Basic Science in Orthopaedics Practice Questions

Q: Tinel's sign is checking the regeneration of

Traumatised or sutured nerve. ***Traumatised or sutured nerve*** - **Tinel's sign** is a clinical test used to assess for nerve regeneration or irritation following injury or repair. - Percussion over the course of a damaged nerve elicits a **tingling sensation** or "pins and needles" in its distribution if regeneration is occurring or if the nerve is compressed. *Ruptured artery* - A ruptured artery is assessed through signs like **pulsatile bleeding**, **hematoma formation**, or **loss of distal pulses**, not by eliciting tingling sensations. - Management typically involves **surgical repair** or **ligation** to control hemorrhage and restore blood flow. *Vein rupture* - **Vein ruptures** typically present with non-pulsatile bleeding, hematoma, or visible bruising. - They are usually assessed with clinical signs and sometimes imaging, not through neurological percussion tests. *All of the options* - **Tinel's sign** is specifically associated with nerve pathology and regeneration, not vascular injuries. - The distinct clinical presentations and diagnostic approaches for arterial and venous injuries differ significantly from those for nerve damage.

Q: Healing of bone is affected by:

All of the options. ***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.

Q: Which of the following nerves has the best prognosis for repair after injury ?

Radial. ***Correct: Radial*** - The **radial nerve has the best prognosis** for repair among peripheral nerves after injury - It is predominantly a **motor nerve** with a relatively simple sensory distribution (posterior arm, forearm, and dorsal hand) - **Motor recovery is more predictable** compared to complex mixed nerves - Its **anatomical course** and branching pattern allow for better surgical access and repair outcomes - Literature consistently shows **better functional recovery rates** following radial nerve repair *Incorrect: Median* - The **median nerve** is a **complex mixed nerve** with extensive sensory and motor components - Injury results in loss of **thenar muscle function** and critical sensory loss in palmar digits - While recovery can be good, it is **not superior to radial nerve** due to the complexity of reinnervation required - Recovery of fine motor control and discriminative sensation is often incomplete *Incorrect: Lateral popliteal (Common peroneal)* - The **common peroneal nerve** has one of the **poorest prognoses** among peripheral nerves - Its **superficial location** around the fibular head makes it highly vulnerable to injury - **Long regeneration distances** from injury site to target muscles (foot dorsiflexors and evertors) - Frequently results in **persistent foot drop** even after repair *Incorrect: Ulnar* - The **ulnar nerve** has a **less favorable prognosis**, especially with proximal injuries at the elbow - Supplies **intrinsic hand muscles** requiring precise reinnervation for functional recovery - Injuries often result in **persistent claw hand deformity** and loss of fine motor coordination - **Delayed muscle atrophy** and long distances for regeneration contribute to poor outcomes

Q: Among the following options, which is the most common site of avascular necrosis?

Talus. ***Talus*** - The **talus** is highly susceptible to **avascular necrosis** due to its precarious blood supply, which primarily enters via the **tarsal canal** and **deltoid artery**. - Its large articular surface, about 60% covered by cartilage, limits direct soft tissue attachment and additional vascularity. *Head of the radius* - The **head of the radius** has a relatively robust blood supply from branches of the **radial recurrent artery**, making avascular necrosis less common. - While fractures can compromise local blood flow, it is not considered a primary site for idiopathic avascular necrosis. *Olecranon* - The **olecranon**, part of the ulna, receives a good collateral blood supply from anastomosing branches around the elbow, including the **posterior ulnar recurrent artery**. - Avascular necrosis here is rare and usually associated with severe trauma or specific medical conditions. *Medial condyle of femur* - Avascular necrosis of the **medial femoral condyle** primarily affects the subchondral bone and is often referred to as **osteonecrosis of the knee**. - While it can occur, particularly in older adults, it is less common than avascular necrosis of the talus or femoral head.

Q: All of the following factors affect osseointegration EXCEPT:

Patient's blood type. ***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.

Q: The following classification is used to estimate nerve injury:

Seddons classification. ***Seddons classification*** - The **Seddons classification** is a well-established system for classifying the severity of nerve injuries. - It categorizes nerve injuries into three main types: **neurapraxia**, **axonotmesis**, and **neurotmesis**. *Seddon's and Sunderland classification* - While both **Seddon's** and **Sunderland's classifications** are used for nerve injury, the question asks for "the following classification" implying a single, primary classification. - **Sunderland's classification** is a more detailed, five-grade system, often considered an extension of Seddon's. *Sunderland classification* - The **Sunderland classification** is a valid and widely used system, but it is not the *only* classification and the question implies a single, specific classification in its phrasing. - Sunderland's system provides more granular detail on the extent of nerve damage compared to Seddon's, with five degrees of injury. *None of the options* - This option is incorrect because the **Seddons classification** is indeed a valid and frequently used method for estimating nerve injury. - There are established classification systems for nerve injuries.

Q: Healing by Haversian remodeling is a type of:

Primary healing.. ***Primary healing*** - This term refers to **direct healing**, where bone fragments are in contact and movement is minimized, leading to direct bone formation without significant callus. - **Haversian remodeling**, common in rigid internal fixation, is the hallmark of primary bone healing, involving direct osteon formation across the fracture site. *Tertiary healing* - This is **not a recognized term** in the classification of bone healing processes. - Bone healing is generally categorized as primary (direct) or secondary (indirect). *Secondary healing* - This involves the formation of a **soft and then hard callus** in cases of unreduced or mobile fractures. - It is characterized by three overlapping phases: **inflammation, repair**, and **remodeling**, and does not primarily rely on Haversian remodeling. *Intermediate healing* - This is **not a formal classification** of bone healing. - Bone healing is typically dichotomized into primary and secondary healing, depending on the stability and reduction of the fracture.

Q: Following are the common sites of Avascular necrosis, EXCEPT:

Patella. ***Patella*** - The patella is rarely affected by **avascular necrosis (AVN)** due to its robust and redundant blood supply, making it an exception to common AVN sites. - While patellar fractures can compromise local blood flow, spontaneous or atraumatic AVN of the patella is exceedingly uncommon compared to other skeletal sites. *Head of the femur* - The **femoral head** is the most common site for **avascular necrosis** due to its precarious blood supply, especially after trauma (e.g., hip dislocation, femoral neck fracture) or in systemic conditions. - Its blood supply relies heavily on the **medial circumflex femoral artery**, which can be easily disrupted. *The body of talus* - The **talus** is highly susceptible to **avascular necrosis**, particularly after fractures or dislocations, as its blood supply enters through a limited number of soft tissue attachments. - The **body of the talus** receives a significant portion of its blood supply from vessels that can be easily compromised by injury. *Proximal half of scaphoid* - The **proximal pole of the scaphoid** is notoriously prone to **avascular necrosis** following scaphoid fractures because its blood supply enters primarily from the distal pole. - A disruption of blood flow (e.g., via the **dorsal carpal branch** of the radial artery) due to a fracture can lead to **non-union** and AVN of the proximal fragment.

Q: All of the following are features of pyle disease except

It is an epiphyseal dysplasia. ***It is an epiphyseal dysplasia*** - **Pyle disease** is a **metaphyseal dysplasia**, not an epiphyseal dysplasia, characterized by widening and deformity of the metaphyses of long bones. - The characteristic **"Erlenmeyer flask"** deformity affects the metaphyseal regions, making this statement the exception among the listed features [1]. *Dental caries and mandibular prognathism* - **Craniofacial anomalies** including **mandibular prognathism** (prominent jaw) are characteristic features of Pyle disease. - **Dental caries** commonly occur due to the associated developmental abnormalities affecting oral structures. *Mental retardation is a common feature* - **Intellectual disability** is frequently observed in patients with Pyle disease, distinguishing it from isolated bone dysplasias. - This neurological involvement reflects the systemic nature of the underlying genetic defect affecting multiple organ systems. *It is an autosomal recessive disease* - Pyle disease follows an **autosomal recessive inheritance pattern**, requiring two copies of the mutated gene for disease manifestation. - This inheritance pattern is important for **genetic counseling** and family planning considerations [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, pp. 1188-1189.

Q: Which type of Radial Nerve injury recovers with conservative management?

Neuropraxia. ***Neuropraxia*** - **Neuropraxia** is a mild form of nerve injury involving demyelination without axonal disruption, allowing for complete recovery with conservative management. - The nerve's electrical conduction is temporarily blocked, but the **axon** and its supporting structures remain intact. *Crush injury* - Crush injuries often result in more severe nerve damage, ranging from **axonotmesis** to **neurotmesis**, generally requiring more than conservative management for recovery. - The extensive compression and potential tissue damage can lead to significant axonal disruption and scar tissue formation, impeding nerve regeneration. *Chemical injury* - Chemical injuries can cause varying degrees of nerve damage, often resulting in **axonopathy** or demyelination, which may or may not recover with conservative management. - The extent of damage is highly dependent on the type and concentration of the chemical, and the duration of exposure. *Neurotmesis* - **Neurotmesis** involves complete transection of the nerve, including the axon and surrounding connective tissue sheaths, making spontaneous recovery highly unlikely. - Surgical intervention, such as **nerve repair** or grafting, is typically required for any functional recovery.

Question 1

Tinel's sign is checking the regeneration of

Accepted Answer

Traumatised or sutured nerve

Answer

Ruptured artery

Answer

Vein rupture

Answer

All of the options

Question 2

Healing of bone is affected by:

Accepted Answer

All of the options

Answer

Hypoxia

Answer

Micromovement

Answer

Muscle interposition

Question 3

Which of the following nerves has the best prognosis for repair after injury ?

Accepted Answer

Radial

Answer

Median

Answer

Ulnar

Answer

Lateral popliteal

Question 4

Among the following options, which is the most common site of avascular necrosis?

Accepted Answer

Talus

Answer

Head of the radius

Answer

Olecranon

Answer

Medial condyle of femur

Question 5

All of the following factors affect osseointegration EXCEPT:

Accepted Answer

Patient's blood type

Answer

Biocompatibility of implant material.

Answer

Implant design.

Answer

Status of the host bed.

Question 6

The following classification is used to estimate nerve injury:

Accepted Answer

Seddons classification

Answer

Seddon's and Sunderland classification

Answer

Sunderland classification

Answer

None of the options

Question 7

Healing by Haversian remodeling is a type of:

Accepted Answer

Primary healing.

Answer

Tertiary healing.

Answer

Secondary healing.

Answer

Intermediate healing.

Question 8

Following are the common sites of Avascular necrosis, EXCEPT:

Accepted Answer

Patella

Answer

Head of the femur

Answer

The body of talus

Answer

Proximal half of scaphoid

Question 9

All of the following are features of pyle disease except

Accepted Answer

It is an epiphyseal dysplasia

Answer

Dental caries and mandibular prognathism

Answer

Mental retardation is a common feature

Answer

It is an autosomal recessive disease

Question 10

Which type of Radial Nerve injury recovers with conservative management?

Accepted Answer

Neuropraxia

Answer

Crush injury

Answer

Chemical injury

Answer

Neurotmesis

Basic Science in Orthopaedics — MCQs

Basic Science in Orthopaedics — MCQs

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