Trauma Practice Questions

Q: What is the radiographic appearance of dead bone on an X-ray?

More radio-opaque. **Explanation:** The correct answer is **A. More radio-opaque**. **Why it is correct:** In orthopaedics, dead bone (known as a **sequestrum**) appears more radio-opaque (whiter) than the surrounding living bone on an X-ray. This phenomenon occurs due to two primary reasons: 1. **Lack of Resorption:** Dead bone has no blood supply (avascular). Therefore, osteoclasts cannot reach the bone to resorb it. 2. **Relative Sclerosis:** In response to infection or injury, the surrounding living bone undergoes hyperemia (increased blood flow), leading to **disuse osteoporosis** (decalcification). Because the dead bone cannot lose calcium, it remains dense while the surrounding bone becomes more radiolucent, making the dead bone appear "whiter" by comparison. **Why the other options are incorrect:** * **B & C (Radiolucent/Less radio-opaque):** These terms describe bone that has lost mineral density (e.g., osteoporosis, osteolysis, or infection). Dead bone retains its original mineral content and often gains density through the precipitation of calcium salts from pus. * **D (Not seen at all):** Dead bone is clearly visible on X-rays and is a hallmark sign of chronic osteomyelitis. **High-Yield NEET-PG Pearls:** * **Sequestrum:** A piece of dead bone that has become separated during the process of necrosis (appears radio-opaque). * **Involucrum:** A layer of new living bone formed around the sequestrum (the "sheath"). * **Cloaca:** An opening in the involucrum through which pus and sequestra may emerge. * **Timmerman’s Sign:** The "ringing" sound produced when a sequestrum is tapped during surgery, indicating its dense, brittle nature.

Q: What type of Monteggia fracture is commonly associated with nerve injuries?

Type II. **Explanation:** The **Monteggia fracture-dislocation** is classified using the **Bado Classification**, which is based on the direction of the radial head dislocation. **Why Type II is correct:** Bado Type II involves a fracture of the ulnar shaft with **posterior or posterolateral dislocation** of the radial head. This specific subtype is most commonly associated with nerve injuries, specifically the **Posterior Interosseous Nerve (PIN)**, a branch of the radial nerve. The mechanism involves the radial head being displaced posteriorly, where it directly compresses or stretches the PIN as it passes through the supinator muscle (Arcade of Frohse). This is particularly common in adults. **Analysis of Incorrect Options:** * **Type I (Anterior):** The most common type overall (especially in children). The radial head dislocates anteriorly. While nerve injuries can occur, they are statistically less frequent than in Type II. * **Type III (Lateral):** Involves ulnar metaphyseal fractures with lateral radial head dislocation. This is more common in the pediatric population and is less frequently associated with nerve palsy compared to Type II. * **Type IV:** Involves fractures of both the radius and ulnar shafts with anterior dislocation of the radial head. It is rare and complex, but Type II remains the classic association for nerve injury in exams. **Clinical Pearls for NEET-PG:** * **Nerve involved:** Posterior Interosseous Nerve (PIN). Note that PIN injury causes **finger drop** (loss of MCP extension) but **no sensory loss**. * **Management:** Most PIN injuries are neuropraxias; hence, observation for 2–3 months is usually recommended before considering exploration. * **Mnemonic (MUGR):** **M**onteggia: **U**lna fracture; **G**aleazzi: **R**adius fracture.

Q: What does the Anterior Cruciate Ligament (ACL) primarily prevent?

Anterior dislocation of the tibia. ### Explanation The **Anterior Cruciate Ligament (ACL)** is the primary intra-articular stabilizer of the knee. Its fundamental biomechanical role is to resist **anterior translation (dislocation) of the tibia** relative to the femur. It also acts as a secondary stabilizer against internal rotation and valgus/varus stress. #### Why the Correct Answer is Right: * **Anterior dislocation of the tibia (Option D):** The ACL originates from the medial aspect of the lateral femoral condyle and inserts onto the anterior intercondylar area of the tibia. Because of this orientation, it tightens during knee extension to prevent the tibia from sliding forward underneath the femur. #### Why Other Options are Incorrect: * **Anterior dislocation of the femur (Option A):** This is functionally equivalent to *posterior* dislocation of the tibia, which is prevented by the **Posterior Cruciate Ligament (PCL)**. * **Posterior dislocation of the tibia (Option B):** This is the primary function of the **PCL**, which prevents the tibia from sliding backward relative to the femur. * **Lateral dislocation of the tibia (Option C):** Medial and lateral stability are primarily maintained by the **Collateral Ligaments** (MCL and LCL). #### NEET-PG High-Yield Clinical Pearls: * **Mechanism of Injury:** Most commonly occurs during non-contact deceleration, "pivoting," or sudden change in direction with a planted foot. * **Clinical Tests:** The **Lachman Test** is the most sensitive clinical test for ACL deficiency. Other tests include the **Anterior Drawer Test** and the **Pivot Shift Test** (most specific). * **Segond Fracture:** An avulsion fracture of the lateral tibial plateau; it is considered pathognomonic for an ACL tear. * **Unhappy Triad (O'Donoghue):** Simultaneous injury to the ACL, Medial Collateral Ligament (MCL), and Medial Meniscus (though recent studies suggest the Lateral Meniscus is more commonly injured in acute settings).

Q: Traumatic avascular necrosis occurs in which of the following fractures?

Neck of femur, Talus, Scaphoid. **Explanation:** The correct answer is **A: Neck of femur, Talus, Scaphoid.** The underlying medical concept for traumatic avascular necrosis (AVN) in these specific bones is their **retrograde blood supply** and **lack of muscular attachments**. These bones are largely covered by articular cartilage, meaning blood vessels must enter through small non-articular areas, often at the distal end, and flow proximally. A fracture across the "waist" or "neck" of these bones mechanically disrupts these vulnerable nutrient vessels, leaving the proximal fragment ischemic. * **Neck of Femur:** The primary supply is via the retinacular vessels (from the medial circumflex femoral artery). Intracapsular fractures frequently tear these vessels, leading to AVN of the femoral head. * **Scaphoid:** Blood enters the distal pole and flows retrogradely to the proximal pole. Fractures at the waist often result in AVN of the proximal fragment. * **Talus:** The blood supply enters through the tarsal canal and sinus tarsi. Fractures of the talar neck (Hawkins classification) frequently disrupt this supply, leading to AVN of the body. **Why other options are incorrect:** * **Options C & D:** The **Surgical neck of the humerus** is not a classic site for AVN. Unlike the anatomical neck (which can undergo AVN), the surgical neck is distal to the insertion of the joint capsule and has a robust collateral blood supply from the anterior and posterior circumflex humeral arteries. **High-Yield Clinical Pearls for NEET-PG:** 1. **Hawkins Sign:** A subchondral radiolucency in the talar body seen 6–8 weeks post-fracture; it indicates intact vascularity (the bone is being resorbed, so it cannot be necrotic). 2. **Preiser’s Disease:** Idiopathic (non-traumatic) AVN of the scaphoid. 3. **Other sites for AVN:** Lunate (Kienbock’s disease), Head of second metatarsal (Freiberg’s disease), and Body of Navicular (Kohler’s disease).

Q: Which of the following is NOT relevant in the management of compartment syndrome?

Exercise. **Explanation:** Compartment syndrome is a surgical emergency characterized by increased pressure within a closed osteofascial space, leading to impaired local circulation and potential tissue necrosis. **Why Exercise is NOT relevant:** **Exercise** is contraindicated in the acute phase of compartment syndrome. Physical activity increases metabolic demand and blood flow to the muscles, which further elevates intracompartmental pressure and exacerbates ischemia. Management focuses on **reducing** pressure, not increasing muscle activity. **Analysis of other options:** * **Fasciotomy:** This is the definitive surgical treatment. It involves incising the fascia to decompress the compartment and restore distal perfusion. * **Splitting of a tight cast:** This is the immediate first step in management. Removing or "bivalving" a restrictive cast/dressing can reduce intracompartmental pressure by up to 30–65%. * **Reexploration:** After a fasciotomy, the wound is left open and requires reexploration (usually within 48–72 hours) for debridement of necrotic tissue and eventual closure or skin grafting. **Clinical Pearls for NEET-PG:** * **Earliest Sign:** Pain out of proportion to the injury and pain on passive stretching of muscles. * **Late Sign:** Pulselessness (indicates irreversible damage; do not wait for this to diagnose). * **Pressure Threshold:** A Delta pressure ($\Delta P$) of **$\leq$ 30 mmHg** (Diastolic BP minus Compartment Pressure) is often used as an indication for fasciotomy. * **Positioning:** Keep the limb at the **level of the heart**. Elevating the limb above the heart reduces arterial inflow and worsens ischemia.

Q: At what age can distraction osteogenesis be performed?

2 years of age. **Explanation:** **Distraction Osteogenesis (DO)**, also known as the Ilizarov technique, is a biological process of regenerating new bone between two bone segments that are gradually separated by controlled mechanical traction. **Why 2 years is the correct answer:** The biological principles of distraction osteogenesis can be applied as soon as the bone is structurally capable of holding the fixator pins and the patient’s metabolic activity is sufficient for rapid bone formation. In clinical practice, especially for congenital conditions like **hemifacial microsomia** (mandibular distraction) or severe **congenital limb length discrepancies**, distraction can be safely and effectively initiated as early as **2 years of age**. At this age, the bone has sufficient cortical thickness to provide stability for the pins, and the osteogenic potential (periosteal activity) is at its peak, allowing for rapid callus formation. **Analysis of Incorrect Options:** * **4, 6, and 8 years of age:** While distraction osteogenesis is frequently performed at these ages, they are not the *earliest* possible age. Waiting until these ages for severe deformities may lead to secondary soft tissue contractures or psychological delays in development. **High-Yield Clinical Pearls for NEET-PG:** * **The Ilizarov Principle:** Based on the "Law of Tension-Stress," which states that gradual traction on living tissues creates a proliferative response. * **The Four Phases of DO:** 1. **Osteotomy:** The bone is surgically cut. 2. **Latency Period:** (5–7 days) Time allowed for initial callus formation. 3. **Distraction Phase:** Bone is pulled apart, typically at a rate of **1 mm/day** (divided into 0.25 mm four times a day to minimize soft tissue trauma). 4. **Consolidation Phase:** The new bone (regenerate) mineralizes and hardens. * **Common Complication:** Pin tract infection is the most frequent complication of this procedure.

Q: A 10-year-old girl sustained an upper limb injury two years ago. She now presents with a valgus deformity of the elbow and paresthesias over the medial aspect of her hand. What is the most likely diagnosis?

Lateral condyle fracture of the humerus. **Explanation:** The clinical presentation of a **valgus deformity** (cubitus valgus) following an old elbow injury in a child, associated with **tardy ulnar nerve palsy** (paresthesias over the medial hand), is a classic complication of a **Lateral Condyle Fracture of the Humerus**. **Why it is correct:** Lateral condyle fractures are "fractures of necessity" (requiring ORIF) because they are intra-articular and prone to non-union. If left untreated or if union fails, the lateral growth plate is disrupted while the medial side continues to grow. This asymmetrical growth leads to a progressive **cubitus valgus** deformity. As the valgus angle increases, the ulnar nerve is stretched around the medial epicondyle, leading to delayed-onset ulnar neuropathy, known as **Tardy Ulnar Nerve Palsy**. **Why other options are incorrect:** * **Supracondylar fracture:** The most common complication is **cubitus varus** (Gunstock deformity). While it can cause immediate nerve injuries (Median/AIBN), it rarely causes tardy ulnar nerve palsy. * **Medial condyle fracture:** This is rare in children and would typically lead to a varus deformity, not valgus. * **Fracture of the proximal ulna:** Isolated ulna fractures do not typically result in progressive elbow valgus or delayed ulnar nerve symptoms. **High-Yield Pearls for NEET-PG:** * **Lateral Condyle Fracture:** Second most common elbow fracture in children; known as the **"Fracture of Wise Men"** (because it is easy to miss but difficult to treat). * **Milch Classification:** Used to categorize these fractures based on the fracture line relative to the trochlear groove. * **Tardy Ulnar Nerve Palsy:** Most commonly associated with non-union of the lateral condyle. Treatment involves ulnar nerve transposition. * **Cubitus Varus:** Most common deformity after supracondylar fractures; primarily a cosmetic issue rather than a functional one.

Question 1

What is the radiographic appearance of dead bone on an X-ray?

Accepted Answer

More radio-opaque

Answer

Radiolucent

Answer

Less radio-opaque

Answer

Not seen at all

Question 2

Which of the following statements regarding dislocation of the shoulder is FALSE?

Accepted Answer

In posterior dislocation, the appearance of the shoulder is abnormal.

Answer

The head of the humerus usually dislocates anteriorly from the shoulder joint.

Answer

The injury is produced by forced extension and external rotation of an abducted arm.

Answer

None of the above

Question 3

What type of Monteggia fracture is commonly associated with nerve injuries?

Accepted Answer

Type II

Answer

Type I

Answer

Type III

Answer

Type IV

Question 4

What does the Anterior Cruciate Ligament (ACL) primarily prevent?

Accepted Answer

Anterior dislocation of the tibia

Answer

Anterior dislocation of the femur

Answer

Posterior dislocation of the tibia

Answer

Lateral dislocation of the tibia

Question 5

Traumatic avascular necrosis occurs in which of the following fractures?

Accepted Answer

Neck of femur, Talus, Scaphoid

Answer

Neck of femur, Scaphoid

Answer

Surgical neck of humerus, Talus

Answer

Surgical neck of humerus, Talus, Scaphoid

Question 6

In rubber band extraction, the extraction of the tooth occurs because of which of the following mechanisms?

Accepted Answer

Necrosis of the periodontal ligament (PDL).

Answer

Tearing of the periodontal ligament (PDL).

Answer

Both tearing and necrosis of the PDL.

Answer

None of the above.

Question 7

Which of the following is NOT relevant in the management of compartment syndrome?

Accepted Answer

Exercise

Answer

Fasciotomy

Answer

Splitting of a tight cast

Answer

Reexploration

Question 8

At what age can distraction osteogenesis be performed?

Accepted Answer

2 years of age

Answer

4 years of age

Answer

6 years of age

Answer

8 years of age

Question 9

What is the most important step in the primary management of a patient with a fractured vertebral column?

Accepted Answer

Maintenance of the airway

Answer

Careful transportation of the patient

Answer

Treatment of shock

Answer

None of the above

Question 10

A 10-year-old girl sustained an upper limb injury two years ago. She now presents with a valgus deformity of the elbow and paresthesias over the medial aspect of her hand. What is the most likely diagnosis?

Accepted Answer

Lateral condyle fracture of the humerus

Answer

Supracondylar fracture of the humerus

Answer

Medial condyle fracture of the humerus

Answer

Fracture of the proximal ulna

Trauma — MCQs

Trauma — MCQs

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