Arthrology and Infections Practice Questions

Q: A 30-year-old HIV-positive male on antiretroviral therapy presents with right hip joint pain for 2 months. He has difficulty with abduction and internal rotation. Which of the following is the most likely diagnosis?

Avascular necrosis. ### **Explanation** **Correct Option: C. Avascular Necrosis (AVN)** The clinical presentation of a young patient with HIV on **Antiretroviral Therapy (ART)** presenting with insidious onset hip pain is a classic scenario for **Avascular Necrosis (AVN)** of the femoral head. * **Pathophysiology:** HIV infection itself and certain ART drugs (especially **Protease Inhibitors**) are strongly associated with metabolic derangements like hyperlipidemia and fat embolism, leading to compromised microcirculation in the femoral head. * **Clinical Sign:** Pain is typically aggravated by weight-bearing. The earliest clinical signs of hip AVN are the restriction of **internal rotation and abduction**, as seen in this patient. **Why other options are incorrect:** * **A. Septic Arthritis:** This usually presents acutely with high-grade fever, systemic toxicity, and an inability to bear any weight. A 2-month history makes this less likely. * **B. Osteoarthritis:** Primary osteoarthritis is rare in a 30-year-old. It is usually a secondary consequence of conditions like AVN or trauma in younger patients. * **D. Tubercular Arthritis:** While common in immunocompromised patients, it typically presents with a "cold abscess," significant constitutional symptoms (night sweats, weight loss), and a more chronic, destructive course on imaging (Phemister triad). **High-Yield Clinical Pearls for NEET-PG:** * **Most sensitive investigation:** MRI (shows "Double Line Sign" on T2WI). * **Staging System:** Ficat and Arlet Classification is most commonly used. * **Risk Factors for AVN:** **S**teroids (most common cause overall), **A**lcohol, **T**rauma (neck of femur fracture), **S**ickle cell anemia, and **H**IV/ART drugs (**S.A.T.S.H**). * **Treatment:** Core decompression is the treatment of choice for early stages (Ficat Stage I & II). Total Hip Arthroplasty (THA) is reserved for advanced stages with secondary collapse.

Q: Which of the following is a feature of the triple deformity of the knee joint?

Posterior subluxation of tibia. The **Triple Deformity of the Knee** is a classic clinical presentation typically seen in advanced cases of **Tuberculosis (TB) of the knee joint** or chronic untreated arthritis. It occurs due to the powerful pull of the hamstring muscles overcoming the weakened joint structures. ### **Explanation of the Correct Option** The "Triple Deformity" consists of three specific anatomical displacements of the tibia relative to the femur: 1. **Flexion:** Due to the predominant action of the hamstrings. 2. **Posterior Subluxation of the Tibia:** The hamstrings pull the proximal tibia backward behind the femoral condyles. 3. **External Rotation of the Tibia:** The biceps femoris (the lateral hamstring) is stronger than the medial hamstrings, causing the tibia to rotate laterally. Therefore, **Posterior subluxation of the tibia** is a hallmark feature of this triad. ### **Explanation of Incorrect Options** * **B. Internal rotation of tibia:** Incorrect. The tibia undergoes **external rotation** because the biceps femoris exerts a stronger rotational pull than the semimembranosus/semitendinosus. * **C. Medial angulation of tibia:** Incorrect. While some valgus (lateral angulation) may occur, medial angulation (varus) is not a standard component of the classic triple deformity description. * **D. Recurvatum:** Incorrect. Recurvatum refers to hyperextension. The triple deformity is characterized by fixed **flexion**, not extension. ### **High-Yield Clinical Pearls for NEET-PG** * **Most common cause:** Tuberculosis of the knee (Stage of Destruction). * **Muscle Dynamics:** The deformity occurs because the knee flexors (hamstrings) are stronger than the extensors (quadriceps). * **Management:** Early stages require traction and splinting; advanced stages with triple deformity often require surgical intervention like arthrodesis (joint fusion) to provide a stable, painless limb.

Q: What is the most commonly affected joint in syphilis?

Knee. **Explanation:** The **Knee joint** is the most commonly affected joint in both congenital and acquired syphilis. The clinical presentation typically manifests in two distinct forms: 1. **Clutton’s Joints (Congenital Syphilis):** This is a hallmark manifestation occurring typically between ages 8 and 15. It is characterized by symmetrical, painless bilateral swelling (effusion) of the knees. It is a chronic hydrarthrosis that does not lead to joint destruction. 2. **Charcot’s Joint (Tertiary Syphilis):** In late-stage acquired syphilis (Tabes Dorsalis), the loss of proprioception and pain sensation leads to a neuropathic joint. The knee is the most frequent site for this "painless, deformed, and unstable" joint, characterized by the "6 Ds": Destruction, Debris, Density, Disorganization, Dislocation, and Distension. **Analysis of Incorrect Options:** * **Ankle:** While the ankle can be involved in neuropathic arthropathy (Charcot’s), it is less common than the knee in the context of Tabes Dorsalis. * **Hip:** Syphilitic involvement of the hip is rare. Hip pathology is more commonly associated with tuberculosis or avascular necrosis. * **Elbow:** Upper limb joints are rarely the primary site for syphilitic arthritis; it predominantly affects weight-bearing joints due to the mechanical stress involved in neuropathic changes. **High-Yield Clinical Pearls for NEET-PG:** * **Clutton’s Joint triad:** Bilateral knee effusion + Painless + Congenital syphilis. * **Hutchinson’s Triad:** Interstitial keratitis, sensorineural deafness, and notched central incisors (Hutchinson’s teeth). * **Pathognomonic sign:** The presence of a "painless but flail joint" should immediately raise suspicion of a Charcot’s joint (Syphilis or Diabetes Mellitus).

Q: The paprika sign observed during debridement is crucial in the management of which of the following conditions?

Chronic osteomyelitis. **Explanation:** The **Paprika Sign** is a vital intraoperative clinical indicator used during the surgical management of **Chronic Osteomyelitis**, specifically during the process of **sequestrectomy and saucerization**. 1. **Why Chronic Osteomyelitis is correct:** The hallmark of chronic osteomyelitis is the presence of a **sequestrum** (dead, avascular bone). Successful treatment requires the complete removal of this necrotic tissue until healthy, vascularized bone is reached. The "Paprika Sign" refers to the appearance of **punctate bleeding points** on the bone surface, resembling paprika spice, after the sclerotic and dead bone has been debrided. This sign confirms that the surgeon has reached viable, living bone with an intact blood supply, which is essential for antibiotic delivery and bone healing. 2. **Why the other options are incorrect:** * **Osteosarcoma:** Management involves wide local excision or limb salvage surgery based on oncological margins, not the assessment of punctate bleeding for viability. * **Osteoid Osteoma:** This is a benign bone-forming tumor characterized by a "nidus." Treatment involves complete excision or radiofrequency ablation of the nidus, rather than extensive debridement to vascular bone. * **Brodie's Abscess:** While a form of subacute osteomyelitis, it is a localized, contained abscess. While debridement is used, the specific term "Paprika Sign" is classically associated with the extensive decortication/saucerization of chronic diffuse osteomyelitis. **High-Yield Clinical Pearls for NEET-PG:** * **Sequestrum:** Dead bone (radiodense). * **Involucrum:** New bone formation around the sequestrum. * **Cloaca:** An opening in the involucrum for pus/debris exit. * **Treatment Goal:** The Paprika Sign ensures an adequate "biological environment" for healing by confirming vascularity.

Q: Windswept deformity in the foot is seen in which condition?

Rheumatoid Arthritis. **Explanation:** **Windswept deformity of the foot** is a classic clinical feature of **Rheumatoid Arthritis (RA)**. It describes a specific combination of forefoot deformities where the toes appear "blown" to one side. This occurs due to a combination of **hallux valgus** (great toe deviating laterally) and **fibular (lateral) deviation** of the lesser toes at the metatarsophalangeal (MTP) joints. The underlying pathology involves chronic synovitis leading to the destruction of collateral ligaments and joint capsules, causing the toes to drift laterally. **Analysis of Incorrect Options:** * **Rickets (Option A):** While Rickets is famous for "Windswept deformity," it occurs at the **knees** (one knee in genu valgum and the other in genu varum), not the foot. This is a common "trap" in exams. * **Hyperparathyroidism (Option C):** This condition typically presents with subperiosteal bone resorption (classically in the phalanges), Brown tumors, and "Salt and Pepper" skull, but not specific windswept foot deformities. * **Scurvy (Option D):** Vitamin C deficiency presents with subperiosteal hemorrhages, Scorbutic rosary, and radiographic signs like Wimberger’s ring sign and Frankel’s line, rather than joint deviations. **High-Yield Clinical Pearls for NEET-PG:** * **Windswept Knee:** Rickets (most common), Osteomalacia, or Skeletal Dysplasias. * **Windswept Foot:** Rheumatoid Arthritis. * **Rheumatoid Foot Triad:** Hallux valgus, Fibular deviation of toes, and Subluxation of MTP joints (leading to "daylight sign"). * **Hand Deformities in RA:** Swan neck deformity, Boutonniere deformity, and Ulnar deviation at MCP joints.

Q: Chronic persistent neutrophilic discharge is seen in which of the following conditions?

Chronic osteomyelitis. **Explanation:** **Chronic Osteomyelitis** is characterized by the presence of necrotic bone, known as a **sequestrum**. This dead bone acts as a persistent nidus for infection because it lacks a blood supply, preventing antibiotics and immune cells from reaching the bacteria. The body attempts to wall off this infection by forming new bone (**involucrum**), but the pus eventually tracks to the skin surface through a **cloaca**, forming a **sinus tract**. This results in a **chronic, persistent neutrophilic (purulent) discharge** that typically lasts for weeks or months. **Why other options are incorrect:** * **Acute Osteomyelitis:** This is a systemic illness presenting with high-grade fever, intense local pain, and swelling. While pus forms, it is usually contained subperiosteally. If it discharges, it is an acute event, not a "chronic persistent" one. * **Septic Arthritis:** This presents as an acute emergency with a hot, swollen joint and restricted range of motion. While the joint aspirate is rich in neutrophils, it does not typically present with a chronic discharging sinus unless it becomes secondarily chronic (which is rare with modern treatment). **High-Yield Clinical Pearls for NEET-PG:** * **Sequestrum:** Dead bone (Radiodense on X-ray). * **Involucrum:** New bone formed around the sequestrum. * **Cloaca:** The opening in the involucrum through which pus/sequestra escape. * **Marjolin’s Ulcer:** A rare but high-yield complication where a long-standing chronic osteomyelitis sinus tract undergoes malignant transformation into **Squamous Cell Carcinoma**. * **Gold Standard Investigation:** MRI is the most sensitive, but a **Sinogram** is used to visualize the extent of the sinus tract.

Q: Pseudotumor syndrome is seen in which of the following conditions?

Hemophilia. **Explanation:** **Hemophilic Pseudotumor** is a rare but serious complication occurring in approximately 1–2% of patients with severe hemophilia. It is caused by recurrent, progressive subperiosteal or soft tissue hemorrhages. 1. **Why Hemophilia is correct:** The "pseudotumor" is actually a chronic, encapsulated hematoma. As the hematoma expands, it exerts pressure on surrounding structures, leading to pressure necrosis of muscles and, more significantly, **bone destruction and remodeling**. Radiologically, it mimics a malignant bone tumor (like osteosarcoma) due to its osteolytic appearance and periosteal reaction, hence the name "pseudotumor." It most commonly involves the femur and pelvis. 2. **Why other options are incorrect:** * **SLE:** Typically presents with non-erosive arthritis (Jaccoud’s arthropathy) or avascular necrosis, but not pseudotumors. * **Thalassemia:** Characterized by marrow hyperplasia leading to a "crew-cut" appearance on skull X-ray and "chipmunk facies," but not localized pseudotumors. * **Hyperparathyroidism:** Associated with **Brown Tumors** (osteitis fibrosa cystica). While these are also "false" tumors, the term "Pseudotumor Syndrome" is classically reserved for the hemophilic entity in orthopedic literature. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site:** Femur (in adults); small bones of hands/feet (in children). * **Management:** Conservative management with factor replacement is tried first, but surgical excision or aspiration is often required if it is large or threatening neurovascular structures. * **Differential Diagnosis:** Must be distinguished from **Brown tumors** (Hyperparathyroidism) and **Giant Cell Tumors**. * **Radiological hallmark:** Large soft tissue mass with adjacent bone destruction and a "soap bubble" appearance.

Q: Tietze's syndrome typically affects the costal cartilages of which ribs?

Second to fifth ribs. **Explanation:** **Tietze’s Syndrome** is a benign, inflammatory condition characterized by painful swelling of the costochondral or costosternal joints. 1. **Why the correct answer is right:** The syndrome most commonly involves the **second to fifth costal cartilages**. The **second rib** is the most frequently affected site. Unlike simple costochondritis, Tietze’s syndrome is distinguished by the presence of **palpable, localized swelling** and tenderness. It is usually unilateral and often follows a history of minor trauma, excessive coughing, or physical exertion. 2. **Analysis of incorrect options:** * **Option A (First and second ribs):** While the second rib is the most common site, the syndrome typically spans a broader range (2nd–5th). Isolated involvement of the first rib is rare. * **Option C (Sixth to eighth ribs):** These are lower ribs. Pain in this region is more likely associated with "Slipping Rib Syndrome" or abdominal pathology rather than classic Tietze’s. * **Option D (All seven ribs):** Tietze’s is characteristically localized to one or two joints; diffuse involvement of all true ribs is not seen in this clinical entity. **High-Yield Clinical Pearls for NEET-PG:** * **Tietze’s vs. Costochondritis:** The hallmark of Tietze’s is **swelling** (edema of cartilage). Costochondritis presents with pain but **no swelling**. * **Demographics:** It usually affects younger adults (under 40), whereas costochondritis is more common in patients over 40. * **Diagnosis:** It is a clinical diagnosis. Investigations (X-ray, ECG) are primarily done to rule out life-threatening causes of chest pain like Myocardial Infarction or Pleurisy. * **Management:** Conservative treatment with NSAIDs, rest, and reassurance, as it is a self-limiting condition.

Q: What is the commonest cause of acute osteomyelitis?

Hematogenous route. **Explanation:** **Hematogenous route (Option D)** is the most common cause of acute osteomyelitis, particularly in the pediatric population. This occurs when bacteria (most commonly *Staphylococcus aureus*) enter the bloodstream from a distant site (like a skin boil or sore throat) and settle in the **metaphysis** of long bones. The metaphysis is the preferred site due to its high vascularity and the presence of "hairpin loops" in the capillary bed, which lead to sluggish blood flow, allowing bacteria to settle and proliferate. **Analysis of Incorrect Options:** * **Trauma (Option A):** While open fractures or deep soft tissue injuries can lead to "Direct Inoculation Osteomyelitis," it is statistically less common than the hematogenous spread in the general population. * **Surgery (Option B):** Post-operative infections (e.g., after ORIF or joint replacement) are significant causes of *chronic* or *iatrogenic* osteomyelitis but do not represent the primary etiology of acute cases globally. * **Fungal infection (Option C):** Fungal osteomyelitis is rare and typically seen only in immunocompromised patients or those on long-term parenteral nutrition. **High-Yield Clinical Pearls for NEET-PG:** * **Most common organism:** *Staphylococcus aureus* (overall). * **Most common organism in Sickle Cell Anemia:** *Salmonella* (though *S. aureus* remains a close second). * **Most common site:** Metaphysis of long bones (Distal Femur > Proximal Tibia). * **Earliest X-ray sign:** Soft tissue swelling (seen at 3–5 days). Bony changes (periosteal reaction/rarefaction) take **10–14 days** to appear. * **Investigation of choice:** **MRI** (most sensitive for early diagnosis).

Question 1

A 30-year-old HIV-positive male on antiretroviral therapy presents with right hip joint pain for 2 months. He has difficulty with abduction and internal rotation. Which of the following is the most likely diagnosis?

Accepted Answer

Avascular necrosis

Answer

Septic arthritis

Answer

Osteoarthritis

Answer

Tubercular arthritis

Question 2

A 7-year-old boy sustained an open compound fracture of the right tibia and fibula. On physical examination, the fractured bones are visible protruding from the skin wound. The fracture is managed with external manipulation and skin closure. One year later, he experiences persistent pain in the right leg and has developed a draining sinus tract in the lateral lower right leg. A radiograph of the lower right leg is most likely to show which of the following?

Accepted Answer

Involucrum and sequestrum

Answer

Cortical nidus with surrounding sclerosis

Answer

Osteolysis with osteosclerosis

Answer

Soft-tissue hemorrhage and swelling

Question 3

Which of the following is a feature of the triple deformity of the knee joint?

Accepted Answer

Posterior subluxation of tibia

Answer

Internal rotation of tibia

Answer

Medial angulation of tibia

Answer

Recurvatum

Question 4

What is the most commonly affected joint in syphilis?

Accepted Answer

Knee

Answer

Ankle

Answer

Hip

Answer

Elbow

Question 5

The paprika sign observed during debridement is crucial in the management of which of the following conditions?

Accepted Answer

Chronic osteomyelitis

Answer

Osteosarcoma

Answer

Osteoid osteoma

Answer

Brodie's abscess

Question 6

Windswept deformity in the foot is seen in which condition?

Accepted Answer

Rheumatoid Arthritis

Answer

Rickets

Answer

Hyperparathyroidism

Answer

Scurvy

Question 7

Chronic persistent neutrophilic discharge is seen in which of the following conditions?

Accepted Answer

Chronic osteomyelitis

Answer

Acute osteomyelitis

Answer

Septic arthritis

Answer

None of the above

Question 8

Pseudotumor syndrome is seen in which of the following conditions?

Accepted Answer

Hemophilia

Answer

Systemic Lupus Erythematosus (SLE)

Answer

Thalassemia

Answer

Hyperparathyroidism

Question 9

Tietze's syndrome typically affects the costal cartilages of which ribs?

Accepted Answer

Second to fifth ribs

Answer

First and second ribs

Answer

Sixth to eighth ribs

Answer

All seven ribs

Question 10

What is the commonest cause of acute osteomyelitis?

Accepted Answer

Hematogenous route

Answer

Trauma

Answer

Surgery

Answer

Fungal infection

Arthrology and Infections — MCQs

Arthrology and Infections — MCQs

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