Orthopaedic Techniques — MCQs

Orthopaedic Techniques Indian Medical PG Practice Questions and MCQs

Question 11: Tapping is required in a screw which is:

A. Fluted
B. Non fluted (Correct Answer)
C. Self drilling
D. Self tapping

Explanation: ### Explanation In orthopaedic surgery, **tapping** is the process of cutting a thread pattern into the bone (the pilot hole) to prepare it for a screw. This is essential for **non-fluted screws**. **1. Why "Non-fluted" is correct:** A standard cortical screw has a blunt tip and a continuous thread without any gaps. Because it lacks a cutting edge, it cannot create its own path through dense cortical bone. If driven directly into a pilot hole without tapping, it would generate excessive torque, leading to bone micro-fractures or screw breakage. Therefore, a "tap" (an instrument that mimics the screw's thread) must be used first to cut the grooves. Non-fluted screws are essentially non-self-tapping screws. **2. Why the other options are incorrect:** * **Fluted (Option A):** A "flute" is a notch or groove cut into the tip of the screw. This flute acts as a cutting edge that carves the thread as the screw is advanced. Therefore, fluted screws are self-tapping and do **not** require a separate tap. * **Self-drilling (Option C):** These screws have a tip shaped like a drill bit (similar to a K-wire). They create their own pilot hole and their own threads simultaneously. No tapping is required. * **Self-tapping (Option D):** By definition, these screws have flutes at the tip to cut their own threads. They eliminate the need for the tapping step in the surgical sequence. ### Clinical Pearls for NEET-PG: * **The Sequence of Screw Insertion:** Drill → Measure → **Tap** → Screw. (Note: Tapping is skipped for self-tapping screws). * **Cancellous vs. Cortical:** Tapping is mandatory for **cortical bone** when using non-fluted screws. In soft **cancellous bone**, tapping is often unnecessary as the bone is porous enough to be compressed by the screw threads (providing better "purchase"). * **Pitch:** The distance between two adjacent threads. Cortical screws have a smaller pitch (finer threads), while cancellous screws have a larger pitch (coarser threads).

Question 12: Which of the following bones is typically addressed with a tube cast?

A. Knee (Correct Answer)
B. Ankle
C. Shoulder
D. Elbow

Explanation: **Explanation:** A **Tube Cast** (also known as a Cylinder Cast) is a specialized orthopedic cast that extends from the upper thigh to just above the malleoli of the ankle. **Why the Knee is Correct:** The primary purpose of a tube cast is to provide **immobilization of the knee joint** while allowing the patient to remain weight-bearing. It is specifically indicated for conditions where the knee must be kept in extension but the ankle and foot do not require stabilization. Common indications include: * Patellar fractures (undisplaced). * Rupture of the patellar tendon or quadriceps tendon (post-repair). * Reduced knee dislocations. * Stable tibial plateau fractures. **Why the other options are incorrect:** * **Ankle:** Injuries to the ankle require a **Below-Knee (Short Leg) Cast** or an **Above-Knee (Long Leg) Cast**. A tube cast is contraindicated here because it stops above the ankle, providing no stability to the joint. * **Shoulder:** The shoulder is typically immobilized using a **Shoulder Spica**, a U-slab, or a simple sling/immobilizer. A circular cast is rarely used due to the complexity of the joint. * **Elbow:** Elbow injuries are managed with an **Above-Elbow (Long Arm) Cast** or a posterior slab. The upper limb equivalent of a tube cast (immobilizing only the elbow) is rarely used because maintaining the cast's position without it slipping is difficult. **High-Yield NEET-PG Pearls:** * **Cylinder Cast Precaution:** Always ensure the cast is molded well above the femoral condyles and proximal to the malleoli to prevent "telescoping" (slipping down). * **Walking Cast vs. Tube Cast:** A walking cast includes the foot; a tube cast allows the patient to wear their own shoe. * **Position:** The knee is typically immobilized in **0–5° of flexion** to prevent stiffness in full extension while allowing for a functional gait.

Question 13: The Thomas test detects which of the following?

A. Shortening of the lower limb
B. Flexion deformity of the hip (Correct Answer)
C. Lengthening of the lower limb
D. Tightness of the tendoachilles tendon

Explanation: **Explanation:** The **Thomas Test** is a clinical maneuver used to detect and measure a **fixed flexion deformity (FFD) of the hip**. In a normal hip, the lumbar spine compensates for a hip flexion deformity by increasing its lordosis, which allows the leg to lie flat on the couch, masking the deformity. **Mechanism:** To perform the test, the patient lies supine, and the unaffected hip is flexed until the thigh touches the abdomen. This maneuver stabilizes the pelvis and **obliterates the compensatory lumbar lordosis**. If a flexion deformity is present in the contralateral (tested) hip, the thigh will spontaneously lift off the examination table. The angle between the table and the lifted thigh represents the degree of fixed flexion deformity. **Analysis of Options:** * **Option A & C:** Shortening or lengthening of the lower limb is assessed using **True and Apparent limb length measurements** (measuring from the ASIS or umbilicus to the medial malleolus), not the Thomas test. * **Option D:** Tightness of the Tendoachilles tendon is assessed using the **Silfverskiöld test**, which differentiates between gastrocnemius tightness and Achilles contracture. **NEET-PG High-Yield Pearls:** * **Prerequisite:** Before performing the Thomas test, ensure the patient does not have a fixed flexion deformity of the *opposite* hip, as this will prevent full stabilization of the pelvis. * **Trendelenburg Test:** Used to assess the stability of the hip and the strength of the abductors (Gluteus medius and minimus). * **Galeazzi Sign:** Used to identify femoral or tibial shortening (discrepancy in knee heights). * **Adams Forward Bend Test:** Used to clinical screening of Scoliosis.

Question 14: Which of the following statements is true regarding lag screw fixation?

A. Any threaded screw can be used in a lag screw fashion. (Correct Answer)
B. The proximal bone segment has the threaded hole.
C. The distal bone segment has the gliding hole.
D. Lag screws are placed perpendicular to the bone segments that they fix.

Explanation: ### Explanation **1. Why Option A is Correct:** The term "lagging" refers to a **technique**, not necessarily a specific type of screw. Any screw (cortical or cancellous) can function as a lag screw if it achieves interfragmentary compression. This is done by ensuring the threads only engage the **distal fragment**, while the proximal fragment contains a "gliding hole" (where the screw slides through without gripping). When the screw head tightens against the near cortex, it pulls the distal fragment toward the proximal one, creating compression. **2. Why the Other Options are Incorrect:** * **Option B & C:** These are reversed. In lag screw technique, the **proximal segment** (near the screw head) must have the **gliding hole** (drilled to the same diameter as the screw's outer threads). The **distal segment** (far fragment) must have the **threaded hole** (drilled to the diameter of the screw's core/inner diameter) to allow the threads to "bite" and pull the fragment. * **Option D:** Lag screws should ideally be placed **perpendicular to the fracture line**, not the bone segments. Placing a screw perpendicular to the fracture ensures maximum interfragmentary compression and prevents shear forces that could cause the fracture to displace. **3. High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard:** Lag screw fixation is the most effective method for achieving **interfragmentary compression**. * **Partially Threaded Screws:** These act as "inherent" lag screws because the smooth shank automatically creates a gliding effect in the proximal fragment. * **Fully Threaded Screws:** To use these in a lag fashion, the surgeon must manually over-drill the proximal cortex to create a gliding hole. * **Sequence of Drilling:** Gliding hole (near cortex) → Drill sleeve insertion → Pilot hole (far cortex) → Countersinking → Measuring → Tapping → Screw insertion.

Question 15: Immobilization of the cervical spine with a plaster jacket is known as?

A. Maneuver jacket.
B. Minerva jacket. (Correct Answer)
C. Sistrunk's jacket.
D. All of the above.

Explanation: **Explanation:** The **Minerva jacket** (or Minerva cast) is a specialized orthopedic plaster or fiberglass cast used to immobilize the **cervical and upper thoracic spine**. It typically extends from the head (incorporating the forehead or chin) down to the rib cage or waist. By stabilizing the head, neck, and trunk as a single unit, it prevents flexion, extension, and rotation of the cervical vertebrae. It is clinically indicated for stable cervical fractures, ligamentous injuries, or post-operative stabilization when a halo vest is not used. **Analysis of Options:** * **Minerva jacket (Correct):** Named after the Roman goddess of wisdom (often depicted wearing a helmet), this cast provides rigid immobilization of the neck and upper back. * **Maneuver jacket (Incorrect):** This is a distractor term. While "maneuvers" are common in orthopedics (e.g., Kocher’s maneuver for shoulder dislocation), there is no standard orthopedic cast known as a "Maneuver jacket." * **Sistrunk’s jacket (Incorrect):** This is a distractor. Sistrunk is a name associated with a surgical procedure for a **thyroglossal cyst** (Sistrunk’s operation), not an orthopedic immobilization technique. **High-Yield Clinical Pearls for NEET-PG:** * **Risser’s Cast:** Used for the treatment of Scoliosis (incorporates a localizer to apply pressure). * **Turnbuckle Cast:** Used for correcting lateral curvatures (Scoliosis). * **Hip Spica:** Used for pediatric femoral shaft fractures or Developmental Dysplasia of the Hip (DDH). * **Halo Vest:** The most rigid form of cervical immobilization, utilizing pins fixed into the skull; it is superior to the Minerva jacket for unstable fractures.

Question 16: What is the action of an intramedullary 'K' nail?

A. Two-point fixation
B. Three-point fixation (Correct Answer)
C. Compression
D. Weight concentration

Explanation: ### Explanation The **Kuntscher nail (K-nail)** is a classic intramedullary device traditionally used for fractures of the femoral shaft. Its primary mechanism of stability is based on the principle of **Three-point fixation**. **1. Why Three-point fixation is correct:** The K-nail has a cloverleaf cross-section which provides some rotational stability, but its longitudinal stability depends on the nail making contact with the inner cortex of the bone at a minimum of three points: * The proximal end of the nail (at the entry point). * The narrowest part of the medullary canal (the **isthmus**). * The distal end of the nail. This "elastic interference fit" creates a stable construct by resisting angulation and displacement through these pressure points. **2. Why the other options are incorrect:** * **Two-point fixation:** This is inherently unstable for long bone fractures as it allows for toggling or "windshield wiper" movement within the canal. * **Compression:** K-nails are non-locking nails and do not provide active compression. Compression is a feature of devices like the **Dynamic Compression Plate (DCP)** or certain types of intramedullary screws. * **Weight concentration:** This is not a recognized biomechanical principle of fracture fixation. In fact, intramedullary nails are **load-sharing devices**, meaning they distribute weight between the bone and the implant, rather than concentrating it. **High-Yield Clinical Pearls for NEET-PG:** * **Shape:** The K-nail is **cloverleaf** in cross-section, which allows for some flexibility and better "grip" on the endosteum. * **Indication:** Best suited for transverse or short-oblique fractures of the **middle one-third (isthmus)** of the femur. * **Limitation:** Because it is a non-locking nail, it provides poor control over rotation and length in comminuted or proximal/distal fractures. This led to the development of **Interlocking Nails**, which are now the gold standard. * **Historical Note:** Gerhard Kuntscher is considered the pioneer of modern intramedullary nailing.

Question 17: Cozen test is used in the diagnosis of which condition?

A. Tennis elbow (Correct Answer)
B. Golfer's elbow
C. Jumper's knee
D. Osteochondritis dissecans

Explanation: **Explanation:** **Cozen’s Test** is a clinical provocative test used to diagnose **Lateral Epicondylitis (Tennis Elbow)**. The underlying medical concept involves the provocation of pain at the common extensor origin (lateral epicondyle) when the involved muscles are stressed. **Why Option A is Correct:** Tennis elbow involves inflammation or microtearing of the **Extensor Carpi Radialis Brevis (ECRB)** muscle. To perform Cozen’s test, the clinician stabilizes the patient's elbow and palpates the lateral epicondyle. The patient is then asked to make a fist, pronate the forearm, and **radially deviate and extend the wrist against resistance**. A positive test is indicated by sudden, sharp pain at the lateral epicondyle. **Why Other Options are Incorrect:** * **B. Golfer’s Elbow (Medial Epicondylitis):** This involves the common flexor origin. It is diagnosed using the **Medial Epicondylitis Test** (passive wrist extension with elbow extension). * **C. Jumper’s Knee (Patellar Tendonitis):** This is an overuse injury of the patellar tendon. Diagnosis is clinical, based on tenderness at the inferior pole of the patella, not upper limb provocative tests. * **D. Osteochondritis Dissecans (OCD):** This involves joint cartilage and underlying bone (commonly the knee or capitellum). Diagnosis is confirmed via X-ray or MRI; the **Wilson Test** is specifically used for OCD of the knee. **NEET-PG High-Yield Pearls:** * **Mill’s Test:** Another common test for Tennis Elbow involving passive stretching of the extensors (elbow extension, forearm pronation, and wrist flexion). * **Maudsley’s Test:** Pain on resisted extension of the **middle finger** (stresses the ECRB and Extensor Digitorum). * **Most common muscle involved in Tennis Elbow:** Extensor Carpi Radialis Brevis (ECRB).

Question 18: What is the probable diagnosis in a patient presenting with bilious vomiting while wearing a spinal POP cast?

A. Acute dilation of the stomach
B. Duodenal obstruction (Correct Answer)
C. Peritonitis
D. Acute pancreatitis

Explanation: ### Explanation The correct diagnosis is **Duodenal Obstruction**, specifically a condition known as **Cast Syndrome** (also called Superior Mesenteric Artery Syndrome). **1. Why Duodenal Obstruction is Correct:** When a patient is in a tight spinal POP cast (especially in hyperextension), the third part of the duodenum can become compressed between the **Superior Mesenteric Artery (SMA)** anteriorly and the **Aorta/Vertebral column** posteriorly. This mechanical compression leads to high intestinal obstruction, manifesting as **bilious vomiting**, abdominal distension, and pain. It is a recognized complication of scoliosis surgery and body casting. **2. Why Incorrect Options are Wrong:** * **Acute Dilation of the Stomach (Option A):** While this can occur secondary to duodenal obstruction, the primary pathology triggered by the cast itself is the vascular compression of the duodenum. * **Peritonitis (Option C):** This presents with guarding, rigidity, and rebound tenderness, usually due to a perforated viscus or infection. It is not a direct complication of spinal casting. * **Acute Pancreatitis (Option D):** While it causes vomiting and epigastric pain, it is not etiologically linked to the mechanical pressure of a spinal cast. **3. NEET-PG High-Yield Pearls:** * **Cast Syndrome:** Also known as Wilkie’s syndrome or SMA syndrome. * **Clinical Presentation:** Persistent bilious vomiting after application of a hip spica or body cast. * **Immediate Management:** The first step is to **remove or bivalve the cast** to relieve pressure. Keep the patient NPO (nothing by mouth) and insert a nasogastric tube for decompression. * **Positioning:** Placing the patient in the **prone position** or **left lateral decubitus** can sometimes relieve the SMA compression.

Question 19: Which of the following statements is NOT true?

A. Cock-up splint for radial nerve palsy
B. Russel traction for trochanteric fractures
C. Boston Brace for scoliosis
D. Crutchfield traction for lumbar spine injuries (Correct Answer)

Explanation: ### Explanation The correct answer is **D. Crutchfield traction for lumbar spine injuries**. **1. Why Option D is the correct (incorrect statement):** Crutchfield traction is a form of **skeletal traction** applied via tongs inserted into the skull (parietal bones). It is used specifically for the stabilization and reduction of **cervical spine** injuries (fractures or dislocations), not lumbar spine injuries. Lumbar injuries are typically managed with bed rest, bracing, or pelvic traction. **2. Analysis of other options:** * **A. Cock-up splint for radial nerve palsy:** This is a **true** statement. In radial nerve palsy (Wrist Drop), the wrist cannot be extended. A cock-up splint maintains the wrist in 20–30 degrees of extension, preventing contractures of the flexors and improving the functional grip of the hand. * **B. Russel traction for trochanteric fractures:** This is a **true** statement. Russel traction is a skin traction that uses a sling under the knee and a system of pulleys to provide longitudinal and upward pull. It is commonly used for femoral shaft and trochanteric fractures, especially in older children or as temporary stabilization in adults. * **C. Boston Brace for scoliosis:** This is a **true** statement. The Boston brace is a low-profile (TLSO) brace used for idiopathic scoliosis with an apex below T8. It is the most commonly used "underarm" brace. **3. High-Yield Clinical Pearls for NEET-PG:** * **Milwaukee Brace:** Used for scoliosis with a high apex (above T8). * **Somersault/Schanz Collar:** Used for cervical spine stabilization. * **Thomas Splint:** Originally designed for TB knee; now primarily used for emergency immobilization of femoral shaft fractures. * **Bohler-Braun Splint:** A frame used to provide skeletal traction for femur and supracondylar fractures. * **Gallows Traction:** Used for femoral fractures in children weighing less than 15 kg (usually <2 years old).

Question 20: The Trendelenburg test is performed to assess the function of which muscles?

A. Gluteus medius and minimus (Correct Answer)
B. Gluteus maximus and minimus
C. Gluteus maximus and medius
D. Gluteus maximus, medius, and minimus

Explanation: ### Explanation **1. Why Gluteus Medius and Minimus are correct:** The Trendelenburg test assesses the **abductor mechanism** of the hip. The primary hip abductors are the **Gluteus medius** (the main abductor) and the **Gluteus minimus**, both of which are innervated by the **Superior Gluteal Nerve**. When a person stands on one leg (the "stance leg"), these muscles must contract to stabilize the pelvis and prevent the opposite side (the "swing leg") from sagging. If these muscles are weak or paralyzed, or if the fulcrum (hip joint) is unstable, the pelvis drops on the unsupported side. This is a **Positive Trendelenburg Sign**, indicating abductor insufficiency on the **weight-bearing side**. **2. Why the other options are incorrect:** * **Gluteus Maximus (Options B, C, D):** This is the primary **extensor** of the hip and is innervated by the Inferior Gluteal Nerve. While it is vital for climbing stairs and rising from a seated position, it does not play a primary role in lateral pelvic stabilization during the Trendelenburg test. Including it in the answer is a common distractor. **3. High-Yield Clinical Pearls for NEET-PG:** * **The "Sound-Side" Drop:** In a positive test, the pelvis drops toward the **normal/healthy** side when standing on the **affected** side. * **Causes of Positive Trendelenburg:** 1. **Neuromuscular:** Superior gluteal nerve palsy, Polio. 2. **Muscular:** Myopathy, Gluteus medius tear. 3. **Structural (Lever arm issues):** Congenital Dislocation of the Hip (CDH/DDH), Coxa Vara, Slipped Capital Femoral Epiphysis (SCFE). 4. **Pain:** Antalgic gait due to osteoarthritis. * **Trendelenburg Gait:** Also known as a "lurching gait." If bilateral, it is called a **Waddling gait**.

Practice by Chapter

Principles of Internal Fixation

Practice Questions

External Fixation

Practice Questions

Intramedullary Nailing

Practice Questions

Plate Osteosynthesis

Practice Questions

Tension Band Wiring

Practice Questions

Minimally Invasive Orthopaedic Surgery

Practice Questions

Arthroscopic Techniques

Practice Questions

Suture Techniques in Orthopaedics

Practice Questions

Navigation and Robotics

Practice Questions

3D Printing Applications

Practice Questions

Bone Grafting Techniques

Practice Questions

Local Flaps and Soft Tissue Coverage

Practice Questions

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