Injury and Healing 1

Question 1

What types of fractures can there be?

Answer 1

Trauma: Low energy or high energy

Stress: Abnormal stresses on the normal bone

Pathological: Normal stresses on abnormal bone

Question 2

What are the characteristics of stress fracture?

Answer 2

Weight bearing bones prone to activity related causes ( military )

Bone weakening = stress fracture = risk of complete fracture

• can also be increased due to disordered eating, osteoporosis, amenorrhea

Question 3

What pathological fracture may occur?

Answer 3

Osteoporosis - soft bone

Malignancy - primary, bone mets

Vitamin D deficiency - osteomalacia/ rickets

Osteomyelitis

Osteogenesis imperfecta

Pagets

Question 4

What are the characteristics of Osteopenia and Osteoporosis?

Answer 4

Loss of bone density
( 2.5 deviations away from normal bone density on DEXA scan)

Osteoclast activity > Osteoblast activity

Female > Male 4:1

Postmenopausal Osteoporosis ( age 50-70 )

Senile Osteoporosis - > 70

Secondary osteoporosis: Any age, 60% Male
Hypogonadism
Glucocorticoid excess
Alcoholism

Associated with ‘fragility fractures’ – hip, spine, wrist

Low energy trauma = fracture

Question 5

How does Vitamin D deficiency lead to bone fractures?

Answer 5

Vitamin D for calcium, magnesium and phosphate absorption

less Calcium or Phosphate = Defect in osteoid matrix mineralization

Rickets in children
Osteomalacia in adults

Question 6

What are the characteristics of congenital Osteogenesis imperfecta?

Answer 6

Brittle Bone

-autosomal dominant or recessive

Decreased Type I Collagen due to:
Decreased secretion
Production of abnormal collagen

Insufficient osteoid production

Effects: Bones, Hearing, Heart, Sight

Question 7

What are the characteristics of Pagets disease?

Answer 7

Genetic & Acquired factors

Excessive bone break down and disorganized remodeling = deformity, pain, fracture or arthritis

May transform into a malignant disease

4 stages:

• Osteoclastic Activity
• Mixed osteoclastic-osteoblastic activity
• Osteoblastic activity
• Malignant degeneration

Question 8

Examples of primary bone cancers?

Answer 8

Osteosarcoma
Chrondosarcoma
Ewing Sacroma
Lymphoma

Question 9

Examples of Secondary bone cancers?

Answer 9

due to primary cancers:

Blastic ( bone forming cancers ) due to : Prostate and breast

Lytic ( Bone eating cancers) due to: kidney, thyroid, lung

Question 10

How to describe fractures?

Answer 10

Soft tissue can be open or closed

Bony fragments can be described as greenstick, simple or multigragmentary

Movement described as displaced or undisplaced

Question 11

How do fractures heal - using general tissue healing principle?

Answer 11

Bleeding –> Inflammation –> New tissue formation –> remodelling

( due to blood –> neutrophils, macrophages –> fibroblasts, osteoblasts, chondroblasts –> macrophages, osteoclasts’/blasts to remodel )

Question 12

How to fractures heal?

Answer 12

Inflammation :
Haematoma formation
Release of Cytokines
Granulation tissue and. blood vessel formation

Repair : 
Soft Callus formation 
(Type II Collagen - Cartilage)
Converted to hard callus 
(Type I Collagen - Bone

Remodelling:
Callus responds to activity, external forces, functional demands and growth
Excess bone is removed

Question 13

What is the Wolff’s law?

Answer 13

Bone Grows and Remodels in response to the forces that are placed on it

Question 14

Describe primary bone healing?

Answer 14

Primary Bone Healing:
Intramembranous healing
Absolute stability
Direct to woven bone

Question 15

Describe Secondary bone healing?

Answer 15

Secondary bone healing 
Endochondral healing
Involves responses in the periosteum and external soft tissues
Relative stability
Endochondral ossification: more callus

Question 16

How long do the following take to heal?:

Phalanges: 
Metacarpals:
Distal radius: 
Forearm: 
Tibia: 
Femur:

Answer 16

Phalanges: 3 weeks
Metacarpals: 4-6 weeks
Distal radius: 4-6 weeks
Forearm: 8-10 weeks
Tibia: 10 weeks
Femur: 12 weeks

• 3-12 weeks depending on size, signs of visible healing on Xray from day 7-10

Question 17

How are fractures managed?

Answer 17

Reduce: bring fracture bones together ( reduction )

Hold : Metal or no metal

Rehabilitate : Move, Physio, Use

Question 18

How do we reduce fractures?

Answer 18

Closed reduction : ( pulling on them ) - manipulation / taction = skin or skeletal pins in bone

Open reduction: Mini incision or full exposure

Question 19

How do we hold fractures?

Answer 19

Closed holding : plaster or traction = skin or skeletal

Fixation Holding

Question 20

How do we hold fractures through fixation?

Answer 20

Internal fixation : Intramedullary - Pin or nails
Extramedullary- Plate/screws or pins

External fixation:
Monoplanar
Multiplanar

Question 21

How do we rehabilitate fractures?

Answer 21

Use : Pain relief = restrain
Move
Strengthen
Weight bear

Question 22

What can go wrong with a tendon?

Answer 22

Tendinosis : abnormal thickening

Tendinitis: Inflammation

Both can lead to rupture

Question 23

How to classify ligament injuries?

Answer 23

Grade I – Slight incomplete tear – no notable joint instability

Grade II – Moderate / Severe Incomplete Tear – Some joint instability. One ligament may be completely torn

Grade III – complete tearing of 1 or more ligaments – Obvious instability = Surgery

• can see bruising under skin

Question 24

How can we treat tendon or ligament tears?

Answer 24

Immobilise : plaster or boot/brace

Surgical repair : suture

Question 25

What are the pros and cons of immobilisation of injured ligaments?

Answer 25

Pro: less ligament laxity (lengthening)

Cons :

• Leads to scar tissue
• protein degradation exceeds protein synthesis r net d in collagen quantity
• production of inferior tissue by blast cells
• resorption of bone at site of ligament insertion
• decreased tissue tensile strength (50% in 6 - 9 weeks)

Question 26

What are the benefits of mobalisation of injured ligaments?

Answer 26

ligament scars are wider, stronger, and are more elastic

Better alignment / quality of collagen

Question 27

How to Ligaments heal?

Answer 27

Inflammatory phase ( hours-days)

Proliferation phase , Growth factors/cytokines ( weeks to months )

Tissue remodelling, Collagenase/enzymes/macrophages/blasts ( months )

Question 28

What factors can affect tissue healing?

Answer 28

• Mechanical environment
  movement
  forces

-Biological environment
Blood supply
Immune function
Infection
Nutrition.