts inward, primarily involving the subtalar and talocalcaneonavicular joints. **Clinical Pearls for NEET-PG:** * **Order of Correction (Ponseti Method):** Corrected in the order of **C-A-V-E**. Cavus is corrected first by supinating the forefoot, followed by Adduction and Varus. **Equinus is always corrected last**, often requiring a Percutaneous Achilles Tenotomy. * **Pirani Score:** Used to assess the severity of CTEV and monitor progress during casting. * **Kite’s Angle:** On X-ray (AP view), the angle between the long axis of the talus and calcaneus is **decreased** in CTEV (normal is 20–40°).

Q: Which of the following conditions causes overgrowth of the epiphysis?

Hemophilia. **Explanation:** The correct answer is **Hemophilia**. **Underlying Mechanism:** In children with Hemophilia, recurrent intra-articular bleeding (hemarthrosis) leads to chronic synovial inflammation (synovitis). This chronic inflammation causes **persistent hyperemia** (increased blood flow) to the joint and the adjacent growth plates. The increased blood supply stimulates the epiphysis, leading to its premature enlargement and overgrowth. This is a classic feature of "Hemophilic Arthropathy," often resulting in a limb length discrepancy or a characteristic "ballooning" of the epiphysis (especially seen in the knee). **Analysis of Incorrect Options:** * **B. Osteogenesis Imperfecta:** This is a defect in Type I collagen. It typically results in "gracile" (thin), fragile bones prone to multiple fractures and bowing deformities, rather than epiphyseal overgrowth. * **C. Marfan’s Syndrome:** While this causes longitudinal overgrowth of long bones (arachnodactyly) due to fibrillin-1 mutations, it is a generalized connective tissue disorder affecting the metaphysis/diaphysis length rather than localized epiphyseal enlargement. * **D. Paget’s Disease:** This involves abnormal bone remodeling (excessive resorption and formation). While it causes bone thickening and deformity, it is rare in the pediatric age group and does not specifically cause epiphyseal overgrowth in the context of growth plates. **NEET-PG High-Yield Pearls:** * **Other causes of epiphyseal overgrowth:** Juvenile Idiopathic Arthritis (JIA) and localized vascular malformations (e.g., Klippel-Trenaunay Syndrome) also cause overgrowth via hyperemia. * **Radiological Sign:** In Hemophilia, look for the **"Squared-off Patella"** (Jordan’s Sign) and widened intercondylar notch of the femur due to chronic hyperemia and pressure. * **Target Joint:** The knee is the most common joint affected by hemarthrosis in hemophiliacs.

Q: Osgood-Schlatter disease is osteochondritis of which anatomical location?

Tibial tuberosity. **Explanation:** **Osgood-Schlatter disease** is a common cause of knee pain in active adolescents. It is a traction-induced **apophysitis** (osteochondritis) of the **tibial tuberosity**. 1. **Why Tibial Tuberosity is Correct:** The condition is caused by repetitive strain and microtrauma from the patellar tendon pulling on the ossification center of the tibial tuberosity during periods of rapid growth. It typically presents in young athletes (10–15 years) with localized pain, swelling, and tenderness over the tibial tubercle, which is exacerbated by jumping or running. 2. **Analysis of Incorrect Options:** * **Lunate (Option B):** Osteochondritis of the lunate is known as **Kienböck’s disease**, which leads to avascular necrosis and wrist pain. * **Calcaneum (Option C):** Osteochondritis (apophysitis) of the calcaneal tuberosity is known as **Sever’s disease**, a common cause of heel pain in children. * **Navicular (Option D):** Osteochondritis of the tarsal navicular bone is known as **Köhler’s disease**, typically seen in younger children (3–7 years). **High-Yield Clinical Pearls for NEET-PG:** * **Radiology:** X-rays may show fragmentation or irregularity of the tibial tuberosity and soft tissue swelling. * **Management:** It is a self-limiting condition. Treatment is conservative, involving rest, ice, activity modification, and NSAIDs. * **Differential Diagnosis:** Must be distinguished from **Sinding-Larsen-Johansson syndrome**, which is traction apophysitis of the **inferior pole of the patella**. * **Key Association:** Often bilateral in 25–50% of cases.

Q: What is the most common sign appreciated in congenital dislocation of the hip in an older child?

Limited abduction of the lower limb. **Explanation:** In Developmental Dysplasia of the Hip (DDH), clinical signs evolve as the child grows. In an **older child** (typically beyond 3–6 months), the hip becomes fixed in a dislocated position due to soft tissue contractures, particularly of the adductor muscles. **1. Why "Limited Abduction" is correct:** As the femoral head remains out of the acetabulum, the adductor muscles shorten and tighten. This leads to a mechanical restriction of hip movement. **Limited abduction** is the most sensitive and reliable clinical sign of DDH in the late stage. Other late features include limb shortening (Galeazzi sign), asymmetry of skin folds, and a Trendelenburg gait once the child starts walking. **2. Why other options are incorrect:** * **Barlow and Ortolani Tests (A & B):** These are "instability" tests used to detect a dislocatable or reducible hip in **neonates** (usually up to 2–3 months). In older children, the hip is no longer "clunking" in or out; it is fixed, making these tests negative. * **Painful range of motion (C):** Congenital dislocation is typically **painless** in childhood. Pain only develops much later in life due to secondary osteoarthritis. If an older child presents with a painful hip, diagnoses like Perthes disease or Slipped Capital Femoral Epiphysis (SCFE) are more likely. **Clinical Pearls for NEET-PG:** * **Best Initial Screening:** Ortolani/Barlow (Neonates); Limited Abduction (Older infants). * **Galeazzi Sign:** Apparent shortening of the femur (knee height discrepancy) seen in unilateral DDH. * **Radiology:** In children <6 months, **Ultrasound (Graf classification)** is the investigation of choice because the femoral head is not yet ossified. After 6 months, X-rays are used (look for Shenton’s line break and increased Acetabular index).

Question 1

What is the most common cause of genu valgum (knock knee)?

Accepted Answer

Idiopathic

Answer

Osteoarthritis

Answer

Rheumatoid arthritis

Answer

Trauma

Question 2

Which of the following is NOT a cause of pseudoarthrosis?

Accepted Answer

Osteomyelitis

Answer

Idiopathic

Answer

Multiple compound fractures

Answer

Neurofibromatosis

Question 3

Which of the following is NOT a feature of cleidocranial dysostosis?

Accepted Answer

Short metacarpals

Answer

Short stature

Answer

Wide foramen magnum

Answer

Absent clavicle

Question 4

What is the etiology of Pyaar's disease?

Accepted Answer

Unknown

Answer

Pyogenic

Answer

Tubercular

Answer

Traumatic

Question 5

Which of the following is the most common complication following surgery after repair of Sprengel deformity?

Accepted Answer

Brachial plexus injury

Answer

Infection

Answer

Mediastinitis

Answer

Dislocation of the shoulder

Question 6

What is the characteristic radiological sign in a case of Legg-Calvé-Perthes disease?

Accepted Answer

Lateral subluxation of the femur head

Answer

Epiphyseal calcification

Answer

Organized calcification

Answer

Restriction of abduction

Question 7

The primary defects in Congenital Talipes Equinovarus (CTEV) are the following EXCEPT:

Accepted Answer

Calcaneus

Answer

Equinus

Answer

Adduction

Answer

Varus

Question 8

Which of the following conditions causes overgrowth of the epiphysis?

Accepted Answer

Hemophilia

Answer

Osteogenesis imperfecta

Answer

Marfan's syndrome

Answer

Paget's disease

Question 9

Osgood-Schlatter disease is osteochondritis of which anatomical location?

Accepted Answer

Tibial tuberosity

Answer

Lunate

Answer

Calcaneum

Answer

Navicular

Question 10

What is the most common sign appreciated in congenital dislocation of the hip in an older child?

Accepted Answer

Limited abduction of the lower limb

Answer

Barlow test

Answer

Ortolani test

Answer

Painful range of motion

Pediatric Orthopaedics — MCQs

Pediatric Orthopaedics — MCQs

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