Orthopaedic Techniques — MCQs

Orthopaedic Techniques Indian Medical PG Practice Questions and MCQs

Question 51: In lag screw technique, what is the function of countersink?

A. Assures an appropriate receptacle for the screw head. (Correct Answer)
B. The hole made in the distal fragment that engages the screw threads.
C. The hole made in the proximal segment that does not engage the screw threads.
D. Non-functional.

Explanation: ### Explanation The **Lag Screw Technique** is a fundamental principle in internal fixation used to achieve **interfragmentary compression**. This is achieved when the screw threads engage only the far (distal) cortex, while the screw head glides through the near (proximal) cortex. **Why Option A is Correct:** The **Countersink** is a specific tool used to enlarge the entry point of the drill hole in the near cortex. Its primary functions are: 1. **Increasing Surface Area:** It creates a uniform "receptacle" or seat for the hemispherical screw head. 2. **Distributing Stress:** By increasing the contact area between the screw head and the bone, it prevents stress concentration, which reduces the risk of the screw head causing a local fracture or "sinking" too deeply into thin cortical bone. 3. **Reducing Profile:** It allows the screw head to sit flush with the bone, minimizing soft tissue irritation. **Analysis of Incorrect Options:** * **Option B:** This describes the **Pilot Hole** (or Thread Hole). It is drilled in the distal fragment with a diameter equal to the screw's core (minor) diameter to allow the threads to bite. * **Option C:** This describes the **Gliding Hole**. It is drilled in the proximal fragment with a diameter equal to the screw's outer (major) diameter so that the threads do not engage, allowing the screw to "glide." * **Option D:** Incorrect, as countersinking is a critical step in AO (Arbeitsgemeinschaft für Osteosynthesefragen) principles to ensure mechanical stability. **High-Yield Clinical Pearls for NEET-PG:** * **Golden Rule of Lagging:** The screw must be perpendicular to the fracture line to prevent displacement. * **Compression:** Lagging converts torsional force into longitudinal compressive force. * **Self-Countersinking:** Modern screws often have "flutes" under the head, making a separate countersink tool unnecessary in some cases. * **Cancellous Screws:** These are generally "self-lagging" because they have a partially threaded shaft; the smooth portion acts as the gliding hole.

Question 52: What material is used in vertebroplasty?

A. Isomethyl methacrylate
B. Isoethyl methacrylate
C. Polyethyl methacrylate
D. Polymethyl methacrylate (Correct Answer)

Explanation: **Explanation:** **Polymethyl methacrylate (PMMA)**, commonly known as "bone cement," is the standard material used in vertebroplasty and kyphoplasty. In these procedures, PMMA is injected into a fractured vertebral body (typically due to osteoporosis or malignancy) to provide immediate internal stabilization and pain relief. * **Why PMMA is correct:** PMMA is a biocompatible polymer that acts as a grout rather than a glue. It undergoes an **exothermic reaction** during polymerization, reaching high temperatures which may contribute to pain relief by destroying local nerve endings (thermal neurolysis). It provides high compressive strength, making it ideal for weight-bearing bones like the vertebrae. * **Why other options are incorrect:** Options A, B, and C (Isomethyl, Isoethyl, and Polyethyl methacrylate) are chemically distinct variants that do not possess the specific mechanical properties, handling characteristics, or long-standing clinical track record required for orthopedic bone augmentation. PMMA remains the gold standard in both arthroplasty (joint replacement) and spinal augmentation. **High-Yield Clinical Pearls for NEET-PG:** * **Composition:** Bone cement is supplied as a powder (polymer) and a liquid (monomer). The liquid contains **Methyl methacrylate** and an inhibitor (Hydroquinone). * **Radiopacity:** To make the cement visible under fluoroscopy during injection, a radio-opaque agent like **Barium sulphate** or **Zirconium dioxide** is added. * **Complications:** The most feared complication of vertebroplasty is **cement leakage**, which can lead to pulmonary embolism or spinal cord compression. * **BCIS (Bone Cement Implantation Syndrome):** Characterized by hypoxia and hypotension during cementation, often due to fat embolism or monomer toxicity.

Question 53: What material is used in veinplasty?

A. Polymethyl methacrylate (Correct Answer)
B. Isobutyl Methacrylate
C. Isoethyl Methacrylate
D. Silicon

Explanation: **Explanation:** The correct answer is **Polymethyl methacrylate (PMMA)**. **Vertebroplasty and Kyphoplasty** (often referred to in older texts or specific contexts as "veinplasty" or "venoplasty" when referring to the filling of venous sinusoids/voids in the vertebral body) are minimally invasive procedures used to treat vertebral compression fractures. The material of choice for these procedures is **PMMA**, a medical-grade bone cement. 1. **Why PMMA is correct:** PMMA acts as a space-filler that provides immediate structural stability to the fractured vertebra. It is a polymer formed by mixing a liquid monomer and a powder polymer. Its high compressive strength and ability to harden quickly (exothermic reaction) make it ideal for stabilizing osteoporotic fractures and painful vertebral hemangiomas. 2. **Why other options are incorrect:** * **Isobutyl and Isoethyl Methacrylate:** These are different chemical variations of methacrylates used primarily in industrial applications or dental liners, but they lack the specific mechanical properties and long-standing clinical track record required for load-bearing orthopedic bone augmentation. * **Silicon:** While used in various prosthetics and soft tissue implants, silicon lacks the compressive strength required to stabilize bone and does not integrate mechanically with the trabecular bone in the same way PMMA does. **High-Yield Clinical Pearls for NEET-PG:** * **Composition:** PMMA powder contains **Barium sulfate** or **Zirconium dioxide** to make it radiopaque (visible under fluoroscopy). * **Complication:** The most common complication of vertebroplasty is **cement leakage**, which can lead to pulmonary embolism or nerve root compression. * **Contraindication:** Active systemic infection or osteomyelitis at the site is an absolute contraindication. * **Thermal Effect:** The exothermic reaction of PMMA can reach temperatures that help in pain relief by causing thermal neurolysis of local nerve endings.

Question 54: Identify the test being performed.

A. Book test (Correct Answer)
B. Egawa test
C. Card test
D. Dugas' test

Explanation: ***Book test*** - The image depicts a technique used to assess the strength of **interossei muscles**. The examiner attempts to separate the patient's fingers while the patient tries to keep them adducted. This is characteristic of the **Book test**. - A positive test (inability to resist abduction) suggests weakness of the **interossei muscles**, often seen in conditions affecting the **ulnar nerve**. *Egawa test* - The **Egawa test** specifically assesses the function of the **dorsal interossei** of the middle finger. - It involves the patient flexing their middle finger while trying to maintain it in a straight line, resisting abduction or adduction. *Card test* - The **Card test** involves holding a piece of paper or a **card** between the fingers (usually between the thumb and index finger, or between adjacent fingers). - It is used to assess the strength of the **adductor pollicis** (if between thumb and index) or **interossei** (if between adjacent fingers), with a positive test (inability to hold the card) indicating muscle weakness, often due to **ulnar nerve palsy**. *Dugas' test* - **Dugas' test** is used to check for **shoulder dislocation**. - The patient is asked to place the hand of the affected arm on the opposite shoulder and attempt to abduct the elbow to the chest wall. Inability to do so indicates a **shoulder dislocation**.

Question 55: Which of the following describes the type of traction shown in the image?

A. Gallow's traction (Correct Answer)
B. Russell's traction
C. Perkin's traction
D. Dunlop's traction

Explanation: ***Gallow's traction*** - Gallow's traction (also called **Bryant's traction**) is a form of **bilateral vertical skin traction** applied to both lower limbs simultaneously - Indicated for **femoral shaft fractures in children under 2 years of age** (or < 12 kg body weight) - Both legs are suspended **vertically** with **bandages/adhesive skin traction**, and the child's **buttocks are just lifted off the bed** (about 2–3 cm clearance) - Advantages: simplicity, good fracture alignment, easy nursing care - Key complication: **vascular compromise** (ischemia of the toes/foot due to tight bandaging) — must check distal circulation regularly *Russell's traction* - Skin traction applied to **one leg** with a sling behind the knee to flex it - Used for femoral shaft fractures in **older children and adults** - Not bilateral or vertical — distinguishable from Gallow's traction *Perkin's traction* - A form of **skeletal traction** through a **Steinmann pin** in the proximal tibia - Used for femoral fractures in **adults**; not applicable to infants *Dunlop's traction* - Traction used specifically for **supracondylar fractures of the humerus** in children - Involves the **upper limb** positioned in a specific orientation — completely different region from the bilateral leg traction seen in the image

Question 56: Identify the splint shown in the image:

A. Bohler-Braun splint (Correct Answer)
B. Thomas splint
C. Denis Browne splint
D. Cock-up splint

Explanation: ***Bohler-Braun splint*** - The **Böhler-Braun splint** is a metal frame traction splint with a characteristic **inclined plane (triangular) design** that elevates and supports the lower limb - **Primary indication**: Balanced skeletal traction for **femoral shaft fractures** and distal femur/condylar fractures — it maintains limb alignment while allowing longitudinal traction to reduce muscle spasm and fracture displacement - The inclined plane supports both the thigh and the leg, distributing the limb weight and facilitating nursing care *Thomas splint* - Also used for femoral shaft fractures but primarily for **emergency transport and pre-hospital immobilization** - Consists of a **proximal ring** fitting around the upper thigh with two side rods — does not have an inclined plane frame; structurally distinct from the Böhler-Braun design *Denis Browne splint* - Used for **congenital talipes equinovarus (club foot)** in infants - Consists of **two foot plates connected by an adjustable crossbar** — a completely different device used in neonates, not a traction frame for fractures *Cock-up splint* - Used for **wrist drop** caused by radial nerve palsy - An **upper limb splint** that holds the wrist in dorsiflexion — entirely unrelated to lower limb traction frames

Question 57: Which test is being done in the image provided?

A. Thomas test (Correct Answer)
B. Trendelenburg test
C. Ober's test
D. FABER test

Explanation: ***Thomas test*** - The **Thomas test** (hip flexion contracture test) is a clinical examination technique used to detect a **fixed flexion deformity / hip flexor contracture** of the hip joint. - The patient lies **supine** on the examination table. The examiner maximally flexes one hip (bringing the knee to the chest) to **obliterate the lumbar lordosis**. If the **contralateral (opposite) leg rises off the table**, it indicates a **hip flexion contracture** on that side. - A positive Thomas test suggests **shortening of the iliopsoas muscle**, causing the hip to remain in a position of flexion. - It was described by **Hugh Owen Thomas**, a pioneer in orthopaedic surgery. *Trendelenburg test* - The Trendelenburg test assesses **hip abductor (gluteus medius) weakness**. The patient stands on one leg; if the contralateral pelvis drops, the test is positive. It does **not** involve the supine position seen here. *Ober's test* - Ober's test assesses **iliotibial band (ITB) / tensor fascia lata tightness**. The patient lies in the lateral decubitus (side-lying) position while the examiner abducts and extends the upper leg. This is a different position and purpose from what is shown. *FABER test* - The FABER (Flexion, ABduction, External Rotation) test assesses **hip joint pathology and sacroiliac joint pain**. The patient's leg is placed in a figure-4 position while supine. It does not involve drawing the knee straight to the chest to eliminate lumbar lordosis.

Question 58: What does the given image show?

A. Kocher bone hook
B. Olsen-Hegar needle holder
C. Heath mallet
D. K nail impactor (Correct Answer)

Explanation: ***K nail impactor*** - The image displays a long, tubular instrument with a telescoping design and a blunt end, consistent with a **K nail impactor**. - This device is used in orthopaedic surgery to **drive K-nails (Kirschner wires)** into bone or to impact other orthopaedic implants. *Kocher bone hook* - A **Kocher bone hook** features a curved hook at the end, designed for retracting or manipulating bone fragments. - The instrument in the image lacks the characteristic hook shape. *Olsen-Hegar needle holder* - An **Olsen-Hegar needle holder** is a scissor-like instrument with jaws for gripping needles and a built-in cutting mechanism. - The instrument shown is a solid, cylindrical piece and not a grasping tool. *Heath mallet* - A **Heath mallet** is a hammer-like instrument, often made of metal or silicone, used for striking osteotomes or chisels during surgery. - While it applies force, the image clearly shows a slender, non-mallet design used for impacting rather than striking.

Question 59: What does the given image show?

A. Doyen's periosteal elevator (Correct Answer)
B. Cobb's spinal elevator
C. Leksell's rongeur
D. Key periosteal elevator

Explanation: ***Doyen's periosteal elevator*** - This instrument is characterized by its **curved, spoon-like working end** and solid handle, designed for **elevating the periosteum** from bone. - Doyen's elevator comes in various sizes and angles, but the distinct hook-like curve is a key identifying feature, distinguishing it from other elevators. *Cobb's spinal elevator* - Cobb's elevator typically has a **flat, broad, and slightly curved blade** with a rounded or tapered tip, suitable for dissecting along bony surfaces, particularly in spinal surgery. - Its design prioritizes broad, even separation of tissue layers, contrasting with the more acute curve of the Doyen's. *Leksell's rongeur* - A rongeur is a biting instrument used for **gnawing away bone or tough tissue**, characterized by hinged jaws with sharp, cup-shaped ends. - The image clearly shows a single-piece instrument without hinged jaws, ruling out a rongeur. *Key periosteal elevator* - The Key elevator typically features a **broader, more rounded or slightly angled tip** and a flat, somewhat spatula-like working end, used for general periosteal elevation. - While also a periosteal elevator, its working end does not exhibit the characteristic deep, hook-like curve seen in the Doyen's elevator.

Question 60: What does the given image show?

A. Capener gouge
B. Kutscher's diamond pointed awl
C. Hibbs osteotome
D. Cobb's spinal elevator (Correct Answer)

Explanation: ***Cobb's spinal elevator*** - The instrument shown is a **Cobb's spinal elevator**, which is characterized by its **angled shaft** and flat, curved tip resembling a spoon or spade. - It is primarily used in **spinal surgery** to elevate and dissect soft tissues, like muscles and periosteum, away from the vertebral column. *Capener gouge* - A Capener gouge typically has a **U-shaped cross-section** at its tip, designed for scooping out bone or creating troughs. - Its tip is generally much **deeper** and more curved than the flat, shovel-like tip of the instrument pictured. *Kutscher's diamond pointed awl* - A Kutscher's diamond pointed awl is used for creating small holes, often in bone, and features a **sharp, pointed tip**, which is not seen in the image. - Its design is more akin to a **punch or drill-like instrument** rather than a broad elevator. *Hibbs osteotome* - A Hibbs osteotome is a type of **chisel-like instrument** with a beveled cutting edge, used for cutting or shaping bone. - It usually has a **straight shaft** and a wide, flat tip, distinct from the curved, spoon-like tip and angled shaft of the depicted instrument.

Practice by Chapter

Principles of Internal Fixation

Practice Questions

External Fixation

Practice Questions

Intramedullary Nailing

Practice Questions

Plate Osteosynthesis

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Tension Band Wiring

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Minimally Invasive Orthopaedic Surgery

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Arthroscopic Techniques

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Suture Techniques in Orthopaedics

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Navigation and Robotics

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3D Printing Applications

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Bone Grafting Techniques

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Local Flaps and Soft Tissue Coverage

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