Trauma Practice Questions

Q: Which of the following is most stable in closed reduction?

Arch bar. In the management of maxillofacial fractures, **Closed Reduction and Internal Fixation (CRIF)** aims to restore the patient's pre-injury dental occlusion without surgical exposure of the fracture site. ### **Why Arch Bar is the Correct Answer** The **Erich Arch Bar** is the gold standard for closed reduction in mandibular and maxillary fractures. It consists of a semi-rigid metal strip with hooks that is contoured to the dental arch and secured to the teeth using circumdental wires. * **Stability:** It provides multi-point fixation across the entire dental arch, distributing occlusal forces evenly. * **Function:** Once applied to both upper and lower arches, they are connected via elastic bands or wires (**Intermaxillary Fixation - IMF**), which provides superior stability for bone healing compared to other closed methods. ### **Why Other Options are Incorrect** * **Screws (A):** In the context of closed reduction, "IMF screws" can be used, but they provide only point-fixation. They are prone to loosening in soft bone and do not offer the same tension-band stability across the fracture line as arch bars. * **Direct Wiring (C):** Also known as "Eyelet wiring" or "Ivy loops." While useful for temporary stabilization, they involve fewer teeth and are less stable than arch bars, often slipping or causing more periodontal stress. ### **High-Yield Clinical Pearls for NEET-PG** * **Indications for Arch Bars:** Minimally displaced fractures, favorable mandibular fractures, and as a supplement to Open Reduction Internal Fixation (ORIF). * **Contraindications:** Patients with severe epilepsy (risk of aspiration during seizures) or poor periodontal health. * **Key Advantage:** It acts as a **tension band** on the alveolar segment of the mandible. * **Removal:** Usually removed after 4–6 weeks once clinical union is achieved.

Q: Which nerve is injured in a subcoracoid dislocation of the humerus?

Axillary nerve. **Explanation:** **1. Why Axillary Nerve is Correct:** The shoulder is the most commonly dislocated joint in the body, with **Anterior Dislocation** (specifically the **subcoracoid** type) being the most frequent variety. The **Axillary nerve (C5, C6)** is the most common nerve injured in this condition (occurring in approximately 5–15% of cases). This is due to its anatomical proximity; the nerve winds around the surgical neck of the humerus within the quadrangular space. When the humeral head is displaced anteriorly and inferiorly, it stretches or compresses the nerve against the neck of the humerus. **2. Why Other Options are Incorrect:** * **Radial Nerve:** This nerve is most commonly injured in fractures of the **shaft of the humerus** (Holstein-Lewis fracture) as it traverses the spiral groove. * **Brachial Plexus:** While the cords of the brachial plexus can be involved in high-energy trauma or infraclavicular dislocations, it is less common than isolated axillary nerve palsy. * **Median Nerve:** This nerve is typically associated with injuries around the elbow, such as **Supracondylar fractures of the humerus**. **3. Clinical Pearls for NEET-PG:** * **Clinical Sign:** Injury to the axillary nerve leads to paralysis of the **Deltoid** (loss of abduction beyond 15°) and **Teres minor**. * **Sensory Loss:** Look for the **"Regimental Badge Sign"**—loss of sensation over the lateral aspect of the upper arm. * **Radiology:** The "Hollow shoulder" appearance and "Light bulb sign" (specific to posterior dislocation) are high-yield radiographic findings. * **Vascular Injury:** The **Axillary artery** is the most common vascular structure injured in anterior dislocations, especially in elderly patients with atherosclerotic vessels.

Q: In Colle's fracture, which of the following describes the displacement of the distal fragment?

All of the above. **Explanation:** Colles' fracture is a distal radius fracture occurring within 2.5 cm of the wrist joint, typically resulting from a fall on an outstretched hand (FOOSH). The characteristic "Dinner Fork Deformity" is produced by a specific pattern of displacement of the distal fragment. **Why "All of the above" is correct:** The distal fragment in a Colles' fracture undergoes six distinct displacements: 1. **Dorsal Shift:** The fragment moves toward the back of the hand. 2. **Dorsal Tilt (Angulation):** The articular surface faces dorsally instead of the normal volar tilt. 3. **Lateral Shift:** The fragment moves toward the radial side. 4. **Lateral Tilt (Angulation):** The fragment tilts toward the radial side. 5. **Supination:** The fragment rotates outward. 6. **Impaction:** The fragment is driven into the proximal shaft (shortening). **Analysis of Options:** * **Option A (Shifted dorsally):** Correct. This contributes to the "hump" seen in the dinner fork deformity. * **Option B (Angulated laterally):** Correct. This leads to the radial deviation of the hand. * **Option C (Supinated):** Correct. The force of the injury and the pull of the brachioradialis muscle rotate the distal fragment into supination. **High-Yield Clinical Pearls for NEET-PG:** * **Reverse Colles:** Known as **Smith’s fracture**, where the displacement is **volar** (ventral), caused by a fall on the back of a flexed wrist. * **Most common complication:** Stiffness of the fingers and shoulder (due to neglect during immobilization). * **Most common late complication:** Malunion (leading to dinner fork deformity). * **Specific Tendon Rupture:** Spontaneous rupture of the **Extensor Pollicis Longus (EPL)** can occur weeks later due to ischemia or attrition at Lister’s tubercle. * **Nerve Involvement:** The **Median nerve** is the most commonly injured nerve in acute presentations.

Q: Which traumatic fracture is most likely to show avascular necrosis?

Femoral neck. **Explanation:** The risk of **Avascular Necrosis (AVN)** is highest in bones with a "precarious" blood supply—specifically those where the blood vessels enter at one end and travel retrograde, or where the bone is largely covered by articular cartilage with limited periosteal entry points. **1. Why Femoral Neck is the Correct Answer:** The femoral neck is an **intracapsular** structure. Its primary blood supply comes from the **medial circumflex femoral artery** via retinacular vessels. A fracture in this region often tears these vessels, leaving the femoral head completely ischemic. Unlike extracapsular fractures (like intertrochanteric), there is no surrounding muscle or robust periosteum to provide collateral circulation, making AVN a very common complication (up to 30-40%). **2. Analysis of Incorrect Options:** * **Surgical neck of humerus:** This is an extracapsular area with a rich blood supply from the anterior and posterior circumflex humeral arteries and surrounding rotator cuff musculature. AVN is rare here compared to the anatomical neck. * **Body of talus:** While the talus is a high-risk site for AVN (Hawkins sign), the question asks which is *most likely*. Statistically, femoral neck fractures are far more common in clinical practice and exams as the classic example of post-traumatic AVN. * **Cuboid:** This is a tarsal bone with excellent ligamentous and vascular attachments; AVN is extremely rare. **Clinical Pearls for NEET-PG:** * **Common sites for AVN:** Femoral head (most common), Scaphoid (proximal pole), Talus (body), and Lunate (Kienbock’s disease). * **Investigation of Choice:** **MRI** is the most sensitive investigation for early detection of AVN (shows changes before X-ray). * **Garden Classification:** Used for femoral neck fractures; Stages III and IV have the highest risk of AVN due to complete displacement.

Q: Pipkin fracture is defined as:

Head of femur fracture. ### Explanation **Correct Answer: B. Head of femur fracture** **Medical Concept:** A **Pipkin fracture** refers specifically to a fracture of the **femoral head** associated with a posterior dislocation of the hip. It is a high-energy injury, typically resulting from a "dashboard injury" where a direct force is transmitted through the femur while the hip is flexed. The Pipkin classification is used to grade these injuries based on the location of the fracture relative to the fovea capitis and the presence of associated femoral neck or acetabular fractures. **Analysis of Incorrect Options:** * **A. Head of radius fracture:** These are common elbow injuries often classified by the **Mason Classification**, not Pipkin. * **C. Fracture dislocation of ankle:** Common eponyms for ankle fractures include **Pott’s fracture**, **Cotton’s fracture** (trimalleolar), or **Lauge-Hansen/Danis-Weber** classifications. * **D. Fracture neck of femur:** These are intracapsular fractures classified by **Garden’s** (based on displacement) or **Pauwels'** (based on verticality of the fracture line) classifications. **High-Yield Clinical Pearls for NEET-PG:** * **Pipkin Classification:** * **Type I:** Fracture inferior to the fovea capitis (small fragment). * **Type II:** Fracture superior to the fovea capitis (large fragment). * **Type III:** Type I or II associated with a femoral neck fracture (high risk of AVN). * **Type IV:** Type I or II associated with an acetabular rim fracture. * **Complications:** The most dreaded complication of Pipkin fractures is **Avascular Necrosis (AVN)** of the femoral head due to disrupted blood supply, followed by post-traumatic arthritis. * **Emergency:** Hip dislocation is an orthopedic emergency; reduction must be performed within 6 hours to minimize AVN risk.

Q: Le Fort fracture is associated with which of the following?

Facial skeleton. **Explanation:** **Le Fort fractures** are classic patterns of midface fractures involving the detachment of the **facial skeleton** from the skull base. They occur due to high-energy blunt trauma and are defined by the involvement of the pterygoid plates of the sphenoid bone. * **Le Fort I (Horizontal):** Separates the alveolar process of the maxilla from the rest of the face (Floating palate). * **Le Fort II (Pyramidal):** Involves the maxilla, zygomaticomaxillary suture, and nasal bones, resulting in a pyramidal-shaped fragment (Floating maxilla). * **Le Fort III (Craniofacial Disjunction):** The entire facial skeleton is separated from the cranial base through the zygomatic arches and orbits (Floating face). **Why other options are incorrect:** * **Lower limb:** Fractures here are classified by systems like Gustilo-Anderson (open fractures) or Schatzker (tibial plateau), not Le Fort. * **Spinal injury:** These use classifications like Denis (Three-column theory) or AO Spine. * **Pelvis fracture:** These are categorized by the Tile or Young-Burgess classifications based on stability and mechanism of injury (e.g., lateral compression). **High-Yield Clinical Pearls for NEET-PG:** 1. **Pterygoid Plates:** A fracture must involve the pterygoid plates to be classified as a Le Fort fracture. 2. **CSF Rhinorrhea:** Most common in Le Fort II and III due to involvement of the ethmoid bone/cribriform plate. 3. **Dish-face deformity:** Characteristically seen in Le Fort III fractures due to the retrusion of the midface. 4. **Airway Management:** In severe maxillofacial trauma, securing the airway is the first priority (often requiring cricothyroidotomy if oral intubation is impossible).

Q: Which treatment plan would lead to rigid fixation of the fracture site?

Eccentric compression plate osteosynthesis. ### Explanation **Concept of Rigid vs. Biological Fixation** In orthopaedics, **rigid (absolute) stability** is achieved when there is no movement at the fracture site under physiological loads. This leads to **primary bone healing** (direct cortical remodeling without callus formation). **Eccentric compression plating** (Option C) achieves this by utilizing the "tension band principle" or specialized plate holes (like the Dynamic Compression Plate) to exert active pressure across the fracture ends, resulting in absolute stability. **Why the other options are incorrect:** * **Direct interdental wiring (Option A):** This provides only **non-rigid** fixation. It stabilizes the teeth but does not provide enough compression or stability to prevent micro-motion at the bone level. * **Miniplates osteosynthesis (Option B):** These provide **semi-rigid** (functionally stable) fixation. They are designed to neutralize forces along the lines of tension (Champy’s lines) but allow for some microscopic movement, usually leading to secondary bone healing with callus. * **Intermaxillary fixation (Option D):** This is a form of **conservative/indirect** stabilization. While it immobilizes the jaw, it does not provide internal rigid compression at the fracture interface. **High-Yield Clinical Pearls for NEET-PG:** * **Primary Bone Healing:** Requires absolute stability (e.g., Compression plates, Lag screws). No callus is seen on X-ray. * **Secondary Bone Healing:** Occurs with relative stability (e.g., IM nails, Casts, External fixators). Callus formation is visible. * **Gold Standard for Mandible:** While miniplates are the most common clinical practice (load-sharing), **compression plates** (load-bearing) are the classic answer for "rigid fixation." * **Absolute Stability Rule:** Always remember: "Compression = Absolute Stability = Primary Healing."

Question 1

Which of the following is most stable in closed reduction?

Accepted Answer

Arch bar

Answer

Screws

Answer

Direct wiring

Answer

None of the above

Question 2

Which nerve is injured in a subcoracoid dislocation of the humerus?

Accepted Answer

Axillary nerve

Answer

Radial nerve

Answer

Brachial plexus

Answer

Median nerve

Question 3

What is the most common complication of an intracapsular fracture of the neck of femur?

Accepted Answer

Malunion

Answer

Non-union

Answer

Myositis ossificans

Answer

Valkmann's ischemic contracture

Question 4

Which of the following types of odontoid fractures is considered unstable?

Accepted Answer

Both Type II and Type III

Answer

Type II

Answer

Type III

Answer

Neither Type II nor Type III

Question 5

In Colle's fracture, which of the following describes the displacement of the distal fragment?

Accepted Answer

All of the above

Answer

Shifted dorsally

Answer

Angulated laterally

Answer

Supinated

Question 6

Which traumatic fracture is most likely to show avascular necrosis?

Accepted Answer

Femoral neck

Answer

Surgical neck of humerus

Answer

Body of talus

Answer

Cuboid

Question 7

Pipkin fracture is defined as:

Accepted Answer

Head of femur fracture

Answer

Head of radius fracture

Answer

Fracture dislocation of ankle

Answer

Fracture neck of femur

Question 8

Which fracture in children requires open reduction?

Accepted Answer

Fracture of tibial epiphysis

Answer

Fracture of shaft of femur

Answer

Fracture of both bones of the forearm

Answer

Fracture of the femoral condyle

Question 9

Le Fort fracture is associated with which of the following?

Accepted Answer

Facial skeleton

Answer

Lower limb

Answer

Spinal injury

Answer

Pelvis fracture

Question 10

Which treatment plan would lead to rigid fixation of the fracture site?

Accepted Answer

Eccentric compression plate osteosynthesis

Answer

Direct interdental wiring

Answer

Miniplates osteosynthesis

Answer

Intermaxillary fixation (IMF)

Trauma — MCQs

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