Pediatric Orthopaedics Practice Questions

Q: Coxa vara is caused by:

All of the above. **Explanation:** **Coxa vara** is a clinical deformity of the hip where the **neck-shaft angle** of the femur is reduced to **less than 120°** (normal is 120°–135°). This reduction in angle leads to a shortened limb and a characteristic abductor lurch (Trendelenburg gait). **Why "All of the Above" is correct:** Coxa vara is not a single disease but a structural manifestation of various underlying pathologies that weaken the femoral neck or affect the proximal femoral growth plate: 1. **SCFE (Slipped Capital Femoral Epiphysis):** In this condition, the femoral head slips posteriorly and inferiorly relative to the neck. This displacement results in a "relative" coxa vara and retroversion of the femoral neck. 2. **Rickets:** Metabolic bone diseases like Rickets (in children) or Osteomalacia (in adults) lead to softened osteoid. Under the physiological stress of weight-bearing, the softened femoral neck bends, leading to an acquired coxa vara. 3. **Paget’s Disease:** This is a disorder of bone remodeling resulting in structurally weak, hypervascular bone. When it involves the proximal femur, the "shepherd’s crook deformity" occurs, which is a severe form of coxa vara. **Clinical Pearls for NEET-PG:** * **Congenital Coxa Vara:** Characterized by a **vertical epiphyseal plate** and a **Fairbank’s triangle** (a triangular bone fragment in the inferior neck) on X-ray. * **Hilgenreiner’s Epiphyseal Angle (HEA):** Used to assess severity; an angle **>60°** usually requires surgical correction (Valgus Osteotomy). * **Differential Diagnosis:** Must be distinguished from Developmental Dysplasia of the Hip (DDH); in coxa vara, the femoral head is *inside* the acetabulum, whereas in DDH, it is displaced. * **Common presentation:** Painless limping, positive Trendelenburg sign, and restricted abduction and internal rotation.

Q: What is the most common type of supracondylar fracture?

Extension. ### Explanation **1. Why Extension is Correct:** Supracondylar fractures of the humerus are the most common pediatric elbow fractures. The **Extension type** is the most frequent, accounting for approximately **95-98%** of all cases. It occurs due to a fall on an outstretched hand (FOOSH) with the elbow in hyperextension. In this mechanism, the olecranon is forced into the olecranon fossa, acting as a fulcrum that causes the distal fragment to displace **posteriorly**. **2. Why Other Options are Incorrect:** * **Flexion (Option B):** This accounts for only **2-5%** of cases. It occurs due to a direct blow to the posterior aspect of the flexed elbow, causing the distal fragment to displace **anteriorly**. * **Neutral (Option A):** This is not a standard classification for supracondylar fractures. Fractures are classified based on the direction of displacement of the distal fragment relative to the proximal shaft. * **Lateral (Option D):** While lateral condyle fractures exist, "Lateral" is not a type of supracondylar fracture; it is a separate anatomical entity (and the second most common elbow fracture in children). **3. Clinical Pearls for NEET-PG:** * **Gartland Classification:** Used for Extension-type fractures (Type I: Undisplaced; Type II: Displaced with intact posterior cortex; Type III: Completely displaced). * **Most Common Nerve Injured:** * Extension type: **Anterior Interosseous Nerve (AIN)**, a branch of the Median nerve (Check for "OK sign"). * Flexion type: **Ulnar Nerve**. * **Most Common Vascular Injury:** Brachial Artery. * **Complications:** * Early: Volkmann’s Ischemic Contracture (VIC). * Late: **Cubitus Varus** (Gunstock deformity) due to malunion (most common). * **Radiology:** Look for the "Fat pad sign" (Sail sign) and the "Anterior Humeral Line" (which should normally bisect the middle third of the capitellum).

Q: In CDH, the hip and knees are held in a flexed position and gradually abducted. A 'click of entrance' is felt as the femoral head slips into the acetabulum from the position of dislocation. What is this maneuver known as?

Ortolani's test. ### Explanation **Correct Option: B. Ortolani’s test** The **Ortolani maneuver** is a clinical test used to identify a dislocated hip that can be **reduced**. In this maneuver, the clinician flexes the infant’s hips and knees to 90 degrees and then gradually **abducts** the hip while applying upward pressure on the greater trochanter. The "click" or "clunk" of entrance occurs as the femoral head slides back over the posterior acetabular rim into the socket. It is essentially a test of **reduction**. **Incorrect Options:** * **A. Barlow’s test:** This is a provocative maneuver used to identify an unstable hip that is currently "in" but can be **dislocated**. The hip is adducted and a downward (posterior) force is applied. It is a test of **dislocatability**. * **C. Thomas test:** This is used to assess **fixed flexion deformity (FFD)** of the hip, commonly seen in conditions like hip tuberculosis or osteoarthritis. * **D. Lasegue test:** Also known as the Straight Leg Raising (SLR) test, it is used to identify nerve root irritation (sciatica) or disc prolapse. **Clinical Pearls for NEET-PG:** 1. **Sequence:** Remember **B**arlow comes before **O**rtolani alphabetically; Barlow **dislocates** (goes out), and Ortolani **reduces** (comes back in). 2. **Age Limit:** These tests are most reliable in newborns. After **3–6 months**, soft tissue contractures develop, making these tests negative. At this stage, **limited abduction** becomes the most sensitive clinical sign of DDH (Developmental Dysplasia of the Hip). 3. **Galeazzi Sign:** Used in older infants to detect limb length discrepancy due to unilateral hip dislocation (the knee on the affected side appears lower). 4. **Imaging:** Ultrasound is the investigation of choice before 6 months (Graf classification); X-rays are used after 6 months once the femoral head ossifies.

Q: What is the cause of congenital pseudoarthrosis?

Unknown. **Explanation:** **Congenital Pseudarthrosis of the Tibia (CPT)** is a rare and challenging condition characterized by a spontaneous fracture of the tibia that fails to heal, leading to a "false joint" (pseudarthrosis). 1. **Why "Unknown" is the correct answer:** Despite its name, the exact underlying etiology of CPT remains **idiopathic (unknown)**. While there is a strong clinical association with other conditions, the precise molecular or mechanical trigger that prevents the bone from uniting at birth or shortly after is not yet fully understood. Histologically, it involves a hamartomatous proliferation of fibrous tissue in the periosteum, which impairs normal bone healing. 2. **Analysis of Incorrect Options:** * **Intrauterine fracture (A):** While the deformity may be present at birth, it is not caused by mechanical trauma in utero. It is a primary failure of bone formation and remodeling. * **Neurofibromatosis (B):** This is the most common **associated** condition (seen in approximately 50% of cases). However, NF-1 is a predisposing factor/association, not the primary cause itself. * **Fibrous dysplasia (C):** Although both involve fibrous replacement of bone, they are distinct clinical entities. Fibrous dysplasia is rarely the cause of a congenital pseudarthrosis. **High-Yield Clinical Pearls for NEET-PG:** * **Most Common Site:** Distal third of the tibia (often with anterior-lateral bowing). * **Association:** Always screen for **Neurofibromatosis Type 1 (NF-1)** (look for Café-au-lait spots). * **Boyd’s Classification:** Used to categorize the types of CPT. * **Treatment:** Extremely difficult; options include the **Ilizarov technique**, vascularized fibular bone grafting, or intramedullary nailing (Williams rod). Amputation is a last resort for recalcitrant cases.

Q: Which of the following conditions is NOT associated with an increase in limb length?

Salter-Harris fracture. **Explanation:** The correct answer is **Salter-Harris fracture**. This is because Salter-Harris fractures involve the **epiphyseal growth plate**. Damage to this sensitive area typically results in **growth arrest or retardation**, leading to **limb length shortening** (limb length discrepancy) or angular deformities, rather than an increase in length. **Why the other options are incorrect:** The other conditions listed are classic causes of **limb overgrowth** due to chronic hyperemia (increased blood flow) near the growth plates: * **Neurofibromatosis (Type 1):** Associated with local gigantism and plexiform neurofibromas. The increased vascularity and neurotrophic factors stimulate the physis, leading to limb lengthening. * **Hemophilia:** Repeated episodes of hemarthrosis (bleeding into joints) cause chronic synovial inflammation and hyperemia. This stimulates the adjacent epiphyseal plates, leading to accelerated longitudinal growth. * **Juvenile Idiopathic Arthritis (JIA):** Similar to hemophilia, the chronic inflammatory state and increased blood supply to the joint (hyperemia) stimulate the growth plates, causing the affected limb to become longer than the healthy side. **High-Yield Clinical Pearls for NEET-PG:** * **Hyperemia Rule:** Any condition causing chronic increased blood flow near a child's physis (e.g., healing femoral shaft fractures, osteomyelitis, or hemangiomas) generally causes **limb lengthening**. * **Salter-Harris Classification:** Types III, IV, and V have the highest risk of growth arrest and subsequent shortening. * **Ollier Disease:** Multiple enchondromatosis typically causes **shortening** and deformity, not lengthening.

Q: In children, scaphoid fractures are rare but usually involve which part of the bone?

Distal pole. ### Explanation **1. Why the Correct Answer is Right (Distal Pole):** In the pediatric population, the scaphoid undergoes a specific sequence of ossification. It begins to ossify at around age 4–5, starting from the **distal pole** and progressing proximally. Because the proximal portion remains cartilaginous for a longer period, it is more resilient to fractures. Most pediatric scaphoid fractures are **avulsion fractures of the distal pole** or involve the tubercle. These are often incomplete (greenstick) fractures because the thick periosteum in children provides stability. **2. Why the Other Options are Incorrect:** * **Waist (Option A):** This is the **most common site in adults** (approx. 70–80%). In children, the waist is often still cartilaginous or protected by the ossification pattern, making fractures here less frequent than in adults. * **Proximal Pole (Option B):** This is the least common site in both children and adults. In children, this area is the last to ossify, meaning it is mostly composed of flexible cartilage that absorbs energy rather than breaking. * **Neck (Option C):** The "neck" is not a standard anatomical description for scaphoid fracture classification; the bone is typically divided into the distal pole, waist, and proximal pole. **3. Clinical Pearls for NEET-PG:** * **Ossification Sequence:** The scaphoid is the last carpal bone to start ossifying (along with the trapezium/trapezoid). * **Blood Supply:** The scaphoid receives its blood supply **retrograde** (distal to proximal). This is why proximal pole fractures in adults have a high risk of **Avascular Necrosis (AVN)** and non-union. * **Management:** Most pediatric distal pole fractures are stable and heal well with 4–6 weeks of casting (Thumb Spica). * **Radiology Tip:** If a scaphoid fracture is suspected clinically but not seen on initial X-rays, the standard protocol is a Thumb Spica cast and **repeat X-ray in 10–14 days**.

Q: A 14-year-old obese child presents with painful limping of the hip. Which of the following investigations is least useful in this clinical setting?

Ultrasound. **Explanation:** The clinical presentation of an **obese adolescent (14 years old)** with a painful limp is a classic "spotter" for **Slipped Capital Femoral Epiphysis (SCFE)**. In SCFE, the femoral head slips posteriorly and inferiorly relative to the femoral neck. **Why Ultrasound is the Least Useful (Correct Option):** While Ultrasound can detect a joint effusion or a subtle step-off at the head-neck junction, it is highly operator-dependent and lacks the specificity required to grade the slip or plan surgical intervention. In the context of an obese patient, the increased soft tissue mass further limits the resolution and diagnostic utility of ultrasound compared to other modalities. **Analysis of Other Options:** * **X-ray (Pelvis and Bilateral Hips):** This is the **initial investigation of choice**. AP and Frog-leg lateral views are essential. Key signs include Klein’s line (which should normally intersect the femoral head) and the "Steel sign" (double density). Bilateral views are mandatory as SCFE is bilateral in 20-40% of cases. * **MRI Scan:** This is the **most sensitive** investigation for "Pre-slip" SCFE, where clinical suspicion is high but X-rays are normal. it is also vital for assessing femoral head vascularity (AVN). * **CT Scan:** Useful for complex cases to accurately measure the degree of posterior tilt and for preoperative planning of corrective osteotomies. **High-Yield Clinical Pearls for NEET-PG:** * **Demographics:** Most common in obese males during the adolescent growth spurt (10–16 years). * **Clinical Sign:** **Drehmann Sign** (Obligatory external rotation of the hip during passive flexion). * **Associated Conditions:** If the patient is not obese or is outside the typical age range, screen for endocrine disorders (Hypothyroidism, Growth hormone deficiency). * **Treatment:** The gold standard is **In-situ pinning** (Single cannulated screw) to prevent further slippage.

Question 1

A six-year-old child presented with a valgus deformity at his right elbow, which has been gradually progressive for the past 3 years. He has a history of a cast applied for 6 weeks after falling on an outstretched hand 3 years prior. What is the probable diagnosis?

Accepted Answer

Malunited lateral condylar fracture of the humerus

Answer

Malunited supracondylar fracture of the humerus

Answer

Posterior dislocation of the elbow

Answer

Fracture of the medial condyle of the humerus

Question 2

Coxa vara is caused by:

Accepted Answer

All of the above

Answer

SCFE

Answer

Rickets

Answer

Paget's disease

Question 3

A 7-year-old boy presents with abrupt onset of hip pain, and his hip is held in abduction. Hemogram is normal, but ESR is elevated. What is the next line of management?

Accepted Answer

Ultrasound-guided aspiration of the hip

Answer

Hospitalize and observe

Answer

Ambulatory observation

Answer

Intravenous antibiotics

Question 4

What is the most common type of supracondylar fracture?

Accepted Answer

Extension

Answer

Neutral

Answer

Flexion

Answer

Lateral

Question 5

In CDH, the hip and knees are held in a flexed position and gradually abducted. A 'click of entrance' is felt as the femoral head slips into the acetabulum from the position of dislocation. What is this maneuver known as?

Accepted Answer

Ortolani's test

Answer

Barlow's test

Answer

Thomas test

Answer

Lasegue test

Question 6

What is the cause of congenital pseudoarthrosis?

Accepted Answer

Unknown

Answer

Intrauterine fracture

Answer

Neurofibromatosis

Answer

Fibrous dysplasia

Question 7

Which of the following conditions is NOT associated with an increase in limb length?

Accepted Answer

Salter-Harris fracture

Answer

Neurofibromatosis

Answer

Hemophilia

Answer

Rheumatoid arthritis of juvenile type

Question 8

In children, scaphoid fractures are rare but usually involve which part of the bone?

Accepted Answer

Distal pole

Answer

Waist

Answer

Proximal pole

Answer

Neck

Question 9

A 14-year-old obese child presents with painful limping of the hip. Which of the following investigations is least useful in this clinical setting?

Accepted Answer

Ultrasound

Answer

CT scan

Answer

MRI scan

Answer

X-ray of the pelvis and bilateral hips

Question 10

A child with post-polio residual paralysis presents with gastrocnemius power - Grade 2, peroneus longus - Grade 3, and tibialis anterior - Grade 4. What is the most likely deformity present?

Accepted Answer

Calcaneo valgus

Answer

Calcaneo varus

Answer

Equino valgus

Answer

Equino varus

Pediatric Orthopaedics — MCQs

Pediatric Orthopaedics — MCQs

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