Arthroscopy — MCQs
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Needle-shaped crystals that are negatively birefringent on polarized microscopy are characteristic of which crystal-associated arthropathy?
Which of the following statements is NOT true regarding inflammatory arthritis?
Which investigation is the investigation of choice for a sport injury of the knee?
Osteoarthritis involves all joints listed below except:
Which of the following crystals are found in pseudogout?
A child presents with long bone pain, weakness, lethargy, and bow legs. Radiographic findings include increased bone density, osteophytes, and a distorted joint space. What is the most likely diagnosis?
What is the pathognomonic finding in pseudogout?
Disk perforation is best examined by?
Bamboo spine appearance is seen in which of the following conditions?
The Thomas test helps to detect which of the following conditions?
Arthroscopy Indian Medical PG Practice Questions and MCQs
Question 21: Needle-shaped crystals that are negatively birefringent on polarized microscopy are characteristic of which crystal-associated arthropathy?
- A. Gout (Correct Answer)
- B. CPPD (Calcium Pyrophosphate Dihydrate deposition disease)
- C. Neuropathic arthropathy
- D. Hemophilic arthropathy
Explanation: ### Explanation The correct answer is **Gout**. **1. Why Gout is Correct:** Gout is a crystal-induced arthropathy caused by the deposition of **Monosodium Urate (MSU)** crystals in the joints. Under polarized light microscopy, these crystals exhibit two pathognomonic features: * **Morphology:** They are thin, **needle-shaped**. * **Birefringence:** they show **strong negative birefringence**. This means they appear **yellow** when aligned parallel to the slow axis of the compensator and blue when perpendicular. **2. Why Other Options are Incorrect:** * **CPPD (Pseudogout):** These crystals are **rhomboid or brick-shaped** and exhibit **weak positive birefringence** (appearing blue when parallel to the compensator). * **Neuropathic Arthropathy (Charcot Joint):** This is a progressive joint destruction due to loss of pain and proprioception (commonly in Diabetes). It is characterized by the "6 Ds" (Destruction, Debris, Disorganization, etc.) rather than specific crystals. * **Hemophilic Arthropathy:** This results from recurrent intra-articular bleeding (hemarthrosis). Diagnosis is based on clinical history and synovial thickening/hemosiderin deposition on MRI, not crystals. **3. NEET-PG High-Yield Pearls:** * **Gold Standard Diagnosis:** Synovial fluid analysis under polarized microscopy is the definitive test for Gout. * **Radiology:** Look for "Punched-out" erosions with overhanging edges (**Martel’s sign**). * **Acute Management:** NSAIDs (first-line), Colchicine, or Corticosteroids. * **Chronic Management:** Xanthine oxidase inhibitors like **Allopurinol** (do not start during an acute attack as it may worsen symptoms). * **Mnemonic:** **N**eedle **N**egative (**N-N**) for Gout.
Question 22: Which of the following statements is NOT true regarding inflammatory arthritis?
- A. Presence of morning stiffness
- B. Sclerosis on X-ray (Correct Answer)
- C. Anemia of chronic disease
- D. Presence of fever, weight loss, and elevated ESR
Explanation: **Explanation:** In Orthopaedics, it is crucial to distinguish between **Inflammatory Arthritis** (e.g., Rheumatoid Arthritis, Ankylosing Spondylitis) and **Degenerative Arthritis** (e.g., Osteoarthritis). **1. Why "Sclerosis on X-ray" is the correct (False) statement:** Subchondral sclerosis (increased bone density/whiteness under the joint surface) is a hallmark of **Osteoarthritis (Degenerative Arthritis)**. In inflammatory arthritis, the primary radiological features are **juxta-articular osteopenia** (decreased bone density near the joint), uniform joint space narrowing, and marginal erosions. Sclerosis occurs as a compensatory response to mechanical stress, which is not the primary pathology in inflammation. **2. Analysis of other options:** * **Option A (Morning Stiffness):** This is a classic feature of inflammatory arthritis. It typically lasts **more than 30–60 minutes** and improves with activity. In contrast, degenerative stiffness lasts only a few minutes. * **Option C & D (Systemic Features):** Inflammatory arthritis is a systemic disease. The release of cytokines (like IL-6 and TNF-α) leads to constitutional symptoms such as **fever, weight loss, and elevated ESR/CRP**. These cytokines also trigger the sequestration of iron, leading to **Anemia of Chronic Disease**. **High-Yield Clinical Pearls for NEET-PG:** * **Radiological Signs of Osteoarthritis (4):** Subchondral Sclerosis, Osteophytes, Subchondral Cysts, and Asymmetrical joint space narrowing. * **Radiological Signs of Rheumatoid Arthritis:** Juxta-articular decalcification (earliest sign), symmetrical joint space narrowing, and bony erosions. * **Synovial Fluid:** Inflammatory arthritis shows a high WBC count (2,000–50,000 cells/mm³) with neutrophil predominance, whereas degenerative fluid is clear and non-inflammatory (<2,000 cells/mm³).
Question 23: Which investigation is the investigation of choice for a sport injury of the knee?
- A. Ultrasonography
- B. Plain radiography
- C. Arthrography
- D. Arthroscopy (Correct Answer)
Explanation: **Explanation:** **Arthroscopy** is considered the "Gold Standard" investigation of choice for sports-related knee injuries. Its superiority lies in its dual role: it provides **direct visualization** of intra-articular structures (ACL, PCL, menisci, and articular cartilage) with nearly 100% accuracy and allows for **simultaneous therapeutic intervention** (e.g., meniscal repair or ACL reconstruction). While MRI is the non-invasive investigation of choice, Arthroscopy remains the definitive diagnostic tool when surgical management is anticipated. **Analysis of Incorrect Options:** * **A. Ultrasonography:** While useful for superficial soft tissue pathologies like Baker’s cysts or patellar tendonitis, it lacks the resolution and depth to accurately evaluate deep intra-articular structures like the cruciate ligaments. * **B. Plain Radiography:** This is the initial investigation to rule out fractures (e.g., Segond fracture) or bony avulsions, but it cannot visualize the soft tissue injuries (ligament/meniscal tears) that comprise the majority of sports injuries. * **C. Arthrography:** This invasive procedure involving dye injection was historically used to detect meniscal tears but has been rendered obsolete by the superior imaging of MRI and the direct visualization of Arthroscopy. **Clinical Pearls for NEET-PG:** * **Investigation of Choice (Non-invasive):** MRI. * **Gold Standard (Definitive):** Arthroscopy. * **Triad of O'Donoghue:** Injury to the ACL, Medial Collateral Ligament (MCL), and Medial Meniscus (though recent studies suggest Lateral Meniscus involvement is more common in acute phases). * **Most common ligament injured in the knee:** ACL.
Question 24: Osteoarthritis involves all joints listed below except:
- A. Hip
- B. Knee
- C. Proximal interphalangeal (PIP) joint
- D. Wrist (Correct Answer)
Explanation: **Explanation:** Osteoarthritis (OA) is a degenerative joint disease that primarily affects **weight-bearing joints** and specific small joints of the hand. **Why the Wrist is the Correct Answer:** The **wrist joint (radiocarpal joint) is typically spared** in primary osteoarthritis. If OA is seen in the wrist, it is almost always **secondary** to trauma (e.g., Scaphoid non-union, SLAC wrist) or specific metabolic conditions. In the hand, primary OA characteristically involves the **Distal Interphalangeal (DIP)** joints, **Proximal Interphalangeal (PIP)** joints, and the **1st Carpometacarpal (CMC)** joint (base of the thumb). **Analysis of Incorrect Options:** * **Hip (A) & Knee (B):** These are the most common sites for primary OA due to the chronic mechanical stress of weight-bearing. The knee is the most frequently affected large joint. * **PIP Joint (C):** Involvement of the PIP joints is a classic feature of primary nodal OA, leading to palpable osteophyte formations known as **Bouchard’s nodes**. **High-Yield Clinical Pearls for NEET-PG:** * **Heberden’s Nodes:** Osteophytes at the **DIP** joints (more common than Bouchard's). * **Bouchard’s Nodes:** Osteophytes at the **PIP** joints. * **First CMC Joint:** The most common site of OA in the carpus (often presenting as "squaring" of the hand). * **Radiological Hallmarks (LOSS):** **L**oss of joint space, **O**steophytes, **S**ubchondral sclerosis, and **S**ubchondral cysts. * **Joint Sparing:** OA typically spares the wrist, elbow, and shoulder unless there is a history of prior injury.
Question 25: Which of the following crystals are found in pseudogout?
- A. Monosodium urate monohydrate
- B. Calcium pyrophosphate dihydrate (Correct Answer)
- C. Calcium hydroxyapatite
- D. Alkaline phosphatase
Explanation: **Explanation:** **Pseudogout**, clinically known as **Calcium Pyrophosphate Deposition Disease (CPPD)**, is a crystal-induced arthropathy characterized by the deposition of **Calcium Pyrophosphate Dihydrate (CPPD)** crystals in the joint space and articular cartilage (chondrocalcinosis). * **Why Option B is Correct:** In pseudogout, CPPD crystals are deposited in the synovium and cartilage. Under **polarized microscopy**, these crystals are classically described as **rhomboid-shaped** and show **weak positive birefringence** (appearing blue when parallel to the compensator axis), which is the pathognomonic finding for this condition. * **Why Other Options are Incorrect:** * **Option A (Monosodium urate):** These crystals are found in **Gout**. They are needle-shaped and show strong negative birefringence. * **Option C (Calcium hydroxyapatite):** These are associated with **calcific tendonitis** and Milwaukee Shoulder. They are too small to be seen under light microscopy and require Alizarin Red staining. * **Option D (Alkaline phosphatase):** This is an enzyme involved in bone metabolism and mineralization, not a crystal found in joint aspirates. **High-Yield Clinical Pearls for NEET-PG:** * **Most Common Joint:** The **Knee** is the most frequently affected joint in pseudogout (unlike Gout, which favors the 1st MTP joint). * **Radiology:** Look for **Chondrocalcinosis** (linear calcification of articular cartilage or menisci). * **Associations:** Pseudogout is often associated with metabolic conditions like **Hyperparathyroidism, Hemochromatosis, Hypomagnesemia,** and **Hypophosphatasia**. * **Demographics:** It typically affects the elderly (>65 years).
Question 26: A child presents with long bone pain, weakness, lethargy, and bow legs. Radiographic findings include increased bone density, osteophytes, and a distorted joint space. What is the most likely diagnosis?
- A. Fluorosis (Correct Answer)
- B. Rickets
- C. Scurvy
- D. Caffey's disease
Explanation: **Explanation:** The clinical presentation of long bone pain, lethargy, and bow legs in a child, combined with specific radiographic findings of **increased bone density (osteosclerosis)** and **osteophyte formation**, is characteristic of **Fluorosis**. 1. **Why Fluorosis is correct:** Chronic ingestion of high levels of fluoride leads to its deposition in bones and teeth. Unlike most pediatric metabolic bone diseases that cause osteopenia, fluorosis causes **osteosclerosis** (increased density). It stimulates osteoblastic activity and leads to the calcification of ligaments and tendons. This results in bony outgrowths (osteophytes), joint space distortion, and physical deformities like **genu varum (bow legs)**. 2. **Why other options are incorrect:** * **Rickets:** While it presents with bow legs and weakness, the hallmark radiographic finding is **decreased bone density** (osteopenia) with cupping, splaying, and fraying of the metaphysis, not increased density. * **Scurvy:** Characterized by subperiosteal hemorrhage and specific signs like the **Wimberger ring sign** and **Frankel’s line**. It presents with osteopenia, not sclerosis. * **Caffey’s Disease (Infantile Cortical Hyperostosis):** Presents with irritability, soft tissue swelling, and new bone formation (periosteal reaction), typically involving the **mandible**, ribs, and clavicle in infants under 6 months. **NEET-PG High-Yield Pearls:** * **Fluorosis Hallmark:** Increased bone density + Calcification of the **interosseous membrane** (especially in the forearm). * **Dental Fluorosis:** Presents as mottling of enamel (chalky white patches or brownish discoloration). * **Safe Limit:** Fluoride in drinking water should ideally be **<1.0 mg/L (1 ppm)**. Skeletal fluorosis typically occurs when levels exceed 3-8 mg/L.
Question 27: What is the pathognomonic finding in pseudogout?
- A. CPPD crystals under microscope (Correct Answer)
- B. Polyarthritis with urinary sediment
- C. Juxta-articular osteopenia
- D. Bone spurs
Explanation: **Explanation:** **Pseudogout**, also known as Calcium Pyrophosphate Deposition Disease (CPPD), is a crystal-induced arthropathy. The **pathognomonic finding** is the identification of **Calcium Pyrophosphate Dihydrate (CPPD) crystals** in the synovial fluid or tissue. Under compensated polarized light microscopy, these crystals are characteristically **rhomboid-shaped** and exhibit **weak positive birefringence** (appearing blue when parallel to the compensator axis), distinguishing them from the needle-shaped, strongly negatively birefringent urate crystals of gout. **Analysis of Incorrect Options:** * **Option B (Polyarthritis with urinary sediment):** This is more suggestive of systemic conditions like Systemic Lupus Erythematosus (SLE) or vasculitis, where renal involvement (glomerulonephritis) manifests as urinary casts/sediment. * **Option C (Juxta-articular osteopenia):** This is a classic early radiographic feature of **Rheumatoid Arthritis**, caused by local inflammatory cytokines. In contrast, pseudogout often shows Chondrocalcinosis (calcification of hyaline or fibrocartilage). * **Option D (Bone spurs):** Also known as osteophytes, these are the hallmark of **Osteoarthritis**, representing a degenerative attempt at joint stabilization. **High-Yield Clinical Pearls for NEET-PG:** 1. **Most Common Site:** The **Knee** joint is the most frequently affected site in pseudogout. 2. **Radiology:** Look for **Chondrocalcinosis** (linear calcification in the joint space). 3. **Associated Conditions:** Always screen for "The 3 Hs": **Hyperparathyroidism, Hemochromatosis, and Hypomagnesemia**, as these metabolic states predispose to CPPD. 4. **Treatment:** Acute attacks are managed with NSAIDs, colchicine, or intra-articular corticosteroids.
Question 28: Disk perforation is best examined by?
- A. MRI
- B. Arthrography (Correct Answer)
- C. CT scan
- D. Arthroscopy
Explanation: ### Explanation **Correct Answer: B. Arthrography** **Why Arthrography is the Correct Choice:** In the context of joint pathology (specifically the Temporomandibular Joint or TMJ), a **disk perforation** refers to a hole in the articular disk that allows the upper and lower joint compartments to communicate. **Arthrography** is considered the gold standard for diagnosing perforations because it involves injecting radiopaque contrast into one compartment (usually the lower). If a perforation exists, the contrast will leak through the disk into the superior compartment. This "flow-through" phenomenon provides direct, functional evidence of a perforation that other modalities may miss. **Analysis of Incorrect Options:** * **A. MRI:** While MRI is the gold standard for diagnosing **disk displacement** (internal derangement) due to its excellent soft-tissue contrast, it has lower sensitivity for detecting small perforations compared to arthrography. * **C. CT Scan:** CT is primarily used to evaluate bony changes (osteophytes, erosions). It does not visualize the non-calcified articular disk or small perforations effectively. * **D. Arthroscopy:** While arthroscopy allows direct visualization of the disk surface, it is an invasive surgical procedure. Arthrography remains the preferred diagnostic investigation for confirming communication between compartments. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard for Disk Displacement:** MRI. * **Gold Standard for Disk Perforation:** Arthrography. * **Double-Contrast Arthrography:** Uses both air and dye to better outline the disk morphology. * **Clinical Sign:** A disk perforation is often associated with **crepitus** (grating sounds) during joint movement, whereas displacement usually presents with a "click."
Question 29: Bamboo spine appearance is seen in which of the following conditions?
- A. Ankylosing spondylitis (Correct Answer)
- B. Rheumatoid arthritis
- C. Osteoarthritis
- D. DISH
Explanation: **Explanation:** **Ankylosing Spondylitis (AS)** is the correct answer. The "Bamboo Spine" is a classic radiographic hallmark of advanced AS, a chronic inflammatory spondyloarthropathy. It occurs due to the fusion of the vertebral bodies by **marginal syndesmophytes**, which are bony growths resulting from the ossification of the outer fibers of the *annulus fibrosus*. This, combined with the ossification of interspinous ligaments and facet joint fusion, creates a rigid, continuous vertical contour resembling a bamboo stalk. **Analysis of Incorrect Options:** * **Rheumatoid Arthritis:** Primarily affects small joints of the hands and feet. In the spine, it typically involves the **atlantoaxial joint** (leading to subluxation) rather than causing diffuse syndesmophyte formation. * **Osteoarthritis:** Characterized by **osteophytes**, which are horizontal, claw-like bony projections, unlike the thin, vertical syndesmophytes of AS. It does not lead to a "bamboo" appearance. * **DISH (Diffuse Idiopathic Skeletal Hyperostosis):** Characterized by "flowing" calcification along the anterior longitudinal ligament (resembling **melted candle wax**). Crucially, DISH preserves the intervertebral disc height and does not involve the sacroiliac joints, distinguishing it from AS. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest Sign:** Sacroiliitis (starts at the lower 2/3rd of the SI joint). * **HLA Association:** Strongly linked with **HLA-B27** (>90% cases). * **Other Radiological Signs:** Dagger sign (ossification of supraspinous/interspinous ligaments), Trolley track sign, and Romanus lesions (shiny corners). * **Clinical Test:** Modified Schober’s test is used to assess restricted spinal flexion.
Question 30: The Thomas test helps to detect which of the following conditions?
- A. Adduction deformity of the hip
- B. Integrity of the abductor mechanism
- C. Fixed flexion deformity of the hip (Correct Answer)
- D. Apparent shortening at the hip joint
Explanation: **Explanation:** The **Thomas Test** is a clinical maneuver used to identify a **Fixed Flexion Deformity (FFD)** of the hip. In a normal hip, the lumbar spine can compensate for a flexion deformity by increasing its lordosis (arching), which allows the leg to lie flat on the couch, masking the deformity. **Mechanism:** To perform the test, the patient lies supine. The clinician flexes the contralateral (normal) hip until the thigh touches the abdomen; this stabilizes the pelvis and **obliterates the compensatory lumbar lordosis**. If an FFD is present in the affected hip, the thigh will spontaneously lift off the examination table. The angle between the thigh and the table represents the degree of fixed flexion deformity. **Analysis of Incorrect Options:** * **Option A (Adduction deformity):** This is assessed by aligning the anterior superior iliac spines (ASIS) horizontally and measuring the angle between the limb and the midline. * **Option B (Abductor mechanism):** The integrity of the abductor mechanism (Gluteus medius and minimus) is evaluated using the **Trendelenburg Test**. * **Option C (Apparent shortening):** This is a measurement of limb length discrepancy caused by pelvic tilting (due to adduction or abduction deformities), not a specific clinical test like Thomas. **High-Yield Clinical Pearls for NEET-PG:** * **Prerequisite:** The Thomas test cannot be accurately performed if the contralateral hip has a stiff or fused joint. * **Psoas Abscess/Tension:** A positive Thomas test is a classic finding in Psoas abscess or Psoas contraction. * **Galeazzi Sign:** Used to differentiate femoral vs. tibial shortening. * **Bryant’s Triangle:** Used to assess supratrochanteric shortening (e.g., in #NOF or CHD).
Practice by Chapter
Principles of Arthroscopy
Practice Questions
Knee Arthroscopy
Practice Questions
Shoulder Arthroscopy
Practice Questions
Hip Arthroscopy
Practice Questions
Ankle Arthroscopy
Practice Questions
Elbow Arthroscopy
Practice Questions
Wrist Arthroscopy
Practice Questions
Arthroscopic Equipment and Setup
Practice Questions
Diagnostic Arthroscopy
Practice Questions
Therapeutic Arthroscopic Procedures
Practice Questions
Complications in Arthroscopy
Practice Questions
Post-Arthroscopy Rehabilitation
Practice Questions
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