Osteoarthritis: Pathophysiology — MCQs
Osteoarthritis is associated with all of the following except -
All of the following are classical mediators of inflammation, except which of the following?
What is the primary action of metalloproteinases in the extracellular matrix?
Osteoarthritis not seen in ?
During performing a total hip replacement, the surgeon found destruction of the articular cartilage and multiple wedge-shaped subchondral depressions. What is this called?
Which of the following joints are commonly affected in osteoarthritis? I. First metatarsophalangeal joint II. Proximal interphalangeal joint III. Ankle joint IV. 5th and 6th cervical vertebrae joint Select the correct answer using the code given below :
Primary osteoarthritis affects all except:
Osteoarthritis is typically not seen in which of the following joints?
Frieberg's disease involves which of the following?
A 56-year-old Type II diabetic presents with complaints of swelling in the left ankle with effusion but only minimal pain. X-rays show severe osteopenia with bone destruction, extensive osteophytosis, and loose bodies. Which of the following is NOT a component of the management of this patient?
Osteoarthritis: Pathophysiology Indian Medical PG Practice Questions and MCQs
Question 1: Osteoarthritis is associated with all of the following except -
- A. Subchondral sclerosis
- B. Ca++deposition in joint space (Correct Answer)
- C. Osteophyte formation
- D. Decreased joint space
Explanation: ***Ca++deposition in joint space*** - **Calcium pyrophosphate dihydrate (CPPD) crystal deposition** in the joint space is characteristic of **pseudogout**, not osteoarthritis [1]. - While some **calcification** may occur in osteophytes, direct **calcium crystal deposition** in the synovial fluid is not a primary feature of osteoarthritis [1]. *Subchondral sclerosis* - **Subchondral sclerosis** refers to the increased bone density that occurs beneath the cartilage in areas of stress in osteoarthritis. - This is a common radiological finding in osteoarthritis, reflecting the bone's response to increased mechanical load. *Osteophyte formation* - **Osteophytes** (bone spurs) are bony projections that form along the joint margins in osteoarthritis [2]. - They are a hallmark feature of the disease, resulting from the body's attempt to repair and stabilize the damaged joint [2]. *Decreased joint space* - **Decreased joint space** on radiographs is a classic sign of osteoarthritis, indicating loss of articular cartilage thickness [2]. - As the cartilage erodes, the distance between the bones within the joint decreases. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Osteoarticular And Connective Tissue Disease, pp. 683-684. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1210-1212.
Question 2: All of the following are classical mediators of inflammation, except which of the following?
- A. Prostaglandins
- B. Interleukin-1 (IL-1)
- C. Tumour necrosis factor-alpha (TNF-alpha)
- D. Myeloperoxidase (MPO) (Correct Answer)
Explanation: ***Myeloperoxidase*** - **Myeloperoxidase** is primarily an enzyme involved in the microbial killing process in neutrophils, not a typical mediator of inflammation. - It catalyzes the production of **hypochlorous acid** (HOCl) during the oxidative burst, more related to pathogen destruction than inflammation mediation. *Tumour necrosis factor-a (TNF-a)* - **TNF-a** is a key pro-inflammatory cytokine that plays a significant role in systemic inflammation and is involved in the acute phase response [1][3]. - It promotes the recruitment of immune cells to sites of inflammation and is involved in the activation of the inflammatory process [1][3]. *Prostaglandins* - **Prostaglandins** are lipid mediators derived from arachidonic acid that have various roles, including enhancing inflammation and pain signaling [1][2]. - They contribute to vasodilation, increased vascular permeability, and sensitization of nociceptors during inflammatory responses [1][2]. *Interleukin-1* - **Interleukin-1** (IL-1) is a crucial inflammatory cytokine that stimulates immune responses and is involved in both acute and chronic inflammation [1][3]. - It can induce fever and promote the expression of adhesion molecules on endothelial cells, facilitating leukocyte migration [1][3]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, p. 101. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 95-96. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 97-99.
Question 3: What is the primary action of metalloproteinases in the extracellular matrix?
- A. Modification of collagen structure
- B. Degradation of extracellular matrix components, including collagen (Correct Answer)
- C. Formation of collagen
- D. Activation of collagen synthesis
Explanation: ***Degradation of extracellular matrix components, including collagen*** - **Metalloproteinases (MMPs)** are a family of zinc-dependent endopeptidases that are crucial for breaking down various components of the **extracellular matrix (ECM)**. - This degradation is essential for processes like **tissue remodeling**, development, wound healing, and also plays a role in disease pathogenesis such as metastasis and inflammation. *Formation of collagen* - The formation of collagen is primarily mediated by **fibroblasts** and involves a complex process of synthesis, hydroxylation, glycosylation, and assembly of procollagen molecules, not MMPs. - MMPs act to break down existing collagen, not to create new collagen fibers. *Modification of collagen structure* - While collagen undergoes post-translational modifications (e.g., hydroxylation, glycosylation) within cells, MMPs are involved in cleaving the peptide bonds, leading to **degradation**, rather than structural modification of intact collagen. - Enzymes like **lysyl hydroxylase** and **prolyl hydroxylase** are responsible for modifying collagen structure. *Activation of collagen synthesis* - Collagen synthesis is primarily regulated by various **growth factors (e.g., TGF-β)** and hormones that stimulate fibroblasts to produce collagen. - MMPs are involved in the breakdown of collagen, which is the opposite of activating its synthesis.
Question 4: Osteoarthritis not seen in ?
- A. Ankle joints (Correct Answer)
- B. Knee joints
- C. Hip joints
- D. 1st metacarpophalangeal joint
Explanation: ***Ankle joints*** - While other joints are frequently affected by osteoarthritis, the **ankle joint** is *relatively spared* from primary osteoarthritis. - Osteoarthritis in the ankle is more commonly **secondary** to trauma, inflammation, or structural abnormalities rather than a primary degenerative process. *Knee joints* - The **knee joint** is one of the most frequently affected joints in osteoarthritis due to its weight-bearing function and complex biomechanics. - **Cartilage degeneration** in the knee leads to pain, stiffness, and reduced mobility. *Hip joints* - The **hip joint** is another common site for osteoarthritis, particularly in older adults, due to its significant weight-bearing role. - **Acetabular and femoral head cartilage erosion** causes deep groin pain and restricted range of motion. *1st metacarpophalangeal joint* - The **1st metacarpophalangeal (MCP) joint** of the thumb is a common site for osteoarthritis, especially in women. - This is due to the significant **stress and forces** placed on this joint during pinching and gripping activities.
Question 5: During performing a total hip replacement, the surgeon found destruction of the articular cartilage and multiple wedge-shaped subchondral depressions. What is this called?
- A. Osteolysis
- B. Osteomyelitis
- C. Osteonecrosis (Correct Answer)
- D. Osteogenesis
Explanation: ***Osteonecrosis*** - **Osteonecrosis**, also known as **avascular necrosis**, is characterized by the death of bone tissue due to a lack of blood supply, which leads to the collapse of the subchondral bone and articular cartilage destruction. - The description of **wedge-shaped subchondral depressions** and **articular cartilage destruction** is highly indicative of osteonecrosis, especially in the context of advanced hip joint pathology requiring total hip replacement. *Osteolysis* - **Osteolysis** refers to the active resorption of bone, often seen around implants in prosthetic joints due to wear particles, leading to bone loss. - While it involves bone destruction, it typically presents as diffuse bone loss rather than specific wedge-shaped subchondral depressions. *Osteomyelitis* - **Osteomyelitis** is an infection of the bone or bone marrow, often leading to bone destruction, but it is primarily characterized by inflammation and pus formation. - The presented scenario does not mention signs of infection (e.g., fever, pus, inflammation) but focuses purely on structural destruction consistent with vascular compromise. *Osteogenesis* - **Osteogenesis** is the process of bone formation or development. - This term describes the creation of bone tissue and is the opposite of bone destruction, making it an incorrect answer for a condition involving cartilage and bone deterioration.
Question 6: Which of the following joints are commonly affected in osteoarthritis? I. First metatarsophalangeal joint II. Proximal interphalangeal joint III. Ankle joint IV. 5th and 6th cervical vertebrae joint Select the correct answer using the code given below :
- A. I, II, III and IV
- B. I and II only
- C. III and IV only
- D. I, II and IV only (Correct Answer)
Explanation: ***I, II and IV only*** - **Osteoarthritis** commonly affects joints that bear significant weight or are subject to repetitive stress, such as the **first metatarsophalangeal joint**, **proximal interphalangeal joints**, and the **cervical spine**. - Degenerative changes in these joints, including cartilage loss and **osteophyte formation**, are characteristic findings in osteoarthritis. *I, II, III and IV* - While the first metatarsophalangeal joint, proximal interphalangeal joints, and cervical vertebrae are commonly affected, the **ankle joint** is typically spared in primary osteoarthritis. - Ankle involvement in osteoarthritis is usually secondary to **trauma** or inflammatory arthritis rather than primary degenerative change. *III and IV only* - This option misses the common involvement of the **first metatarsophalangeal joint** and **proximal interphalangeal joints**, which are frequently affected in osteoarthritis. - The ankle joint is less commonly involved in primary osteoarthritis compared to other load-bearing joints like the **knee** and **hip**. *I and II only* - This option incorrectly omits the **cervical vertebrae**, which are a very common site for osteoarthritis, often leading to neck pain and **radiculopathy**. - While the metatarsophalangeal and proximal interphalangeal joints are correct, the exclusion of the cervical spine makes this option incomplete.
Question 7: Primary osteoarthritis affects all except:
- A. Metacarpophalangeal joint (Correct Answer)
- B. Hip Joint
- C. Distal interphalangeal joint
- D. Knee joint
Explanation: ***Metacarpophalangeal joint*** - The **metacarpophalangeal (MCP) joints** are typically spared in primary osteoarthritis, making their involvement a less common presentation. - Involvement of the MCP joints, particularly with significant inflammation, might suggest other conditions like **rheumatoid arthritis**. *Hip Joint* - The hip joint is a common site for primary osteoarthritis due to its **weight-bearing function** and susceptibility to mechanical stress. - Patients often experience **groin pain** and reduced range of motion, particularly internal rotation. *Distal interphalangeal joint* - The **distal interphalangeal (DIP) joints** are very commonly affected in primary osteoarthritis, leading to the formation of **Heberden's nodes**. - These nodes are bony enlargements that indicate osteophyte formation and cartilage loss. *Knee joint* - The knee joint is another frequently affected large joint in primary osteoarthritis, often presenting with **pain**, **stiffness**, and **crepitus**. - Its **weight-bearing role** contributes significantly to its vulnerability to degenerative changes.
Question 8: Osteoarthritis is typically not seen in which of the following joints?
- A. Ankle joints (Correct Answer)
- B. Knee joints
- C. Hip joints
- D. First metacarpophalangeal joint
Explanation: **Explanation:** Primary **Osteoarthritis (OA)** is a degenerative joint disease that characteristically affects weight-bearing joints and specific small joints of the hand. **Why Ankle Joints are the Correct Answer:** The **ankle (talocrural) joint** is remarkably resistant to primary osteoarthritis. This is due to the unique properties of ankle cartilage, which is thinner but has higher proteoglycan density and lower water content compared to the knee or hip, making it more resistant to compressive forces. While the ankle is a weight-bearing joint, OA here is almost always **secondary** (e.g., following intra-articular fractures, ligamentous instability, or rheumatoid arthritis) rather than primary/idiopathic. **Analysis of Incorrect Options:** * **Knee Joints:** The most common site for primary OA. It typically involves the medial compartment due to the mechanical axis of the lower limb. * **Hip Joints:** A major weight-bearing joint frequently affected by primary OA, often leading to total hip arthroplasty in elderly patients. * **First Metacarpophalangeal (MCP) Joint:** While OA commonly affects the **First Carpometacarpal (CMC)** joint (base of the thumb) and the **Distal Interphalangeal (DIP)** joints (Heberden’s nodes), the first MCP joint is also a recognized site for degenerative changes due to the high stresses of pinch and grip. **High-Yield Clinical Pearls for NEET-PG:** * **Nodal Distribution:** OA typically affects DIP joints (Heberden’s nodes) and PIP joints (Bouchard’s nodes). **MCP joints (except the 1st) and wrists are usually spared** (if involved, think Rheumatoid Arthritis). * **Radiological Hallmarks:** Joint space narrowing (asymmetrical), subchondral sclerosis, subchondral cysts, and osteophyte formation. * **Kellgren-Lawrence Grading:** The standard radiological classification system for OA severity. * **Eburnation:** A pathological feature where subchondral bone becomes polished and ivory-like due to complete loss of overlying cartilage.
Question 9: Frieberg's disease involves which of the following?
- A. Tibial tuberosity
- B. Calcaneal tuberosity
- C. 2nd metatarsal (Correct Answer)
- D. 5th metatarsal
Explanation: **Explanation:** **Freiberg’s disease** is an **osteochondrosis** (avascular necrosis) affecting the head of the metatarsal. It most commonly involves the **2nd metatarsal head (Option C)** because it is the longest and most rigid metatarsal, making it susceptible to repetitive microtrauma and excessive loading during the toe-off phase of gait. It is typically seen in adolescent girls and presents with pain, swelling, and limited range of motion at the metatarsophalangeal joint. **Analysis of Incorrect Options:** * **Option A (Tibial tuberosity):** This is the site for **Osgood-Schlatter disease**, a traction apophysitis caused by repetitive strain from the patellar tendon. * **Option B (Calcaneal tuberosity):** This is the site for **Sever’s disease**, an apophysitis of the calcaneus common in active children. * **Option D (5th metatarsal):** The base of the 5th metatarsal is the site for **Iselin’s disease** (apophysitis). While the 5th metatarsal is also prone to Jones fractures, it is not the classic site for Freiberg’s. **High-Yield Clinical Pearls for NEET-PG:** * **Demographics:** Most common in adolescent females (ratio ~3:1). * **Radiology:** Early stages show flattening and sclerosis of the metatarsal head; late stages show joint space narrowing and secondary osteoarthritis. * **Hierarchy of Involvement:** 2nd Metatarsal (most common) > 3rd Metatarsal > 4th Metatarsal. * **Management:** Conservative (activity modification, orthotics) is first-line; surgery (debridement or osteotomy) is reserved for refractory cases.
Question 10: A 56-year-old Type II diabetic presents with complaints of swelling in the left ankle with effusion but only minimal pain. X-rays show severe osteopenia with bone destruction, extensive osteophytosis, and loose bodies. Which of the following is NOT a component of the management of this patient?
- A. Resting and splinting
- B. Aspiration and compression bandage
- C. Total ankle replacement (Correct Answer)
- D. Ankle arthrodesis
Explanation: ### **Explanation** The clinical presentation of a diabetic patient with a swollen, effused ankle, minimal pain despite severe radiological destruction (osteopenia, osteophytosis, and loose bodies), is classic for **Charcot’s Arthropathy (Neuropathic Joint)**. #### **Why Total Ankle Replacement (TAR) is NOT recommended:** Total Ankle Replacement is **contraindicated** in Charcot’s neuroarthropathy. The underlying pathology involves a loss of protective sensation and autonomic dysfunction, leading to repetitive microtrauma and bone collapse. Because the bone quality is poor (severe osteopenia/destruction) and the joint is unstable due to ligamentous laxity, a prosthetic implant would lack the necessary structural support, leading to early loosening, periprosthetic fracture, and high rates of infection or amputation. #### **Analysis of Other Options:** * **Resting and splinting (A):** This is the cornerstone of management during the acute (Eichenholtz Stage 0 or I) phase to prevent further bone destruction and deformity. * **Aspiration and compression bandage (B):** Used to manage significant joint effusion and reduce swelling, which helps in decreasing inflammatory markers and improving skin integrity. * **Ankle arthrodesis (D):** While challenging, surgical fusion (arthrodesis) is a recognized treatment for late-stage, unstable Charcot joints to provide a stable, plantigrade foot, especially when conservative measures fail. #### **Clinical Pearls for NEET-PG:** * **The "6 D’s" of Charcot Joint:** Destruction, Debris, Density (increased/sclerosis), Disorganization, Dislocation, and Distension. * **Most common cause:** Diabetes Mellitus (affects foot/ankle). Other causes include Syphilis (Tabes dorsalis - affects knee) and Syringomyelia (affects shoulder/elbow). * **Clinical Paradox:** The hallmark is the **disparity** between the severe radiographic destruction and the relatively painless clinical presentation. * **Treatment Goal:** The primary goal is a stable, infection-free, plantigrade foot; mobility (via replacement) is sacrificed for stability.
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