AP: Fracture Healing and Repair

Question 1

What is a fracture?

Answer 1

Disruptions in bone, related to both the nature/strength of mechanical injury and the strength of the bone.

Question 2

What is a stress/fatigue fracture?

Answer 2

Abnormal stress on a normal bone (e.g. long distance running, ballet dancing)

Question 3

What is an insufficiency fracture?

Answer 3

Normal stress on abnormal bone (e.g. osteoporosis).

Question 4

What is an avulsion fracture?

Answer 4

Fracture resulting from repeated trauma at sites of tendinous or ligamentous insertion into bone.

Question 5

What is the name of avulsion of the tibial tubercle that results in its fragmentation?

Answer 5

Osgood Schlatter’s disease.

Question 6

What are the six categorisation techniques which fractures are characterised by?

Answer 6

1. Anatomical location (mid shaft, proximal shaft, intertrochanteric etc.)
2. Direction (oblique, transverse etc.)
3. Linear or comminuted (break or splinter of the bone into more than two fragments).
4. Impacted.
5. Open (skin is perforated) or closed.
6. Pathological.

Question 7

What is a pathological fracture?

Answer 7

A fracture occurs through an area of bone weakened by pre-existing disease –> This is often applied to fracture in bone affected by primary or secondary neoplasms e.g. metastatic breast carcinoma.

Question 8

What are the 6 stages of fracture healing (and when do they occur)?

Answer 8

1. Hematoma stage (hours to days)
2. Inflammatory stage (within 48 hours)
3. Granulation Tissue (2-12 days)
4. Soft callus (one week to several months)
5. “Hard” callus. (one week to several months)
6. Remodelling (several months)

Question 9

What is the general process of healing of bone fracture?

Answer 9

• Disruption of bone, periosteal and soft tissues - Haematoma encases bone and fragments - Repair tissues/callus

Question 10

What are the principal factors that affect healing?

Answer 10

1) wound immobilisation
2) vascular supply
3) presence of infection
4) physical stress

Question 11

Describe the ideal situation for fracture healing?

Answer 11

1) Good vascular supply 2) Minimal necrosis 3) Precise anatomical reduction 4) Immobilisation 5) Absence of infection

Question 12

Define a fracture.

Answer 12

A disruption in trabecular or cortical bone.

Question 13

Most fractures through cortex have a ____-shaped configuration, which is a result of the combination of the direction of force that may be applied to the bone, and the hollow cylindrical structure of cortical bone. When the structure of the bone is more solid, or when the bone is weakened, the fracture is often _______.

Answer 13

• Most fractures through cortex have a spiral-shaped configuration. - When the structure of the bone is more solid, or when the bone is weakened, the fracture is often transverse.

Question 14

Incomplete stress or fatigue fracture in the cortex occurs as a result of ______ ______ to a bone. Give three examples of actions that cause a stress/fatigue fracture.

Answer 14

Incomplete stress or fatigue fracture in the cortex occurs as a result of repeated stress to a bone. - Long distance running. - Marching. - Ballet dancing.

Question 15

An insufficiency fracture is a fracture in bone affected by what?

Answer 15

Non-neoplastic disease.

Question 16

• Describe the pathology of Legg Calve Perthes disease. - In what group does it most commonly occur?

Answer 16

• Interruption to vascular supply to the femoral head (form of osteonecrosis). - In children (boys, aged 5-10)

Question 17

What are the four principal systemic factors that affect healing of fractures?

Answer 17

• Age. - Functional activity. - Nutrition. - Hormonal status.

Question 18

What are the five principal local factors that affect healing of fractures?

Answer 18

• Amount of local trauma. - Presence of vascular injury. - Quantity of bone loss. - Degree of fracture stabilisation and presence of infection.

Question 19

What is the most common site of AVN?

Answer 19

femoral head, secondary to displaced fracture

Question 20

What is a pseudoarthrosis?

Answer 20

Excessive movement or space between fragments = fibrous union of bone.

Question 21

Avascular necrosis is the —– of blood flow to the ——– often causing ——-, and in younger, non traumatic patients can present similarly to ———– except the onset is ———. Common sites of fracture/collapse of the subchondral bone are —— and ——.

Common causes (4)

Answer 21

Avascular necrosis is the interruption of blood flow to the head of long bones often causing fracture, and in younger, non traumatic patients can present similarly to osteoarthritis except the onset is more sudden. Common sites of fracture/collapse of the subchondral bone are hip and knee.

Common causes:

1. trauma
2. Perthes disease
3. steroid use
4. chronic alcoholism

Question 22

Osteochondritis dessicans is:

Answer 22

Separation of an osteochondral fragment = Osteonecrosis localised to a subchondral area of bone.

Question 23

What is Slipped Capital Femoral Epiphyses (SCFE)?

Answer 23

fracture in the proximal epiphysis of the femur (usually during a growth spurt) = slippage of the femoral head posteriorly/inferiorly within the acetabulum.