Trauma Practice Questions

Q: What is the permissible ischemia time for proximal limb amputations?

6 hours. **Explanation:** The permissible ischemia time for an amputated part is dictated by the amount of muscle mass present. Muscle is highly sensitive to hypoxia; irreversible changes and necrosis begin within a few hours of oxygen deprivation. **1. Why 6 hours is correct:** Proximal limb amputations (e.g., arm, thigh) involve large volumes of skeletal muscle. Under **warm ischemia** (room temperature), the threshold for irreversible muscle necrosis is approximately **6 hours**. Replanting a limb after this window significantly increases the risk of "Reperfusion Injury" and "Crush Syndrome," where the release of myoglobin, potassium, and lactic acid into the systemic circulation can lead to acute renal failure and cardiac arrhythmias. **2. Analysis of Incorrect Options:** * **4 hours (A):** While safe, it is not the maximum permissible limit. * **8 hours (C) & 12 hours (D):** These exceed the safe threshold for warm ischemia in proximal segments. However, these timeframes are relevant for **distal amputations** (fingers/toes) because they contain minimal muscle and can tolerate longer periods of ischemia (up to 8 hours warm and 24+ hours cold). **Clinical Pearls for NEET-PG:** * **Cold Ischemia:** Cooling the amputated part (4°C) doubles the permissible time. For proximal limbs, cold ischemia time is **12 hours**; for distal parts, it can extend to **24 hours**. * **Golden Rule of Transport:** "Wrap in saline-soaked gauze, place in a plastic bag, and immerse the bag in a container of ice water." Never place the part directly on ice (prevents frostbite). * **Sequence of Repair in Replantation:** Bone fixation → Extensor tendons → Flexor tendons → Arteries → Nerves → Veins → Skin. (Mnemonic: **BEF-A-N-V-S**).

Q: The femur is fractured at which location?

Upper third of shaft. ***Upper third of shaft*** - The **upper third of the femoral shaft** is anatomically defined as the proximal portion between the **lesser trochanter** and the junction with the middle third. - Fractures here are significant due to **deforming muscle forces** - the **iliopsoas** and **gluteal muscles** cause **flexion and abduction** of the proximal fragment, making reduction challenging. *Middle third of shaft* - This region lies between the upper and lower thirds, roughly at the **mid-diaphysis** of the femur. - While common for femoral shaft fractures, it lacks the specific **anatomical landmarks** and **muscle deformity patterns** characteristic of upper third fractures. *Lower third of shaft* - Located in the **distal diaphysis**, approaching the **supracondylar region** near the knee joint. - Fractures here may involve the **gastrocnemius muscle** causing **posterior angulation** of the distal fragment, different from upper third mechanics. *Neck region* - Refers to the **femoral neck** between the **femoral head** and **intertrochanteric region**, not the shaft. - **Femoral neck fractures** have different classification systems (**Garden classification**) and are typically **intracapsular** with risk of **avascular necrosis**.

Q: All of the following show compression osteosynthesis except:

Champys mini plates.. **Explanation:** The core concept of **Compression Osteosynthesis** is the application of pressure across a fracture site to achieve primary bone healing. This stability minimizes interfragmentary motion and promotes direct cortical remodeling without callus formation. **Why Champy’s Miniplates are the correct answer:** Champy’s miniplates utilize the principle of **Stress Sharing (Semi-rigid fixation)** rather than compression. They are primarily used in mandibular fractures along "lines of tension." Instead of compressing the bone ends together, they neutralize tension forces while allowing the bone to bear the functional compressive load. Because they do not actively squeeze the fracture fragments together, they do not provide compression osteosynthesis. **Analysis of Incorrect Options:** * **Dynamic Compression Plates (DCP):** These achieve horizontal compression through the "spherical gliding principle." The screw head slides down the inclined plane of the plate hole, shifting the bone fragment toward the fracture line. * **Eccentric Compression Plates:** These are a variation of compression plating where screws are placed at the periphery (eccentrically) of the plate holes to exert a compressive force across the fracture. * **Lag Screw:** This is the most fundamental method of achieving **interfragmentary compression**. By engaging threads only in the far cortex, the screw pulls the two fragments together as it is tightened. **High-Yield Clinical Pearls for NEET-PG:** * **Primary Bone Healing:** Occurs with rigid internal fixation (compression) and involves Haversian remodeling (no callus). * **Secondary Bone Healing:** Occurs with relative stability (e.g., intramedullary nails, casts) and involves callus formation. * **Gold Standard for Interfragmentary Compression:** The Lag Screw. * **Champy’s Principle:** Specifically refers to internal fixation of the mandible at the "ideal lines of osteosynthesis."

Q: For which fracture is a tube (cylinder) cast typically applied?

Knee. **Explanation:** A **Tube Cast (Cylinder Cast)** is a specialized orthopedic cast that extends from the upper thigh to just above the malleoli (ankles). Its primary purpose is to immobilize the **knee joint** while allowing the patient to remain mobile and bear weight through the foot. **Why Option D is Correct:** The cylinder cast is specifically designed for injuries where the knee must be kept in extension but the ankle does not require immobilization. It is the treatment of choice for: * **Patellar fractures** (undisplaced or post-fixation). * **Patellar tendon or Quadriceps tendon ruptures** (after surgical repair). * **Reduced knee dislocations** to maintain stability. * **Stable ligamentous injuries** of the knee. **Why Other Options are Incorrect:** * **A. Shoulder:** Injuries here require a U-slab, shoulder spica, or a simple sling/Velpeau bandage. * **B. Hip:** Hip fractures or dislocations require a **Hip Spica** cast, which incorporates the trunk and the affected limb. * **C. Pelvis:** Pelvic fractures are managed with pelvic binders, external fixators, or bed rest; casts are not used due to the anatomy of the pelvic ring. **High-Yield Clinical Pearls for NEET-PG:** * **Position:** A cylinder cast is usually applied with the knee in **0° to 5° of flexion** to prevent stiffness in full extension. * **Prevention of Slippage:** To prevent the cast from sliding down the tapering leg, the padding is often applied over a layer of tincture of benzoin or the cast is molded carefully above the femoral condyles. * **Distinction:** Unlike a "Long Leg Cast," the cylinder cast **excludes the foot and ankle**, allowing for normal ankle range of motion and easier ambulation.

Q: In which of the following femoral fractures is avascular necrosis common?

Transcervical. **Explanation:** The risk of **Avascular Necrosis (AVN)** in femoral fractures is primarily determined by the anatomical location of the fracture relative to the joint capsule and the blood supply to the femoral head. **Why Transcervical is Correct:** The femoral head receives its primary blood supply from the **medial circumflex femoral artery** via the **retinacular vessels**. A transcervical fracture is an **intracapsular** fracture. Because these vessels run along the surface of the femoral neck, a fracture in this region frequently shears or compresses them. Furthermore, the intracapsular environment lacks a periosteal layer (limiting healing) and is bathed in synovial fluid, which contains fibrinolysins that inhibit clot formation, further predisposing the head to ischemia and subsequent AVN. **Why Other Options are Incorrect:** * **Perotrochanteric & Subtrochanteric:** These are **extracapsular** fractures. The blood supply to the femoral head remains proximal to these fracture lines and is generally undisturbed. These areas have a rich cancellous bone supply and a thick periosteum, leading to high union rates but no significant risk of AVN. * **Shaft of Femur:** This is far distal to the femoral head's vascular supply. While it carries risks of fat embolism or malunion, it has no association with AVN of the femoral head. **NEET-PG High-Yield Pearls:** * **Garden’s Classification:** Used for subcapital/transcervical fractures; Stages III and IV have the highest risk of AVN. * **Pauwels’ Classification:** Based on the angle of the fracture line; higher angles (Type III) indicate greater instability and shear force. * **Clinical Sign:** In neck of femur fractures, the limb is typically **shortened and externally rotated.** * **Management:** In elderly patients with displaced transcervical fractures, **Hemiarthroplasty or Total Hip Replacement** is preferred over fixation due to the high risk of AVN and non-union.

Q: What is the earliest ischemic feature following a supracondylar fracture reduction?

Pain. **Explanation:** The correct answer is **Pain**. This question refers to the early detection of **Volkmann’s Ischemia** or **Compartment Syndrome**, which are the most dreaded complications following a supracondylar fracture of the humerus. **1. Why Pain is the Correct Answer:** Pain is the **earliest and most reliable** clinical indicator of ischemia. Specifically, it is characterized as "pain out of proportion" to the injury and **pain on passive extension** of the fingers (stretch sign). This occurs because ischemic muscle tissue becomes highly sensitive to stretching long before nerves or vessels are completely compromised. **2. Analysis of Incorrect Options:** * **Coldness (A):** This is a late sign of vascular compromise (Poikilothermia). By the time the limb is cold, significant irreversible damage may have already occurred. * **Swelling (C):** While swelling is a common finding in trauma and contributes to increased compartmental pressure, it is a physical finding rather than a primary "ischemic feature" used for early diagnosis. * **Tingling (D):** Paresthesia (tingling/numbness) indicates nerve ischemia. While it is an early sign, it typically follows the onset of severe, unremitting pain. **Clinical Pearls for NEET-PG:** * **The 5 P’s of Compartment Syndrome:** Pain (earliest), Pallor, Paresthesia, Pulselessness (late), and Paralysis (very late). * **Pulselessness:** The presence of a radial pulse **does not** rule out compartment syndrome. * **Management:** If ischemia is suspected post-reduction, the first step is to remove all tight bandages and extend the elbow. If symptoms persist, urgent fasciotomy is indicated. * **Contracture:** If untreated, this leads to **Volkmann’s Ischemic Contracture (VIC)**, characterized by a "claw-like" hand deformity.

Q: The time necessary for fracture healing depends on which of the following factors?

All of the above. **Explanation:** Fracture healing is a complex biological process influenced by both systemic and local factors. The correct answer is **All of the above** because each factor plays a critical role in determining the rate of union. 1. **Age of the Patient:** This is a primary systemic factor. Fractures heal significantly faster in children due to a thick, active periosteum and high osteogenic potential. For example, a femoral shaft fracture may heal in 3–4 weeks in a newborn, whereas it takes 12–16 weeks in an adult. 2. **Location of the Fracture:** Bone type and blood supply vary by location. Cancellous bone (e.g., metaphyseal regions) has a rich blood supply and a large contact area, leading to faster healing than cortical bone (e.g., diaphyseal shafts). Furthermore, fractures in areas with poor blood supply (e.g., scaphoid waist or femoral neck) are prone to delayed union. 3. **Type of the Fracture:** The nature of the injury dictates the healing environment. Comminuted or displaced fractures take longer to heal than simple, undisplaced ones. Open fractures often involve soft tissue damage and compromised vascularity, further slowing the process. **Why other options are incorrect:** Options A, B, and C are individual components of the healing process. Selecting only one would be incomplete, as they all interact simultaneously to determine the final healing time. **High-Yield Clinical Pearls for NEET-PG:** * **Perkins’ Timetable:** A classic rule of thumb for fracture union in adults: Upper limb (Callus in 2-3 weeks, Union in 4-6 weeks, Consolidation in 6-8 weeks); Lower limb takes double this time. * **Most important local factor:** Blood supply to the fracture fragments. * **Negative factors:** Smoking, diabetes, malnutrition, and corticosteroids significantly delay fracture healing.

Q: A 30-year-old man sustained a femur fracture in a road traffic accident. Two days later, he developed sudden breathlessness. What is the most probable cause?

Fat embolism. **Explanation:** The clinical presentation of sudden breathlessness following a long bone fracture (like the femur) after an asymptomatic interval of 24–72 hours is a classic hallmark of **Fat Embolism Syndrome (FES)**. **Why Fat Embolism is correct:** FES occurs when fat globules are released from the bone marrow of a fractured long bone into the systemic circulation. These globules cause mechanical obstruction in the pulmonary capillaries and trigger a biochemical inflammatory response. The "lucid interval" (typically 24–48 hours) followed by the triad of **dyspnea, confusion (neurological symptoms), and a petechial rash** (usually over the chest and axilla) is pathognomonic for this condition. **Why other options are incorrect:** * **Pneumonia:** While it causes breathlessness, it typically presents with fever, productive cough, and takes longer than 48 hours to develop post-trauma. * **Congestive Heart Failure:** This is unlikely in a young 30-year-old patient without a prior cardiac history or massive fluid overload. * **Bronchial Asthma:** This would present with wheezing and usually a known prior history of atopy or triggers, rather than being a direct complication of a femur fracture. **High-Yield Clinical Pearls for NEET-PG:** * **Gurd’s Criteria:** Used for diagnosis (Major: Petechial rash, respiratory insufficiency, CNS depression). * **Snowstorm Appearance:** The characteristic finding on a Chest X-ray (diffuse bilateral pulmonary infiltrates). * **Early Fixation:** The most effective way to prevent FES is the early stabilization/internal fixation of the fracture. * **Treatment:** Primarily supportive (Oxygenation/Ventilation). Steroids are controversial but sometimes mentioned.

Question 1

What is the permissible ischemia time for proximal limb amputations?

Accepted Answer

6 hours

Answer

4 hours

Answer

8 hours

Answer

12 hours

Question 2

The femur is fractured at which location?

Accepted Answer

Upper third of shaft

Answer

Middle third of shaft

Answer

Lower third of shaft

Answer

Neck region

Question 3

All of the following show compression osteosynthesis except:

Accepted Answer

Champys mini plates.

Answer

Dynamic compression plates.

Answer

Eccentric compression plates.

Answer

Lag screw.

Question 4

For which fracture is a tube (cylinder) cast typically applied?

Accepted Answer

Knee

Answer

Shoulder

Answer

Hip

Answer

Pelvis

Question 5

Which of the following statements is true regarding fat embolism?

Accepted Answer

Most patients with major trauma involving long bones have urinary fat globules.

Answer

All patients with urinary fat globules develop fat embolism.

Answer

Peak incidence of respiratory insufficiency for pulmonary fat embolism is around day 7 after injury.

Answer

Heparin as an anticoagulant decreases mortality and morbidity in fat embolism syndrome.

Question 6

In which of the following femoral fractures is avascular necrosis common?

Accepted Answer

Transcervical

Answer

Perotrochanteric

Answer

Subtrochanteric

Answer

Shaft of femur

Question 7

What is the earliest ischemic feature following a supracondylar fracture reduction?

Accepted Answer

Pain

Answer

Coldness

Answer

Swelling

Answer

Tingling

Question 8

The time necessary for fracture healing depends on which of the following factors?

Accepted Answer

All of the above

Answer

Age of the patient

Answer

Location of the fracture

Answer

Type of the fracture

Question 9

Trendelenburg's sign is negative in an Inter-Trochanteric fracture because of which structure?

Accepted Answer

Tensor fascia lata

Answer

Gluteus medius

Answer

Gluteus maximus

Answer

Gluteus minimus

Question 10

A 30-year-old man sustained a femur fracture in a road traffic accident. Two days later, he developed sudden breathlessness. What is the most probable cause?

Accepted Answer

Fat embolism

Answer

Pneumonia

Answer

Congestive heart failure

Answer

Bronchial asthma

Trauma — MCQs

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