Tissue Engineering in Orthopaedics Indian Medical PG Practice Questions and MCQs
Practice Indian Medical PG questions for Tissue Engineering in Orthopaedics. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Tissue Engineering in Orthopaedics Indian Medical PG Question 1: Which of the following is the POOREST recipient bed for a skin graft?
- A. Fat (Correct Answer)
- B. Muscle
- C. Deep fascia
- D. Skull bone
Tissue Engineering in Orthopaedics Explanation: ***Fat***
- **Fat** is a poor recipient for a skin graft due to its **limited vascularity**, which hinders the necessary process of revascularization for graft survival.
- The high metabolic demand of a graft cannot be adequately met by the relatively avascular subcutaneous fat, leading to graft failure.
*Muscle*
- **Muscle tissue** is an excellent recipient bed for skin grafts due to its **rich blood supply**.
- Its robust vascularity effectively supports the revascularization and survival of the grafted tissue.
*Deep fascia*
- **Deep fascia** provides a good vascularized bed for skin grafts, as it has a reasonable blood supply from underlying muscles and surrounding tissues.
- This vascularization is sufficient to nourish and ensure the take of a skin graft.
*Skull bone*
- **Skull bone** (specifically the periosteum covering it) can serve as an adequate graft bed due to its vascular supply.
- If the **periosteum** is intact and healthy, it offers sufficient blood flow for graft survival.
Tissue Engineering in Orthopaedics Indian Medical PG Question 2: Which type of collagen is most abundant in hyaline cartilage?
- A. Type I
- B. Type II (Correct Answer)
- C. Type III
- D. Type IV
Tissue Engineering in Orthopaedics Explanation: ***Type II***
- **Type II collagen** is the predominant type found in **hyaline cartilage**, providing tensile strength and elasticity [1].
- It is crucial for the **structural integrity** and functionality of cartilage in articular surfaces [1].
*Type I*
- Predominantly found in **bone**, tendons, and skin, contributing to tensile strength but not a major component of hyaline cartilage [2].
- It forms the structure of **fibrocartilage**, such as in the **intervertebral discs**.
*Type IV*
- Mainly located in **basement membranes** and plays a role in filtration and structural support of epithelial cells, not in hyaline cartilage.
- It is critical in the formation of structures like **glomeruli** in kidneys, differing from cartilage's needs.
*Type III*
- Found in **reticular fibers** and supporting tissues throughout the body, important for organ structure but not prominent in hyaline cartilage.
- Often associated with **vascular structures** and is not involved in the composition of cartilage.
Tissue Engineering in Orthopaedics Indian Medical PG Question 3: All of the following factors affect osseointegration EXCEPT:
- A. Biocompatibility of implant material.
- B. Implant design.
- C. Patient's blood type (Correct Answer)
- D. Status of the host bed.
Tissue Engineering in Orthopaedics Explanation: ***Patient's blood type***
- A patient's **blood type** (e.g., A, B, AB, O) is determined by antigens present on red blood cells and plays no direct role in the biological processes of bone healing or the integration of a dental implant with bone.
- While systemic factors can influence osseointegration, blood type itself does not affect the cellular and molecular mechanisms required for direct bone-to-implant contact.
*Biocompatibility of implant material*
- The **biocompatibility** of the implant material (e.g., **titanium**) is crucial for osseointegration, as it must not elicit adverse reactions and must permit host bone growth on its surface.
- Materials that are cytotoxic or inflammatory will prevent bone apposition and lead to fibrous encapsulation rather than direct bone contact.
*Implant design*
- **Implant design**, including features like **surface roughness**, thread pitch, and macro-geometry, significantly influences the initial stability and long-term success of osseointegration.
- A greater surface area and appropriate surface treatments can enhance bone cell attachment and differentiation, promoting faster and stronger bone integration.
*Status of the host bed*
- The **status of the host bone bed** refers to its quality and quantity (e.g., bone density, vascularity), which are critical for the biological processes of osseointegration.
- Adequate bone volume and good bone quality provide a stable foundation and sufficient blood supply for bone regeneration around the implant.
Tissue Engineering in Orthopaedics Indian Medical PG Question 4: Functional matrix theory suggests that the primary determinants of growth of skeletal tissues reside in:
- A. Cartilages
- B. Sutures
- C. Skeletal
- D. Non-skeletal tissues (Correct Answer)
Tissue Engineering in Orthopaedics Explanation: ***Non-skeletal tissues***
- The **functional matrix theory** posits that the growth and development of skeletal tissues, particularly in the craniofacial region, are primarily determined by the surrounding soft tissues and their functions. [1]
- These **non-skeletal tissues**, such as muscles, nerves, blood vessels, and fat, exert forces and provide stimuli that dictate the growth and remodeling of adjacent bones.
*Cartilages*
- While **cartilage** (e.g., condylar cartilage of the mandible) is a significant growth center, the functional matrix theory suggests its growth is still influenced by surrounding functional demands, not solely intrinsic factors.
- Cartilage growth alone does not entirely explain the comprehensive craniofacial growth patterns according to this theory.
*Sutures*
- **Sutures** are important growth sites in the cranium and maxilla, contributing to bone apposition and separation. [1]
- However, the functional matrix theory views sutural growth as a secondary event, responding to the expansive forces generated by the growth of underlying soft tissues and functional spaces.
*Skeletal*
- The functional matrix theory explicitly argues against the idea that **skeletal tissues** themselves (bones and cartilage) are the primary determinants of their own growth.
- Instead, it emphasizes that skeletal growth is adaptive and reactive to the influences of the associated non-skeletal tissues and their functions.
Tissue Engineering in Orthopaedics Indian Medical PG Question 5: Which of the following has the greatest concentration of osteogenic cells?
- A. Marrow- cancellous graft. (Correct Answer)
- B. Marrow- cortical graft.
- C. Costochondral graft.
- D. Cortical graft
Tissue Engineering in Orthopaedics Explanation: ***Marrow- cancellous graft***
- **Cancellous bone** contains a high concentration of **bone marrow**, which is rich in **osteogenic stem cells** and growth factors essential for bone formation.
- These cells contribute significantly to **osteogenesis**, making cancellous grafts potent for bone healing and fusion.
*Marrow- cortical graft*
- While cortical grafts provide structural support, the **bone marrow** within them is less abundant and less readily accessible compared to cancellous grafts.
- The primary contribution of a cortical graft with marrow is **mechanical strength**, with less emphasis on osteogenic cell concentration.
*Costochondral graft*
- A costochondral graft includes both **cartilage** and bone, making it useful for specific reconstructions, such as mandibular condyle regeneration.
- However, its primary osteogenic potential comes from the osseous component, which typically has a lower concentration of osteogenic cells compared to a cancellous bone graft.
*Cortical graft*
- **Cortical bone** is dense and provides significant **structural support**, but it contains very few **osteogenic cells** and has limited intrinsic capacity for new bone formation.
- Its main roles are providing **load-bearing strength** and acting as a scaffold, rather than contributing a high concentration of osteogenic cells.
Tissue Engineering in Orthopaedics Indian Medical PG Question 6: During reconstruction of an amputated limb which of the following is done first?
- A. Arterial repair
- B. Venous repair
- C. Fixation of the bone (Correct Answer)
- D. Nerve anastomoses
Tissue Engineering in Orthopaedics Explanation: ***Fixation of the bone***
- **Bone stabilization** is the crucial first step to create a rigid framework, allowing for subsequent precise vascular and nerve repairs.
- This prevents movement and tension on delicate repairs, which could lead to failure of the reconnected vessels and nerves.
*Arterial repair*
- While critical for blood supply, arterial repair is performed *after* bone fixation to ensure the vessels are not disrupted by later bone manipulation.
- It's typically done before venous repair to establish arterial flow and identify any potential venous back pressure that needs addressing.
*Venous repair*
- Venous repair is usually performed after arterial repair, as establishing arterial inflow can help distend the veins, making them easier to identify and repair.
- Repairing veins first without establishing arterial flow immediately is less effective and may lead to congestion once arterial flow is restored.
*Nerve anastomoses*
- Nerve repair is typically the last major step in an amputation reconstruction, following bone stabilization and full vascular repair.
- Nerves are fragile and require a stable, well-perfused environment to optimize the chances of successful regeneration.
Tissue Engineering in Orthopaedics Indian Medical PG Question 7: Primary osteoarthritis affects all except:
- A. Metacarpophalangeal joint (Correct Answer)
- B. Hip Joint
- C. Distal interphalangeal joint
- D. Knee joint
Tissue Engineering in Orthopaedics 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.
Tissue Engineering in Orthopaedics Indian Medical PG Question 8: Which of the following is the commonest material used to make an orthopedic implant?
- A. Methyl-methacrylate
- B. Polyethylene (UHMWPE)
- C. Titanium (Correct Answer)
- D. Stainless steel
Tissue Engineering in Orthopaedics Explanation: ***Titanium***
- **Titanium** and its alloys (e.g., Ti-6Al-4V) are widely favored for orthopedic implants due to their **excellent biocompatibility**, high strength-to-weight ratio, and corrosion resistance.
- Its **osseointegrative properties** allow bone to grow directly onto the implant surface, providing stable fixation without an intervening fibrous layer.
*Methyl-methacrylate*
- **Methyl-methacrylate** is primarily used as a **bone cement** (PMMA) to fix implants to bone, rather than as the primary material for the implant itself.
- It provides immediate mechanical stability but does not integrate with bone.
*Polyethylene (UHMWPE)*
- **Ultra-high molecular weight polyethylene (UHMWPE)** is commonly used as a bearing surface in joint replacements (e.g., acetabular liner in hip replacements) for its **low friction** and good wear resistance.
- It is not typically used for the structural components of the implant that bear the primary load.
*Stainless steel*
- **Stainless steel** (e.g., 316L) was historically a common implant material, particularly for temporary fixation devices like plates and screws.
- While it has good strength and corrosion resistance, it generally has a **lower biocompatibility** and more elastic modulus mismatch with bone compared to titanium, making it less preferred for permanent, load-bearing implants.
Tissue Engineering in Orthopaedics Indian Medical PG Question 9: Healing of bone is affected by:
- A. Hypoxia
- B. Micromovement
- C. Muscle interposition
- D. All of the options (Correct Answer)
Tissue Engineering in Orthopaedics Explanation: ***All of the options***
- **Hypoxia**, **micromovement**, and **muscle interposition** are all factors known to impede or negatively affect the normal healing process of a bone fracture.
- The successful healing of a bone fracture relies on a series of biological events that can be disrupted by these adverse conditions, leading to delayed union or non-union.
*Hypoxia*
- **Hypoxia**, or insufficient oxygen supply, impairs the metabolic activity of cells essential for bone healing, such as osteoblasts and chondrocytes.
- It interferes with **angiogenesis**, the formation of new blood vessels, which is critical for delivering nutrients and oxygen to the healing bone.
*Micromovement*
- Excessive **micromovement** at the fracture site prevents the formation of a stable callus and can stimulate the development of fibrous tissue or cartilage instead of bone.
- While some motion is beneficial, uncontrolled or excessive micromotion can lead to a **non-union** or pseudarthrosis, as it constantly disrupts the delicate tissue bridges attempting to form.
*Muscle interposition*
- **Muscle interposition** refers to muscle tissue becoming trapped between the bone fragments, physically separating them and preventing direct bone-to-bone contact.
- This physical barrier inhibits the formation of the **fracture hematoma** and subsequent callus, thus mechanically hindering the healing process.
Tissue Engineering in Orthopaedics Indian Medical PG Question 10: In articular cartilage, most active chondrocytes are seen in ?
- A. Zone 1
- B. Zone 4
- C. Zone 2 (Correct Answer)
- D. Zone 3
Tissue Engineering in Orthopaedics Explanation: ***Zone 2***
- The **transitional zone (Zone 2)** contains chondrocytes that are more metabolically active and contribute significantly to **collagen and proteoglycan synthesis**. [1]
- These chondrocytes are typically **larger and more rounded** than those in the superficial layer and are organized in columns.
*Zone 1*
- **Zone 1 (superficial or tangential zone)** consists of **flattened chondrocytes** that are metabolically less active.
- Its primary role is to resist **shear forces** and reduce friction. [1]
*Zone 4*
- **Zone 4 (calcified zone)** is the deepest layer of articular cartilage, characterized by **chondrocytes embedded in a calcified matrix**.
- This zone anchors the cartilage to the subchondral bone and has **minimal metabolic activity**.
*Zone 3*
- **Zone 3 (deep or radial zone)** has chondrocytes arranged in **columns perpendicular to the articular surface**. [1]
- While active in matrix production, their activity is generally **less pronounced** compared to the transitional zone.
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