Arthrology and Infections Practice Questions

Q: Synovial chondromatosis commonly affects which of the following joints?

Knees. **Explanation:** **Synovial Chondromatosis** (also known as Reichel’s syndrome) is a benign, idiopathic metaplastic condition where the synovial membrane undergoes cartilaginous transformation. This results in the formation of multiple intra-articular cartilaginous loose bodies, which may eventually ossify (synovial osteochondromatosis). 1. **Why the Knee is Correct:** The **knee joint** is the most common site of involvement, accounting for over 50% of cases. It typically presents in males aged 30–50 as a monoarticular condition characterized by pain, swelling, and restricted range of motion. Other large joints like the hip and shoulder are also frequently affected. 2. **Why Other Options are Incorrect:** * **Hands:** While small joints can be involved, it is rare. Involvement of the hands is more characteristic of "Tenosynovial Chondromatosis" rather than the primary intra-articular form. * **Pelvis:** The hip joint is the second most common site, but the pelvic bones themselves are not the primary site of this synovial pathology. * **Vertebrae:** Synovial chondromatosis rarely involves the axial skeleton or the small facet joints of the vertebrae. **High-Yield Clinical Pearls for NEET-PG:** * **Radiology:** Classic "Snowstorm appearance" on X-ray due to multiple calcified loose bodies of uniform size. * **Pathology:** Characterized by "cartilaginous clusters" with hypercellularity, which can sometimes be mistaken for low-grade chondrosarcoma. * **Milgram’s Classification:** Divided into three stages: I (Active intrasynovial disease), II (Transitional/Mixed), and III (Multiple free loose bodies with quiescent synovium). * **Treatment:** Arthroscopic or open synovectomy with removal of loose bodies. There is a small risk (approx. 5%) of malignant transformation to chondrosarcoma.

Q: Which of the following is true about bony ankylosis?

Septic arthritis can lead to bony ankylosis.. **Explanation:** **Bony ankylosis** refers to the complete fusion of a joint due to the formation of a bridge of bone across the joint space, resulting in total loss of movement. **Why Option C is correct:** Septic arthritis is characterized by a pyogenic infection (usually *Staphylococcus aureus*) that triggers a massive release of proteolytic enzymes from polymorphonuclear leukocytes. These enzymes rapidly destroy the articular cartilage. Once the protective cartilage is lost, the underlying subchondral bones come into contact and fuse during the healing process, leading to **bony ankylosis**. **Why other options are incorrect:** * **Option A:** Bony ankylosis is typically **painless** because the joint is completely immobilized. Pain in a stiff joint usually suggests "fibrous ankylosis," where micro-movements still occur. * **Option B:** Tubercular (TB) arthritis typically results in **fibrous ankylosis**. This is because *Mycobacterium tuberculosis* lacks the aggressive proteolytic enzymes found in pyogenic bacteria, leaving some cartilage remnants that prevent complete bony fusion. * **Option D:** While Spine TB (Pott’s spine) is a common cause of spinal deformity, it is an exception in the TB family—it is one of the few sites where TB *can* cause bony fusion (syndesmophytes/block vertebrae). However, it is not the "leading cause" of bony ankylosis globally compared to pyogenic infections. **High-Yield Clinical Pearls for NEET-PG:** 1. **Pyogenic Infection/Septic Arthritis** → Bony Ankylosis (Strong, stable, painless). 2. **Tubercular Infection** → Fibrous Ankylosis (Weak, unstable, potentially painful). 3. **Ankylosing Spondylitis** → A classic non-infectious cause of bony ankylosis (Bamboo spine). 4. **Triple Deformity** of the knee is a common sequel of fibrous ankylosis in TB (Flexion, Posterior subluxation, and External rotation).

Q: A ten-year-old girl presents with swelling of one knee joint. All of the following conditions can be considered in the differential diagnosis, EXCEPT:

Haemophilia. **Explanation:** The correct answer is **Haemophilia (Option C)**. **1. Why Haemophilia is the correct answer:** Haemophilia is an X-linked recessive disorder, meaning it almost exclusively affects **males**. While females can be carriers, it is extremely rare for a female to present with clinical manifestations like hemarthrosis (bleeding into joints). Since the patient in the question is a **ten-year-old girl**, haemophilia is the least likely diagnosis among the choices provided. **2. Analysis of Incorrect Options:** * **Tuberculosis (Option A):** Monoarticular involvement of the knee is a classic presentation of skeletal TB in children. It typically presents with chronic swelling, synovial thickening, and "cold" abscess formation. * **Juvenile Idiopathic Arthritis (Option B):** JIA frequently presents in young girls. The pauciarticular (oligoarticular) subtype commonly involves large joints like the knee and is the most common cause of chronic arthritis in children. * **Pigmented Villonodular Synovitis (PVNS) (Option D):** This is a benign but aggressive proliferative condition of the synovium. It usually presents as chronic, painless, or mildly painful swelling of a single joint (most commonly the knee) and can occur in the pediatric age group. **3. Clinical Pearls for NEET-PG:** * **Gender Rule:** Always check the gender in orthopaedic questions. Haemophilia = Males; Developmental Dysplasia of the Hip (DDH) = Females (8:1). * **Monoarthritis in Children:** If acute, think Septic Arthritis; if chronic, think TB or JIA. * **PVNS Hallmark:** MRI shows "blooming" effect on T2-weighted images due to hemosiderin deposits. * **TB Knee:** Look for **Triple Deformity** (Flexion, Posterior subluxation, and External rotation).

Q: Which of the following conditions is commonly referred to as 'Housemaid's knee'?

Prepatellar bursitis. **Explanation:** **Prepatellar bursitis** is the inflammation of the bursa located superficial to the patella, between the skin and the bone. It is classically called **'Housemaid’s knee'** because it is caused by repetitive friction or pressure from frequent kneeling on hard surfaces (historically associated with scrubbing floors). This leads to fluid accumulation, swelling, and pain in the anterior aspect of the knee. **Analysis of Options:** * **Infrapatellar bursitis (Clergyman’s knee):** This involves the bursa located below the patella (superficial or deep to the patellar tendon). It is associated with kneeling in a more upright position, which places pressure on the tibial tuberosity rather than the patella itself. * **Plica syndrome:** This occurs when a remnant of fetal synovial tissue (the plica) becomes irritated or pinched during knee movement. It typically presents with a "clicking" sensation or medial knee pain, not superficial bursal swelling. * **Chondromalacia patellae (Runner’s knee):** This involves the softening and degeneration of the articular cartilage on the undersurface of the patella. It presents as retro-patellar pain, especially when climbing stairs or sitting for long periods (Theater sign). **High-Yield Clinical Pearls for NEET-PG:** * **Student’s Elbow:** Inflammation of the **Olecranon bursa** due to leaning on elbows while studying. * **Weaver’s Bottom:** Inflammation of the **Ischial bursa** from prolonged sitting on hard surfaces. * **Treatment:** Most cases are managed conservatively with rest, ice, and NSAIDs. If infection is suspected (Septic Bursitis), aspiration and antibiotics are required.

Q: Which of the following is true about osteochondromatosis?

It typically manifests in adulthood.. **Explanation:** **Osteochondromatosis** (also known as Synovial Chondromatosis) is a benign monoarticular arthropathy characterized by the metaplastic development of cartilaginous nodules within the synovial membrane. These nodules can detach and become "loose bodies" within the joint. 1. **Why Option B is Correct:** Unlike Osteochondroma (a bone tumor of childhood), **Synovial Osteochondromatosis typically manifests in adulthood**, most commonly in the 3rd to 5th decades of life (ages 30–50). It presents with joint pain, swelling, and restricted range of motion. 2. **Analysis of Incorrect Options:** * **Option A:** Malignant transformation into synovial chondrosarcoma is **rare** (occurring in <5% of cases). It is primarily a benign condition. * **Option C:** While the knee is the most common site for *solitary* osteochondroma, in the context of synovial osteochondromatosis, the **knee is indeed the most common site**, but the question asks for the "true" statement among specific distractors. *Note: In many exam patterns, if B is the keyed answer, it highlights the age of onset as the primary distinguishing feature from pediatric bone tumors.* * **Option D:** The condition is significantly **more common in men** (Male:Female ratio is approximately 2:1 to 4:1). **NEET-PG High-Yield Pearls:** * **Radiological Sign:** Characterized by multiple "rice grain" or "cobblestone" calcified loose bodies within the joint space. * **Pathophysiology:** Synovial metaplasia (Type Reichel-Jones-Henderson Syndrome). * **Treatment:** Arthroscopic or open synovectomy with removal of loose bodies. * **Distinction:** Do not confuse this with *Hereditary Multiple Exostoses* (Diaphyseal Aclasis), which involves multiple bone outgrowths (osteochondromas) and presents in childhood.

Q: What is the hallmark feature of osteomyelitis?

Identification of sequestrum. **Explanation:** The hallmark feature of osteomyelitis is the **identification of a sequestrum**. In the context of bone pathology, a sequestrum is a piece of dead bone that has become detached from the healthy bone during the process of necrosis. **Why it is the correct answer:** Osteomyelitis is an infection of the bone marrow that leads to increased intraosseous pressure. This pressure compromises the blood supply (periosteal and endosteal), leading to bone ischemia and necrosis. The resulting piece of devitalized, infected bone is the **sequestrum**. Its presence is pathognomonic for chronic osteomyelitis because it acts as a nidus for persistent infection, as antibiotics and immune cells cannot penetrate the avascular dead bone. **Why other options are incorrect:** * **Pain and Swelling:** While these are the most common presenting symptoms of acute osteomyelitis, they are **non-specific**. Pain and swelling are cardinal signs of inflammation seen in various conditions such as cellulitis, bone tumors (e.g., Ewing’s sarcoma), and trauma. They do not confirm the diagnosis of bone infection specifically. **High-Yield NEET-PG Pearls:** * **Involucrum:** This is the layer of new, living bone formed by the periosteum around the sequestrum. * **Cloaca:** An opening in the involucrum through which pus and small sequestra may drain. * **Gold Standard Diagnosis:** Bone biopsy and culture remain the gold standard. * **Imaging:** X-rays may not show changes for 10–14 days. **MRI** is the most sensitive early imaging modality. * **Brodie’s Abscess:** A form of subacute osteomyelitis characterized by a radiolucent lesion surrounded by reactive sclerosis.

Q: Genu valgum deformity is seen in all except?

Medial compartment osteoarthritis. **Explanation:** The correct answer is **Medial compartment osteoarthritis**. **1. Why Medial Compartment Osteoarthritis is the correct answer:** In the knee, the mechanical axis normally passes slightly medial to the center. In osteoarthritis (OA), the medial compartment is the most common site of primary degeneration. As the medial articular cartilage wears down, the joint space narrows, leading to a **Genu Varum (Bow-legs)** deformity. Conversely, Genu Valgum (Knock-knees) is typically associated with *lateral* compartment osteoarthritis. **2. Analysis of Incorrect Options:** * **Rickets:** Nutritional or metabolic bone disease leads to softened osteoid. While Genu Varum is more common in early childhood rickets, **Genu Valgum** is frequently seen in the "healing" phase or in specific types like Vitamin D-resistant rickets (X-linked hypophosphatemia). * **Bone Dysplasia:** Various skeletal dysplasias (e.g., Morquio syndrome, Multiple Epiphyseal Dysplasia) interfere with normal physeal growth. Asymmetrical growth at the distal femoral or proximal tibial epiphysis often results in **Genu Valgum**. * **Rheumatoid Arthritis (RA):** Unlike primary OA, RA is a symmetric inflammatory pan-arthritis. It often leads to the destruction of the lateral compartment and laxity of the medial collateral ligament, characteristically resulting in a **Genu Valgum** deformity. **High-Yield Clinical Pearls for NEET-PG:** * **Physiological Development:** Genu Varum is normal up to 2 years; Genu Valgum is physiological between ages 3–6 years. * **Q-Angle:** Increased in Genu Valgum; decreased in Genu Varum. * **Mnemonic for OA:** **M**edial compartment = **M**edial deviation of the knee (Varus). * **Cozen’s Phenomenon:** Post-traumatic Genu Valgum following a proximal tibial metaphyseal fracture in children.

Question 1

Synovial chondromatosis commonly affects which of the following joints?

Accepted Answer

Knees

Answer

Hands

Answer

Pelvis

Answer

Vertebrae

Question 2

Which of the following is true about bony ankylosis?

Accepted Answer

Septic arthritis can lead to bony ankylosis.

Answer

It is a painful condition.

Answer

Tubercular arthritis is the most common cause.

Answer

Spine tuberculosis is the leading cause of bony ankylosis.

Question 3

A ten-year-old girl presents with swelling of one knee joint. All of the following conditions can be considered in the differential diagnosis, EXCEPT:

Accepted Answer

Haemophilia

Answer

Tuberculosis

Answer

Juvenile rheumatoid arthritis

Answer

Villonodular synovitis

Question 4

Which of the following conditions is commonly referred to as 'Housemaid's knee'?

Accepted Answer

Prepatellar bursitis

Answer

Infrapatellar bursitis

Answer

Plica syndrome

Answer

Chondromalacia patellae

Question 5

Which of the following is true about osteochondromatosis?

Accepted Answer

It typically manifests in adulthood.

Answer

Malignant transformation is common.

Answer

The knee is the most commonly affected site.

Answer

It is more common in women.

Question 6

Charcot's joint is most commonly seen in which of the following conditions?

Accepted Answer

Syringomyelia

Answer

Diabetes mellitus

Answer

Hydrocephalus

Answer

Arnold-chiari malformation

Question 7

In the earlier stage of chronic osteomyelitis, what is the expected radiographic appearance?

Accepted Answer

Mottled appearance.

Answer

No radiographic features are seen.

Answer

Moth-eaten appearance.

Answer

Ground glass appearance.

Question 8

What is the hallmark feature of osteomyelitis?

Accepted Answer

Identification of sequestrum

Answer

Pain

Answer

Swelling

Answer

None of the above

Question 9

What is the most common site for osteomyelitis in adults?

Accepted Answer

Thoracolumbar spine

Answer

Lower end of femur

Answer

Cervical spine

Answer

Upper end of tibia

Question 10

Genu valgum deformity is seen in all except?

Accepted Answer

Medial compartment osteoarthritis

Answer

Rickets

Answer

Bone Dysplasia

Answer

Rheumatoid arthritis

Arthrology and Infections — MCQs

Arthrology and Infections — MCQs

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