Which of the following is TRUE about bone healing in elderly patients?
Q54
What are the potential causes of delayed union of a fracture following surgical treatment?
Basic Science in Orthopaedics Indian Medical PG Practice Questions and MCQs
Question 51: Healing of bone is affected by:
A. Hypoxia
B. Micromovement
C. Muscle interposition
D. All of the options (Correct Answer)
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.
Question 52: Healing by Haversian remodeling is a type of:
A. Tertiary healing.
B. Secondary healing.
C. Primary healing. (Correct Answer)
D. Intermediate healing.
Explanation: ***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.
Question 53: Which of the following is TRUE about bone healing in elderly patients?
A. Enhanced Angiogenesis
B. Better Callus Formation
C. Faster Healing Rate
D. Delayed Union is More Common (Correct Answer)
Explanation: ***Delayed Union is More Common***
- **Aging** is associated with a decrease in the number and activity of **osteoblasts** and stem cells, leading to a slower bone remodeling process.
- Reduced **blood supply** to the fracture site and the presence of comorbidities in elderly patients contribute to delayed healing and an increased risk of complications like non-union.
*Enhanced Angiogenesis*
- **Angiogenesis**, the formation of new blood vessels, tends to be reduced in elderly patients due to age-related changes in growth factor production and endothelial cell function.
- A compromised blood supply to the fracture site negatively impacts the delivery of essential nutrients and cells required for bone repair.
*Better Callus Formation*
- **Callus formation**, a crucial step in secondary bone healing, is often impaired in elderly individuals.
- This impairment is due to decreased cellular activity, reduced growth factor production, and a less robust inflammatory response.
*Faster Healing Rate*
- Bone healing is generally **slower** in elderly patients compared to younger individuals.
- This diminished healing rate is attributed to a decline in osteogenic potential, reduced vascularity, and frequently, poorer overall health status.
Question 54: What are the potential causes of delayed union of a fracture following surgical treatment?
A. Inadequate circulation
B. Inadequate mobilization
C. Infection
D. All of the above (Correct Answer)
Explanation: ***All of the above***
- **Infection**, **inadequate circulation**, and **inadequate mobilization** are all well-established factors that can significantly impede the normal healing process of a fracture, leading to delayed union.
- Addressing these issues is crucial for promoting successful bone healing and preventing non-union.
*Infection*
- **Infection** at the fracture site consumes nutrients essential for healing and can lead to bone destruction, significantly delaying union or causing non-union.
- It also triggers an inflammatory response that can interfere with the formation of a stable callus.
*Inadequate circulation*
- **Inadequate circulation** reduces the supply of oxygen, nutrients, and growth factors necessary for osteoblast activity and new bone formation.
- A compromised blood supply directly impairs the cellular processes involved in bone repair.
*Inadequate mobilization*
- **Inadequate immobilization** (excessive motion) at the fracture site prevents the formation of a stable callus and can disrupt the repair process.
- While some motion is beneficial, excessive motion causes repeated microtrauma, interfering with proper tissue differentiation and bone formation, leading to fibrous tissue instead of stable bone.
