Degenerative Disorders — MCQs

Q: Frieberg's disease involves which of the following?

2nd metatarsal. **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.

Q: What is the deformity most commonly seen in primary osteoarthritis of the knee joint?

Genu varus. ### Explanation **Correct Answer: C. Genu varus** In primary osteoarthritis (OA) of the knee, the **medial compartment** is the most common site of cartilage degeneration. This occurs because the mechanical axis of the lower limb normally passes slightly medial to the center of the knee joint, causing the medial compartment to bear approximately 60-70% of the load during walking. As the medial articular cartilage thins and the joint space narrows, the tibia tilts medially relative to the femur, resulting in a **bow-legged** appearance known as **Genu varus**. **Analysis of Incorrect Options:** * **A. Genu valgum (Knock-knees):** This is less common in primary OA. It occurs when the lateral compartment undergoes preferential degeneration. It is more frequently associated with Rheumatoid Arthritis or secondary OA. * **B. Genu recurvatum:** This refers to hyperextension of the knee. It is typically caused by ligamentous laxity (e.g., polio, Ehlers-Danlos syndrome) or quadriceps weakness, rather than primary degenerative changes. * **D. Procurvatum:** This is a forward bowing of the bone (fixed flexion deformity). While OA can lead to a fixed flexion deformity due to posterior capsular contracture, "Genu varus" is the classic coronal plane deformity described. **Clinical Pearls for NEET-PG:** * **Kellgren-Lawrence Grading:** The standard radiological classification for OA (Grade 0-4), based on joint space narrowing, osteophytes, and sclerosis. * **First Sign on X-ray:** Often subchondral sclerosis or small osteophytes; however, joint space narrowing is the hallmark. * **Management:** High Tibial Osteotomy (HTO) is a high-yield surgical option for young, active patients with isolated medial compartment OA and varus deformity to realign the weight-bearing axis. * **Heberden’s Nodes:** Found at the DIP joints (characteristic of primary OA).

Q: Stress fracture occurs most commonly in which of the following bones?

Metatarsals. **Explanation:** A **stress fracture** (also known as a fatigue fracture) occurs due to repetitive mechanical stress or rhythmic muscle action on a bone that has not had time to adapt to the load. Unlike traumatic fractures, these result from cumulative micro-trauma. **Why Metatarsals are correct:** The **metatarsals** are the most common site for stress fractures in the human body, specifically the **second and third metatarsals**. This is because they are relatively thin and rigid compared to the first metatarsal, bearing significant weight during the "toe-off" phase of the gait cycle. When occurring in the metatarsal shaft, it is classically referred to as a **"March Fracture,"** historically associated with military recruits or long-distance runners. **Analysis of Incorrect Options:** * **Metacarpals:** These are rare sites for stress fractures as they are not weight-bearing bones. * **Calcaneum:** This is the **second most common** site for stress fractures. It typically presents with heel pain aggravated by the "squeeze test" (mediolateral compression of the calcaneus). * **Talus:** While stress fractures can occur in the talar neck or body (often in athletes), they are significantly less common than those in the metatarsals or calcaneum. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site overall:** 2nd Metatarsal (March Fracture). * **Most common site in athletes:** Tibia (specifically the junction of the middle and lower thirds). * **Investigation of Choice:** **MRI** is the most sensitive and specific early investigation (shows marrow edema). * **X-ray findings:** Often negative in the first 2–3 weeks; later shows a faint hairline crack or exuberant callus formation. * **Female Athlete Triad:** Amenorrhea, disordered eating, and osteoporosis significantly increase the risk of stress fractures.

Q: A 74-year-old woman presents with a months-long history of pain in her right hand and lower back, which is worsening and interfering with her daily activities. The pain increases as the day progresses. She denies any history of trauma and is otherwise healthy. Over-the-counter acetaminophen usually provides relief. On examination, there is soft tissue swelling and tenderness of her second and third distal interphalangeal joints in the right hand, and she experiences pain in her lower back upon forward flexion. There is no erythema or joint effusion in any other joints. What is the most likely explanation for the joint pain in osteoarthritis?

Osteophytes can cause pain.. **Explanation:** The clinical presentation of a 74-year-old with activity-related pain, involvement of the distal interphalangeal (DIP) joints (Heberden’s nodes), and lower back pain without systemic symptoms is classic for **Osteoarthritis (OA)**. **Why Option D is Correct:** In OA, the articular cartilage is aneural (lacks nerves). Therefore, the pain does not originate from the cartilage itself but from secondary structural changes. **Osteophytes** (bony outgrowths) are a hallmark of OA; they cause pain by stretching the periosteum (which is richly innervated) and by causing mechanical impingement on surrounding soft tissues and nerves. **Analysis of Incorrect Options:** * **Option A:** While OA is primarily degenerative, **secondary synovitis** (synovial inflammation) often occurs due to the release of cartilage breakdown products into the joint space, contributing significantly to the pain. * **Option B:** While ligaments can be strained due to joint instability, "ligament inflammation" is not the primary or most common driver of pain in OA compared to subchondral and periosteal changes. * **Option C:** While **microfractures** of the subchondral bone (due to loss of shock-absorbing cartilage) are a known source of pain, "clinically visible fractures" (macro-fractures) are not a standard feature of OA. **NEET-PG High-Yield Pearls:** * **Nodal Involvement:** DIP joints (Heberden’s nodes) and PIP joints (Bouchard’s nodes) are characteristic. The MCP joints are typically spared (unlike Rheumatoid Arthritis). * **Pain Pattern:** Mechanical pain (worsens with use, improves with rest). * **Radiological Hallmarks (LOSS):** **L**oss of joint space, **O**steophytes, **S**ubchondral sclerosis, and **S**ubchondral cysts. * **First-line Management:** Weight loss, physical therapy, and Acetaminophen (as seen in this patient).

Q: Which compartment of the knee is most commonly involved in osteoarthritis?

Medial compartment. **Explanation:** **1. Why the Medial Compartment is Correct:** The knee joint consists of three compartments: medial tibiofemoral, lateral tibiofemoral, and patellofemoral. In the normal standing position (neutral alignment), the mechanical axis of the lower limb passes slightly medial to the center of the knee joint. Consequently, approximately **60–70% of the weight-bearing load** is transmitted through the **medial compartment**. This chronic mechanical stress leads to accelerated wear and tear of the articular cartilage, making it the most common site for primary osteoarthritis. **2. Analysis of Incorrect Options:** * **Lateral Compartment:** This compartment bears significantly less load than the medial side. Isolated lateral compartment OA is less common and is often associated with a valgus (knock-knee) deformity. * **Medial and Lateral Compartments:** While "tricompartmental" OA occurs in advanced stages, the disease typically **starts** in a single compartment. The medial compartment is almost always the initial site of involvement. * **Patellofemoral Compartment:** While frequently involved (especially in activities like climbing stairs), it is rarely the *most* common or isolated site compared to the medial tibiofemoral joint in primary OA. **3. Clinical Pearls for NEET-PG:** * **Deformity:** Medial compartment OA leads to loss of joint space medially, resulting in **Genu Varum** (Bow-leg deformity). * **Radiological Hallmarks:** Look for the "LOSS" mnemonic: **L**oss of joint space, **O**steophytes, **S**ubchondral sclerosis, and **S**ubchondral cysts. * **Kellgren-Lawrence Grading:** This is the standard radiological classification used to assess the severity of Knee OA. * **Management:** High Tibial Osteotomy (HTO) is a surgical option specifically designed to shift weight from the diseased medial compartment to the healthy lateral compartment in young, active patients.

Q: Osteoarthritis involves which of the following joints except?

Wrist. ### Explanation **Core Concept:** Osteoarthritis (OA) is a degenerative joint disease that primarily affects **weight-bearing joints** and specific small joints of the hand. A key diagnostic feature of primary OA is that it **spares the wrist, elbow, and shoulder** unless there is a history of trauma or a specific occupational predisposition. **Why the Wrist is the Correct Answer:** The wrist joint is generally **not** involved in primary osteoarthritis. If a patient presents with wrist arthritis, clinicians should suspect secondary causes such as **Rheumatoid Arthritis** (which typically involves the wrist), trauma (SLAC lesion), or metabolic conditions like CPPD (Pseudogout). The only exception in the wrist region is the **first carpometacarpal (CMC) joint** (base of the thumb), which is a very common site for OA. **Analysis of Incorrect Options:** * **Hip (A) & Knee (B):** These are the most common large, weight-bearing joints affected by OA due to mechanical stress and cartilage wear over time. * **PIP Joint (C):** Small joints of the hands are frequently involved in primary OA. Involvement of the PIP joints leads to palpable osteophytes known as **Bouchard’s nodes**, while involvement of the Distal Interphalangeal (DIP) joints leads to **Heberden’s nodes**. **NEET-PG High-Yield Pearls:** * **Nodal Involvement:** DIP (Heberden’s) > PIP (Bouchard’s) > First CMC joint. * **Joint Sparing:** Primary OA characteristically spares the **Wrist, Elbow, and Ankle**. * **Radiological Hallmarks (LOSS):** **L**oss of joint space, **O**steophytes, **S**ubchondral sclerosis, and **S**ubchondral cysts. * **First CMC Joint:** OA here causes a "squared-off" appearance of the hand.

Q: Herberden's arthropathy affects:

Distal interphalangeal joint. **Explanation:** **Heberden’s nodes** are a classic clinical hallmark of **Osteoarthritis (OA)**, a degenerative joint disease. They represent bony overgrowths (osteophytes) that occur at the **Distal Interphalangeal (DIP) joints** of the fingers. These nodes result from repeated cartilaginous damage and subsequent reactive bone formation, often leading to a characteristic "knobby" appearance of the fingers. **Analysis of Options:** * **Distal Interphalangeal (DIP) Joint (Correct):** This is the primary site for Heberden’s nodes. In contrast, similar bony enlargements at the **Proximal Interphalangeal (PIP) joints** are known as **Bouchard’s nodes**. * **Lumbar Spine:** While OA commonly affects the lumbar spine (spondylosis), the specific eponymous term "Heberden's" is reserved for the DIP joints. * **Sacroiliac Joint:** This joint is typically involved in Seronegative Spondyloarthropathies (like Ankylosing Spondylitis), not primary nodal OA. * **Knee Joint:** The knee is the most common large joint affected by OA, but its involvement is characterized by joint space narrowing and osteophytes, not Heberden's nodes. **High-Yield Clinical Pearls for NEET-PG:** 1. **Nodal OA:** Heberden’s nodes are more common in women and often have a strong genetic predisposition. 2. **Symmetry:** These nodes are typically bilateral and symmetrical. 3. **Differentiating RA vs. OA:** Rheumatoid Arthritis (RA) characteristically **spares the DIP joints**, whereas OA frequently involves them. 4. **First Carpometacarpal (CMC) Joint:** This is another high-yield site for OA in the hand, leading to a "squared" appearance of the hand base.

A 74-year-old woman presents with a months-long history of pain in her right hand and lower back, which is worsening and interfering with her daily activities. The pain increases as the day progresses. She denies any history of trauma and is otherwise healthy. Over-the-counter acetaminophen usually provides relief. On examination, there is soft tissue swelling and tenderness of her second and third distal interphalangeal joints in the right hand, and she experiences pain in her lower back upon forward flexion. There is no erythema or joint effusion in any other joints. What is the most likely explanation for the joint pain in osteoarthritis?

Q7Easy

Which compartment of the knee is most commonly involved in osteoarthritis?

Q8Easy

Eburnation is seen in which of the following conditions?

Q9Easy

Osteoarthritis involves which of the following joints except?

Q10Easy

Herberden's arthropathy affects:

Degenerative Disorders Indian Medical PG Practice Questions and MCQs

Question 1: 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 2: 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 3: 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.

Question 4: What is the deformity most commonly seen in primary osteoarthritis of the knee joint?

A. Genu valgum
B. Genu recurvatum
C. Genu varus (Correct Answer)
D. Procurvatum

Explanation: ### Explanation **Correct Answer: C. Genu varus** In primary osteoarthritis (OA) of the knee, the **medial compartment** is the most common site of cartilage degeneration. This occurs because the mechanical axis of the lower limb normally passes slightly medial to the center of the knee joint, causing the medial compartment to bear approximately 60-70% of the load during walking. As the medial articular cartilage thins and the joint space narrows, the tibia tilts medially relative to the femur, resulting in a **bow-legged** appearance known as **Genu varus**. **Analysis of Incorrect Options:** * **A. Genu valgum (Knock-knees):** This is less common in primary OA. It occurs when the lateral compartment undergoes preferential degeneration. It is more frequently associated with Rheumatoid Arthritis or secondary OA. * **B. Genu recurvatum:** This refers to hyperextension of the knee. It is typically caused by ligamentous laxity (e.g., polio, Ehlers-Danlos syndrome) or quadriceps weakness, rather than primary degenerative changes. * **D. Procurvatum:** This is a forward bowing of the bone (fixed flexion deformity). While OA can lead to a fixed flexion deformity due to posterior capsular contracture, "Genu varus" is the classic coronal plane deformity described. **Clinical Pearls for NEET-PG:** * **Kellgren-Lawrence Grading:** The standard radiological classification for OA (Grade 0-4), based on joint space narrowing, osteophytes, and sclerosis. * **First Sign on X-ray:** Often subchondral sclerosis or small osteophytes; however, joint space narrowing is the hallmark. * **Management:** High Tibial Osteotomy (HTO) is a high-yield surgical option for young, active patients with isolated medial compartment OA and varus deformity to realign the weight-bearing axis. * **Heberden’s Nodes:** Found at the DIP joints (characteristic of primary OA).

Question 5: Stress fracture occurs most commonly in which of the following bones?

A. Metatarsals (Correct Answer)
B. Metacarpals
C. Calcaneum
D. Talus

Explanation: **Explanation:** A **stress fracture** (also known as a fatigue fracture) occurs due to repetitive mechanical stress or rhythmic muscle action on a bone that has not had time to adapt to the load. Unlike traumatic fractures, these result from cumulative micro-trauma. **Why Metatarsals are correct:** The **metatarsals** are the most common site for stress fractures in the human body, specifically the **second and third metatarsals**. This is because they are relatively thin and rigid compared to the first metatarsal, bearing significant weight during the "toe-off" phase of the gait cycle. When occurring in the metatarsal shaft, it is classically referred to as a **"March Fracture,"** historically associated with military recruits or long-distance runners. **Analysis of Incorrect Options:** * **Metacarpals:** These are rare sites for stress fractures as they are not weight-bearing bones. * **Calcaneum:** This is the **second most common** site for stress fractures. It typically presents with heel pain aggravated by the "squeeze test" (mediolateral compression of the calcaneus). * **Talus:** While stress fractures can occur in the talar neck or body (often in athletes), they are significantly less common than those in the metatarsals or calcaneum. **High-Yield Clinical Pearls for NEET-PG:** * **Most common site overall:** 2nd Metatarsal (March Fracture). * **Most common site in athletes:** Tibia (specifically the junction of the middle and lower thirds). * **Investigation of Choice:** **MRI** is the most sensitive and specific early investigation (shows marrow edema). * **X-ray findings:** Often negative in the first 2–3 weeks; later shows a faint hairline crack or exuberant callus formation. * **Female Athlete Triad:** Amenorrhea, disordered eating, and osteoporosis significantly increase the risk of stress fractures.

Question 6: A 74-year-old woman presents with a months-long history of pain in her right hand and lower back, which is worsening and interfering with her daily activities. The pain increases as the day progresses. She denies any history of trauma and is otherwise healthy. Over-the-counter acetaminophen usually provides relief. On examination, there is soft tissue swelling and tenderness of her second and third distal interphalangeal joints in the right hand, and she experiences pain in her lower back upon forward flexion. There is no erythema or joint effusion in any other joints. What is the most likely explanation for the joint pain in osteoarthritis?

A. Synovial inflammation is not the cause of pain.
B. Ligament inflammation is a common cause of pain.
C. Clinically visible fractures are a common cause of pain.
D. Osteophytes can cause pain. (Correct Answer)

Explanation: **Explanation:** The clinical presentation of a 74-year-old with activity-related pain, involvement of the distal interphalangeal (DIP) joints (Heberden’s nodes), and lower back pain without systemic symptoms is classic for **Osteoarthritis (OA)**. **Why Option D is Correct:** In OA, the articular cartilage is aneural (lacks nerves). Therefore, the pain does not originate from the cartilage itself but from secondary structural changes. **Osteophytes** (bony outgrowths) are a hallmark of OA; they cause pain by stretching the periosteum (which is richly innervated) and by causing mechanical impingement on surrounding soft tissues and nerves. **Analysis of Incorrect Options:** * **Option A:** While OA is primarily degenerative, **secondary synovitis** (synovial inflammation) often occurs due to the release of cartilage breakdown products into the joint space, contributing significantly to the pain. * **Option B:** While ligaments can be strained due to joint instability, "ligament inflammation" is not the primary or most common driver of pain in OA compared to subchondral and periosteal changes. * **Option C:** While **microfractures** of the subchondral bone (due to loss of shock-absorbing cartilage) are a known source of pain, "clinically visible fractures" (macro-fractures) are not a standard feature of OA. **NEET-PG High-Yield Pearls:** * **Nodal Involvement:** DIP joints (Heberden’s nodes) and PIP joints (Bouchard’s nodes) are characteristic. The MCP joints are typically spared (unlike Rheumatoid Arthritis). * **Pain Pattern:** Mechanical pain (worsens with use, improves with rest). * **Radiological Hallmarks (LOSS):** **L**oss of joint space, **O**steophytes, **S**ubchondral sclerosis, and **S**ubchondral cysts. * **First-line Management:** Weight loss, physical therapy, and Acetaminophen (as seen in this patient).

Question 7: Which compartment of the knee is most commonly involved in osteoarthritis?

A. Medial compartment (Correct Answer)
B. Lateral compartment
C. Medial and lateral compartments
D. Patellofemoral compartment

Explanation: **Explanation:** **1. Why the Medial Compartment is Correct:** The knee joint consists of three compartments: medial tibiofemoral, lateral tibiofemoral, and patellofemoral. In the normal standing position (neutral alignment), the mechanical axis of the lower limb passes slightly medial to the center of the knee joint. Consequently, approximately **60–70% of the weight-bearing load** is transmitted through the **medial compartment**. This chronic mechanical stress leads to accelerated wear and tear of the articular cartilage, making it the most common site for primary osteoarthritis. **2. Analysis of Incorrect Options:** * **Lateral Compartment:** This compartment bears significantly less load than the medial side. Isolated lateral compartment OA is less common and is often associated with a valgus (knock-knee) deformity. * **Medial and Lateral Compartments:** While "tricompartmental" OA occurs in advanced stages, the disease typically **starts** in a single compartment. The medial compartment is almost always the initial site of involvement. * **Patellofemoral Compartment:** While frequently involved (especially in activities like climbing stairs), it is rarely the *most* common or isolated site compared to the medial tibiofemoral joint in primary OA. **3. Clinical Pearls for NEET-PG:** * **Deformity:** Medial compartment OA leads to loss of joint space medially, resulting in **Genu Varum** (Bow-leg deformity). * **Radiological Hallmarks:** Look for the "LOSS" mnemonic: **L**oss of joint space, **O**steophytes, **S**ubchondral sclerosis, and **S**ubchondral cysts. * **Kellgren-Lawrence Grading:** This is the standard radiological classification used to assess the severity of Knee OA. * **Management:** High Tibial Osteotomy (HTO) is a surgical option specifically designed to shift weight from the diseased medial compartment to the healthy lateral compartment in young, active patients.

Question 8: Eburnation is seen in which of the following conditions?

A. Malunion
B. Non-union (Correct Answer)
C. Osteomyelitis
D. Osteoradionecrosis

Explanation: **Explanation:** **Eburnation** refers to a degenerative process where the bone ends become dense, smooth, and polished, resembling ivory. This occurs due to constant friction between two bony surfaces that have lost their protective cartilage or soft tissue covering. **Why Non-union is the correct answer:** In an **atrophic or established non-union** (specifically a "pseudoarthrosis" or false joint), the fracture ends fail to unite. Persistent abnormal mobility at the fracture site leads to constant rubbing of the bone ends against each other. Over time, this mechanical friction causes the bone to become sclerotic, smooth, and ivory-like (eburnation). This is a hallmark pathological feature of a long-standing non-union where a fluid-filled cavity may even form between the bone ends. **Analysis of Incorrect Options:** * **Malunion:** This refers to a fracture that has healed, but in an anatomically incorrect position (e.g., with angulation or rotation). Since the bone is united, there is no friction between bone ends, and thus no eburnation. * **Osteomyelitis:** This is an infection of the bone characterized by the formation of a *sequestrum* (dead bone) and *involucrum* (new bone). It involves suppuration and necrosis, not the mechanical polishing seen in eburnation. * **Osteoradionecrosis:** This is bone death caused by radiation therapy, leading to vascular insufficiency. It presents with bone fragility and sequestration, not friction-induced polishing. **NEET-PG High-Yield Pearls:** * **Eburnation** is most commonly associated with **Osteoarthritis (OA)** due to the loss of articular cartilage and subchondral bone rubbing. * In the context of fractures, eburnation is the defining feature of **Pseudoarthrosis** (a type of non-union). * **Radiological sign of Non-union:** Rounding off and sclerosis of fracture ends with closure of the medullary canal. * **Treatment of Non-union with eburnation:** Requires freshening of the bone ends (removing the eburnated bone), opening the medullary canal, and bone grafting.

Question 9: Osteoarthritis involves which of the following joints except?

A. Hip
B. Knee
C. Proximal Interphalangeal (PIP) joint
D. Wrist (Correct Answer)

Explanation: ### Explanation **Core Concept:** Osteoarthritis (OA) is a degenerative joint disease that primarily affects **weight-bearing joints** and specific small joints of the hand. A key diagnostic feature of primary OA is that it **spares the wrist, elbow, and shoulder** unless there is a history of trauma or a specific occupational predisposition. **Why the Wrist is the Correct Answer:** The wrist joint is generally **not** involved in primary osteoarthritis. If a patient presents with wrist arthritis, clinicians should suspect secondary causes such as **Rheumatoid Arthritis** (which typically involves the wrist), trauma (SLAC lesion), or metabolic conditions like CPPD (Pseudogout). The only exception in the wrist region is the **first carpometacarpal (CMC) joint** (base of the thumb), which is a very common site for OA. **Analysis of Incorrect Options:** * **Hip (A) & Knee (B):** These are the most common large, weight-bearing joints affected by OA due to mechanical stress and cartilage wear over time. * **PIP Joint (C):** Small joints of the hands are frequently involved in primary OA. Involvement of the PIP joints leads to palpable osteophytes known as **Bouchard’s nodes**, while involvement of the Distal Interphalangeal (DIP) joints leads to **Heberden’s nodes**. **NEET-PG High-Yield Pearls:** * **Nodal Involvement:** DIP (Heberden’s) > PIP (Bouchard’s) > First CMC joint. * **Joint Sparing:** Primary OA characteristically spares the **Wrist, Elbow, and Ankle**. * **Radiological Hallmarks (LOSS):** **L**oss of joint space, **O**steophytes, **S**ubchondral sclerosis, and **S**ubchondral cysts. * **First CMC Joint:** OA here causes a "squared-off" appearance of the hand.

Question 10: Herberden's arthropathy affects:

A. Lumbar spine
B. Sacroiliac joint
C. Distal interphalangeal joint (Correct Answer)
D. Knee joint

Explanation: **Explanation:** **Heberden’s nodes** are a classic clinical hallmark of **Osteoarthritis (OA)**, a degenerative joint disease. They represent bony overgrowths (osteophytes) that occur at the **Distal Interphalangeal (DIP) joints** of the fingers. These nodes result from repeated cartilaginous damage and subsequent reactive bone formation, often leading to a characteristic "knobby" appearance of the fingers. **Analysis of Options:** * **Distal Interphalangeal (DIP) Joint (Correct):** This is the primary site for Heberden’s nodes. In contrast, similar bony enlargements at the **Proximal Interphalangeal (PIP) joints** are known as **Bouchard’s nodes**. * **Lumbar Spine:** While OA commonly affects the lumbar spine (spondylosis), the specific eponymous term "Heberden's" is reserved for the DIP joints. * **Sacroiliac Joint:** This joint is typically involved in Seronegative Spondyloarthropathies (like Ankylosing Spondylitis), not primary nodal OA. * **Knee Joint:** The knee is the most common large joint affected by OA, but its involvement is characterized by joint space narrowing and osteophytes, not Heberden's nodes. **High-Yield Clinical Pearls for NEET-PG:** 1. **Nodal OA:** Heberden’s nodes are more common in women and often have a strong genetic predisposition. 2. **Symmetry:** These nodes are typically bilateral and symmetrical. 3. **Differentiating RA vs. OA:** Rheumatoid Arthritis (RA) characteristically **spares the DIP joints**, whereas OA frequently involves them. 4. **First Carpometacarpal (CMC) Joint:** This is another high-yield site for OA in the hand, leading to a "squared" appearance of the hand base.

Practice by Chapter

Osteoarthritis: Pathophysiology

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Osteoarthritis of Hip

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Osteoarthritis of Knee

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Osteoarthritis of Shoulder

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Osteoarthritis of Ankle and Foot

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Degenerative Spinal Conditions

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Conservative Management of Degenerative Disorders

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Pharmacotherapy of Osteoarthritis

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Surgical Options for Osteoarthritis

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Rehabilitation in Degenerative Disorders

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Novel Therapies in Osteoarthritis

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Quality of Life Assessment

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