Trauma Practice Questions

Q: What is a straddle fracture?

Pelvic fracture. **Explanation:** A **Straddle Fracture** is a specific type of unstable pelvic fracture characterized by **bilateral fractures of the superior and inferior pubic rami**. It is typically caused by a direct blow to the midline of the symphysis pubis, such as falling onto a hard object (e.g., a manhole cover or a bicycle frame). **Why the correct answer is right:** * **Pelvic Fracture:** The term "straddle" refers to the mechanism of injury involving the perineum. This injury results in a "floating" anterior segment of the pelvis. It is clinically significant because it is associated with a high incidence (up to 20%) of **genitourinary injuries**, particularly ruptures of the posterior urethra or bladder. **Why the incorrect options are wrong:** * **A. Fracture of the skull:** Skull fractures are classified by location (vault, base) or type (depressed, linear), but "straddle" is not a term used in neurotrauma. * **B. Fracture of C5 vertebra:** Cervical fractures have specific names like Jefferson (C1) or Hangman’s (C2). C5 is a common site for burst fractures, but not straddle fractures. * **C. Multiple rib fractures:** This describes a **Flail Chest** (if 3 or more ribs are broken in 2 or more places), which causes paradoxical respiration. **High-Yield Clinical Pearls for NEET-PG:** * **Malgaigne Fracture:** The most common vertical shear pelvic fracture (ipsilateral rami fracture + sacroiliac joint disruption). * **Duverney Fracture:** Isolated fracture of the iliac wing (stable). * **Open Book Injury:** Disruption of the pubic symphysis with injury to the sacroiliac ligaments. * **Investigation of Choice:** AP view X-ray is the initial screening tool, but **CT Scan** is the gold standard for defining pelvic ring stability. * **Management:** In hemodynamically unstable pelvic fractures, the first step is **Pelvic Binding** to reduce pelvic volume and tamponade bleeding.

Q: Which of the following statements is NOT true regarding anterior dislocation of the hip?

Associated with shortening of the limb.. **Explanation:** In hip dislocations, the clinical presentation is determined by the final position of the femoral head relative to the acetabulum. In **Anterior Dislocation of the Hip**, the femoral head is displaced anteriorly and usually inferiorly (obturator type) or superiorly (pubic type). **1. Why Option D is the Correct Answer (The "False" Statement):** In anterior dislocations, the femoral head is displaced away from the acetabulum in a manner that typically results in **lengthening** of the limb, not shortening. Shortening is a hallmark feature of **posterior** hip dislocations. Therefore, the statement "Associated with shortening of the limb" is incorrect regarding anterior dislocation. **2. Analysis of Other Options:** * **Option A (Femoral nerve injury):** In anterior dislocations, the femoral head moves forward, putting direct pressure on the **femoral nerve** and vessels. (In contrast, the sciatic nerve is at risk in posterior dislocations). * **Option B (Lateral rotation):** The displacement of the head anterior to the axis of the femur causes the limb to assume a position of **external (lateral) rotation** and abduction. * **Option C (Lengthening):** As the head is displaced inferiorly and anteriorly, the effective length of the limb increases. **Clinical Pearls for NEET-PG:** | Feature | Posterior Dislocation (Most Common) | Anterior Dislocation | | :--- | :--- | :--- | | **Attitude** | Flexion, Adduction, **Internal Rotation** | Flexion, Abduction, **External Rotation** | | **Limb Length** | **Shortening** | **Lengthening** | | **Nerve Injury** | Sciatic Nerve | Femoral Nerve | | **Mechanism** | Dashboard injury | Forced abduction/extension | * **Mnemonic for Posterior Dislocation:** **S**hortened, **A**dducted, **I**nternally rotated (**SAI**). * **X-ray finding:** In anterior dislocation, the lesser trochanter is more visible due to external rotation.

Q: What is the most common direction of elbow dislocation?

Posterior. The elbow is the second most commonly dislocated large joint in adults (after the shoulder). **Posterior dislocation** is the most common type, occurring in approximately 80-90% of cases. **Why Posterior is Correct:** The mechanism of injury is typically a **fall on an outstretched hand (FOOSH)** with the elbow in slight flexion. In this position, the force is transmitted through the forearm, driving the olecranon process of the ulna posteriorly and superiorly relative to the distal humerus. The strong bony stability of the trochlear notch is overcome, often resulting in the rupture of the ulnar collateral ligament and the anterior capsule. **Analysis of Incorrect Options:** * **Anterior Dislocation:** Rare; it usually occurs due to a direct blow to the posterior aspect of the flexed elbow (e.g., a fall on the point of the olecranon), driving the ulna forward. * **Medial/Lateral Dislocation:** These are extremely uncommon and are usually associated with extensive soft tissue disruption or complex fracture-dislocations. **High-Yield Clinical Pearls for NEET-PG:** * **Classification:** Elbow dislocations are named based on the position of the **radius and ulna relative to the humerus**. * **The "Terrible Triad" of the Elbow:** Includes (1) Posterior elbow dislocation, (2) Coronoid process fracture, and (3) Radial head fracture. * **Nerve Injury:** The **Ulnar nerve** is the most commonly injured nerve in posterior dislocations, followed by the Median nerve. * **Vascular Complication:** Always check the radial pulse to rule out **Brachial artery** injury. * **Clinical Sign:** In a posterior dislocation, the normal isosceles triangle formed by the olecranon and the two epicondyles is lost.

Q: Which of the following fractures can cause cubitus varus deformity as a complication?

Supracondylar fracture of the humerus. **Explanation:** **Supracondylar fracture of the humerus** is the most common cause of **Cubitus Varus** (also known as "Gunstock deformity"). This deformity occurs primarily due to the **malunion** of the distal fragment, specifically when there is a failure to correct the **medial tilt, internal rotation, and posterior displacement**. While it is a cosmetic deformity rather than a functional one, it is a high-yield topic for NEET-PG. **Analysis of Options:** * **Option A (Lateral Condyle Fracture):** This fracture typically leads to **Cubitus Valgus** (increased carrying angle) due to non-union or growth arrest of the lateral epiphysis. Cubitus valgus is classically associated with **Tardy Ulnar Nerve Palsy**. * **Option C (Radial Head Fracture):** This involves the proximal radius and usually results in restricted forearm rotation (pronation/supination) or elbow stiffness, but does not typically alter the carrying angle of the humerus. * **Option D (Chronic Osteomyelitis):** While it can cause growth disturbances or bone destruction, it is not a primary or common cause of cubitus varus compared to the mechanical malunion of a supracondylar fracture. **High-Yield Clinical Pearls for NEET-PG:** * **Most common complication of Supracondylar Fracture:** Stiffness (overall); **Cubitus Varus** (most common deformity). * **Most serious complication:** Volkmann’s Ischemic Contracture (VIC) due to brachial artery injury or compartment syndrome. * **Nerve Injuries:** The **Anterior Interosseous Nerve (AIN)** is the most common nerve injured in extension-type fractures; the Ulnar nerve is most common in flexion-type. * **Baumann’s Angle:** Used radiologically to assess the reduction and predict the risk of cubitus varus.

Q: A 21-year-old man presents with shoulder pain after falling off his bike. What is your diagnosis?

Acromioclavicular dislocation. ***Acromioclavicular dislocation*** - **Fall on shoulder** mechanism commonly causes **AC joint injury** with **widened AC joint space** and **elevated distal clavicle** on X-ray - Clinical **piano key sign** (depressible distal clavicle) and **point tenderness** over AC joint are characteristic findings *Anterior glenohumeral joint dislocation* - Would show **humeral head displacement** anteriorly with loss of normal **glenohumeral joint relationship** on X-ray - Associated with **axillary nerve injury** and **Bankart lesions**, not consistent with AC joint pathology shown *Posterior glenohumeral dislocation* - Rare injury showing **lightbulb sign** on AP X-ray with **fixed internal rotation** of humerus - Often missed but would demonstrate **glenohumeral joint abnormality**, not isolated AC joint changes *All of the above* - Only **one specific diagnosis** can be made based on the radiographic evidence of AC joint pathology - **Multiple simultaneous dislocations** are extremely rare and not supported by typical imaging findings

Q: What is the pathognomic sign of a traumatic fracture?

Crepitus. ### Explanation In orthopaedics, clinical signs of a fracture are categorized into **Probable (Suggestive)** and **Definitive (Pathognomonic)** signs. **Why Crepitus is the Correct Answer:** Crepitus is the palpable or audible grating sensation produced by the friction of two broken bone ends rubbing against each other. It is considered a **pathognomonic (definitive) sign** because it can *only* occur if there is a breach in the continuity of the bone. Other definitive signs include abnormal mobility and visible deformity where no joint exists. **Analysis of Incorrect Options:** * **A. Tenderness:** This is a **suggestive sign**. While localized bone tenderness is a sensitive indicator of a fracture, it is non-specific as it also occurs in contusions, infections (osteomyelitis), or ligamentous injuries. * **B. Swelling:** This is a **general sign** of inflammation. It results from hematoma formation and soft tissue edema, which are common in sprains, strains, and various non-traumatic inflammatory conditions. * **C. Bruising (Ecchymosis):** This indicates subcutaneous bleeding. While common in fractures, it is also seen in simple soft tissue bruising or bleeding diathesis, making it non-diagnostic for a fracture. **High-Yield Clinical Pearls for NEET-PG:** * **Definitive Signs of Fracture:** 1. Abnormal mobility, 2. Crepitus, 3. Bony deformity. * **Clinical Caution:** One should **never** intentionally elicit crepitus or abnormal mobility to diagnose a fracture, as it causes extreme pain and risks further neurovascular injury. * **Exception:** Crepitus is absent in impacted fractures, as the bone ends are wedged together and do not move against each other. * **Differential Diagnosis:** Do not confuse "Bony Crepitus" with "Joint Crepitus" (seen in Osteoarthritis) or "Gas Crepitus" (seen in Gas Gangrene/Subcutaneous Emphysema).

Q: What is the absolute pressure threshold for indication of surgical compartment release in compartment syndrome?

30 mm Hg. **Explanation:** Acute Compartment Syndrome (ACS) is a surgical emergency where increased pressure within a fibro-osseous space compromises tissue perfusion. The diagnosis is primarily clinical, but intracompartmental pressure (ICP) measurement is the gold standard for objective assessment. **Why 30 mm Hg is the correct answer:** Traditionally, an **absolute ICP of 30 mm Hg** is considered the threshold for performing an emergency fasciotomy. This value is based on the physiological principle that when tissue pressure exceeds 30 mm Hg, it overcomes the capillary perfusion pressure, leading to muscle and nerve ischemia. **Analysis of Incorrect Options:** * **A & B (15 & 20 mm Hg):** These values represent elevated pressures but are generally considered "gray zones." While they require close monitoring, they do not meet the threshold for surgical intervention unless clinical symptoms are rapidly deteriorating. * **D (Varies from compartment to compartment):** While different compartments have different baseline pressures, the threshold for ischemia (30 mm Hg) is a standardized surgical guideline across all extremities. **Clinical Pearls for NEET-PG:** 1. **Delta Pressure ($\Delta P$):** Modern practice often favors the "Delta Pressure" over absolute pressure. $\Delta P = \text{Diastolic Blood Pressure} - \text{ICP}$. A **$\Delta P < 30$ mm Hg** is a more reliable indicator for fasciotomy, especially in hypotensive patients. 2. **Earliest Sign:** Pain out of proportion to the injury and pain on passive stretching of the muscles. 3. **Latest Sign:** Pulselessness (indicates irreversible damage; the "6 Ps" are often late findings). 4. **Whitesides’ Technique:** A common manometric method used to measure ICP. 5. **Volkmann’s Ischemic Contracture:** The permanent sequela of untreated compartment syndrome in the forearm.

Question 1

What is a straddle fracture?

Accepted Answer

Pelvic fracture

Answer

Fracture of the skull

Answer

Fracture of the C5 vertebra

Answer

Multiple rib fractures on both sides of the midline

Question 2

Which of the following statements is NOT true regarding anterior dislocation of the hip?

Accepted Answer

Associated with shortening of the limb.

Answer

Femoral nerve is more commonly injured.

Answer

The limb is rotated laterally.

Answer

Associated with lengthening of the limb.

Question 3

What is the most common direction of elbow dislocation?

Accepted Answer

Posterior

Answer

Answer

Equal frequency of anterior and posterior

Answer

Medial

Question 4

Which of the following fractures can cause cubitus varus deformity as a complication?

Accepted Answer

Supracondylar fracture of the humerus

Answer

Fracture of the lateral condyle of the humerus

Answer

Fracture of the radial head

Answer

Chronic osteomyelitis

Question 5

All of the following are types of avascular nonunion of fracture except?

Accepted Answer

Oligotrophic nonunion

Answer

Torsion wedge nonunion

Answer

Comminuted nonunion

Answer

Defect nonunion

Question 6

A 32-year-old biker sustained an injury over his left hip joint. X-ray revealed a posterior dislocation of the right hip joint. What is the clinical attitude of the affected lower limb?

Accepted Answer

Internal rotation, flexion, and adduction

Answer

External rotation, extension, and abduction

Answer

Internal rotation, extension, and abduction

Answer

External rotation, flexion, and abduction

Question 7

What is the treatment of choice in a fracture neck of femur in a 40-year-old male presenting after 2 days?

Accepted Answer

Closed reduction and internal fixation by cancellous screws

Answer

Hemiarthroplasty

Answer

Closed reduction and internal fixation by Austin Moore pins

Answer

Plaster and rest

Question 8

A 21-year-old man presents with shoulder pain after falling off his bike. What is your diagnosis?

Accepted Answer

Acromioclavicular dislocation

Answer

Anterior glenohumeral joint dislocation

Answer

Posterior glenohumeral dislocation

Answer

All of the above

Question 9

What is the pathognomic sign of a traumatic fracture?

Accepted Answer

Crepitus

Answer

Tenderness

Answer

Swelling

Answer

Bruising

Question 10

What is the absolute pressure threshold for indication of surgical compartment release in compartment syndrome?

Accepted Answer

30 mm Hg

Answer

15 mm Hg

Answer

20 mm Hg

Answer

Varies from compartment to compartment

Trauma — MCQs

Trauma — MCQs

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